Jean M. Morrison William M. Benzel Chris S. Holm-Denoma Sarah Bala 20181022 CSV Denver, CO U.S. Geological Survey Additional information about Originator: Morrison, J. M., https://orcid.org/0000-0002-6614-8783, Benzel, W.M., https://orcid.org/, Holm-Denoma, C.D., https://orcid.org/0000-0003-3229-5440, Bala, Sara https://doi.org/10.5066/P9HUPMG0 Splits of the less than 38 micron size fraction were processed to make oriented clay mounts and analyzed using X-ray diffraction (XRD) as part of a study examining the occurrence of chromium and natural and anthropogenic hexavalent Chromium, Cr(VI) in groundwater. Data will be used to estimate naturally-occurring background Cr(VI) concentrations upgradient, near the plume margins, and downgradient from a mapped Cr(VI) contamination plume near Hinkley, CA (Izbicki and Groover, 2016). These clay mineralogy XRD results are part of a data release including grain size distribution, photographic, and associated chemical and mineral analysis data for 36 sediment core and alluvium samples as well as select grains from magnetic and heavy mineral separates collected near Hinkley, CA. The cooperator for this study is the Lahontan Regional Water Quality Control Board. Results are provided in this data release organized by analysis type. Data were collected to determine the source of several elements of interest, particularly chromium and arsenic in alluvium and core material from wells collected from the Hinkley area. References: Izbicki, J.A., and Groover, Krishangi, A Plan for Study of Hexavalent Chromium, Cr(VI), in Groundwater near a Mapped Plume, Hinkley, California, 2016: U.S. Geological Survey Open-File Report 2016-1004, 12 p., https://doi.org/10.3133/ofr20161004. 20161101 20180801 observed Complete None planned -117.6202 -117.1071 34.9972 34.3425 ISO 19115 Topic Category health geoscientificInformation USGS Thesaurus chromium scanning electron microscopy chemical analysis x-ray fluorescence atomic emission spectroscopy geochemistry chemical analysis mass spectroscopy rocks and deposits unconsolidated deposits soil chemistry contamination and pollution groundwater None background level USGS Metadata Identifier USGS:5ba17894e4b08583a5c42e4f Common geographic areas California Geographic Names Information System (GNIS) Hinkley None. Please see 'Distribution Info' for details. None. Any user who modifies the data is obligated to describe the types of modifications they perform. Data have been checked to ensure the accuracy. The U.S. Geological Survey strongly recommends that careful attention be paid to the metadata file associated with these data. Acknowledgment of the U.S. Geological Survey would be appreciated in products derived from these data. User specifically agrees not to misrepresent the data, nor to imply that changes made were approved or endorsed by the U.S. Geological Survey. Please refer to http://www.usgs.gov/privacy.html for the USGS disclaimer. Jean M. Morrison U.S. Geological Survey Physical Geologist mailing address

P.O. Box 25046, MS-973

Lakewood CO 80225 United States 303-236-2444 303-236-3200 jmorrison@usgs.gov The samples used in the analyses were provided by John Izbicki and Krishangi Groover. The cooperator for this study is the Lahontan Regional Water Quality Control Board. Izbicki, J.A. Groover, Krishangi 2016 Reston, VA U.S. Geological Survey http://dx.doi.org/10.3133/ofr20161004 Data were peer reviewed and examined for anomalous values. Data has been reviewed for duplication and omission. The data only cover samples collected as part of the U.S. Geological Survey hexavalent chromium, Cr(VI), study, Hinkley, Calif. (Izbicki and Groover, 2016) (http://dx.doi.org/10.3133/ofr20161004). Spatial locations were determined from commercial handheld global positioning system (GPS) units. In general, the GPS units used by field scientists recorded sample locations to within approximately 10 meters of the true location. Not applicable. Alluvial and sediment samples were collected near Hinkley, CA and submitted for analysis by John Izbicki and Krishangi Groover. 201505 QUALITATIVE XRD MINERAL IDENTIFICATION FOR CLAY MINERALOGY: Approximately 2 gram split of sample was treated with sodium acetate solution buffered to a pH of 5.3 until all carbonate was removed. The sample washed free of acetate by multiple spins in a centrifuge until the clay defloculated. The less than 8 micron fraction was isolated by centrifuge. This fraction was vacuum filtered onto a 0.45 micron membrane and then transfered onto a glass slide. X-ray Diffraction scans were collected on the slide four times: air-dried, ethylene glycolated, heat-treated at 400°C for 30 minutes and heat-treated at 550°C for 30 minutes. X-ray diffraction scans were collected on a PANalytical X’Pert Pro MPD diffractometer with Bragg Bertano optics using copper radiation. The samples were scanned using the following set up: PANalytical “X’Pert Pro – MPD X-ray Diffractometer; Theta/Theta geometry; Cu long-fine-focus X-ray tube (Ni filtered); “X’celerator” solid state “strip” detector; instrument conditions are 45 kV, 40 mA; 15 mm beam mask; ½° anti-scatter slit; ¼° divergence slit; ½° receiving anti-scatter slit; ¼° receiving divergence slit; step size 0.0167 degrees in continuous scan mode; scan range of 2 to 35 degrees two-theta; sample spinner off; scan rate was 1 degree per minute. Identification of mineral phases was performed using Material Data Inc. (MDI) Jade 2010 search-match software using the ICDD’s “2018 PDF-4” and National Institute Standards and Technology “FIZ/NIST Inorganic ICSD” databases. References: Powder Diffraction File, PDF-4+ 2010; Kabekkodu, S., Ed.; JCPDS-International Centre for Diffraction Data: Newtown Square, PA, 2010. FIZ/NIST Inorganic Crystal Structure Database, ICSD, NIST Standard Reference Database Number 84, National Institute of Standards and Technology, Gaithersburg, MD 20899, produced cooperatively with Fachinformationszentrum Karlsruhe, Germany 2018 Geographic Names Index System (GNIS) placenames Vector Entity point 36 0.000001 0.000001 Decimal degrees North_American_Datum_1983 GRS_1980 6378137.0 298.257222101 Hinkley_XRD_Clay_Scans.csv This is a CSV file containing X-ray diffraction scan results for clay mineralogy. U.S. Geological Survey Sample_Control_No Denver Federal Center Sample Control Number U.S. Geological Survey Unique identifier assigned to sample for laboratory analysis. Field_Name Hinkley Field Collection Number U.S. Geological Survey Unique identifier assigned to sample at the time of collection in the field. Depth_feet_top depth below surface in feet U.S. Geological Survey 72 166 feet Depth_Feet_bottom depth below surface in feet U.S. Geological Survey 77 173 feet Sample_Description Description of sample U.S. Geological Survey Sample description, whole rock Counts_at_X_Degrees_Two_theta_Detector Counts at X degrees U.S. Geological Survey Single description representing many fields of counts at X degrees, where X increases from 2 to 35 by 0.0167 degree increments. The data dictionary file, DataDictionary_XRD_Clay_Scans.csv, describes the content of the data file, Hinkley_XRD_Clay_Scans.csv https://www.sciencebase.gov/catalog/item/5ba17894e4b08583a5c42e4f U.S. Geological Survey - ScienceBase mailing and physical

Denver Federal Center, Building 810, Mail Stop 302

Denver CO 80225 USA 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. Digital Data, ZIP, TIFF, PDF, SHP none https://doi.org/10.5066/P9HUPMG0 None 20200929 Michaela R. Johnson U.S. Geological Survey Research Geologist mailing address

Mail Stop 964, W 6th Ave Kipling St

Lakewood CO 80225 United States 303-236-2464 303-236-3200 mrjohns@usgs.gov Content Standard for Digital Geospatial Metadata FGDC-STD-001-1998