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Overview

Examples of late-stage, ore-grade rare earth element mineralization.
Two examples of late-stage, ore-grade rare earth element (REE) mineralization, Elk Creek carbonatite, NE. Secondary electron microscope (SEM) backscatter images displaying (A) fine-grained, intergrown lathes of parisite and synchysite filling a void in dolomitic carbonatite, and (B) fine-grained crystals of monazite filling a void in dolomitic carbonatite. Ln in mineral formula designates lanthanide elements (REEs). Images from the USGS Denver Microbeam Laboratory.

The project's objective is to better understand the role fluids play in the formation of ore-grade rare earth element enrichment. In many rare earth element deposits, enrichment of rare earth elements is largely controlled by their transport in fluids (orthomagmatic, hydrothermal, groundwater). The processes controlling the fate and transport of rare earth elements in fluids is poorly understood because a complex set of variables affect rare earth element solubility including solution chemistry, pH, redox conditions, solid phase mineralogy and composition, temperature, and pressure. Rare earth elements may not behave uniformly as light and heavy (atomic number) rare earth elements can fractionate in aqueous systems. Understanding the fundamental processes that control the fate and transport of rare earth elements can help guide exploration for key lanthanides (chemical elements with atomic numbers 57 - 71).

The project focuses on carbonatite-related deposits because these deposits are the world's primary source of light rare earth elements: lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Ne), samarium (Sm), and europium (Eu), and also the transition metal niobium (Nb). Carbonatities have been mined for phosphates, fluorine (F), copper (Cu), vanadium (V), titanium (Ti), and tantalum (Ta) and are potential sources of other critical elements: thorium (Th), yttrium (Y), and other rare earth elements. Carbonatite-related deposits include multiple styles of mineralization, allowing for comparison of ore-grade enrichment styles and the evaluation of the role of fluids in rare earth element deposit formation.

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Collaborators

  • University of Colorado, G. Lang Farmer (isotope geochemistry)
  • University of Nebraska, Richard M. Kettler
  • University of Science and Technology Beijing, Yuling Xie
  • Anthony Mariano, Rare Earth Element Consultant

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Products

Abstracts

Blessington, M.J., Kettler, R.M., Verplanck, P.L., and Farmer, G.L., 2013, Niobium Mineralization in a Magnetite-rich Carbonatite, Elk Creek, Nebraska (USA): Mineralogical Magazine, 77(5), p. 718. doi: 10.1180/minmag.2013.077.5.2

Verplanck, P.L., 2013, Rare earth element fate and transport in fluids: insight into ore-grade enrichment: Geological Society of America Abstracts with Programs, v. 15, no. 7, p. 848.

Verplanck, P.L., Blessington, M.J., Kettler, R.M., Farmer, G.L., and Lowers, H.A., 2014, Rare earth element and niobium mineralization in the Elk Creek Carbonatite, S.E. Nebraska: Critical Minerals 2014: Rare earths and beyond, Denver, Colorado, USA, August 3-5, 2014.

Verplanck, P.L., Farmer, G.L., Blessington, M.J., and Kettler, R.M., 2014, Rare earth element variations in the Elk Creek Carbonatite, S.E. Nebraska: Geological Society of America Abstracts with Programs, v. 46, no. 4, p. 21.

Verplanck, P.L., Farmer, G.L., Kettler, R.M., Joeckel, R.M., and Drenth, B.J., 2013, Overview of the Elk Creek carbonatite, southeastern Nebraska, USA: Geological Society of America Abstracts with Programs, v. 45, no. 5. p. 41.

Verplanck, P.L., Farmer, G.L., Kettler, R.M., Lowers, H.A., Koenig, A.E., and Blessington, M.J., 2014, Rare earth element enrichments in the Elk Creek Carbonatite, Nebraska, USA: Acta Geologica Sinca, 88, p. 466-467. doi: 10.1111/1755-6724.12373_25

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Project Contact

Philip Verplanck
Phone: 303-236-1902
Email: plv@usgs.gov
Central Mineral and Environmental Resources Science Center

Mineral Resources Program Science Priority

The use of firm, trade, and brand names is for identification purposes only and does not constitute endorsement by the U.S. government.

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