CHARACTERIZATION OF A ULTRA HIGH PURITY QUARTZ DEPOSIT, SPRUCE PINE MINING DISTRICT, NORTH CAROLINA

SUSINA, Dana L., Department of Geology, University of Georgia, 210 Field Street, Athens, GA 30602-2501, SWANSON, Samuel E., Department of Geology, University of Georgia, Athens, GA 30602 and CHRISTIANSEN, W., U.S. Geological Survey, Box 25046, Denver Federal Center, Denver, CO 80225, dsusina@uga.edu

Granitoid rocks of the Spruce Pine plutonic suite (SPPS) in western North Carolina are the source of ultra high purity quartz. The SPPS consists of several small plutons and hundreds of dikes and sills composed of coarse-grained to pegmatitic peraluminous garnet muscovite graniodiorite.

Ultra high purity quartz is produced from some SPPS plutons, but other plutons do not produce a quartz that can be processed to a ultra high purity grade. Identification of suitable ultra high purity quartz ore is done by mining up to 100 tons of potential ore and running the quartz through the processing lines. The purpose of this study is to compare the mineralogy of granodiorite from a ultra high purity quartz mine (QM) to other bodies of granodiorite within the SPPS to determine if any mineralogic criteria characterize the granodiorite capable of producing ultra high purity quartz.

Spruce Pine granitoid rocks are coarse-grained. Large grains of feldspar, quartz and muscovites are enclosed in a fine-grained fabric forming a mortar texture. Examination of the quartz using cathode luminescence reveal a pattern of fracture-heal-fracture-heal within the quartz. Fluid inclusions are concentrated along the annealed fractures.

Major element compositions of QM minerals are similar to trends from other Spruce Pine granitoid rocks. QM muscovite has an appreciable celadonite component with a mg# of 30-40 and plots in the center of the compositional field for Spruce Pine muscovite. Garnet is mostly almandine-spessertine with Mn/Mn+Fe = 0.4 to 0.5. A Ca-rich rim (up to 45 % glossular component) on some grains. Antiperthitic plagioclase is a sodic oligoclase and perthitic K-feldspar contains a few mole percent albite component, similar to other Spruce Pine . Oxygen isotope compositions of quartz from QM (δ ¹⁸O = 11.1 to 11.6) are within the range of values for quartz from other Spruce granodiorites (δ ¹⁸O = 11.2 to 12.0). None of the mineralogic criteria we measured distinguish the QM rocks from other Spruce Pine granitoid rocks and thus do not offer a guide to exploration.

Session No. 132

T35. Critical Metals (REE, In, Te, Nb, Ta, Ga, Li, etc.) for the New Energy Future

Monday, 1 November 2010: 1:30 PM-5:30 PM

Room 601 (Colorado Convention Center)

Geological Society of America Abstracts with Programs. Vol. 42, No. 5, p.335

© Copyright 2010 The Geological Society of America (GSA), all rights reserved. Permission is hereby granted to the author(s) of this abstract to reproduce and distribute it freely, for noncommercial purposes. Permission is hereby granted to any individual scientist to download a single copy of this electronic file and reproduce up to 20 paper copies for noncommercial purposes advancing science and education, including classroom use, providing all reproductions include the complete content shown here, including the author information. All other forms of reproduction and/or transmittal are prohibited without written permission from GSA Copyright Permissions.

Back to: T35. Critical Metals (REE, In, Te, Nb, Ta, Ga, Li, etc.) for the New Energy Future

<< Previous Abstract | Next Abstract >>