HR: 1340h
AN: V43B-1570    [Abstracts]
TI: Acid Mine Drainage and Metal Sulfate Minerals in the Shasta Mining District, California
AU: * Livingston, J D
EM: jdlivingston@snowcrest.net
AF: College of Natural Sciences, California State University, Chico, CA 95929 United States
AU: Murphy, W M
EM: wmurphy@csuchico.edu
AF: College of Natural Sciences, California State University, Chico, CA 95929 United States
AU: Miller, R M
EM: rmmiller@csuchico.edu
AF: College of Natural Sciences, California State University, Chico, CA 95929 United States
AU: Ayars, E J
EM: eayars@csuchico.edu
AF: College of Natural Sciences, California State University, Chico, CA 95929 United States
AB: Metal sulfate minerals were collected at four surface water drainage sites during September and October of 2004 in the Shasta Mining District, southern Klamath Mountains, Shasta County, California and analyzed by X-ray fluorescence, atomic absorption spectroscopy, and X-ray diffraction to determine elements present, quantities of Fe, Cu, and Zn, and mineralogy. The Shasta Mining District produced major quantities of Cu, Zn, and pyrite (S) with minor amounts of Au, Ag, and Fe from massive sulfide bodies (Kinkel et al., 1956). Three study sites are located on Iron Mountain and one study site is at Bully Hill. Although mining occurred during a period of just over 100 years, it is estimated that acid mine drainage (AMD) will continue from Iron Mountain for over 3,200 years (Nordstrom and Alpers, 1998). AMD at the study sites produces blooms of metal sulfates during California's Mediterranean climate summer. The minerals readily dissolve in the "first flush" of seasonal rain creating runoff water of low pH with high amounts of dissolved metals (Bayless and Olyphant, 1993; Jambor et al., 2000). Data were examined for mineralogical changes in time and space and for zoning of minerals on a scale of centimeters. Sulfate mineral samples are complex with some samples composed of over a dozen different minerals. Site 1 is located on Spring Creek downstream from the Iron Mountain superfund remediation site, so levels of Fe, Cu, and Zn in the sulfates at this site are lower than at the other sites. Two site 1 samples from the same location taken a month apart show Ca, Fe, Cu, Sr, Y, and Sn, and the first sample also has detectable Br. The metal sulfates identified from the first visit are celestine, cesanite, chessexite, hectorfloresite, and ungemachite, and the mineralogy of the second visit is bilinite, epsomite, millosevichite, and anhydrite. The Fe bearing sulfate mineral during the first visit is ungemachite, but bilinite was the Fe bearing mineral at the time of the second visit. Analyses indicate a dynamic evolution of sulfate minerals at individual locations over time, mineralogical and chemical differences among individual locations at a site, and mineralogical zonations in individual samples.
DE: 1039 Alteration and weathering processes (3617)
DE: 1042 Mineral and crystal chemistry (3620)
DE: 1090 Field relationships (3690, 8486)
DE: 3665 Mineral occurrences and deposits
SC: Volcanology, Geochemistry, Petrology [V]
MN: Fall Meeting 2005