Mark W. Carter David B. Spears Virginia M. Latane E. Allen Crider Benjamin R. Weinmann Holly Mangum Ryan J. McAleer J. Wright Horton Anjana K. Shah Sean P. Regan 20250214 vector digital data Scientific Investigations Map 3533 Reston, Va U.S. Geological Survey Carter, M.W., Spears, D.B., Latane, V.M., Crider, E.A., Weinmann, B.R., Mangum, H., McAleer, R.J., Horton, J.W., Jr., Shah, A.K., and Regan, S.P., 2025, Geologic map of the Buckner 7.5-minute quadrangle, Louisa County, Virginia: U.S. Geological Survey Scientific Investigations Map 3533, 1 sheet, scale 1:24,000, 37-p. pamphlet, https://doi.org/10.3133/sim3533 https://doi.org/10.5066/P9OE8CKX Mark W. Carter David B. Spears Virginia M. Latane E. Allen Crider Benjamin R. Weinmann Holly Mangum Ryan J. McAleer J. Wright Horton Anjana K. Shah Sean P. Regan 2025 Publication Scientific Investigations Map 3533 N/A U.S. Geological Survey https://doi.org/10.3133/sim3533 The database for the Buckner 7.5-minute quadrangle straddles three terrane boundaries in the Piedmont Physiographic Province in central Virginia: the Chopawamsic terrane, the Elk Hill Complex, and the Goochland terrane. In much of the map area, the Elk Hill Complex separates the Chopawamsic and Goochland terranes. Rocks of the Chopawamsic terrane include Ordovician metavolcanic and metasedimentary rocks of the Chopawamsic Formation, Ordovician to Silurian granodiorite sheet intrusions, and Paleozoic mafic intrusions. Silurian to Devonian rocks of the Quantico Formation, mostly garnet-mica schist, crop out in the northwesternmost part of the map area, and are in unconformable contact with rocks of the Chopawamsic Formation on the southeastern limb of the Quantico synclinorium. The main map unit in the Elk Hill Complex is Neoproterozoic mica gneiss, which is in pre-metamorphic fault contact with rocks of the Chopawamsic Formation to the west. The main map unit of the Goochland terrane is the Maidens Gneiss. Except for Jurassic diabase dikes, all rocks on the Buckner 7.5-minute quadrangle were metamorphosed to amphibolite facies during the Alleghanian orogeny and preserve multiple compositional and phyllosilicate penetrative foliations. Evidence of amphibolite-facies metamorphism during the Taconic orogeny is preserved in rocks of the Elk Hill Complex. The entire width of the Maidens Gneiss on the Buckner 7.5-minute quadrangle is within the Spotsylvania high-strain zone and amphibolite-facies mylonitic textures are pervasive. Quartz veins and Jurassic diabase dikes crosscut all older rocks of the quadrangle. Multiple levels of terrace deposits are present along and near the major streams of the quadrangle. The lower terrace deposits are likely remnants of former positions of the Little River on the landscape, whereas higher deposits may be remnants of former deposits of the Atlantic Coastal Plain that covered this portion of the Piedmont Province. A linear cluster of aftershocks from the magnitude 5.8 earthquake that occurred near Mineral, Virginia, in 2011 defines the Fredericks Hall fault, which is at depth on the Buckner quadrangle. Most of the aftershocks occurred in the core of the Elk Creek antiform and have no relation to faults mapped at the surface. Several abandoned crushed stone and building stone quarries, as well as a mica prospect, exist in the quadrangle. This database is intended to serve as a foundation for applying geologic information to problems involving land use decisions, groundwater availability and quality, earth resources such as natural aggregate for construction, assessment of natural hazards (earthquakes), and engineering and environmental studies for waste disposal sites and construction projects. BucknerVASIM3533.gdb is a composite geodataset that conforms to GeMS (Geologic Map Schema)--a standard format for the digital publication of geologic maps", available at http://ngmdb.usgs.gov/Info/standards/GeMS/. Metadata records associated with each element within the geodataset contain more detailed descriptions of their purposes, constituent entities, and attributes). An OPEN shapefile versions of the dataset is also available. It consists of shapefiles, DBF files, and delimited text files and retains all information in the native geodatabase, but some programming will likely be necessary to assemble these components into usable formats. These metadata were prepared with the aid of script GeMS_FGDCMetadata.py, version of 2/27/24. 20250301 ground condition Complete None planned -77.8799 -77.7453 38.0030 37.8720 ISO 19115 Topic Category geoscientificInformation environment USGS Thesaurus structural geology stratigraphy mineralogy petrology geochronology radiometric dating uranium-lead analysis potassium-argon analysis optical microscopy petrography geologic maps geologic time scales earth sciences economic geology metamorphism (geologic) tectonic processes alteration deformation (geologic) folding (geologic) fracture (geologic) faulting (geologic) geologic structure foliation (geologic) lineation (geologic) igneous rocks volcanic rocks plutonic rocks metamorphic rocks gravel deposits sand deposits bedrock geologic units geologic contacts surficial geologic units Holocene Pleistocene Pliocene Miocene Jurassic Mesozoic Paleozoic Devonian Silurian Ordovician Neoproterozoic Mesoproterozoic Lithologic classification of geologic map units Gneiss Metasedimentary rock Metavolcanic rock Phyllite Schist Diabase Alluvium Quartzite Sand Gravel Silt Granofels Amphibolite Mylonite Ultramafic intrusive rock Gabbro Pegmatite Felsic gneiss Felsic volcanic rock Tonalite Garbenschiefer Felsic metasedimentary rocks Felsic metavolcanic rocks Granodiorite Phyllonite Geologic names Chopawamsic Formation Elk Hill Complex Quantico Formation Maidens Gneiss USGS Metadata Identifier USGS:649f041ed34ef77fcb041d6e Common Geographic Areas United States Virginia Louisa Buckner Lake Anna None. Acknowledgment of the U.S. Geological Survey would be appreciated in products derived from these data. None. Acknowledgment of the U.S. Geological Survey would be appreciated in products derived from these data. Although software enables the user to display images at various scales, map data in this report should not be used at scales greater than 1:24,000. U.S. Geological Survey, Northeast Region Benjamin R Weinmann Geologist mailing address

12201 Sunrise Valley Dr

Reston VA 20192 US 703-648-6901 bweinmann@usgs.gov Prepared in cooperation with the Virginia Department of Energy, Geology and Mineral Resources Program and the U.S. Geological Survey National Cooperative Geologic Mapping program. Windows 10 Enterprise, version 1809 (17763.1518); Esri ArcGIS 10.8.1.14362 Geologic information was garnered from 1:24,000-scale mapping of geologic material based on observation from fieldwork, previously published geologic maps, and unpublished geologic data in the region. The geologic information might change if additional outcrops are discovered or exposed as the natural land changes, or as the result of development, or advances in scientific research are made. The features in the database are not based on legal parcels or definitions. Sources on the published geologic map that may have been used to create this dataset may not appear in the DataSources table. This metadata may not account for all sources used in the creation of the dataset in the source inputs of this metadata. Individual definition sources may contain pipe-delimited information where multiple sources were used or use the abbreviation/short name presented within the source inputs of this metadata. Confidence that a feature exists and confidence that a feature is correctly identified are described in per-feature attributes ExistenceConfidence and IdentityConfidence. Geologic information was garnered from 1:24,000-scale mapping of bedrock material based on observation from and geologic fieldwork in the region. The geologic information might change if additional outcrops are discovered or exposed as the natural land changes or as the result of development. The features in the database are not based on legal parcels or definitions. Topology tests were performed to ensure the integrity of the data. These tests checked for polygon overlaps and gaps and line pseudos, dangles, overlaps, and intersections. Additional tests were conducted to ensure that linework from geologic contacts match polygon boundaries where necessary. There should be no duplicates in the data set where it is not intended. Dataset is considered complete for the information presented, as described in the abstract. Users are advised to read the rest of the metadata record carefully for additional details. Estimated accuracy of horizontal location is given on a per-feature basis by attribute LocationConfidenceMeters. Values are expected to be correct within a factor of 2. Data were delineated on classic U.S. Geological Survey (USGS) 7.5-minute topographic maps at 1:24,000 scale. Therefore, the horizontal accuracy is assumed to be within National Map Accuracy Standards, with a horizontal accuracy of 45.6 feet at the 95% confidence level. In addition, the horizontal accuracy standard requires that the positions of 90 percent of all points tested must be accurate within 1/50th of an inch (0.05 centimeters) on the map. For more information see U.S. Geological Survey Fact Sheet 171-99. Estimated accuracy of horizontal location is given on a per-feature basis by attribute LocationConfidenceMeters. Values are expected to be correct within a factor of 2. A LocationConfidenceMeters value of -9 or -9999 indicates that no value has been assigned. The data were delineated on classic U.S. Geological Survey (USGS) 7.5-minute topographic maps at 1:24,000 scale. Therefore, the vertical accuracy is assumed to be within National Map Accuracy Standards, with a vertical accuracy of 11.9 feet at the 95% confidence level. In addition, the vertical accuracy standard requires that the elevation of 90 percent of all points tested much be correct within half of the contour interval. For more information see U.S. Geological Survey Fact Sheet 171-99. US Geological Survey Federal Geographic Data Committee 2006 publication Reston, VA U.S. Geological Survey Federal Geographic Data Committee [prepared for the Federal Geographic Data Committee by the U.S. Geological Survey], 2006, FGDC Digital Cartographic Standard for Geologic Map Symbolization: Reston, Va., Federal Geographic Data Committee Document Number FGDC-STD-013-2006, 290 p., 2 plates. https://ngmdb.usgs.gov/fgdc_gds/geolsymstd.php Digital and/or Hardcopy 2006 publication date FGDC This citation was used in the production of this database, either in the description of map units, or the production of geologic polygons, or the additional supporting structural and cartographic information. U.S. Geological Survey National Cooperative Geologic Mapping Program 2020 publication Techniques and Methods book 11, chap. B10 Reston, VA US Geological Survey U.S. Geological Survey National Cooperative Geologic Mapping Program, 2020, GeMS (Geologic Map Schema)—A standard format for the digital publication of geologic maps: U.S. Geological Survey Techniques and Methods, book 11. chap. B10, 74 p. https://doi.org/10.3133/tm11B10 Digital and/or Hardcopy 2020 publication date GeMS This citation was used in the production of this database, either in the description of map units, or the production of geologic polygons, or the additional supporting structural and cartographic information. K.K.E. Neuendorf J.P. Mehl Jr. J.A. Jackson 2011 5 publication Alexandria, VA American Geosciences Institute Neuendorf, K.K.E., Mehl, J.P., Jr., and Jackson, J.A., eds., 2011, Glossary of geology (5th ed., revised): Alexandria, Va., American Geosciences Institute, 783 p. https://glossary.americangeosciences.org/ Digital and/or Hardcopy 2011 publication date AGI This citation was used in the production of this database, either in the description of map units, or the production of geologic polygons, or the additional supporting structural and cartographic information. U.S. Geological Survey Science Publishing Network (SPN) 2015 publication U.S. Geological Survey Science Publishing Network, MapStyleGuide_DMU_print_1sht_v1-1_01-15.pdf. Digital and/or Hardcopy 2015 publication date USGS This citation was used in the production of this database, either in the description of map units, or the production of geologic polygons, or the additional supporting structural and cartographic information. M.W. Carter D.B. Spears V.M. Latane E.A. Crider B.R. Weinmann H. Mangum R.J. McAleer J.W. Horton Jr. A.K. Shah S.P. Regan 2025 publication Scientific Investigations Map 3533 Reston, VA US Geological Survey Carter, M.W., Spears, D.B., Latane, V.M., Crider, E.A., Weinmann, B.R., Mangum, H., McAleer, R.J., Horton, J.W., Jr., Shah, A.K., and Regan, S.P., 2025, Geologic map of the Buckner 7.5-minute quadrangle, Louisa County, Virginia: U.S. Geological Survey Scientific Investigations Map 3533, 1 sheet, scale 1:24,000, 37-p. pamphlet https://doi.org/10.3133/sim3533 24000 Digital and/or Hardcopy 2025 publication date BCKNRVADAS01 This citation was used in the production of this database, either in the description of map units, or the production of geologic polygons, or the additional supporting structural and cartographic information. N.E Powell R.J. McAleer R.S Regan M.W Carter 2024 dataset https://www.sciencebase.gov U.S. Geological Survey "Powell, N.E., McAleer, R.J., Regan, S.P., and Carter, M.W., 2024, 238U/206Pb SHRIMP, 40Ar/39Ar geochronologic, and geochemical data from the central Virginia Piedmont: U.S. Geological Survey data release. ." https://doi.org/10.5066/p9hc25rr Digital and/or Hardcopy 2024 publication date BCKNRVADAS02 This citation was used in the production of this database, either in the description of map units, or the production of geologic polygons, or the additional supporting structural and cartographic information. M.W. Carter R.J. McAleer C.S. Holm-Denoma D.B. Spears S.P. Regan W.C. Burton N.H. Evans 2020 publication Professional Paper 1861 Reston, VA US Geological Survey Carter, M.W., McAleer, R.J., Holm-Denoma, C.S., Spears, D.B., Regan, S.P., Burton, W.C., and Evans, N.H., 2020, Geochronologic age constraints on tectonostratigraphic units of the central Virginia Piedmont, USA: U.S. Geological Survey Professional Paper 1861, 28 p. https://doi.org/10.3133/pp1861 Digital and/or Hardcopy 2020 publication date BCKNRVADAS03 This citation was used in the production of this database, either in the description of map units, or the production of geologic polygons, or the additional supporting structural and cartographic information. H.F. Malenda 2015 publication Bethlehem, PA Lehigh University Malenda, H.F., 2015, New Quaternary geochronometric constraints on river incision in the Virginia Piedmont—Relative contributions of climate, base-level fall, knickpoint retreat, and active tectonics: Bethlehem, Pa., Lehigh University, M.S. thesis, 82 p. http://preserve.lehigh.edu/etd/2709 Digital and/or Hardcopy 2015 publication date BCKNRVADAS04 This citation was used in the production of this database, either in the description of map units, or the production of geologic polygons, or the additional supporting structural and cartographic information. M.W. Carter W.C. Burton R.J. McAleer M.L. DiGiacomo-Cohen R.T. Sauer 2019 publication Charlottesville, VA Virginia Division of Geology and Mineral Resources Carter, M.W., Burton, W.C., McAleer, R.J., DiGiacomo-Cohen, M.L., and Sauer, R.T., 2019, Geology of the Mineral and Lake Anna West quadrangles, Virginia: Virginia Division of Geology and Mineral Resources Publication 189, 41 p., 2 pls., scale 1:24,000. 24000 Digital and/or Hardcopy 2019 publication date BCKNRVADAS05 This citation was used in the production of this database, either in the description of map units, or the production of geologic polygons, or the additional supporting structural and cartographic information. M.J. Kunk A.J. Froelich D. Gottfried 1992 publication Abstracts with Program v. 24, no. 1 Boulder, CO Geological Society of America Kunk, M.J., Froelich, A.J., and Gottfried, D., 1992, Timing of emplacement of diabase dikes and sheets in the Culpeper basin and vicinity, Virginia and Maryland—40Ar/39Ar age spectrum results from hornblende and K-feldspar in granophyres [abs.]: Geological Society of America Abstracts with Programs, v. 24, no. 1, p. 25. Digital and/or Hardcopy 1992 publication date BCKNRVADAS06 This citation was used in the production of this database, either in the description of map units, or the production of geologic polygons, or the additional supporting structural and cartographic information. F. Jourdan A. Marzoli H. Bertrand S. Cirilli L.H. Tanner D.J. Kontak G. McHone P.R. Renne G. Bellieni 200906 publication Lithos v. 110, nos. 1–4 N/A Elsevier BV Jourdan, F., Marzoli, A., Bertrand, H., Cirilli, S., Tanner, L.H., Kontak, D.J., McHone, G., Renne, P.R., and Bellieni, G., 2009, 40Ar/39Ar ages of CAMP in North America—Implications for the Triassic–Jurassic boundary and the 40K decay constant bias: Lithos, v. 110, nos. 1–4, p. 167–180. https://doi.org/10.1016/j.lithos.2008.12.011 Digital and/or Hardcopy 200906 publication date BCKNRVADAS07 This citation was used in the production of this database, either in the description of map units, or the production of geologic polygons, or the additional supporting structural and cartographic information. W. Manspeizer J. DeBoer J.K. Costain A.J. Froelich C. Coruh P.E. Olsen G.J. McHone J.H. Puffer D.C. Prowell 19890101 publication Boulder, CO Geological Society of America Manspeizer, W., DeBoer, J., Costain, J.K., Froelich, A.J., Çoruh, C., Olsen, P.E., McHone, G.J., Puffer, J.H., and Prowell, D.C., 1989, Post-Paleozoic activity, in Hatcher, R.D., Jr., Thomas, W.A., and Viele, G.W., eds., The Appalachian-Ouachita orogen in the United States, v. F–2 of The geology of North America: Boulder, Colo., Geological Society of America, p. 319–374. https://doi.org/10.1130/DNAG-GNA-F2.319 Digital and/or Hardcopy 19890101 publication date BCKNRVADAS08 This citation was used in the production of this database, either in the description of map units, or the production of geologic polygons, or the additional supporting structural and cartographic information. C.B. Brown 1937 publication N/A Virginia Geological Survey Brown, C.B., 1937, Outline of the geology and mineral resources of Goochland County, Virginia: Virginia Geological Survey Bulletin 48, 68 p. Digital and/or Hardcopy 1937 publication date BCKNRVADAS09 This citation was used in the production of this database, either in the description of map units, or the production of geologic polygons, or the additional supporting structural and cartographic information. D.B.Spears B.E. Owens C.M. Bailey 2004 publication Circular 2004 Reston, VA US Geological Survey Spears, D.B., Owens, B.E., and Bailey, C.M., 2004, The Goochland-Chopawamsic terrane boundary, central Virginia Piedmont, in Southworth, S., and Burton, W., eds., Geology of the National capital region—Field trip guidebook—Joint meeting of Northeast and Southeast Sections, Tysons Corner, Va., March 24-27, 2004, Field Trip Guidebook: U.S. Geological Survey Circular 1264, p. 223–245. https://doi.org/10.3133/cir1264 Digital and/or Hardcopy 2004 publication date BCKNRVADAS10 This citation was used in the production of this database, either in the description of map units, or the production of geologic polygons, or the additional supporting structural and cartographic information. D.B. Spears N.H. Evans 2020 publication Open-File Report 2020–01 Charlottesville, VA Virginia Division of Geology and Mineral Resources Spears, D.B., and Evans, N.H., 2020, Geologic map of the Cartersville quadrangle, Virginia: Virginia Division of Geology and Mineral Resources Open-File Report 2020–01, 1 sheet, scale 1:24,000. 24000 Digital and/or Hardcopy 2020 publication date BCKNRVADAS11 This citation was used in the production of this database, either in the description of map units, or the production of geologic polygons, or the additional supporting structural and cartographic information. R.B. Mixon L. Pavlides D.S. Powars A.J. Froelich R.E. Weems J.S. Schindler W.L. Newell L.E. Edwards L.W. Ward 2000 publication Geologic Investigations Series Map I–2607 Reston, VA US Geological Survey Mixon, R.B., Pavlides, L., Powars, D.S., Froelich, A.J., Weems, R.E., Schindler, J.S., Newell, W.L., Edwards, L.E., and Ward, L.W., 2000, Geologic map of the Fredericksburg 30’ x 60’ quadrangle, Virginia and Maryland: U.S. Geological Survey Geologic Investigations Series Map I–2607, scale 1:100,000, 2 pls., 34-p. pamphlet. https://doi.org/10.3133/i2607 100000 Digital and/or Hardcopy 2000 publication date BCKNRVADAS12 This citation was used in the production of this database, either in the description of map units, or the production of geologic polygons, or the additional supporting structural and cartographic information. L. Pavlides 1980 publication Professional Paper 1146 Reston, VA US Geological Survey Pavlides, L., 1980, Revised nomenclature and stratigraphic relationships of the Fredericksburg Complex and Quantico Formation of the Virginia Piedmont: U.S. Geological Survey Professional Paper 1146, 29 p., 1 pl. https://doi.org/10.3133/pp1146 Digital and/or Hardcopy 1980 publication date BCKNRVADAS13 This citation was used in the production of this database, either in the description of map units, or the production of geologic polygons, or the additional supporting structural and cartographic information. L. Pavlides T. W. Stern J.G. Arth K.G. Muth M.F. Newell 1982 publication Professional Paper 1231–B Reston, VA US Geological Survey Pavlides, L., Stern, T.W., Arth, J.G., Muth, K.G., and Newell, M.F., 1982, Middle and Upper Paleozoic granitic rocks in the Piedmont near Fredericksburg, Virginia—Geochronology: U.S. Geological Survey Professional Paper 1231–B, 9 p. https://doi.org/10.3133/pp1231B Digital and/or Hardcopy 1982 publication date BCKNRVADAS14 This citation was used in the production of this database, either in the description of map units, or the production of geologic polygons, or the additional supporting structural and cartographic information. D.B. Spears N.H. Evans A.K. Gilmer 2013 publication Open-File Report 2013–04 Charlottesville, VA Virginia Division of Geology and Mineral Resources Spears, D.B., Evans, N.H., and Gilmer, A.K., 2013, Geologic map of the Pendleton quadrangle, Virginia: Virginia Division of Geology and Mineral Resources Open-File Report 2013–04, 1 sheet, scale 1:24,000. 24000 Digital and/or Hardcopy 2013 publication date BCKNRVADAS15 This citation was used in the production of this database, either in the description of map units, or the production of geologic polygons, or the additional supporting structural and cartographic information. W.C. Burton D.B. Spears R.W. Harrison N.H. Evans J.S. Schindler R. Counts 20140401 publication Field Guide 35 Boulder, CO Geological Society of America Burton, W.C., Spears, D.B., Harrison, R.W., Evans, N.H., Schindler, J.S., and Counts, R., 2014, Geology and neotectonism in the epicentral area of the 2011 M5.8 Mineral, Virginia, earthquake, in Bailey, C.M., and Coiner, L.V., eds., Elevating geoscience in the southeastern United States—New ideas about old terranes—Field guides for the GSA Southeastern Section Meeting, Blacksburg, Virginia, 2014: [Blacksburg, Va.], Geological Society of America Field Guide 35, p. 103–127. https://doi.org/10.1130/2014.0035(04) Digital and/or Hardcopy 20140401 publication date BCKNRVADAS16 This citation was used in the production of this database, either in the description of map units, or the production of geologic polygons, or the additional supporting structural and cartographic information. W.C. Burton R.W. Harrison D.B. Spears N.H. Evans S. Mahan 2015 publication Special Paper 509 Boulder, CO Geological Society of America Burton, W.C., Harrison, R.W., Spears, D.B., Evans, N.H., and Mahan, S., 2015a, Geologic framework and evidence for neotectonism in the epicentral area of the 2011 Mineral, Virginia, earthquake, in Horton, J.W., Jr., Chapman, M.C., and Green, R.A., eds., The 2011 Mineral, Virginia, earthquake, and its significance for seismic hazards in eastern North America: Geological Society of America Special Paper 509, p. 345–376. https://doi.org/10.1130/2015.2509(20) Digital and/or Hardcopy 2015 publication date BCKNRVADAS17 This citation was used in the production of this database, either in the description of map units, or the production of geologic polygons, or the additional supporting structural and cartographic information. N.A. Duke 1983 publication Winnipeg, Manitoba, Canada University of Manitoba Duke, N.A., 1983, A metallogenic study of the central Virginian gold-pyrite belt: Winnipeg, Manitoba, Canada, University of Manitoba, Ph. D. thesis, 289 p. Digital and/or Hardcopy 1983 publication date BCKNRVADAS18 This citation was used in the production of this database, either in the description of map units, or the production of geologic polygons, or the additional supporting structural and cartographic information. R.T. Sauer 1984 publication London, Ontario, Canada University of Western Ontario (Western University) Sauer, R.T., 1984, A metamorphosed stratiform alteration zone as footwall to massive sulfide, Mineral District, Virginia: London, Ontario, Canada, University of Western Ontario (Western University), M.S. thesis, 196 p. Digital and/or Hardcopy 1984 publication date BCKNRVADAS19 This citation was used in the production of this database, either in the description of map units, or the production of geologic polygons, or the additional supporting structural and cartographic information. D.G. Coler G.L. Wortman S.D. Samson J. P. Hibbard R. Stern 200007 publication The Journal of Geology v. 108, no. 4 Chicago, IL University of Chicago Press Coler, D.G., Wortman, G.L., Samson, S.D., Hibbard, J.P., and Stern, R., 2000, U-Pb geochronologic, Nd isotopic, and geochemical evidence for the correlation of the Chopawamsic and Milton terranes, Piedmont Zone, southern Appalachian orogen: The Journal of Geology, v. 108, no. 4, p. 363–380. https://doi.org/10.1086/314411 Digital and/or Hardcopy 200007 publication date BCKNRVADAS20 This citation was used in the production of this database, either in the description of map units, or the production of geologic polygons, or the additional supporting structural and cartographic information. D.B. Spears C.M. Bailey 2002 publication Charlottesville, VA Virginia Division of Mineral Resource Spears, D.B., and Bailey, C.M., [2002], Geology of the central Virginia Piedmont between the Arvonia syncline and the Spotsylvania high-strain zone—Thirty-second annual Virginia Geological Field Conference, October 11–13, 2002, Charlottesville, Virginia: [Charlottesville, Va.], [Virginia Division of Mineral Resources], 36 p. Digital and/or Hardcopy 2002 publication date BCKNRVADAS21 This citation was used in the production of this database, either in the description of map units, or the production of geologic polygons, or the additional supporting structural and cartographic information. D.B. Spears 2011 publication Charlottesville, VA Virginia Division of Geology and Mineral Resources Spears, D.B., 2011, Geology of the Lakeside Village quadrangle, Virginia: Charlottesville, Va., Virginia Division of Geology and Mineral Resources Publication 177, 1 sheet, scale 1:24,000, 19-p. pamphlet. 24000 Digital and/or Hardcopy 2011 publication date BCKNRVADAS22 This citation was used in the production of this database, either in the description of map units, or the production of geologic polygons, or the additional supporting structural and cartographic information. S.S. Farrar 1984 publication Special Paper 194 Boulder, CO Geological Society of America Farrar, S.S., 1984, The Goochland granulite terrane—Remobilized Grenville basement in the eastern Virginia Piedmont, in Bartholomew, M.J., ed., The Grenville event in the Appalachians and related topics: Geological Society of America Special Paper 194, p. 215–227. Digital and/or Hardcopy 1984 publication date BCKNRVADAS23 This citation was used in the production of this database, either in the description of map units, or the production of geologic polygons, or the additional supporting structural and cartographic information. B.E. Owens Z.X. Peng R.D. Tucker C.R. Shirvell 2004 publication Abstracts with Programs v. 36, no. 2 Boulder, CO Geological Society of America Owens, B.E., Peng, Z.X., Tucker, R.D., and Shirvell, C.R., 2004, New U-Pb zircon evidence for Paleozoic (Devonian) protoliths for metaigneous portions of the Maidens Gneiss, Goochland terrane, Virginia [abs.]: Geological Society of America Abstracts with Programs, v. 36, no. 2, p. 80. Digital and/or Hardcopy 2004 publication date BCKNRVADAS24 This citation was used in the production of this database, either in the description of map units, or the production of geologic polygons, or the additional supporting structural and cartographic information. B.E. Owens R. Buchwaldt C.R. Shirvell 2010 publication Memoir 206 Boulder, CO Geological Society of America Owens, B.E., Buchwaldt, R., and Shirvell, C.R., 2010, Geochemical and geochronological evidence for Devonian magmatism revealed in the Maidens gneiss, Goochland terrane, Virginia, in Tollo, R.P., Bartholomew, M.J., Hibbard, J.P., and Karabinos, P.M., eds., From Rodinia to Pangea—The lithotectonic record of the Appalachian region: Boulder, Colo., Geological Society of America Memoir 206, p. 725–738. https://doi.org/10.1130/2010.1206(28) Digital and/or Hardcopy 2010 publication date BCKNRVADAS25 This citation was used in the production of this database, either in the description of map units, or the production of geologic polygons, or the additional supporting structural and cartographic information. C.R. Shirvell R.J. Tracy B.E. Owens 2004 publication Abstracts with Programs v. 36, no. 2 Boulder, CO Geological Society of America Shirvell, C.R., Tracy, R.J., and Owens, B.E., 2004, Paleozoic (not Mesoproterozoic) high-grade metamorphism in the Goochland terrane, Virginia—New results from electron microprobe dating of monazite [abs.]: Geological Society of America Abstracts with Programs, v. 36, no. 2, p. 80. Digital and/or Hardcopy 2004 publication date BCKNRVADAS26 This citation was used in the production of this database, either in the description of map units, or the production of geologic polygons, or the additional supporting structural and cartographic information. A. J. Martin I. Kadel-Harder B.E. Owens K. Kitajima S.D. Samson S.K. Verma 20190602 publication International Geology Review v. 62, no. 5 London, UK Informa UK Limited Martin, A.J., Kadel-Harder, I., Owens, B.E., Kitajima, K., Samson, S.D., Verma, S.K., 2019, Five hundred million years of punctuated addition of juvenile crust during extension in the Goochland Terrane, central Appalachian Piedmont Province: International Geology Review, v. 62, no. 5, p. 523–548. https://doi.org/10.1080/00206814.2019.1622156 Digital and/or Hardcopy 20190602 publication date BCKNRVADAS27 This citation was used in the production of this database, either in the description of map units, or the production of geologic polygons, or the additional supporting structural and cartographic information. A geodatabase was created using the GeMS (https://pubs.er.usgs.gov/publication/tm11B10) database schema (11/2020). A peer reviewed Adobe Illustrator file and a Microsoft Excel spreadsheet were provided from the author. The Illustrator file was exported as a TIFF image and registered and rectified in ArcGIS 10.8. The ContactsandFaults and GeologicLines feature classes were carefully digitized, smoothed, and generalized as shapefiles and loaded into the database. Surficial contacts (MapUnitOverlayLines) and shorelines for water polygons were digitized directly off lidar. Shoreline lines were used to create the water polygons and those were loaded into OverlayPolys. Federal Geographic Data Committee (FGDC) reference values (https://ngmdb.usgs.gov/fgdc_gds/geolsymstd/download.php) were inserted into the ContactsandFaults feature class "Symbol" field and the information in the Type field was changed to better reflect the explanation of map symbols in the author-provided Illustrator file. The associated MapUnitPolys feature class was created with the feature to polygon tool. The Symbol field in the MapUnitPolys feature class was populated with the appropriate numbers from the FGDC CMYK color chart. The MapUnitPolys feature class was matched to the USGSsymbols.style file for color reproduction. The information in the Type field for the GeologicLines feature class was renamed to better reflect the explanation of map symbols and the appropriate FGDC reference values were inserted into the Symbol field based on the author-provided Illustrator file. The MapUnitOverlayLines were used to create intersection points and split the ContactsAndFaults and GeologicLines to create concealed contacts where covered by surficial units or water. The IsConcealed field was changed to "Y" and the Symbol field was changed to the appropriate FGDC reference value. The point data were originally provided by the author in an Excel spreadsheet. Using ArcCatalog, the Excel spreadsheet was converted to a shapefile and loaded into the OrientationPoints feature class. The Type and Symbol fields were then changed to better reflect the information provided in the author-prepared Illustrator file. A field, "IsVisible" was added to multiple feature classes for cartographic purposes in order to let users know what structural measurements and (or) contacts are not visible on the published geologic map. The Label field in the OrientationPoints feature class was populated from the Inclination field except where horizontal, vertical, or not visible structural symbols were indicated. Mineral resources data and thin sections locations included in an Excel spreadsheet were converted to a shapefile using ArcCatalog and loaded into the GenericPoints feature class. Attributes for this feature class were completed using information from the author's Illustrator file. Structural measurements not containing azimuth or inclination values were cut and pasted into the Stations feature class. ArcGIS Representation classes were initially used to symbolize all line and point feature classes. The OrientationPoints representations were pulled apart where overlapping symbols existed, or they were hidden (made not visible) where structural measurements were overlapping. Labels on the published geologic map were created using multiple annotation feature classes and were merged into a single annotation feature class after edit. 20220301 U.S. Geological Survey, Northeast Region E. Allen Crider Jr. Geologist mailing

Mail Stop 926A, 12201 Sunrise Valley Dr

Reston VA 20192 US 703-648-6906 ecrider@usgs.gov Following edit, representation classes used in production of the map were removed and the database and symbols were adjusted using a custom FGDC.styleX file in ArcGIS Pro 3.2.2. The custom.styleX file has been provided with the data release. The entire dataset was then exported to Illustrator at 1:24,000 scale to produce the published geologic map for edit. After editing, labels, types, and symbol fields for multiple feature classes were readjusted in order to more closely match the edit. To reproduce the published geologic map users of the data should use definition queries from the "PlotAtScale" and "IsVisible" fields. The edited text was inserted into the DataSources, DescriptionofMapUnits, and Glossary object classes (tables). Metadata was created from the tables, and additional information was added to the metadata in areas where table information was insufficient to complete the metadata. 20250301 U.S. Geological Survey, Northeast Region Ernest A Crider Jr. Geologist mailing

Mail Stop 926A, 12201 Sunrise Valley Dr

Reston VA 20192 US 703-648-6906 bweinmann@usgs.gov Vector G-polygon 136 Universal Transverse Mercator 18 0.9996 -75.0 0.0 500000.0 0.0 coordinate pair 0.6096 0.6096 meters North_American_Datum_1983 GRS 1980 6378137.0 298.257222101 DescriptionOfMapUnits Non-spatial table that captures content of the Description of Map Units (or equivalent List of Map Units and associated pamphlet text) included in a traditional paper geologic map. Has an internal hierarchy expressed by attribute HierarchyKey GeMS OBJECTID Internal feature number ESRI Unrepresentable domain MapUnit Short plain-text identifier of the map unit. Foreign key to DescriptionOfMapUnits table. GeMS SObg Granodiorite of Elk Creek BCKNRVADAS12 | BCKNRVADAS13 | BCKNRVADAS14 | BCKNRVADAS03 DSqs Garnet-mica schist of the Quantico Formation BCKNRVADAS01 Ocu Rocks of the uppermost part of the Chopawamsic Formation BCKNRVADAS15 | BCKNRVADAS16 | BCKNRVADAS17 Ocm Layered amphibolite of the Chopowamsic Formation BCKNRVADAS20 | BCKNRVADAS05 Hc Colluvial-alluvial material BCKNRVADAS01 Qt4 Low-level terrace deposits BCKNRVADAS01 Ocf Felsic metasedimentary and metavolcanic rocks of the Chopowamsic Formation BCKNRVADAS05 | BCKNRVADAS18 | BCKNRVADAS19 | BCKNRVADAS03 | BCKNRVADAS15 Qal1 Younger alluvium BCKNRVADAS01 Qt3 Lowest-level terrace deposits BCKNRVADAS01 qtz Vein quartz BCKNRVADAS01 Qt5 Mid-level terrace deposits BCKNRVADAS01 Pzmy Biotite-muscovite phyllonite BCKNRVADAS01 Nt7 Highest-level terrace deposits Carter, M.W., Burton, W.C., McAleer, R.J., DiGiacomo-Cohen, M.L., and Sauer, R.T., 2019, Geology of the Mineral and Lake Anna West quadrangles, Virginia: Virginia Division of Geology and Mineral Resources Publication 189, 41 p., 2 pls., scale 1:24,000. Qtd Terrace deposits, undivided BCKNRVADAS01 Jd Diabase BCKNRVADAS06 | BCKNRVADAS07 | BCKNRVADAS08 Qal2 Older alluvium BCKNRVADAS01 Obtg Hornblende-biotite tonalitic gneiss Carter, M.W., McAleer, R.J., Holm-Denoma, C.S., Spears, D.B., Regan, S.P., Burton, W.C., and Evans, N.H., 2020, Geochronologic age constraints on tectonostratigraphic units of the central Virginia Piedmont, USA: U.S. Geological Survey Professional Paper 1861, 28 p. Za Amphibolite of the Elk Hill Complex BCKNRVADAS01 Oci Biotite gneiss of the Chopowamsic Formation BCKNRVADAS15 | BCKNRVADAS05 Yms Quartz-mica schist BCKNRVADAS01 Pzg Metagranitoid Spears, D.B., and Evans, N.H., 2020, Geologic map of the Cartersville quadrangle, Virginia: Virginia Division of Geology and Mineral Resources Open-File Report 2020–01, 1 sheet, scale 1:24,000. Pzdg Amphibolitic metadiorite and metagabbro BCKNRVADAS09 | BCKNRVADAS10 DYmm Biotite gneiss BCKNRVADAS23 | BCKNRVADAS24 | BCKNRVADAS25 | BCKNRVADAS26 Zmg Mica gneiss of the Elk Hill Complex BCKNRVADAS03 | BCKNRVADAS21 af Artificial fill BCKNRVADAS01 Ymq Granofels BCKNRVADAS01 QNt6 Upper-level terrace deposits Malenda, H.F., 2015, New Quaternary geochronometric constraints on river incision in the Virginia Piedmont—Relative contributions of climate, base-level fall, knickpoint retreat, and active tectonics: Bethlehem, Pa., Lehigh University, M.S. thesis, 82 p. Sq Quartzite of the Quantico Formation BCKNRVADAS03 | BCKNRVADAS05 Zfg Felsic gneiss of the Elk Hill Complex Spears, D.B., 2011, Geology of the Lakeside Village quadrangle, Virginia: Charlottesville, Va., Virginia Division of Geology and Mineral Resources Publication 177, 1 sheet, scale 1:24,000, 19-p. pamphlet. ZYma Amphibolite Martin, A.J., Kadel-Harder, I., Owens, B.E., Kitajima, K., Samson, S.D., Verma, S.K., 2019, Five hundred million years of punctuated addition of juvenile crust during extension in the Goochland Terrane, central Appalachian Piedmont Province: International Geology Review, v. 62, no. 5, p. 523–548. Ocum Altered ultramafic rocks of the Chopowamsic Formation Carter, M.W., Burton, W.C., McAleer, R.J., DiGiacomo-Cohen, M.L., and Sauer, R.T., 2019, Geology of the Mineral and Lake Anna West quadrangles, Virginia: Virginia Division of Geology and Mineral Resources Publication 189, 41 p., 2 pls., scale 1:24,000. Name Name of map unit, as shown in boldface in traditional DMU, e.g., "Shnabkaib Member". Identifies unit within its hierarchical context. GeMS Unrepresentable domain FullName Name of map unit including identification of containing higher rank unit(s), e.g., "Shnabkaib Member of Moenkopi Formation". GeMS Unrepresentable domain Age Age of map unit as shown in Description of Map Units. Examples of values are "late Holocene", "Pliocene and Miocene", "Lower Cretaceous". GeMS Unrepresentable domain Description Free-format text description of map unit. Commonly structured according to one or more accepted traditions (e.g., lithology, thickness, color, weathering and outcrop characteristics, distinguishing features, genesis, age constraints) and terse. GeMS Unrepresentable domain HierarchyKey String that records hierarchical structure. Has form nn-nn-nn, nnn-nnn, or similar. Numeric, left-padded with zeros, dash-delimited. Each HierarchyKey fragment of each row MUST be the same length to allow text-based sorting of table entries. GeMS Unrepresentable domain ParagraphStyle Token that identifies formatting of paragraph(s) within traditional Description of Map Units that correspond to this table entry. GeMS DMU Heading 2 Times New Roman, Bold, 10 pt, 12 pt leading, all caps, centered, 12 pt space before U.S. Geological Survey Science Publishing Network, MapStyleGuide_DMU_print_1sht_v1-1_01-15.pdf. DMU Heading 4 Times New Roman, Regular, 10 pt, 12 pt leading, centered, 8 pt space before U.S. Geological Survey Science Publishing Network, MapStyleGuide_DMU_print_1sht_v1-1_01-15.pdf. DMU Heading 1 (DMU Title) Times New Roman, Bold, 12 pt, 12 pt leading, all caps, centered U.S. Geological Survey Science Publishing Network, MapStyleGuide_DMU_print_1sht_v1-1_01-15.pdf. DMU Heading 3 Times New Roman, Regular, 10 pt, 12 pt leading, all caps, centered, 10 pt space before U.S. Geological Survey Science Publishing Network, MapStyleGuide_DMU_print_1sht_v1-1_01-15.pdf. DMU Unit 1 Times New Roman, Regular, 10 pt, 12 pt leading, left justified, 66 pt left indent, –20 pt 1st line indent, 4 pt space before U.S. Geological Survey Science Publishing Network, MapStyleGuide_DMU_print_1sht_v1-1_01-15.pdf. Label Plain-text equivalent of the desired annotation for a feature: for example "14 Ma", or "^c" which (when used with the FGDC GeoAge font) results in the geologic map-unit label TRc (with TR run together to make the Triassic symbol). GeMS Unrepresentable domain Symbol Reference to a point marker, line symbol, or area-fill symbol that is used on the map graphic to denote the feature: perhaps a star for a K-Ar age locality, or a heavy black line for a fault. GeMS Unrepresentable domain AreaFillRGB {Red, Green, Blue} tuples that specify the suggested color (e.g., "255,255,255", "124,005,255") of area fill for symbolizing MapUnit. Each color value is an integer between 0 and 255, values are zero-padded to a length of 3 digits, and values are separated by commas with no space: NNN,NNN,NNN. GeMS Unrepresentable domain AreaFillPatternDescription Text description (e.g., "random small red dashes") provided as a convenience for users who must recreate symbolization. GeMS Unrepresentable domain DescriptionSourceID Source of map-unit description; foreign key to table Datasources. GeMS BCKNRVADAS11 Spears, D.B., and Evans, N.H., 2020, Geologic map of the Cartersville quadrangle, Virginia: Virginia Division of Geology and Mineral Resources Open-File Report 2020–01, 1 sheet, scale 1:24,000. BCKNRVADAS01 BCKNRVADAS05 | BCKNRVADAS18 | BCKNRVADAS19 | BCKNRVADAS03 | BCKNRVADAS15 BCKNRVADAS05 | BCKNRVADAS18 | BCKNRVADAS19 | BCKNRVADAS03 | BCKNRVADAS15 BCKNRVADAS01 BCKNRVADAS06 | BCKNRVADAS07 | BCKNRVADAS08 BCKNRVADAS06 | BCKNRVADAS07 | BCKNRVADAS08 BCKNRVADAS01 BCKNRVADAS23 | BCKNRVADAS24 | BCKNRVADAS25 | BCKNRVADAS26 BCKNRVADAS23 | BCKNRVADAS24 | BCKNRVADAS25 | BCKNRVADAS26 BCKNRVADAS01 BCKNRVADAS03 Carter, M.W., McAleer, R.J., Holm-Denoma, C.S., Spears, D.B., Regan, S.P., Burton, W.C., and Evans, N.H., 2020, Geochronologic age constraints on tectonostratigraphic units of the central Virginia Piedmont, USA: U.S. Geological Survey Professional Paper 1861, 28 p. BCKNRVADAS01 BCKNRVADAS01 BCKNRVADAS01 BCKNRVADAS01 BCKNRVADAS05 Carter, M.W., Burton, W.C., McAleer, R.J., DiGiacomo-Cohen, M.L., and Sauer, R.T., 2019, Geology of the Mineral and Lake Anna West quadrangles, Virginia: Virginia Division of Geology and Mineral Resources Publication 189, 41 p., 2 pls., scale 1:24,000. BCKNRVADAS01 BCKNRVADAS04 Malenda, H.F., 2015, New Quaternary geochronometric constraints on river incision in the Virginia Piedmont—Relative contributions of climate, base-level fall, knickpoint retreat, and active tectonics: Bethlehem, Pa., Lehigh University, M.S. thesis, 82 p. BCKNRVADAS01 BCKNRVADAS12 | BCKNRVADAS13 | BCKNRVADAS14 | BCKNRVADAS03 BCKNRVADAS12 | BCKNRVADAS13 | BCKNRVADAS14 | BCKNRVADAS03 BCKNRVADAS01 BCKNRVADAS09 | BCKNRVADAS10 BCKNRVADAS09 | BCKNRVADAS10 BCKNRVADAS01 BCKNRVADAS15 | BCKNRVADAS16 | BCKNRVADAS17 BCKNRVADAS15 | BCKNRVADAS16 | BCKNRVADAS17 BCKNRVADAS01 BCKNRVADAS20 | BCKNRVADAS05 BCKNRVADAS20 | BCKNRVADAS05 BCKNRVADAS01 BCKNRVADAS22 Spears, D.B., 2011, Geology of the Lakeside Village quadrangle, Virginia: Charlottesville, Va., Virginia Division of Geology and Mineral Resources Publication 177, 1 sheet, scale 1:24,000, 19-p. pamphlet. BCKNRVADAS01 BCKNRVADAS03 | BCKNRVADAS05 BCKNRVADAS03 | BCKNRVADAS05 BCKNRVADAS01 BCKNRVADAS15 | BCKNRVADAS05 BCKNRVADAS15 | BCKNRVADAS05 BCKNRVADAS01 BCKNRVADAS03 | BCKNRVADAS21 BCKNRVADAS03 | BCKNRVADAS21 BCKNRVADAS01 BCKNRVADAS27 Martin, A.J., Kadel-Harder, I., Owens, B.E., Kitajima, K., Samson, S.D., Verma, S.K., 2019, Five hundred million years of punctuated addition of juvenile crust during extension in the Goochland Terrane, central Appalachian Piedmont Province: International Geology Review, v. 62, no. 5, p. 523–548. BCKNRVADAS01 GeoMaterial Categorization of map unit based on lithologic and genetic character, term selected from NGMDB standard term list defined in Appendix A of GeMS documentation, available at http://ngmdb.usgs.gov/Info/standards/GeMS.. GeMS Fine-grained, mafic-composition intrusive igneous rock Rock that solidified from molten or partly molten material (magma) at shallow depth beneath Earths surface, thereby cooling quickly. Generally fine grained but may contain large mineral crystals (phenocrysts). Mostly found as tabular dikes or sills. Composed mostly of dark-colored minerals. Includes basaltic rock. GeMS Metamorphic rock Rock derived from preexisting rocks and altered by essentially solid-state mineralogical, chemical, or structural changes, in response to marked changes in temperature, pressure, deformation, and (or) chemical environment, generally at depth in Earths crust. GeMS "Made" or human-engineered land Modern, unconsolidated material known to have human-related origin. GeMS Alluvial sediment, mostly coarse-grained Unconsolidated material deposited by streams or other bodies of running water as sorted or semisorted sediment in streambed, or on its floodplain or delta, or as cone or fan at base of mountain slope. Sediment is mostly sand, gravel, and coarser material but may also contain some silt and clay. GeMS Regional metamorphic rock, of unspecified origin Rock derived from preexisting rocks and altered by essentially solid-state mineralogical, chemical, or structural changes, in response to marked regional changes in temperature, pressure, deformation, and (or) chemical environment, generally at depth in Earths crust. Origin of preexisting rock is mixed (for example, igneous and sedimentary) or is not known. GeMS Clastic sediment Sediment formed by weathering and erosion of preexisting rocks or minerals; eroded particles or clasts are transported and deposited by gravity, air, water, or ice. GeMS Medium and high-grade regional metamorphic rock, of unspecified origin Rock derived from preexisting rocks and altered by essentially solid-state mineralogical, chemical, or structural changes, in response to relatively intense regional changes in temperature, pressure, deformation, and (or) chemical environment, generally at depth in Earths crust. Origin of preexisting rock is mixed (for example, igneous and sedimentary) or is not known. Includes amphibolite, granulite, schist, and gneiss. GeMS Contact-metamorphic rock Altered rock that originated by local processes of thermal metamorphism, genetically related to intrusion and extrusion of magmas and taking place at or near contact with body of igneous rock. Metamorphic changes are effected by heat and fluids emanating from magma and by some deformation because of emplacement of igneous mass. GeMS Lower-grade metamorphic rock, of unspecified origin Rock derived from preexisting rocks and altered by essentially solid-state mineralogical, chemical, or structural changes, in response to relatively mild regional changes in temperature, pressure, deformation, and (or) chemical environment, generally at depth in Earths crust. Origin of preexisting rock is mixed (for example, igneous and sedimentary) or is not known. Includes slate and phyllite. GeMS Sand and gravel of unspecified origin Sediment composed mostly of sand and (or) gravel, formed by weathering and erosion of preexisting rocks or minerals; eroded particles or clasts are transported and deposited by gravity, air, water, or ice. GeMS Alluvial sediment, mostly fine-grained Unconsolidated material deposited by streams or other bodies of running water as sorted or semisorted sediment in streambed, or on its floodplain or delta, or as cone or fan at base of mountain slope. Sediment is mostly silt and clay but may also contain some sand and gravel. GeMS Deformation-related metamorphic rock Rock derived from preexisting rocks by essentially solid-state mineralogical, chemical, or structural changes in response to strong deformation, commonly in association with marked changes in temperature, pressure, and (or) chemical environment. Generally forms in narrow, planar zones of local deformation (for example, along faults); characterized by foliation or alignment of mineral grains. Includes mylonite and cataclasite. GeMS Colluvium and other widespread mass-movement sediment Sediment formed by slow, relatively widespread, downslope transport of particles or clasts produced by weathering and breakdown of underlying rock, sediment, and (or) soil. Composed of poorly sorted and poorly stratified material that ranges in size from clay to boulders. GeMS Metaigneous rock Rock derived from preexisting igneous rocks and altered by essentially solid-state, mineralogical, chemical, or structural changes, in response to marked changes in temperature, pressure, shear stress, and (or) chemical environment, generally at depth in Earths crust. GeMS GeoMaterialConfidence Describes appropriateness of GeoMaterial term for describing the map unit. GeMS High The term and definition adequately characterize the overall lithologic nature of rocks and sediments in the map unit. Regarding the subjective term "adequately characterize", we refer to context and objectives of this classification as described in the GeMS documentation. GeMS documentation Medium The term and definition generally characterize the overall lithology of the map unit, but there are one or more significant minor lithologies that are not adequately described by the selected term. GeMS documentation DescriptionOfMapUnits_ID Primary key. GeMS Arbitrary string. Values should be unique within this database. DataSources Non-spatial table of sources of all spatial features, sources of some attributes of spatial features, and sources of some attributes of non-spatial table entries. GeMS OBJECTID Internal feature number ESRI Unrepresentable domain Source Plain-text short description that identifies the data source. GeMS Unrepresentable domain Notes Additional information specific to a particular feature or table entry. GeMS Unrepresentable domain. Free text. Values of <null> or #null indicate no entry. URL Universal Resource Locator (URL) or Document Object Identifier (DOI), identifies a document on the World Wide Web. GeMS Unrepresentable domain DataSources_ID Primary key. GeMS Arbitrary string. Values should be unique within this database. Glossary Non-spatial table that, for certain fields (including all Type fields, Confidence fields, and GeneralLithology), lists the terms that populate these fields, term definitions, and sources for definitions. GeMS OBJECTID Internal feature number ESRI Unrepresentable domain Term Plain-language word for a concept. Values must be unique within database as a whole. GeMS Unrepresentable domain Definition Plain-language definition. GeMS Unrepresentable domain DefinitionSourceID Source of definition; foreign key to DataSources. GeMS AGI | BCKNRVADAS02 AGI | BCKNRVADAS02 BCKNRVADAS01 AGI | BCKNRVADAS01 AGI | BCKNRVADAS01 BCKNRVADAS01 BCKNRVADAS01 BCKNRVADAS01 BCKNRVADAS01 GeMS U.S. Geological Survey National Cooperative Geologic Mapping Program, 2020, GeMS (Geologic Map Schema)—A standard format for the digital publication of geologic maps: U.S. Geological Survey Techniques and Methods, book 11. chap. B10, 74 p. standard format for the digital publication of geologic maps: U.S. Geological Survey Techniques and Methods, book 11, chap. B10, 74 p. BCKNRVADAS01 AGI Neuendorf, K.K.E., Mehl, J.P., Jr., and Jackson, J.A., eds., 2011, Glossary of geology (5th ed., revised): Alexandria, Va., American Geosciences Institute, 783 p. BCKNRVADAS01 FGDC Federal Geographic Data Committee [prepared for the Federal Geographic Data Committee by the U.S. Geological Survey], 2006, FGDC Digital Cartographic Standard for Geologic Map Symbolization: Reston, Va., Federal Geographic Data Committee Document Number FGDC-STD-013-2006, 290 p., 2 plates. BCKNRVADAS01 USGS U.S. Geological Survey Science Publishing Network, MapStyleGuide_DMU_print_1sht_v1-1_01-15.pdf. BCKNRVADAS01 Glossary_ID Primary key. GeMS Arbitrary string. Values should be unique within this database. GeoMaterialDict Non-spatial table that provides values of GeoMaterial, placed in a hierarchy, and their definitions. For further information, see Appendix A in GeMS documentation, available at http://ngmdb.usgs.gov/Info/standards/GeMS. GeMS OBJECTID Internal feature number ESRI Unrepresentable domain HierarchyKey String that records hierarchical structure. Has form nn-nn-nn, nnn-nnn, or similar. Numeric, left-padded with zeros, dash-delimited. Each HierarchyKey fragment of each row MUST be the same length to allow text-based sorting of table entries. GeMS Unrepresentable domain GeoMaterial Categorization of map unit based on lithologic and genetic character, term selected from NGMDB standard term list defined in Appendix A of GeMS documentation, available at http://ngmdb.usgs.gov/Info/standards/GeMS.. GeMS Glacial till Mostly unsorted and unstratified material, generally unconsolidated, deposited directly by and underneath or adjacent to glacier without subsequent reworking by meltwater. Consists of heterogeneous mixture of clay, silt, sand, gravel, and boulders, ranging widely in size and shape. GeMS Felsic-composition lava flows Lateral, surficial outpourings of molten lava from vent or fissure; also, solidified bodies of rock that form when they cool. Because of their high silica content and resulting high viscosity, parental magmas tend to erupt explosively, and so these deposits are uncommon. Includes fine-grained, light-colored rock with rhyolitic, dacitic, trachytic, and latitic composition. GeMS Medium and high-grade regional metamorphic rock, of unspecified origin Rock derived from preexisting rocks and altered by essentially solid-state mineralogical, chemical, or structural changes, in response to relatively intense regional changes in temperature, pressure, deformation, and (or) chemical environment, generally at depth in Earths crust. Origin of preexisting rock is mixed (for example, igneous and sedimentary) or is not known. Includes amphibolite, granulite, schist, and gneiss. GeMS Other materials Other materials GeMS Metasedimentary rock Rock derived from preexisting sedimentary rocks and altered by essentially solid-state mineralogical, chemical, or structural changes, in response to marked changes in temperature, pressure, deformation, and (or) chemical environment, generally at depth in Earths crust. GeMS Mass movement sediment Sediment formed by downslope transport of particles or clasts produced by weathering and breakdown of underlying rock, sediment, and (or) soil. Composed of poorly sorted and poorly stratified material that ranges in size from clay to boulders. Includes colluvial, landslide, talus, and rock-avalanche deposits. GeMS Alluvial sediment, mostly fine-grained Unconsolidated material deposited by streams or other bodies of running water as sorted or semisorted sediment in streambed, or on its floodplain or delta, or as cone or fan at base of mountain slope. Sediment is mostly silt and clay but may also contain some sand and gravel. GeMS Coastal zone sediment Mud and sand, with lesser amounts of gravel, deposited on beaches, on barrier islands, or in nearshore-marine, deltaic, or various low-energy shoreline (mud flat, tidal flat, sabka, algal flat) environments. GeMS Metamorphic rock Rock derived from preexisting rocks and altered by essentially solid-state mineralogical, chemical, or structural changes, in response to marked changes in temperature, pressure, deformation, and (or) chemical environment, generally at depth in Earths crust. GeMS "Made" or human-engineered land Modern, unconsolidated material known to have human-related origin. GeMS Volcaniclastic (fragmental) material Rock and unconsolidated material consisting of particles or clasts that were formed by volcanic explosion or aerial expulsion from volcanic vent. GeMS Marine sediment, mostly fine-grained Mostly clay- and silt-sized sediment, deposited in relatively deep, quiet water, far removed from areas where coarser grained clastic sediments are washed into marine environment. Includes sediment derived from marine organisms. GeMS Carbonate sediment Sediment formed by biotic or abiotic precipitation from aqueous solution of carbonates of calcium, magnesium, or iron (for example, limestone, dolomite). GeMS Marine sediment, mostly coarse-grained Mud, sand, and gravel eroded from rocks and sediment on land, transported by streams, and deposited in marine deltas and basins. Mostly siliceous in composition. GeMS Igneous rock Rock and fragmental material that solidified from molten or partly molten material (magma). GeMS Intrusive igneous rock Rock that solidified from molten or partly molten material (magma) below Earths surface. GeMS Ice-contact and ice-marginal sediment Mostly sand-, silt-, and gravel-sized particles or clasts derived from rock or preexisting sediment that has been eroded and transported by glaciers. As glacier melted, material was deposited by running water essentially in contact with glacial ice or was transported and deposited by glacially fed streams. Includes sediment deposited into water bodies adjacent to glacier. GeMS Rock and sediment Various rocks and sediment, not differentiated. GeMS Ice-contact and ice-marginal sediment, mostly fine-grained Mostly silt- and clay-sized particles or clasts, with lesser amounts of sand and gravel, derived from rock or preexisting sediment that has been eroded and transported by glaciers. As glacier melted, material was deposited by running water essentially in contact with glacial ice or was transported and deposited by glacially fed streams. Includes sediment deposited into water bodies adjacent to glacier. GeMS Meta-carbonate rock Rock derived from preexisting carbonate sedimentary rocks and altered by essentially solid-state mineralogical, chemical, or structural changes, in response to marked changes in temperature, pressure, deformation, and (or) chemical environment, generally at depth in Earths crust. Characterized by recrystallization of carbonate minerals in source rock. Includes marble (for which preexisting rock was dominantly limestone or other rock composed of calcite), dolomitic marble, meta-dolostone, and meta-dolomite (for which preexisting rock contained appreciable amount of magnesium). GeMS Ultramafic intrusive igneous rock Rock that solidified from molten or partly molten material (magma) at some depth beneath Earths surface, thereby cooling slowly enough for mineral crystals to grow large enough to be visible to naked eye. Composed almost entirely of mafic minerals (for example, hypersthene, augite, olivine). GeMS Clastic sedimentary rock Sedimentary rock, composed predominantly of particles or clasts derived by erosion, weathering, or mass-wasting of preexisting rock and deposited by gravity, air, water, or ice. GeMS Fine-grained intrusive igneous rock Rock that solidified from molten or partly molten material (magma) at shallow depth beneath Earths surface, thereby cooling quickly. Generally fine grained but may contain large mineral crystals (phenocrysts). Mostly found as tabular dikes or sills. GeMS Debris flows, landslides, and other localized mass-movement sediment Sediment formed by relatively localized, downslope transport of particles or clasts produced by weathering and breakdown of underlying rock, sediment, and (or) soil. Composed of poorly sorted and poorly stratified material that ranges in size from clay to boulders. Speed of downslope transport ranges from rapid to imperceptible. GeMS Coastal zone sediment, mostly fine-grained Mostly clay and silt, deposited in lagoons, tidal flats, backbarriers, and coastal marshes. GeMS Carbonate rock Sedimentary rock, consisting chiefly of carbonate minerals such as limestone or dolomite. GeMS Mudstone Sedimentary rock, composed predominantly of particles or clasts derived by erosion and weathering of preexisting rock; consists mostly of mud (that is, silt- and clay-sized particles). Includes shale and siltstone. GeMS Intermediate-composition pyroclastic flows Hot ash, pumice, and rock fragments erupted from volcano. Material moves downslope commonly in chaotic flows; once deposited, hot fragments may compact under their own weight and weld together. Parental magma commonly erupts from stratovolcanoes as thick lava flows but also can generate strong explosive eruptions to form pyroclastic flows. Includes rocks that are, in color and mineral composition, intermediate between felsic and mafic rocks (for example, andesite). GeMS Colluvium and other widespread mass-movement sediment Sediment formed by slow, relatively widespread, downslope transport of particles or clasts produced by weathering and breakdown of underlying rock, sediment, and (or) soil. Composed of poorly sorted and poorly stratified material that ranges in size from clay to boulders. GeMS Quartzite Rock derived from preexisting quartz-rich sedimentary rocks (commonly sandstone) and altered by essentially solid-state mineralogical, chemical, or structural changes, in response to marked changes in temperature, pressure, shear stress, and (or) chemical environment, generally at depth in Earths crust. GeMS Coarse-grained, felsic-composition intrusive igneous rock Rock that solidified from molten or partly molten material (magma) at some depth beneath Earths surface, thereby cooling slowly enough for mineral crystals to grow large enough to be visible to naked eye. Composed mostly of light-colored minerals (for example, feldspar, quartz). Includes granitic, syenitic, and monzonitic rock. GeMS Meta-felsic and intermediate rock Rock derived from preexisting felsic and intermediate-composition rocks by essentially solid-state, mineralogical, chemical, or structural changes, in response to marked changes in temperature, pressure, deformation, and (or) chemical environment, generally at depth in Earths crust. Composed mostly of light-colored minerals; relatively enriched in silica. Includes metagranite, metadiorite, and meta-andesite. GeMS Peat and muck Unconsolidated material, principally composed of plant remains, with lesser amounts of fine-grained clastic sediment. Deposited in water-saturated environment such as swamp, marsh, or bog. With lithification, such material becomes coal. GeMS Lower-grade metamorphic rock, of unspecified origin Rock derived from preexisting rocks and altered by essentially solid-state mineralogical, chemical, or structural changes, in response to relatively mild regional changes in temperature, pressure, deformation, and (or) chemical environment, generally at depth in Earths crust. Origin of preexisting rock is mixed (for example, igneous and sedimentary) or is not known. Includes slate and phyllite. GeMS Dune sand Mostly sand-sized sediment, deposited by wind. Typically characterized by various dune landforms. GeMS Coarse-grained, intermediate-composition intrusive igneous rock Rock that solidified from molten or partly molten material (magma) at some depth beneath Earths surface, thereby cooling slowly enough for mineral crystals to grow large enough to be visible to naked eye. Intermediate in color and in mineral composition (between felsic and mafic igneous rock). Includes dioritic rock. GeMS Slate and phyllite, of sedimentary-rock origin Fine-grained rock derived from preexisting sedimentary rocks and altered by essentially solid-state mineralogical, chemical, or structural changes, in response to marked changes in temperature, pressure, deformation, and (or) chemical environment, generally at depth in Earths crust. Includes phyllite and slate (compact, fine-grained rock that possesses strong cleavage and, hence, can be split into slabs and thin plates). Mostly formed from fine-grained material such as mudstone. GeMS Mafic-composition air-fall tephra Fragments of volcanic rock and lava, of various sizes, carried into the air by explosions and by hot gases in eruption columns or lava fountains; known as tephra. As tephra falls to ground, with increasing distance from volcano, average size of individual rock particles and thickness of resulting deposit decrease. Because of their low silica content and resulting low viscosity, parental magmas tend to erupt gently as lava flows, and so these deposits are uncommon. Includes basalt; rocks are commonly dark-colored. GeMS Sand and gravel of unspecified origin Sediment composed mostly of sand and (or) gravel, formed by weathering and erosion of preexisting rocks or minerals; eroded particles or clasts are transported and deposited by gravity, air, water, or ice. GeMS Evaporitic rock Sedimentary rock, composed primarily of minerals produced by evaporation of saline solution. Examples include gypsum, anhydrite, other diverse sulfates, halite (rock salt), primary dolomite, and rocks composed of various nitrates and borates. GeMS Deformation-related metamorphic rock Rock derived from preexisting rocks by essentially solid-state mineralogical, chemical, or structural changes in response to strong deformation, commonly in association with marked changes in temperature, pressure, and (or) chemical environment. Generally forms in narrow, planar zones of local deformation (for example, along faults); characterized by foliation or alignment of mineral grains. Includes mylonite and cataclasite. GeMS Metaigneous rock Rock derived from preexisting igneous rocks and altered by essentially solid-state, mineralogical, chemical, or structural changes, in response to marked changes in temperature, pressure, shear stress, and (or) chemical environment, generally at depth in Earths crust. GeMS Intermediate-composition lava flows Lateral, surficial outpourings of molten lava from vent or fissure; also, solidified bodies of rock that form when they cool. Parental magma commonly erupts from stratovolcanoes as thick lava flows. Includes rocks that are, in color and in mineral composition, intermediate between felsic and mafic rocks (for example, andesite). GeMS Clastic sediment Sediment formed by weathering and erosion of preexisting rocks or minerals; eroded particles or clasts are transported and deposited by gravity, air, water, or ice. GeMS Sedimentary rock Consolidated material (rock) composed of particles transported and deposited by gravity, air, water, or ice, or accumulated by other natural agents operating at Earths surface, such as chemical precipitation or secretion by organisms. Does not here include sedimentary material directly deposited as result of volcanic activity. GeMS Felsic-composition air-fall tephra Fragments of volcanic rock and lava, of various sizes, carried into air by explosions and by hot gases in eruption columns or lava fountains; known as tephra. As tephra falls to ground, with increasing distance from volcano, average size of individual rock particles and thickness of resulting deposit decrease. Because of their high silica content and resulting high viscosity, felsic-composition magmas tend to erupt explosively, readily forming pumice and volcanic ash. Composed of light-colored rocks (for example, rhyolite, dacite, trachyte, latite). GeMS Schist and gneiss, of sedimentary-rock origin Foliated rock derived from preexisting sedimentary rocks by essentially solid-state mineralogical, chemical, or structural changes in response to marked changes in temperature, pressure, deformation, and (or) chemical environment, generally at depth in Earths crust. Includes schist (characterized by such strong foliation or alignment of minerals that it readily splits into flakes or slabs) and gneiss (characterized by alternating, irregular bands of different mineral composition). Mostly formed from fine-grained material such as mudstone. GeMS Lacustrine sediment, mostly fine-grained Mostly well-sorted and well-bedded material, generally silt and clay sized, with lesser amounts of sand, deposited in perennial to intermittent lakes. GeMS Coastal zone sediment, mostly coarse-grained Mostly sand, silt, and gravel, deposited on beaches, in dunes, and in shallow-marine and related alluvial environments. GeMS Fine-grained, felsic-composition intrusive igneous rock Rock that solidified from molten or partly molten material (magma) at shallow depth beneath Earths surface, thereby cooling quickly. Generally fine grained but may contain large mineral crystals (phenocrysts). Mostly found as tabular dikes or sills. Composed mostly of light-colored minerals. Includes rhyolitic, dacitic, trachytic, and latitic rock. GeMS Iron-rich sedimentary rock Sedimentary rock, in which at least half (by volume) of observed minerals are iron bearing (hematite, magnetite, limonite group minerals, siderite, iron sulfides). GeMS Mafic-composition lava flows Lateral, surficial outpourings of molten lava from vent or fissure; also, solidified bodies of rock that form when they cool. Low-silica parental magmas have low viscosity and tend to form extensive sheets that have generally low relief. Includes basaltic shield volcanoes, which may become very large (for example, in Hawaii). Composed of fine-grained, dark rocks, including basaltic. GeMS Mostly carbonate rock Mostly carbonate rock, interbedded with other sedimentary rock types. GeMS Mostly sandstone Mostly sandstone, interbedded with other sedimentary rocks that locally may include conglomerate and finer grained clastic rocks (mudstone), carbonates, and (or) coal. GeMS Extrusive igneous material Molten material that was erupted onto Earths surface, fusing into rock or remaining as unconsolidated particles. Includes pyroclastic flows, air-fall tephra, lava flows, and volcanic mass flows. GeMS Playa sediment Fine-grained clastic sediment and evaporitic salts, deposited in ephemeral lakes in centers of undrained basins. Includes material deposited in playas, mud flats, salt flats, and adjacent saline marshes. Generally interbedded with eolian sand and with lacustrine sediment deposited during wetter climatic periods; commonly intertongues upslope with sediment deposited by alluvial fans. GeMS Sandstone Sedimentary rock, composed predominantly of particles or clasts derived by erosion and weathering of preexisting rock; consists mostly of sand-sized particles, with or without fine-grained matrix of silt or clay. GeMS Sediment Unconsolidated material (sediment) composed of particles deposited by gravity, air, water, or ice, or as accumulated by other natural agents operating at Earths surface such as chemical precipitation or secretion by organisms. Does not include sedimentary material directly deposited as a result of volcanic activity. GeMS Dolomite Carbonate sedimentary rock, consisting chiefly of dolomite. Although dolostone is the proper analog to limestone, it has not often been applied to dolomitic units. GeMS Igneous and metamorphic rock Consists of coarse-grained intrusive igneous rock and generally medium- to high-grade metamorphic rock. GeMS Air-fall tephra Fragments of volcanic rock and lava, of various sizes, carried into air by explosions and by hot gases in eruption columns or lava fountains; known as tephra. As tephra falls to ground, with increasing distance from volcano, average size of individual rock particles and thickness of resulting deposit decrease. Fine tephra deposited at some distance from volcano is known as volcanic ash. GeMS Exotic-composition intrusive igneous rock Rock that solidified from molten or partly molten material (magma) below Earths surface that has exotic mineralogical, textural, or field setting characteristics. Typically dark colored with abundant phenocrysts. Includes kimberlite, lamprophyre, lamproite, and foiditic rocks. GeMS Glacial till, mostly silty Mostly unsorted and unstratified material, generally unconsolidated, deposited directly by and underneath or adjacent to glacier without subsequent reworking by meltwater. Consists of heterogeneous mixture of clay, silt, sand, gravel, and boulders, ranging widely in size and shape. Relatively loamy (silty) in texture. GeMS Rock Various rock types, not differentiated. GeMS Meta-volcaniclastic rock Rock derived from preexisting volcaniclastic rocks by essentially solid-state, mineralogical, chemical, or structural changes, in response to marked changes in temperature, pressure, deformation, and (or) chemical environment, generally at depth in Earths crust. Composed of deformed but recognizable particles or clasts of volcanic explosive material. GeMS Felsic-composition pyroclastic flows Hot ash, pumice, and rock fragments erupted from volcano or caldera. Material moves downslope commonly in chaotic flows; once deposited, hot fragments may compact under their own weight and weld together. Because of their high-silica content and resulting high viscosity, parental magmas tend to erupt explosively. Includes rhyolite, dacite, trachyte, latite; rocks are commonly light-colored. GeMS Regional metamorphic rock, of unspecified origin Rock derived from preexisting rocks and altered by essentially solid-state mineralogical, chemical, or structural changes, in response to marked regional changes in temperature, pressure, deformation, and (or) chemical environment, generally at depth in Earths crust. Origin of preexisting rock is mixed (for example, igneous and sedimentary) or is not known. GeMS Intermediate-composition air-fall tephra Fragments of volcanic rock and lava, of various sizes, carried into the air by explosions and by hot gases in eruption columns or lava fountains; known as tephra. As tephra falls to ground, with increasing distance from volcano, average size of individual rock particles and thickness of resulting deposit decrease. Parental magma commonly erupts from stratovolcanoes as thick lava flows but also can generate strong explosive eruptions to form pyroclastic flows. Includes rocks that are, in color and mineral composition, intermediate between felsic and mafic rocks (for example, andesite). GeMS Pyroclastic flows Hot ash, pumice, and rock fragments erupted from volcano or caldera. Material moves downslope commonly in chaotic flows; once deposited, hot fragments may compact under their own weight and weld together. GeMS Conglomerate Sedimentary rock, composed predominantly of particles or clasts derived by erosion and weathering of preexisting rock; contains more than 30 percent gravel-sized clasts. GeMS Lacustrine sediment Mostly well-sorted and well-bedded material that ranges in grain size from clay to gravel, deposited in perennial to intermittent lakes. Much of sediment is derived from material eroded and transported by streams. Includes deposits of lake-marginal beaches and deltas. GeMS Coarse-grained intrusive igneous rock Rock that solidified from molten or partly molten material (magma) at some depth beneath Earths surface, thereby cooling slowly enough for mineral crystals to grow large enough to be visible to naked eye. GeMS Coarse-grained, mafic-composition intrusive igneous rock Rock that solidified from molten or partly molten material (magma) at some depth beneath Earths surface, thereby cooling slowly enough for mineral crystals to grow large enough to be visible to naked eye. Composed mostly of feldspar and dark-colored minerals. Includes gabbroic rock. GeMS Silt and clay of unspecified origin Sediment composed mostly of silt and (or) clay, formed by weathering and erosion of preexisting rocks or minerals; eroded particles or clasts are transported and deposited by gravity, air, water, or ice. GeMS Unmapped area Unmapped area GeMS Coal and lignite Organic-rich sedimentary rock, formed from compaction and alteration of plant remains. Coal is consolidated, harder, black rock. Lignite is semiconsolidated, brown to black, earthy material that may contain large particles of recognizable plant parts and tends to crack upon drying. GeMS Sandstone and mudstone Sandstone and mudstone (including shale and siltstone), in approximately equal (or unspecified) proportions. GeMS Mostly mudstone Mostly mudstone, interbedded with other sedimentary rocks that locally may include coarser grained clastic rocks (sandstone, conglomerate), carbonates, and (or) coal. GeMS Glacial till, mostly sandy Mostly unsorted and unstratified material, generally unconsolidated, deposited directly by and underneath or adjacent to glacier without subsequent reworking by meltwater. Consists of heterogeneous mixture of clay, silt, sand, gravel, and boulders, ranging widely in size and shape. Relatively sandy in texture. GeMS Water or ice Water or ice GeMS Alluvial sediment, mostly coarse-grained Unconsolidated material deposited by streams or other bodies of running water as sorted or semisorted sediment in streambed, or on its floodplain or delta, or as cone or fan at base of mountain slope. Sediment is mostly sand, gravel, and coarser material but may also contain some silt and clay. GeMS Fine-grained, intermediate-composition intrusive igneous rock Rock that solidified from molten or partly molten material (magma) at shallow depth beneath Earths surface, thereby cooling quickly. Generally fine grained but may contain large mineral crystals (phenocrysts). Mostly found as tabular dikes or sills. Intermediate in color and in mineral composition (between felsic and mafic igneous rock). Includes andesitic rock. GeMS Ice-contact and ice-marginal sediment, mostly coarse-grained Mostly sand- and gravel-sized particles or clasts, with lesser amounts of silt and clay, derived from rock or preexisting sediment that has been eroded and transported by glaciers. As glacier melted, material was deposited by running water essentially in contact with glacial ice or was transported and deposited by glacially fed streams. Includes sediment deposited into water bodies adjacent to glacier. GeMS Alluvial sediment Unconsolidated material deposited by streams or other bodies of running water as sorted or semisorted sediment in streambed, or on its floodplain or delta, or as cone or fan at base of mountain slope. Grain size varies from clay to gravel. GeMS Glacial till, mostly clayey Mostly unsorted and unstratified material, generally unconsolidated, deposited directly by and underneath or adjacent to glacier without subsequent reworking by meltwater. Consists of heterogeneous mixture of clay, silt, sand, gravel, and boulders, ranging widely in size and shape. Relatively clayey in texture. GeMS Contact-metamorphic rock Altered rock that originated by local processes of thermal metamorphism, genetically related to intrusion and extrusion of magmas and taking place at or near contact with body of igneous rock. Metamorphic changes are effected by heat and fluids emanating from magma and by some deformation because of emplacement of igneous mass. GeMS Meta-mafic rock Rock derived from preexisting mafic rocks by essentially solid-state, mineralogical, chemical, or structural changes, in response to marked changes in temperature, pressure, deformation, and (or) chemical environment, generally at depth in Earths crust. Composed mostly of iron- and magnesium-bearing, dark-colored and (or) green minerals. Includes greenstone, amphibolite, and metagabbro. GeMS Marine sediment Mud and sand, deposited in various marine environments. May originate from erosion of rocks and sediment or may be derived from marine organisms (of carbonate or siliceous composition). GeMS Sedimentary and extrusive igneous material Either (1) sedimentary rock and (or) unconsolidated material (sediment) and extrusive igneous material (volcanic rock and [or] sediment) or (2) volcanic rock and (or) sediment and such material after erosion and redeposition. GeMS Chert Sedimentary rock, composed chiefly of microcrystalline or cryptocrystalline quartz. GeMS Limestone Carbonate sedimentary rock, consisting chiefly of calcite. GeMS Sedimentary material An aggregation of particles deposited by gravity, air, water, or ice, or as accumulated by other natural agents operating at Earths surface such as chemical precipitation or secretion by organisms. May include unconsolidated material (sediment) and (or) sedimentary rock. Does not include sedimentary material directly deposited as a result of volcanic activity. GeMS Eolian sediment Silt- and sand-sized sediment, deposited by wind. GeMS Volcanic mass flow Volcanic deposits formed by mass movement (for example, debris avalanches, debris flows, lahar deposits), in many cases triggered by volcanic eruption. Debris avalanches that occur on volcanoes clearly without eruptive trigger may be classified as sedimentary (for example, as Debris flows, landslides, and other localized mass-movement sediment). GeMS Fine-grained, mafic-composition intrusive igneous rock Rock that solidified from molten or partly molten material (magma) at shallow depth beneath Earths surface, thereby cooling quickly. Generally fine grained but may contain large mineral crystals (phenocrysts). Mostly found as tabular dikes or sills. Composed mostly of dark-colored minerals. Includes basaltic rock. GeMS Meta-ultramafic rock Rock derived from preexisting ultramafic rocks by essentially solid-state, mineralogical, chemical, or structural changes, in response to marked changes in temperature, pressure, deformation, and (or) chemical environment, generally at depth in Earths crust. Composed mostly of magnesium-bearing minerals (for example, serpentine, talc, magnesite). GeMS Lava flows Lateral, surficial outpourings of molten lava from vent or fissure; also, solidified bodies of rock that form when they cool. Composed generally of fine-grained, dark-colored rocks (for example, basalt), which tend to form extensive sheets that have generally low relief, except in vent areas where cinder cones or shield volcanoes may form. Includes basaltic shield volcanoes, which may become very large (for example, Hawaii). GeMS Residual material Unconsolidated material, developed in place by weathering of underlying rock or sediment. Usually forms relatively thin surface layer that conceals unweathered or partly altered source material. Material from which soils are formed. GeMS Lacustrine sediment, mostly coarse-grained Mostly well-sorted and well-bedded material, generally sand and gravel sized, with lesser amounts of silt and clay, deposited in perennial to intermittent lakes. Much of sediment is derived from material eroded and transported by streams. Mostly deposits of lake-marginal beaches and deltas. GeMS Mafic-composition pyroclastic flows Hot ash, pumice, and rock fragments erupted from volcano. Material moves downslope commonly in chaotic flows; once deposited, hot fragments may compact under their own weight and weld together. Because of their low silica content and resulting low viscosity, parental magmas tend to erupt gently as lava flows rather than more forcefully as pyroclastic flows. Includes basalt; rocks are commonly dark-colored. GeMS Loess Silty sediment, deposited by wind, commonly near glacial margin. GeMS IndentedName Name with addition of leading spaces to help show rank within a hierarchical list. GeMS Unrepresentable domain Definition Plain-language definition. GeMS Unrepresentable domain MapUnitPolys Polygons that record distribution of map units (including water, snowfields, glaciers, and unmapped area) on the particular map horizon. In the original file geodatabase, this dataset is found within the GeologicMap feature dataset. GeMS OBJECTID Internal feature number ESRI Unrepresentable domain Shape Internal geometry object ESRI Unrepresentable domain Shape_Length Internal feature length, double ESRI Unrepresentable domain Shape_Area Internal feature area, double ESRI Unrepresentable domain MapUnit Short plain-text identifier of the map unit. Foreign key to DescriptionOfMapUnits table. GeMS SObg Granodiorite of Elk Creek BCKNRVADAS12 | BCKNRVADAS13 | BCKNRVADAS14 | BCKNRVADAS03 DSqs Garnet-mica schist of the Quantico Formation BCKNRVADAS01 Ocu Rocks of the uppermost part of the Chopawamsic Formation BCKNRVADAS15 | BCKNRVADAS16 | BCKNRVADAS17 Ocm Layered amphibolite of the Chopowamsic Formation BCKNRVADAS20 | BCKNRVADAS05 Ocf Felsic metasedimentary and metavolcanic rocks of the Chopowamsic Formation BCKNRVADAS05 | BCKNRVADAS18 | BCKNRVADAS19 | BCKNRVADAS03 | BCKNRVADAS15 qtz Vein quartz BCKNRVADAS01 Pzmy Biotite-muscovite phyllonite BCKNRVADAS01 Obtg Hornblende-biotite tonalitic gneiss Carter, M.W., McAleer, R.J., Holm-Denoma, C.S., Spears, D.B., Regan, S.P., Burton, W.C., and Evans, N.H., 2020, Geochronologic age constraints on tectonostratigraphic units of the central Virginia Piedmont, USA: U.S. Geological Survey Professional Paper 1861, 28 p. Jd Diabase BCKNRVADAS06 | BCKNRVADAS07 | BCKNRVADAS08 Za Amphibolite of the Elk Hill Complex BCKNRVADAS01 Oci Biotite gneiss of the Chopowamsic Formation BCKNRVADAS15 | BCKNRVADAS05 Yms Quartz-mica schist BCKNRVADAS01 Pzg Metagranitoid Spears, D.B., and Evans, N.H., 2020, Geologic map of the Cartersville quadrangle, Virginia: Virginia Division of Geology and Mineral Resources Open-File Report 2020–01, 1 sheet, scale 1:24,000. Pzdg Amphibolitic metadiorite and metagabbro BCKNRVADAS09 | BCKNRVADAS10 DYmm Biotite gneiss BCKNRVADAS23 | BCKNRVADAS24 | BCKNRVADAS25 | BCKNRVADAS26 Zmg Mica gneiss of the Elk Hill Complex BCKNRVADAS03 | BCKNRVADAS21 Ymq Granofels BCKNRVADAS01 Sq Quartzite of the Quantico Formation BCKNRVADAS03 | BCKNRVADAS05 Zfg Felsic gneiss of the Elk Hill Complex Spears, D.B., 2011, Geology of the Lakeside Village quadrangle, Virginia: Charlottesville, Va., Virginia Division of Geology and Mineral Resources Publication 177, 1 sheet, scale 1:24,000, 19-p. pamphlet. ZYma Amphibolite Martin, A.J., Kadel-Harder, I., Owens, B.E., Kitajima, K., Samson, S.D., Verma, S.K., 2019, Five hundred million years of punctuated addition of juvenile crust during extension in the Goochland Terrane, central Appalachian Piedmont Province: International Geology Review, v. 62, no. 5, p. 523–548. Ocum Altered ultramafic rocks of the Chopowamsic Formation Carter, M.W., Burton, W.C., McAleer, R.J., DiGiacomo-Cohen, M.L., and Sauer, R.T., 2019, Geology of the Mineral and Lake Anna West quadrangles, Virginia: Virginia Division of Geology and Mineral Resources Publication 189, 41 p., 2 pls., scale 1:24,000. IdentityConfidence Confidence that feature is correctly identified. FGDC certain Identity of a feature can be determined using relevant observations and scientific judgment; therefore, one can be reasonably confident in the credibility of this interpretation. Federal Geographic Data Committee [prepared for the Federal Geographic Data Committee by the U.S. Geological Survey], 2006, FGDC Digital Cartographic Standard for Geologic Map Symbolization: Reston, Va., Federal Geographic Data Committee Document Number FGDC-STD-013-2006, 290 p., 2 plates. Label Plain-text equivalent of the desired annotation for a feature: for example "14 Ma", or "^c" which (when used with the FGDC GeoAge font) results in the geologic map-unit label TRc (with TR run together to make the Triassic symbol). GeMS Unrepresentable domain Symbol Reference to a point marker, line symbol, or area-fill symbol that is used on the map graphic to denote the feature: perhaps a star for a K-Ar age locality, or a heavy black line for a fault. GeMS Unrepresentable domain DataSourceID Source of data; foreign key to table DataSources. GeMS BCKNRVADAS01 BCKNRVADAS01 BCKNRVADAS01 Notes Additional information specific to a particular feature or table entry. GeMS Unrepresentable domain. Free text. Values of <null> or #null indicate no entry. MapUnitPolys_ID Primary key. GeMS Arbitrary string. Values should be unique within this database. DataSourcePolys Polygons that delineate data sources for all parts of the map. In the original file geodatabase, this dataset is found within the GeologicMap feature dataset. GeMS OBJECTID Internal feature number ESRI Unrepresentable domain Shape Internal geometry object ESRI Unrepresentable domain Shape_Length Internal feature length, double ESRI Unrepresentable domain Shape_Area Internal feature area, double ESRI Unrepresentable domain DataSourceID Source of data; foreign key to table DataSources. GeMS Unrepresentable domain Notes Additional information specific to a particular feature or table entry. GeMS Unrepresentable domain. Free text. Values of <null> or #null indicate no entry. DataSourcePolys_ID Primary key. GeMS Arbitrary string. Values should be unique within this database. MapUnitOverlayPolys Polygons that delineate underlying material, overlying material, or some other aspect of earth materials that is described in table DescriptionOfMapUnits, e.g., dike swarm, colluvium. On a map graphic, such polygons are commonly shown by a patterned overprint. In the original file geodatabase, this dataset is found within the GeologicMap feature dataset. GeMS OBJECTID Internal feature number ESRI Unrepresentable domain Shape Internal geometry object ESRI Unrepresentable domain Shape_Length Internal feature length, double ESRI Unrepresentable domain Shape_Area Internal feature area, double ESRI Unrepresentable domain MapUnit Short plain-text identifier of the map unit. Foreign key to DescriptionOfMapUnits table. GeMS Nt7 Highest-level terrace deposits Carter, M.W., Burton, W.C., McAleer, R.J., DiGiacomo-Cohen, M.L., and Sauer, R.T., 2019, Geology of the Mineral and Lake Anna West quadrangles, Virginia: Virginia Division of Geology and Mineral Resources Publication 189, 41 p., 2 pls., scale 1:24,000. Qtd Terrace deposits, undivided BCKNRVADAS01 Qal2 Older alluvium BCKNRVADAS01 QNt6 Upper-level terrace deposits Malenda, H.F., 2015, New Quaternary geochronometric constraints on river incision in the Virginia Piedmont—Relative contributions of climate, base-level fall, knickpoint retreat, and active tectonics: Bethlehem, Pa., Lehigh University, M.S. thesis, 82 p. Hc Colluvial-alluvial material BCKNRVADAS01 Qt4 Low-level terrace deposits BCKNRVADAS01 Qal1 Younger alluvium BCKNRVADAS01 Qt3 Lowest-level terrace deposits BCKNRVADAS01 af Artificial fill BCKNRVADAS01 Qt5 Mid-level terrace deposits BCKNRVADAS01 IdentityConfidence Confidence that feature is correctly identified. FGDC certain Identity of a feature can be determined using relevant observations and scientific judgment; therefore, one can be reasonably confident in the credibility of this interpretation. Federal Geographic Data Committee [prepared for the Federal Geographic Data Committee by the U.S. Geological Survey], 2006, FGDC Digital Cartographic Standard for Geologic Map Symbolization: Reston, Va., Federal Geographic Data Committee Document Number FGDC-STD-013-2006, 290 p., 2 plates. Label Plain-text equivalent of the desired annotation for a feature: for example "14 Ma", or "^c" which (when used with the FGDC GeoAge font) results in the geologic map-unit label TRc (with TR run together to make the Triassic symbol). GeMS Unrepresentable domain Symbol Reference to a point marker, line symbol, or area-fill symbol that is used on the map graphic to denote the feature: perhaps a star for a K-Ar age locality, or a heavy black line for a fault. GeMS Unrepresentable domain DataSourceID Source of data; foreign key to table DataSources. GeMS BCKNRVADAS01 BCKNRVADAS01 BCKNRVADAS01 Notes Additional information specific to a particular feature or table entry. GeMS Unrepresentable domain. Free text. Values of <null> or #null indicate no entry. MapUnitOverlayPolys_ID Primary key. GeMS Arbitrary string. Values should be unique within this database. OverlayPolys Polygons that delineate underlying material, overlying material, or some aspect of earth materials other than the geologic map unit, e.g., dike swarm, alteration zone. On a map graphic, such polygons are commonly shown by a patterned overprint. In the original file geodatabase, this dataset is found within the GeologicMap feature dataset. GeMS OBJECTID Internal feature number ESRI Unrepresentable domain Shape Internal geometry object ESRI Unrepresentable domain Shape_Length Internal feature length, double ESRI Unrepresentable domain Shape_Area Internal feature area, double ESRI Unrepresentable domain Type Classifier that specifies what kind of geologic feature is represented by a database element: that a certain line within feature class ContactsAndFaults is a contact, or thrust fault, or water boundary; or that a point in GeochronPoints represents a K-Ar date. GeMS water body Bodies of water in this database and accompanying published geologic map were delineated using a mixture or lidar imagery and previously published material. They reside in the OverlayPolys feature class and were used to delineate concealed contacts and faults. BCKNRVADAS01 IdentityConfidence Confidence that feature is correctly identified. FGDC certain Identity of a feature can be determined using relevant observations and scientific judgment; therefore, one can be reasonably confident in the credibility of this interpretation. Federal Geographic Data Committee [prepared for the Federal Geographic Data Committee by the U.S. Geological Survey], 2006, FGDC Digital Cartographic Standard for Geologic Map Symbolization: Reston, Va., Federal Geographic Data Committee Document Number FGDC-STD-013-2006, 290 p., 2 plates. Label Plain-text equivalent of the desired annotation for a feature: for example "14 Ma", or "^c" which (when used with the FGDC GeoAge font) results in the geologic map-unit label TRc (with TR run together to make the Triassic symbol). GeMS Unrepresentable domain Symbol Reference to a point marker, line symbol, or area-fill symbol that is used on the map graphic to denote the feature: perhaps a star for a K-Ar age locality, or a heavy black line for a fault. GeMS Unrepresentable domain DataSourceID Source of data; foreign key to table DataSources. GeMS BCKNRVADAS01 BCKNRVADAS01 BCKNRVADAS01 Notes Additional information specific to a particular feature or table entry. GeMS Unrepresentable domain. Free text. Values of <null> or #null indicate no entry. OverlayPolys_ID Primary key. GeMS Arbitrary string. Values should be unique within this database. ContactsAndFaults Contacts between map units, faults that bound map units, and associated dangling faults. Includes concealed faults and contacts, waterlines, snowfield and glacier boundaries, and map boundary. In the original file geodatabase, this dataset is found within the GeologicMap feature dataset. GeMS OBJECTID Internal feature number ESRI Unrepresentable domain Shape Internal geometry object ESRI Unrepresentable domain Shape_Length Internal feature length, double ESRI Unrepresentable domain Type Classifier that specifies what kind of geologic feature is represented by a database element: that a certain line within feature class ContactsAndFaults is a contact, or thrust fault, or water boundary; or that a point in GeochronPoints represents a K-Ar date. GeMS fault, premetamorphic reverse A pre-metamorphic reverse fault. Long-dashed where location is approximately located to within 50 meters (m); short-dashed where location is inferred to within 100 m; dotted where concealed by water or surficial materials. Rectangles on upthrown block BCKNRVADAS01 map boundary The line that surrounds a map, separating the map from the margin. Neat lines usually consist of parallels and meridians, but conventional or arbitrary grid lines may be used. Neuendorf, K.K.E., Mehl, J.P., Jr., and Jackson, J.A., eds., 2011, Glossary of geology (5th ed., revised): Alexandria, Va., American Geosciences Institute, 783 p. fault, high-strain reverse A reverse fault formed under high-strain. Long-dashed where location is approximately located to within 50 meters (m); short-dashed where location is inferred to within 100 m; dotted where concealed by water or surficial materials. Rectangles on upthrown block BCKNRVADAS01 fault, high-angle brittle reverse A high-angle reverse fault formed under brittle conditions. Long-dashed where location is approximately located to within 50 meters (m); short-dashed where location is inferred to within 100 m; dotted where concealed by water or surficial materials. Rectangles on upthrown block BCKNRVADAS01 contact Trace of a plane or irregular surface between two types or ages of rock. Contacts are long-dashed where approximately located to within 50 meters (m) AGI | BCKNRVADAS01 IsConcealed Flag for contacts and faults covered by overlying map unit. GeMS Unrepresentable domain LocationConfidenceMeters Estimated half-width in meters of positional uncertainty envelope; position is relative to other features in database. GeMS Positive real number. Value of -9, -99, or -999 indicates value is unknown. ExistenceConfidence Confidence that feature exists. FGDC certain Identity of a feature can be determined using relevant observations and scientific judgment; therefore, one can be reasonably confident in the credibility of this interpretation. Federal Geographic Data Committee [prepared for the Federal Geographic Data Committee by the U.S. Geological Survey], 2006, FGDC Digital Cartographic Standard for Geologic Map Symbolization: Reston, Va., Federal Geographic Data Committee Document Number FGDC-STD-013-2006, 290 p., 2 plates. IdentityConfidence Confidence that feature is correctly identified. FGDC certain Identity of a feature can be determined using relevant observations and scientific judgment; therefore, one can be reasonably confident in the credibility of this interpretation. Federal Geographic Data Committee [prepared for the Federal Geographic Data Committee by the U.S. Geological Survey], 2006, FGDC Digital Cartographic Standard for Geologic Map Symbolization: Reston, Va., Federal Geographic Data Committee Document Number FGDC-STD-013-2006, 290 p., 2 plates. Label Plain-text equivalent of the desired annotation for a feature: for example "14 Ma", or "^c" which (when used with the FGDC GeoAge font) results in the geologic map-unit label TRc (with TR run together to make the Triassic symbol). GeMS Unrepresentable domain Symbol Reference to a point marker, line symbol, or area-fill symbol that is used on the map graphic to denote the feature: perhaps a star for a K-Ar age locality, or a heavy black line for a fault. GeMS Unrepresentable domain DataSourceID Source of data; foreign key to table DataSources. GeMS BCKNRVADAS01 BCKNRVADAS01 BCKNRVADAS01 Notes Additional information specific to a particular feature or table entry. GeMS Unrepresentable domain. Free text. Values of <null> or #null indicate no entry. ContactsAndFaults_ID Primary key. GeMS Arbitrary string. Values should be unique within this database. IsVisible Field is included to allow queries to hide contacts in the database for cartographic purposes. For instance, if an inclination value for a structural measurement needs to be displayed and a geologic contact needs to be hidden for that purpose. BCKNRVADAS01 Y Contact and (or) fault is not hidden for cartographic purposes. BCKNRVADAS01 N Contact and (or) fault is hidden for cartographic purposes. Producer defined GeologicLines Lines that represent dikes, coal seams, ash beds, fold hinge-surface traces, isograds, and other linear features. All have these properties: (A) They do not participate in map-unit topology. (B) They correspond to features that exist within the Earth and may be concealed beneath younger, covering, material. (C) They are located with an accuracy that likely can be estimated. In the original file geodatabase, this dataset is found within the GeologicMap feature dataset. GeMS OBJECTID Internal feature number ESRI Unrepresentable domain Shape Internal geometry object ESRI Unrepresentable domain Shape_Length Internal feature length, double ESRI Unrepresentable domain Type Classifier that specifies what kind of geologic feature is represented by a database element: that a certain line within feature class ContactsAndFaults is a contact, or thrust fault, or water boundary; or that a point in GeochronPoints represents a K-Ar date. GeMS dike Jurassic diabase dike located using aeromagnetic survey data; not exposed at the surface; may be up to several hundred meters below the surface; for a description of the Jd unit, see the DescriptionofMapUnits table in this database BCKNRVADAS01 syncline, overturned Trace of a fold of which the core contains the stratigraphically younger rocks; it is generally concave upward. The fold has been overturned Neuendorf, K.K.E., Mehl, J.P., Jr., and Jackson, J.A., eds., 2011, Glossary of geology (5th ed., revised): Alexandria, Va., American Geosciences Institute, 783 p. anticline Trace of a fold, generally convex upward, whose core contains the stratigraphically older rocks Neuendorf, K.K.E., Mehl, J.P., Jr., and Jackson, J.A., eds., 2011, Glossary of geology (5th ed., revised): Alexandria, Va., American Geosciences Institute, 783 p. IsConcealed Flag for contacts and faults covered by overlying map unit. GeMS Unrepresentable domain LocationConfidenceMeters Estimated half-width in meters of positional uncertainty envelope; position is relative to other features in database. GeMS Positive real number. Value of -9, -99, or -999 indicates value is unknown. ExistenceConfidence Confidence that feature exists. FGDC certain Identity of a feature can be determined using relevant observations and scientific judgment; therefore, one can be reasonably confident in the credibility of this interpretation. Federal Geographic Data Committee [prepared for the Federal Geographic Data Committee by the U.S. Geological Survey], 2006, FGDC Digital Cartographic Standard for Geologic Map Symbolization: Reston, Va., Federal Geographic Data Committee Document Number FGDC-STD-013-2006, 290 p., 2 plates. IdentityConfidence Confidence that feature is correctly identified. FGDC certain Identity of a feature can be determined using relevant observations and scientific judgment; therefore, one can be reasonably confident in the credibility of this interpretation. Federal Geographic Data Committee [prepared for the Federal Geographic Data Committee by the U.S. Geological Survey], 2006, FGDC Digital Cartographic Standard for Geologic Map Symbolization: Reston, Va., Federal Geographic Data Committee Document Number FGDC-STD-013-2006, 290 p., 2 plates. Symbol Reference to a point marker, line symbol, or area-fill symbol that is used on the map graphic to denote the feature: perhaps a star for a K-Ar age locality, or a heavy black line for a fault. GeMS Unrepresentable domain Label Plain-text equivalent of the desired annotation for a feature: for example "14 Ma", or "^c" which (when used with the FGDC GeoAge font) results in the geologic map-unit label TRc (with TR run together to make the Triassic symbol). GeMS Unrepresentable domain DataSourceID Source of data; foreign key to table DataSources. GeMS BCKNRVADAS01 BCKNRVADAS01 BCKNRVADAS01 Notes Additional information specific to a particular feature or table entry. GeMS Unrepresentable domain. Free text. Values of <null> or #null indicate no entry. GeologicLines_ID Primary key. GeMS Arbitrary string. Values should be unique within this database. CartographicLines Lines (e.g., cross-section lines) that have no real-world physical existence, such that LocationConfidenceMeters, ExistenceConfidence, and IdentityConfidence attributes are meaningless, and that are never shown as concealed beneath a covering unit. In the original file geodatabase, this dataset is found within the GeologicMap feature dataset. GeMS OBJECTID Internal feature number ESRI Unrepresentable domain Shape Internal geometry object ESRI Unrepresentable domain Shape_Length Internal feature length, double ESRI Unrepresentable domain Type Classifier that specifies what kind of geologic feature is represented by a database element: that a certain line within feature class ContactsAndFaults is a contact, or thrust fault, or water boundary; or that a point in GeochronPoints represents a K-Ar date. GeMS cross section Surface line used to diagram or drawing that shows features transected by a given plane Neuendorf, K.K.E., Mehl, J.P., Jr., and Jackson, J.A., eds., 2011, Glossary of geology (5th ed., revised): Alexandria, Va., American Geosciences Institute, 783 p. Symbol Reference to a point marker, line symbol, or area-fill symbol that is used on the map graphic to denote the feature: perhaps a star for a K-Ar age locality, or a heavy black line for a fault. GeMS Unrepresentable domain Label Plain-text equivalent of the desired annotation for a feature: for example "14 Ma", or "^c" which (when used with the FGDC GeoAge font) results in the geologic map-unit label TRc (with TR run together to make the Triassic symbol). GeMS Unrepresentable domain DataSourceID Source of data; foreign key to table DataSources. GeMS BCKNRVADAS01 BCKNRVADAS01 BCKNRVADAS01 Notes Additional information specific to a particular feature or table entry. GeMS Unrepresentable domain. Free text. Values of <null> or #null indicate no entry. CartographicLines_ID Primary key. GeMS Arbitrary string. Values should be unique within this database. OrientationPoints Point structure data (e.g., bedding attitudes, foliation attitudes, slip vectors measured at a point, etc.), one point per measurement. Multiple measurements at a single station (e.g., bedding and cleavage) should have the same StationsID. In the original file geodatabase, this dataset is found within the GeologicMap feature dataset. GeMS OBJECTID Internal feature number ESRI Unrepresentable domain Shape Internal geometry object ESRI Unrepresentable domain Type Classifier that specifies what kind of geologic feature is represented by a database element: that a certain line within feature class ContactsAndFaults is a contact, or thrust fault, or water boundary; or that a point in GeochronPoints represents a K-Ar date. GeMS intersection lineation Structural measurement of a lineation formed by the intersection of two planar surfaces, at least one of which is penetrative, e.g., bedding and cleavage. Neuendorf, K.K.E., Mehl, J.P., Jr., and Jackson, J.A., eds., 2011, Glossary of geology (5th ed., revised): Alexandria, Va., American Geosciences Institute, 783 p. crenulation axis Structural measurement of the axis of a type foliation that results from a preferred orientation of rock layers or mineral grains due to microscale folding Neuendorf, K.K.E., Mehl, J.P., Jr., and Jackson, J.A., eds., 2011, Glossary of geology (5th ed., revised): Alexandria, Va., American Geosciences Institute, 783 p. slickenline Structural measurement of a lineation on a slickenside defined by grooves, ridges, and/or striations. Neuendorf, K.K.E., Mehl, J.P., Jr., and Jackson, J.A., eds., 2011, Glossary of geology (5th ed., revised): Alexandria, Va., American Geosciences Institute, 783 p. foliation, mylonitic Structural measurement of a planar arrangement of textural or structural features in mylonitic rock BCKNRVADAS01 dike and (or) vein Structural measurement of outcrop-scale Jurassic diabase dike (Jd) and (or) quartz (qtz) veins. For a description of the Jd and qtz units, see the DescriptionofMapUnits table in this database BCKNRVADAS01 crenulation cleavage Structural measurement of the plane of a type foliation that results from a preferred orientation of rock layers or mineral grains due to microscale folding Neuendorf, K.K.E., Mehl, J.P., Jr., and Jackson, J.A., eds., 2011, Glossary of geology (5th ed., revised): Alexandria, Va., American Geosciences Institute, 783 p. foliation Structural measurement of a planar arrangement of textural or structural features Neuendorf, K.K.E., Mehl, J.P., Jr., and Jackson, J.A., eds., 2011, Glossary of geology (5th ed., revised): Alexandria, Va., American Geosciences Institute, 783 p. compositional layering Structural measurements of alternating layers of different minerals in igneous and metamorphic rocks Neuendorf, K.K.E., Mehl, J.P., Jr., and Jackson, J.A., eds., 2011, Glossary of geology (5th ed., revised): Alexandria, Va., American Geosciences Institute, 783 p. fold axis Structural measurement of a line which, when moved parallel to itself, traces out a folded surface Neuendorf, K.K.E., Mehl, J.P., Jr., and Jackson, J.A., eds., 2011, Glossary of geology (5th ed., revised): Alexandria, Va., American Geosciences Institute, 783 p. outcrop-scale fault Structural measurement of outcrop-scale faulting BCKNRVADAS01 joint Structural measurement of a fracture dividing rock into two sections that have not moved away from each other BCKNRVADAS01 foliation, phyllosilicate Structural measurement of a planar arrangement of textural or structural features in phyllosilicate rock BCKNRVADAS01 axial plane Structural measurement of a surface that connects the hinge lines of the strata in a fold Neuendorf, K.K.E., Mehl, J.P., Jr., and Jackson, J.A., eds., 2011, Glossary of geology (5th ed., revised): Alexandria, Va., American Geosciences Institute, 783 p. mineral lineation Structural measurement of a linear fabric element defined by the preferred orientation of inequant mineral grains (e.g. prismatic grains of hornblende) or elongated grain aggregates Neuendorf, K.K.E., Mehl, J.P., Jr., and Jackson, J.A., eds., 2011, Glossary of geology (5th ed., revised): Alexandria, Va., American Geosciences Institute, 783 p. Azimuth Strike or trend, measured in degrees clockwise from geographic North. Use right-hand rule (dip is to right of azimuth direction). Horizontal planar features may have any azimuth. GeMS 0 360 degrees (angular measure) Inclination Dip or plunge, measured in degrees down from horizontal. Negative values allowed when specifying vectors (not axes) that point above the horizon, e.g., paleocurrents. Types defined as horizontal (e.g., horizontal bedding) shall have Inclination=0. GeMS 0 90 degrees (angular measure) Symbol Reference to a point marker, line symbol, or area-fill symbol that is used on the map graphic to denote the feature: perhaps a star for a K-Ar age locality, or a heavy black line for a fault. GeMS Unrepresentable domain Label Plain-text equivalent of the desired annotation for a feature: for example "14 Ma", or "^c" which (when used with the FGDC GeoAge font) results in the geologic map-unit label TRc (with TR run together to make the Triassic symbol). GeMS Unrepresentable domain LocationConfidenceMeters Estimated half-width in meters of positional uncertainty envelope; position is relative to other features in database. GeMS Positive real number. Value of -9, -99, or -999 indicates value is unknown. IdentityConfidence Confidence that feature is correctly identified. GeMS questionable Identity of a feature cannot be determined using relevant observations and scientific judgment; therefore, one cannot be reasonably confident in the credibility of this interpretation. For example, IdentityConfidence = questionable is appropriate when a geologist reasons "I can see some kind of planar feature that separates map units in this outcrop, but I cannot be certain if it is a contact or a fault." Federal Geographic Data Committee [prepared for the Federal Geographic Data Committee by the U.S. Geological Survey], 2006, FGDC Digital Cartographic Standard for Geologic Map Symbolization: Reston, Va., Federal Geographic Data Committee Document Number FGDC-STD-013-2006, 290 p., 2 plates. certain Identity of a feature can be determined using relevant observations and scientific judgment; therefore, one can be reasonably confident in the credibility of this interpretation. Federal Geographic Data Committee [prepared for the Federal Geographic Data Committee by the U.S. Geological Survey], 2006, FGDC Digital Cartographic Standard for Geologic Map Symbolization: Reston, Va., Federal Geographic Data Committee Document Number FGDC-STD-013-2006, 290 p., 2 plates. OrientationConfidenceDegrees Estimated angular precision of combined azimuth AND inclination measurements, in degrees. GeMS Positive real number. Value of -9, -99, or -999 indicates value is unknown. PlotAtScale At what scale (or larger) should this observation or analysis be plotted? At smaller scales, it should not be plotted. Useful to prevent crowding of display at small scales and to display progressively more data at larger and larger scales. Value is scale denominator. GeMS Positive real number. StationsID Foreign key to Stations point feature class. GeMS Unrepresentable domain MapUnit Short plain-text identifier of the map unit. Foreign key to DescriptionOfMapUnits table. GeMS Ymq Granofels BCKNRVADAS01 SObg Granodiorite of Elk Creek BCKNRVADAS12 | BCKNRVADAS13 | BCKNRVADAS14 | BCKNRVADAS03 Ocu Rocks of the uppermost part of the Chopawamsic Formation BCKNRVADAS15 | BCKNRVADAS16 | BCKNRVADAS17 Jd Diabase BCKNRVADAS06 | BCKNRVADAS07 | BCKNRVADAS08 Pzmy Biotite-muscovite phyllonite BCKNRVADAS01 Obtg Hornblende-biotite tonalitic gneiss Carter, M.W., McAleer, R.J., Holm-Denoma, C.S., Spears, D.B., Regan, S.P., Burton, W.C., and Evans, N.H., 2020, Geochronologic age constraints on tectonostratigraphic units of the central Virginia Piedmont, USA: U.S. Geological Survey Professional Paper 1861, 28 p. Za Amphibolite of the Elk Hill Complex BCKNRVADAS01 Ocm Layered amphibolite of the Chopowamsic Formation BCKNRVADAS20 | BCKNRVADAS05 Oci Biotite gneiss of the Chopowamsic Formation BCKNRVADAS15 | BCKNRVADAS05 DSqs Garnet-mica schist of the Quantico Formation BCKNRVADAS01 Ocf Felsic metasedimentary and metavolcanic rocks of the Chopowamsic Formation BCKNRVADAS05 | BCKNRVADAS18 | BCKNRVADAS19 | BCKNRVADAS03 | BCKNRVADAS15 Pzg Metagranitoid Spears, D.B., and Evans, N.H., 2020, Geologic map of the Cartersville quadrangle, Virginia: Virginia Division of Geology and Mineral Resources Open-File Report 2020–01, 1 sheet, scale 1:24,000. Zfg Felsic gneiss of the Elk Hill Complex Spears, D.B., 2011, Geology of the Lakeside Village quadrangle, Virginia: Charlottesville, Va., Virginia Division of Geology and Mineral Resources Publication 177, 1 sheet, scale 1:24,000, 19-p. pamphlet. ZYma Amphibolite Martin, A.J., Kadel-Harder, I., Owens, B.E., Kitajima, K., Samson, S.D., Verma, S.K., 2019, Five hundred million years of punctuated addition of juvenile crust during extension in the Goochland Terrane, central Appalachian Piedmont Province: International Geology Review, v. 62, no. 5, p. 523–548. Pzdg Amphibolitic metadiorite and metagabbro BCKNRVADAS09 | BCKNRVADAS10 DYmm Biotite gneiss BCKNRVADAS23 | BCKNRVADAS24 | BCKNRVADAS25 | BCKNRVADAS26 Zmg Mica gneiss of the Elk Hill Complex BCKNRVADAS03 | BCKNRVADAS21 Ocum Altered ultramafic rocks of the Chopowamsic Formation Carter, M.W., Burton, W.C., McAleer, R.J., DiGiacomo-Cohen, M.L., and Sauer, R.T., 2019, Geology of the Mineral and Lake Anna West quadrangles, Virginia: Virginia Division of Geology and Mineral Resources Publication 189, 41 p., 2 pls., scale 1:24,000. LocationSourceID Source of location; foreign key to table DataSources. GeMS BCKNRVADAS01 BCKNRVADAS01 BCKNRVADAS01 OrientationSourceID Source of orientation data; foreign key to table DataSources. GeMS BCKNRVADAS01 BCKNRVADAS01 BCKNRVADAS01 Notes Additional information specific to a particular feature or table entry. GeMS Unrepresentable domain. Free text. Values of <null> or #null indicate no entry. OrientationPoints_ID Primary key. GeMS Arbitrary string. Values should be unique within this database. SymbolX This field is used to display information in ArcGIS Pro using the StyleX file provided. The StyleX file has been modified to include specialized symbols used on the published geologic map. Values in this field are identical to the Symbol field for most features. If the symbol values have been modified it has been to allow for multiple symbols to be displayed using classic geologic symbols rather than radiating symbols or to displayed more customized non-FGDC specific symbols. BCKNRVADAS01 Unrepresentable domain GeochronPoints Point locations of samples and accompanying geochronological measurements. Type field identifies geochronological method. In the original file geodatabase, this dataset is found within the GeologicMap feature dataset. GeMS OBJECTID Internal feature number ESRI Unrepresentable domain Shape Internal geometry object ESRI Unrepresentable domain Type Classifier that specifies what kind of geologic feature is represented by a database element: that a certain line within feature class ContactsAndFaults is a contact, or thrust fault, or water boundary; or that a point in GeochronPoints represents a K-Ar date. GeMS SHRIMP U/Pb zircon geochronology Acronym for super high resolution ion microprobe. SHRIMP is used for a calculation of an age in years for geologic material, often zircon, based on the known radioactive decay rate of uranium-238 to lead-206, uranium-235 to lead-207, and thorium-232 to lead-208, whose ratios give three independent ages for the same sample. Label number corresponds to field station and sample number in associated data release (Powell and others, 2024) N | P Ar/Ar geochronology Age dating of a mineral or rock in years, based on measurement of the ratio of radiogenic argon-40 to potassium-40 and the known radioactive decay rate of potassium-40 to argon-40. Label number corresponds to field station and sample number in associated data release (Powell and others, 2024) N | P FieldSampleID Sample ID given at time of collection. GeMS Unrepresentable domain AlternateSampleID Museum #, lab #, etc. GeMS Unrepresentable domain MapUnit Short plain-text identifier of the map unit. Foreign key to DescriptionOfMapUnits table. GeMS SObg Granodiorite of Elk Creek BCKNRVADAS12 | BCKNRVADAS13 | BCKNRVADAS14 | BCKNRVADAS03 Pzmy Biotite-muscovite phyllonite BCKNRVADAS01 Obtg Hornblende-biotite tonalitic gneiss Carter, M.W., McAleer, R.J., Holm-Denoma, C.S., Spears, D.B., Regan, S.P., Burton, W.C., and Evans, N.H., 2020, Geochronologic age constraints on tectonostratigraphic units of the central Virginia Piedmont, USA: U.S. Geological Survey Professional Paper 1861, 28 p. Ocf Felsic metasedimentary and metavolcanic rocks of the Chopowamsic Formation BCKNRVADAS05 | BCKNRVADAS18 | BCKNRVADAS19 | BCKNRVADAS03 | BCKNRVADAS15 Zmg Mica gneiss of the Elk Hill Complex BCKNRVADAS03 | BCKNRVADAS21 Symbol Reference to a point marker, line symbol, or area-fill symbol that is used on the map graphic to denote the feature: perhaps a star for a K-Ar age locality, or a heavy black line for a fault. GeMS Unrepresentable domain Label Plain-text equivalent of the desired annotation for a feature: for example "14 Ma", or "^c" which (when used with the FGDC GeoAge font) results in the geologic map-unit label TRc (with TR run together to make the Triassic symbol). GeMS Unrepresentable domain LocationConfidenceMeters Estimated half-width in meters of positional uncertainty envelope; position is relative to other features in database. GeMS Positive real number. Value of -9, -99, or -999 indicates value is unknown. PlotAtScale At what scale (or larger) should this observation or analysis be plotted? At smaller scales, it should not be plotted. Useful to prevent crowding of display at small scales and to display progressively more data at larger and larger scales. Value is scale denominator. GeMS Positive real number. MaterialAnalyzed Earth-material which was analyzed, e.g., wood, shell, zircon, basalt, whole-rock. GeMS Unrepresentable domain NumericAge Age of map unit as shown in Description of Map Units. Examples of values are "late Holocene", "Pliocene and Miocene", "Lower Cretaceous". GeMS Unrepresentable domain AgePlusError Positive (older) age error, measured in AgeUnits. Type of error (RMSE, 1 sigma, 2 sigma, 95% confidence limit) should be stated in Notes field. GeMS Positive real number. Value of -9, -99, or -999 indicates value is unknown. AgeMinusError Negative (younger) age error, measured in AgeUnits. Type of error (RMSE, 1 sigma, 2 sigma, 95% confidence limit) should be stated in Notes field. GeMS Positive real number. Value of -9, -99, or -999 indicates value is unknown. ErrorMeasure Measure of error whose values are recorded in AgePlusError and AgeMinusError fields GeMS Unrepresentable domain AgeUnits Units for NumericAge, AgePlusError, AgeMinusError. GeMS Ma Mega-annum Neuendorf, K.K.E., Mehl, J.P., Jr., and Jackson, J.A., eds., 2011, Glossary of geology (5th ed., revised): Alexandria, Va., American Geosciences Institute, 783 p. StationsID Foreign key to Stations point feature class. GeMS Unrepresentable domain LocationSourceID Source of location; foreign key to table DataSources. GeMS BCKNRVADAS01 BCKNRVADAS01 BCKNRVADAS01 AnalysisSourceID Source of analysis; foreign key to table DataSources. GeMS BCKNRVADAS03 Carter, M.W., McAleer, R.J., Holm-Denoma, C.S., Spears, D.B., Regan, S.P., Burton, W.C., and Evans, N.H., 2020, Geochronologic age constraints on tectonostratigraphic units of the central Virginia Piedmont, USA: U.S. Geological Survey Professional Paper 1861, 28 p. BCKNRVADAS01 BCKNRVADAS02 Powell, N.E., McAleer, R.J., Regan, S.P., and Carter, M.W., 2024, 238U/206Pb SHRIMP, 40Ar/39Ar geochronologic, and geochemical data from the central Virginia Piedmont: U.S. Geological Survey data release. . BCKNRVADAS01 Notes Additional information specific to a particular feature or table entry. GeMS Unrepresentable domain. Free text. Values of <null> or #null indicate no entry. GeochronPoints_ID Primary key. GeMS Arbitrary string. Values should be unique within this database. Stations Point locations of field observations and (or) samples. In the original file geodatabase, this dataset is found within the GeologicMap feature dataset. GeMS OBJECTID Internal feature number ESRI Unrepresentable domain Shape Internal geometry object ESRI Unrepresentable domain FieldID Station number assigned by person who originally located this station. Commonly, key to field sheet and (or) field notebook GeMS Unrepresentable domain LocationConfidenceMeters Estimated half-width in meters of positional uncertainty envelope; position is relative to other features in database. GeMS Positive real number. Value of -9, -99, or -999 indicates value is unknown. ObservedMapUnit Short plain-text identifier of the map unit. Foreign key to DescriptionOfMapUnits table. GeMS Unrepresentable domain MapUnit Short plain-text identifier of the map unit. Foreign key to DescriptionOfMapUnits table. GeMS SObg Granodiorite of Elk Creek BCKNRVADAS12 | BCKNRVADAS13 | BCKNRVADAS14 | BCKNRVADAS03 DSqs Garnet-mica schist of the Quantico Formation BCKNRVADAS01 Ocu Rocks of the uppermost part of the Chopawamsic Formation BCKNRVADAS15 | BCKNRVADAS16 | BCKNRVADAS17 Ocm Layered amphibolite of the Chopowamsic Formation BCKNRVADAS20 | BCKNRVADAS05 Hc Colluvial-alluvial material BCKNRVADAS01 Ocf Felsic metasedimentary and metavolcanic rocks of the Chopowamsic Formation BCKNRVADAS05 | BCKNRVADAS18 | BCKNRVADAS19 | BCKNRVADAS03 | BCKNRVADAS15 Qal1 Younger alluvium BCKNRVADAS01 Pzmy Biotite-muscovite phyllonite BCKNRVADAS01 Jd Diabase BCKNRVADAS06 | BCKNRVADAS07 | BCKNRVADAS08 Za Amphibolite of the Elk Hill Complex BCKNRVADAS01 Obtg Hornblende-biotite tonalitic gneiss Carter, M.W., McAleer, R.J., Holm-Denoma, C.S., Spears, D.B., Regan, S.P., Burton, W.C., and Evans, N.H., 2020, Geochronologic age constraints on tectonostratigraphic units of the central Virginia Piedmont, USA: U.S. Geological Survey Professional Paper 1861, 28 p. Qal2 Older alluvium BCKNRVADAS01 Oci Biotite gneiss of the Chopowamsic Formation BCKNRVADAS15 | BCKNRVADAS05 Yms Quartz-mica schist BCKNRVADAS01 Pzg Metagranitoid Spears, D.B., and Evans, N.H., 2020, Geologic map of the Cartersville quadrangle, Virginia: Virginia Division of Geology and Mineral Resources Open-File Report 2020–01, 1 sheet, scale 1:24,000. Pzdg Amphibolitic metadiorite and metagabbro BCKNRVADAS09 | BCKNRVADAS10 DYmm Biotite gneiss BCKNRVADAS23 | BCKNRVADAS24 | BCKNRVADAS25 | BCKNRVADAS26 Zmg Mica gneiss of the Elk Hill Complex BCKNRVADAS03 | BCKNRVADAS21 af Artificial fill BCKNRVADAS01 Ymq Granofels BCKNRVADAS01 Zfg Felsic gneiss of the Elk Hill Complex Spears, D.B., 2011, Geology of the Lakeside Village quadrangle, Virginia: Charlottesville, Va., Virginia Division of Geology and Mineral Resources Publication 177, 1 sheet, scale 1:24,000, 19-p. pamphlet. ZYma Amphibolite Martin, A.J., Kadel-Harder, I., Owens, B.E., Kitajima, K., Samson, S.D., Verma, S.K., 2019, Five hundred million years of punctuated addition of juvenile crust during extension in the Goochland Terrane, central Appalachian Piedmont Province: International Geology Review, v. 62, no. 5, p. 523–548. Ocum Altered ultramafic rocks of the Chopowamsic Formation Carter, M.W., Burton, W.C., McAleer, R.J., DiGiacomo-Cohen, M.L., and Sauer, R.T., 2019, Geology of the Mineral and Lake Anna West quadrangles, Virginia: Virginia Division of Geology and Mineral Resources Publication 189, 41 p., 2 pls., scale 1:24,000. Symbol Reference to a point marker, line symbol, or area-fill symbol that is used on the map graphic to denote the feature: perhaps a star for a K-Ar age locality, or a heavy black line for a fault. GeMS Unrepresentable domain Label Plain-text equivalent of the desired annotation for a feature: for example "14 Ma", or "^c" which (when used with the FGDC GeoAge font) results in the geologic map-unit label TRc (with TR run together to make the Triassic symbol). GeMS Unrepresentable domain PlotAtScale At what scale (or larger) should this observation or analysis be plotted? At smaller scales, it should not be plotted. Useful to prevent crowding of display at small scales and to display progressively more data at larger and larger scales. Value is scale denominator. GeMS Positive real number. DataSourceID Source of data; foreign key to table DataSources. GeMS BCKNRVADAS01 BCKNRVADAS01 BCKNRVADAS01 Notes Additional information specific to a particular feature or table entry. GeMS Unrepresentable domain. Free text. Values of <null> or #null indicate no entry. LocationMethod Technique used to determine this station location GeMS Unrepresentable domain TimeDate Time and date of observation at this station GeMS Unrepresentable domain Observer Name and affiliation of person who located this station GeMS Unrepresentable domain SignificantDimensionMeters Significant dimension of exposure (in meters) at this station GeMS Unrepresentable domain GPSX Measured GPS coordinate (easting). May differ from map coordinate because of GPS error or (more likely) base map error. GeMS Unrepresentable domain GPSY Measured GPS coordinate (northing). May differ from map coordinate because of GPS error or (more likely) base map error. GeMS Unrepresentable domain PDOP Significant dimension of exposure (in meters) at this station GeMS Unrepresentable domain Stations_ID Primary key. GeMS Arbitrary string. Values should be unique within this database. GenericPoints Feature class for the location of mineral resources and additional point information as identified on the published geologic map BCKNRVADAS01 OBJECTID Internal feature number ESRI Unrepresentable domain Shape Internal geometry object ESRI Unrepresentable domain Type Classifier that specifies what kind of geologic feature is represented by a database element: that a certain line within feature class ContactsAndFaults is a contact, or thrust fault, or water boundary; or that a point in GeochronPoints represents a K-Ar date. GeMS abandoned mine or quarry Location of abandoned mines and quarries. Mineral resource commodities associated with this feature include: Au, gold; cs, crushed stone; ds, dimension stone; fill, saprolitic fill material; ky, kyanite; mi, mica; ?, indicates uncertainty for which commodity was prospected or mined BCKNRVADAS01 oil well An abandoned well from which petroleum was obtained by pumping or by natural flow Neuendorf, K.K.E., Mehl, J.P., Jr., and Jackson, J.A., eds., 2011, Glossary of geology (5th ed., revised): Alexandria, Va., American Geosciences Institute, 783 p. photo locality Photograph locations obtained during this study. Photographs are available for viewing in the pamphlet attached to the published geologic map BCKNRVADAS01 prospect Locations of areas that are or were potential sites of mineral deposits, based on preliminary exploration; or areas that have been explored in a preliminary way but have not given evidence of economic value. Mineral resource commodities associated with this feature include: Au, gold; cs, crushed stone; ds, dimension stone; fill, saprolitic fill material; ky, kyanite; mi, mica; ?, indicates uncertainty for which commodity was prospected or mined AGI | BCKNRVADAS01 thin section and (or) geochemistry locality Location of thin sections and geochemical samples prepared for this database and associated published geologic map BCKNRVADAS01 Symbol Reference to a point marker, line symbol, or area-fill symbol that is used on the map graphic to denote the feature: perhaps a star for a K-Ar age locality, or a heavy black line for a fault. GeMS Unrepresentable domain Label Plain-text equivalent of the desired annotation for a feature: for example "14 Ma", or "^c" which (when used with the FGDC GeoAge font) results in the geologic map-unit label TRc (with TR run together to make the Triassic symbol). GeMS Unrepresentable domain LocationConfidenceMeters Estimated half-width in meters of positional uncertainty envelope; position is relative to other features in database. GeMS Positive real number. Value of -9, -99, or -999 indicates value is unknown. PlotAtScale At what scale (or larger) should this observation or analysis be plotted? At smaller scales, it should not be plotted. Useful to prevent crowding of display at small scales and to display progressively more data at larger and larger scales. Value is scale denominator. GeMS Positive real number. StationsID Foreign key to Stations point feature class. GeMS Unrepresentable domain MapUnit Short plain-text identifier of the map unit. Foreign key to DescriptionOfMapUnits table. GeMS SObg Granodiorite of Elk Creek BCKNRVADAS12 | BCKNRVADAS13 | BCKNRVADAS14 | BCKNRVADAS03 Pzmy Biotite-muscovite phyllonite BCKNRVADAS01 Jd Diabase BCKNRVADAS06 | BCKNRVADAS07 | BCKNRVADAS08 Obtg Hornblende-biotite tonalitic gneiss Carter, M.W., McAleer, R.J., Holm-Denoma, C.S., Spears, D.B., Regan, S.P., Burton, W.C., and Evans, N.H., 2020, Geochronologic age constraints on tectonostratigraphic units of the central Virginia Piedmont, USA: U.S. Geological Survey Professional Paper 1861, 28 p. Za Amphibolite of the Elk Hill Complex BCKNRVADAS01 Qtd Terrace deposits, undivided BCKNRVADAS01 QNt6 Upper-level terrace deposits Malenda, H.F., 2015, New Quaternary geochronometric constraints on river incision in the Virginia Piedmont—Relative contributions of climate, base-level fall, knickpoint retreat, and active tectonics: Bethlehem, Pa., Lehigh University, M.S. thesis, 82 p. Ocm Layered amphibolite of the Chopowamsic Formation BCKNRVADAS20 | BCKNRVADAS05 Oci Biotite gneiss of the Chopowamsic Formation BCKNRVADAS15 | BCKNRVADAS05 Ocf Felsic metasedimentary and metavolcanic rocks of the Chopowamsic Formation BCKNRVADAS05 | BCKNRVADAS18 | BCKNRVADAS19 | BCKNRVADAS03 | BCKNRVADAS15 Pzg Metagranitoid Spears, D.B., and Evans, N.H., 2020, Geologic map of the Cartersville quadrangle, Virginia: Virginia Division of Geology and Mineral Resources Open-File Report 2020–01, 1 sheet, scale 1:24,000. ZYma Amphibolite Martin, A.J., Kadel-Harder, I., Owens, B.E., Kitajima, K., Samson, S.D., Verma, S.K., 2019, Five hundred million years of punctuated addition of juvenile crust during extension in the Goochland Terrane, central Appalachian Piedmont Province: International Geology Review, v. 62, no. 5, p. 523–548. Pzdg Amphibolitic metadiorite and metagabbro BCKNRVADAS09 | BCKNRVADAS10 DYmm Biotite gneiss BCKNRVADAS23 | BCKNRVADAS24 | BCKNRVADAS25 | BCKNRVADAS26 Zmg Mica gneiss of the Elk Hill Complex BCKNRVADAS03 | BCKNRVADAS21 Qt5 Mid-level terrace deposits BCKNRVADAS01 LocationSourceID Source of location; foreign key to table DataSources. GeMS BCKNRVADAS01 BCKNRVADAS01 BCKNRVADAS01 DataSourceID Source of data; foreign key to table DataSources. GeMS BCKNRVADAS01 BCKNRVADAS01 BCKNRVADAS01 Notes Additional information specific to a particular feature or table entry. GeMS Unrepresentable domain. Free text. Values of <null> or #null indicate no entry. GenericPoints_ID Primary key. GeMS Arbitrary string. Values should be unique within this database. MapUnitOverlayLines Surficial contacts and water contacts for the published geologic map. These boundaries correspond to the MapOverlayUnitPolys and some features of the OverlayPolys feature classes BCKNRVADAS01 OBJECTID Internal feature number ESRI Unrepresentable domain Shape Internal geometry object ESRI Unrepresentable domain Type Classifier that specifies what kind of geologic feature is represented by a database element: that a certain line within feature class ContactsAndFaults is a contact, or thrust fault, or water boundary; or that a point in GeochronPoints represents a K-Ar date. GeMS contact Trace of a plane or irregular surface between two types or ages of rock. Contacts are long-dashed where approximately located to within 50 meters (m) AGI | BCKNRVADAS01 shoreline The intersection of a specified plane of water with a body of water. Shorelines in this database and accompanying published geologic map were delineated using a mixture of lidar imagery and previously published material. BCKNRVADAS01 map boundary The line that surrounds a map, separating the map from the margin. Neat lines usually consist of parallels and meridians, but conventional or arbitrary grid lines may be used. Neuendorf, K.K.E., Mehl, J.P., Jr., and Jackson, J.A., eds., 2011, Glossary of geology (5th ed., revised): Alexandria, Va., American Geosciences Institute, 783 p. IsConcealed Flag for contacts and faults covered by overlying map unit. GeMS Unrepresentable domain LocationConfidenceMeters Estimated half-width in meters of positional uncertainty envelope; position is relative to other features in database. GeMS Positive real number. Value of -9, -99, or -999 indicates value is unknown. ExistenceConfidence Confidence that feature exists. FGDC certain Identity of a feature can be determined using relevant observations and scientific judgment; therefore, one can be reasonably confident in the credibility of this interpretation. Federal Geographic Data Committee [prepared for the Federal Geographic Data Committee by the U.S. Geological Survey], 2006, FGDC Digital Cartographic Standard for Geologic Map Symbolization: Reston, Va., Federal Geographic Data Committee Document Number FGDC-STD-013-2006, 290 p., 2 plates. IdentityConfidence Confidence that feature is correctly identified. FGDC certain Identity of a feature can be determined using relevant observations and scientific judgment; therefore, one can be reasonably confident in the credibility of this interpretation. Federal Geographic Data Committee [prepared for the Federal Geographic Data Committee by the U.S. Geological Survey], 2006, FGDC Digital Cartographic Standard for Geologic Map Symbolization: Reston, Va., Federal Geographic Data Committee Document Number FGDC-STD-013-2006, 290 p., 2 plates. Label Plain-text equivalent of the desired annotation for a feature: for example "14 Ma", or "^c" which (when used with the FGDC GeoAge font) results in the geologic map-unit label TRc (with TR run together to make the Triassic symbol). GeMS Unrepresentable domain Symbol Reference to a point marker, line symbol, or area-fill symbol that is used on the map graphic to denote the feature: perhaps a star for a K-Ar age locality, or a heavy black line for a fault. GeMS Unrepresentable domain DataSourceID Source of data; foreign key to table DataSources. GeMS BCKNRVADAS01 BCKNRVADAS01 BCKNRVADAS01 Notes Additional information specific to a particular feature or table entry. GeMS Unrepresentable domain. Free text. Values of <null> or #null indicate no entry. MapUnitOverlayLines_ID Primary key. GeMS Arbitrary string. Values should be unique within this database. Shape_Length Internal feature length, double ESRI Unrepresentable domain IsVisible Field is included to allow queries to hide contacts in the database for cartographic purposes. For instance, if an inclination value for a structural measurement needs to be displayed and a geologic contact needs to be hidden for that purpose. BCKNRVADAS01 Y Contact and (or) fault is not hidden for cartographic purposes. BCKNRVADAS01 N Contact and (or) fault is hidden for cartographic purposes. BCKNRVADAS01 GeologicMapLabels ArcGIS annotation feature class for the geologic labels associated with each feature class in this database. Annotation from the GeologicLines feature class was not included in this annotation. ESRI OBJECTID Internal feature number ESRI Unrepresentable domain Shape Internal geometry object ESRI Unrepresentable domain FeatureID Value controls placement or representation of annotation ESRI Unrepresentable domain ZOrder Value controls placement or representation of annotation ESRI Unrepresentable domain AnnotationClassID Value controls placement or representation of annotation ESRI Unrepresentable domain Element Value controls placement or representation of annotation ESRI Unrepresentable domain SymbolID Value controls placement or representation of annotation ESRI Unrepresentable domain Status Value controls placement or representation of annotation ESRI Unrepresentable domain TextString Value controls placement or representation of annotation ESRI Unrepresentable domain FontName Value controls placement or representation of annotation ESRI Unrepresentable domain FontStyle Value controls placement or representation of annotation ESRI Unrepresentable domain FontSize Value controls placement or representation of annotation ESRI Unrepresentable domain Underline Value controls placement or representation of annotation ESRI Unrepresentable domain VerticalAlignment Value controls placement or representation of annotation ESRI Unrepresentable domain HorizontalAlignment Value controls placement or representation of annotation ESRI Unrepresentable domain XOffset Value controls placement or representation of annotation ESRI Unrepresentable domain YOffset Value controls placement or representation of annotation ESRI Unrepresentable domain Angle Value controls placement or representation of annotation ESRI Unrepresentable domain FontLeading Value controls placement or representation of annotation ESRI Unrepresentable domain WordSpacing Value controls placement or representation of annotation ESRI Unrepresentable domain CharacterWidth Value controls placement or representation of annotation ESRI Unrepresentable domain CharacterSpacing Value controls placement or representation of annotation ESRI Unrepresentable domain FlipAngle Value controls placement or representation of annotation ESRI Unrepresentable domain Override BLOB field that stores feature-specific overrides to the cartographic representation rules. ESRI Unrepresentable domain Shape_Length Internal feature length, double ESRI Unrepresentable domain Shape_Area Internal feature area, double ESRI Unrepresentable domain Detailed descriptions of entities, attributes, and attribute values are given in metadata for constituent elements of the database. See also "GeMS (Geologic Map Schema)--a standard format for the digital publication of geologic maps", available at http://ngmdb.usgs.gov/Info/standards/GeMS/. Carter, M.W., Spears, D.B., Latane, V.M., Crider, E.A., Weinmann, B.R., Mangum, H., McAleer, R.J., Horton, J.W., Jr., Shah, A.K., and Regan, S.P., 2025, Geologic map of the Buckner 7.5-minute quadrangle, Louisa County, Virginia: U.S. Geological Survey Scientific Investigations Map 3533, 1 sheet, scale 1:24,000, 37-p. pamphlet, https://doi.org/10.3133/sim3533 U.S. Geological Survey GS ScienceBase mailing address

Denver Federal Center, Building 810, Mail Stop 302

Denver CO 80225 United States 1-888-275-8747 sciencebase@usgs.gov Unless otherwise stated, all data, metadata and related materials are considered to satisfy the quality standards relative to the purpose for which the data were collected. Although these data and associated metadata have been reviewed for accuracy and completeness and approved for release by the U.S. Geological Survey (USGS), no warranty expressed or implied is made regarding the display or utility of the data for other purposes, nor on all computer systems, nor shall the act of distribution constitute any such warranty. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Digital Data https://doi.org/10.5066/P9OE8CKX None 20250214 U.S. Geological Survey, Northeast Region E. Allen Crider Jr. Geologist mailing address

Mail Stop 926A, 12201 Sunrise Valley Dr

Reston VA 20192 US 703-648-6906 ecrider@usgs.gov FGDC Content Standard for Digital Geospatial Metadata FGDC-STD-001-1998