Research Training Program

Smithsonian Institution
National Museum of Natural History

PROJECT SUMMARY
1996

Jennifer M. Weant
North Carolina State University
Ralieigh, North Carolina
Michael Wise, Ph. D.
Supervising Scientist
Department of Mineral Sciences
"This opportunity has been the culmination of my education. I will carry with me all that I learned here. "

Regional Geological and Geochemical Distribution of United States Pegmatite Localities

ABSTRACT
Pegmatites are very coarse grained igneous rocks that generally occur as tabular, lens-shaped or turnip-shaped bodies in igneous and metamorphic rocks. Pegmatites have been found to occur in gabbros, granites, gneisses, schists, syenites, nepheline-syenites, diorites, and ultramafic rocks. Pegmatites have been the object of study over the past century because of their high concentration of rare-element bearing minerals that are potentially good sources of: lithium, beryllium, tantalum, uranium, cesiurn, and tin. Pegmatites have also been mined for optical quartz, fluorite, ceramic and dental feldspar, mica, and ceramic amblygonite. Previous classifications of pegmatites, along with their mineralogy, geographical location, tectonic environment, metamorphic grade of the pegmatites, and the type of host rock were put into a database. This database includes only pegmatite localities in the United States. The database was then sorted and a map was created showing different pegmatite classifications and mineralogies relative to a geologic map. From this map, pegmatites were correlated to their respective regional environments. LCT family pegmatite fields are concentrated along mountain zones, NYF pegmatite fields are concentrated mainly in the Cordilleras, and muscovite class pegmatite fields are exposed primarily in the southeastern United States.

This research was supported by a grant from the National Science Foundation Research Experiences for Undergraduates program, Award Number DBI-9531331.

Letter of Gratitude