Foley, Nora K. 20200708 Alpha-numeric and numeric, cvs, spreadsheet Reston. VA U.S. Geological Survey https://doi.org/10.5066/P9MJRRP4 This dataset contains whole major element geochemical data used to calculate values of the chemical alteration index (CIA), data for Nd, Sm, Y, and total REE and expected ranges for total REEY for samples of regolith overlying the Stewartsville pluton, Virginia. The southeastern United States was first identified as prospective for regolith-hosted REE deposits based on the recognition that the region has been subjected to a long history of intense differential chemical weathering and saprolitization, comparable to that which formed the REE clay deposits of South China and Southeast Asia since the break-up of Pangea (Foley and Ayuso, 2013). Foley et al. (2014) established that due to their inherent high concentrations of REE, anorogenic (A-type) and highly fractionated igneous (I-type) granitic rocks of southeastern United States were highly prospective source rocks for deposits of this type. More recently, additional studies investigated accumulation processes resulting in high concentrations of REE in granite-derived regolith deposits related to the Stewartsville pluton and other plutons in Virginia. The Stewartsville pluton was emplaced along the flank of the Blue Ridge province during regional crustal extension related to the opening of the Iapetus Ocean and breakup of the supercontinent Rodinia. The studied rock samples consist of medium- to coarse-grained biotite granite and are mineralogically complex. They contain phenocrysts of quartz, sericitized and albitized k-feldspar, sodic plagioclase, and mafic clots and stringers that are composed primarily of biotite and stilpnomelane and, less typically, include magnetite and remnant cores of green and green-brown hornblende. Feldspar contains inclusions of synchysite and fergusonite; other accessory minerals include abundant and diagnostic allanite and fluorite, as well as apatite, epidote, garnet, Nb-rutile, fergusonite, monazite, titanite, xenotime, gadolinite, and zircon (Foley and Ayuso, 2015 and references therein). Granite outcrop exposures in the Piedmont and Blue Ridge areas of Virginia tend to be intensely weathered, with overlying regoliths ranging from thin and discontinuous to meters thick and laterally extensive, and often with overlying B-horizon type soils. Saprolite can extend down to depths of tens of meters below the B-horizon. In the case of the Stewartsville Pluton, regolith is well developed in multiple exposures. The sampled section described in this data release is >20 meters high by >60 meters long. The profile includes nearly fresh rock, partially to highly weathered saprolite, indurated gravels and sands, and poorly delineated layers of subsoil and topsoil. Granite at the base of the profile is iron stained (mostly goethite) and weathered on exposed surfaces and along cracks. Partially weathered sections of the outcrop display a range of rock textures throughout, rather than systematic changes from base to surface. For example, in the lower parts, cobble and boulder-sized relics of spheroidally weathered granite knobs retain distinctive primary textures but are surrounded by nearly disaggregated granite that crumbles to sand and gravel-sized fragments when sampled. Subsoils, mainly B-horizon, comprise the uppermost meter of the section and contain a higher proportion of clay minerals (i.e. kaolinite-nontronite-iron-oxide mixtures) than the underlying saprolite. The data were obtained in support of studies aimed at assessing prospective granite-derived regolith in the southeastern United States for the potential for rare earth element resources, such as the regolith-related REE, or REE-ion adsorption clay type deposits. Regolith-hosted REE deposits, also known as “ion-adsorption” clay-hosted REE deposits are currently mined only in South China. This deposit type supplies virtually all heavy (Gd-Lu) REE and a significant portion of light (La-Eu) REE to global markets (Foley and Ayuso, 2015); thus, discoveries of highly prospective US domestic resources of this type are of great societal value. Associated references: Foley, N.K., and Ayuso, R.A., 2013, REE mobility in high-alumina altered metavolcanic deposits, South Carolina, USA. Journal of Geochemical Exploration, 133, 50-67. Foley, N.K., Ayuso, R.A., Bern, C.R., Hubbard, B.E., Vazquez, J.A., 2014, REE Distribution and Mobility in Regolith formed on Granite Bedrock of the Southeast United States: Acta Geologica Sinica (English Edition), vol. 88, suppl. 2; 14th Quadrennial International Association on the Genesis of Ore Deposits Symposium, Mineral Resources: Discovery and Utilization, Kunming, China, p. 428-431. Foley, N.K., Ayuso, R.A., 2015, REE enrichment in granite-derived regolith deposits of the Southeastern United States: Prospective source rocks and accumulation processes. In: Simandl, G.J., Neetz, M. (Eds.), Symposium on Strategic and Critical Materials Proceedings, British Columbia Geological Survey Paper 2015-3, p. 131-138. Foley, N.K., Ayuso, R.A., Hubbard, B., Bern, C., Shah, A., 2015, Geochemical, remote sensing, geophysical, and mineralogical characteristics of REE in granite-derived regolith of the southeastern United States: 13th Biennial Meeting, Proceedings of the Society for Geology Applied to Mineral Deposits, v. 2, p. 725-730. The approximate latitude-longitude locational point of the studied profile is: 37.226275, -79.814755. Last character in the Sample_number denotes additional information: C = core; R = rim; and f = split having less than 1 millimeter grain size. CIA were calculated following standard methods: Nesbitt, H.W., Young, G.M., 1982, Early Proterozoic climates and plate motions inferred from major element chemistry of lutites: Nature 299, 715-717. Nesbitt, H.W., Young, G.M., 1989, Formation and diagenesis of weathering profiles: J. Geol. 97, 129–147. 2013 2016 ground condition In work As needed -79.854125976991 -79.656372070749 37.249659241474 37.157778930065 USGS Thesaurus regolith geochemistry mineral resources USGS Metadata Identifier USGS:5ea0629d82cefae35a129d78 Geographic Names Information System (GNIS) Virginia Southeastern United States Appalachian Federal Geographic Data Committee pluton regolith pluton USGS Thesaurus: Time Periods Neoproterozoic Recent none none Nora K Foley NORTHEAST REGION: EASTERN MINERAL & ENVIRON RES SC Research Geologist Mailing and Physical

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Reston VA 20192 US 703-648-6179 nfoley@usgs.gov No formal attribute accuracy tests were conducted No formal logical accuracy tests were conducted Data set 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. No formal positional accuracy tests were conducted No formal positional accuracy tests were conducted Samples collected. Splits prepared. Splits sent to Actlabs, Ancaster, Canada, for analysis of major and trace elements by total digestion methods. Data reviewed for completeness. Chemical Index of Alteration values calculated from major element oxide data. 2016 Nora K Foley NORTHEAST REGION: EASTERN MINERAL & ENVIRON RES SC Research Geologist Mailing and Physical

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Reston VA 20192 US 703-648-6179 nfoley@usgs.gov Geographic Names Information System (GNIS) placenames Point Chemical alteration index values, rare earth element, major element, and yttrium data for a profile of a regolith overlying the Stewartsville pluton, Virginia Chemical alteration index values, rare earth element, major element, and yttrium data for a profile of a regolith overlying the Stewartsville pluton, Virginia Author-conceived Sample_number A unique alphanumeric identifier Producer-defined A unique alphanumeric identifier Material_sampled A general descriptor of the type of material sampled Producer defined knob A partially weathered granite boulder having a competent core and weathered rim Producer-defined regolith A layer of loose in-situ material covering the bedrock comprising soil, sand, and partially altered rock Producer-defined rock Denotes underlying plutonic bedrock Producer-defined Latitude Locational data of sample, the value of latitude Producer-defined 37.226275 37.226275 degrees Longitude Locational data of sample, the value of longitude Producer-defined -79.814755 -79.814755 degrees Pos_rel The relative position of the sample in the studied profile from base to uppermost soil layer Producer defined 5 85 percent Al2O3 The measured value of aluminum oxide in the sample Producer_defined 11.06 13.16 percent CaO The measured value of calcium oxide in the sample Producer_defined 0.15 1.13 percent Na2O The measured value of sodium oxide in the sample Producer_defined 0.6 2.48 percent K2O The measured value of potassium oxide in the sample Producer_defined 5.15 6.5 percent Nd The measured value of neodymium in the sample Producer_defined 51 831 parts per million Sm The measured value of samarium in the sample Producer_defined 12.8 202 parts per million Y The measured value of yttrium in the sample Producer_defined 60 728 parts per million TREE A calculated value for the total concentration of rare earth elements in the sample Producer_defined 308.54 2879.81 parts per million CIA_calc Calculated value of the Chemical Index of Alteration Producer_defined 56.75 63.16 REEY_range_max A maximum value for estimated range of the total concentration of rare earth elements and yttrium in the sample Producer_defined 370 3600 parts per million REEY_range_min A minimum value for estimated range of the total concentration of rare earth elements and yttrium in the sample Producer defined 300 2880 parts per million Nora K Foley NORTHEAST REGION: EASTERN MINERAL & ENVIRON RES SC Research Geologist Mailing and Physical

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Reston VA 20192 US 703-648-6179 nfoley@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. No 20200819 Nora K Foley NORTHEAST REGION: EASTERN MINERAL & ENVIRON RES SC Research Geologist Mailing and Physical

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Reston VA 20192 US 703-648-6179 nfoley@usgs.gov Content Standard for Digital Geospatial Metadata FGDC-STD-001-1998