Open-File Report 2011–1207
IntroductionThere is increased concern about the future availability of rare earth elements (REE) because of China's dominance as the supplier of more than 95 percent of world REE output, their decision to restrict exports of rare earth products, and the rapid increase in world-wide consumption of rare earth product. As a result, countries such as the United States, Japan, and member nations of the European Union face a future of tight supplies and high prices for rare earth products unless other sources of REE are found and developed (Long and others, 2010; U.S. Geological Survey, 2011, p. 128–129, 184–185). We report and describe a significant new deposit of light rare earth elements (LREE), estimated at 1 Mt, within the Khanneshin carbonatite complex of south Afghanistan. The potential resource is located in a remote and rugged part of the igneous complex in a region previously identified by Soviet geologists in the 1970s. This report reviews the geologic setting of LREE deposit, presents new geochemical data documenting the grade of LREE mineralization, briefly describes the mineralogy and mineralogical associations of the deposit, and presents a preliminary estimate of LREE resources based on our current understanding of the geology. |
Posted September 14, 2011
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Tucker, R.D., Belkin, H.E., Schulz, K.J., Peters, S.G., and Buttleman, K.P., 2011, Rare earth element mineralogy, geochemistry, and preliminary resource assessment of the Khanneshin carbonatite complex, Helmand Province, Afghanistan: U.S. Geological Survey Open-File Report 2011–1207, 50 p., available only at https://pubs.usgs.gov/of/2011/1207/.
Abstract
Introduction
Geology of the Khanneshin Carbonatite Complex
Geologic Setting
Geology
Rocks of the Central Vent
Volcanic and Volcano-Sedimentary rocks
Satellite Vents, Dikes, and Minor Intrusive Rocks
History of Igneous Activity
Metallogeny
The Zone of LREE Enrichment
Styles of LREE Mineralization
Whole-Rock Geochemistry
Mineralogy
Structural Control on Alkaline Igneous Magmatism and LREE Mineralization
Estimation of LREE Resources
Analysis of the Soviet-Defined Zone
Analysis by Remote Sensing
Conclusions
References Cited