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Chemical alteration index values and rare earth element data and expected ranges for regolith overlying the Stewartsville pluton, Virginia


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Foley, N.K., 2020, Chemical alteration index values and rare earth element data and expected ranges for regolith overlying the Stewartsville pluton, Virginia: U.S. Geological Survey data release,


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 [...]


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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.



  • Geology, Energy & Minerals (GEM) Science Center
  • USGS Data Release Products



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DOI doi:10.5066/P9MJRRP4

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