Issue: This research proposes to investigate the geochemical and mineralogical distribution of Rare Earth Elements (REE) in magmatic-hydrothermal alteration systems in which quartz-alunite alteration is often associated with productive gold-silver-mercury mineralization. Processes that lead to transport and concentration of REE in high sulfidation systems will be studied in order to assess the potential for unconventional REE resources in quartz-alunite alteration associated with both mineralized and unmineralized hydrothermal systems. The research will focus on high-sulfidation gold-silver-mercury deposits that have previously been well documented for other elements, but not REE. Deposits to be studied include high-sulfidation gold-silver-mercury deposits in Nevada, including Paradise Peak and Goldfield, and the McDermitt mercury deposit.
Objectives: Quartz-alunite alteration from well-studied high sulfidation gold-silver-mercury deposits will be chemically analyzed for REE. Samples containing high concentrations of REE will be studied to determine the mineralogy and residence of the REE. Standard mineralogic studies (SEM and microprobe) will be complemented with X-ray absorption spectroscopy at the Stanford Synchrotron to determine the chemical speciation of the REE.
Relevance: Sources of REE are a major concern because China, which accounts for at least 90% of the world’s supply, has imposed export restrictions resulting in price distortions and disruptions in the supply of these critical elements. President Obama stated that “American manufacturers need to have access to REE …so that our companies can build products right here in America”. Developing additional resources of REE in the U.S. is clearly important and challenging since viable economic concentrations of REE are uncommon and extraction methods can present environmental problems. Identifying new potential resources of REE and characterizing the mineral residence of the REE in these resources contributes to addressing this national problem.
Geology, Minerals, Energy, and Geophysics Science Center