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.
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
Central Mineral and Environmental Resources Science Center