2000 GSA Annual Meeting -- Reno, Nevada
2000 GSA Annual Meeting -- Reno, Nevada
Author(s): BRIGGS, Paul H. and TUTTLE, Michele L., U.S. Geological Survey, P.O. Box 25046, MS 973, Denver, CO 80225, pbriggs@usgs.gov
Keywords: sulfur species, sulfur isotopes
Colorado and New Mexico historic mine-waste piles represent variations in mineral deposit types, climate zones, and sulfur phases. Epithermal, polymetallic deposits were sampled in the Silverton District, Colorado (moderate-subpolar climate) and Steeple Rock District, New Mexico (arid climate). Polymetallic vein and replacement deposits were sampled from the Leadville District, Colorado (moderate-subpolar climate) and the Hillsboro District, New Mexico (arid climate). The sequentially extracted sulfur phases included elemental sulfur, water-soluble sulfate salts, acid-soluble sulfate minerals, monosulfide minerals, and disulfide minerals. X-ray diffraction analysis of the mine-waste samples confirms presence of secondary sulfate minerals such as jarosite, plumbojarosite, and gypsum and primary sulfide minerals such as galena, sphalerite and pyrite. Total sulfur concentrations (0.02-5.8 wt.%) in nine mine-waste piles were determined independently from the separation sequence. The proportion of the sulfur in each phase varies from 0-12% elemental sulfur, 2-17% water-soluble sulfate salts, 9-70% acid-soluble sulfate minerals, 0-7% monosulfide minerals, and 18-85% disulfide minerals. Sulfur isotopes of the separated forms monitored the extraction process and may be useful for predicting weathering sequences at specific mine-waste sites. There is good agreement (90-100% recoveries) between the sum of the forms of sulfur and the total sulfur, implying that the analytical scheme recovers all the sulfur. Distinct differences in sulfur phases were observed among the deposit types and climates.
© Copyright 2000 The Geological Society of America. All rights reserved.