Crustal Imaging and Characterization Team
Task Contact: Randolph Koski | Pat Shanks
Our objective in this task is to demonstrate the usefulness and application of our experimental results in studies of real-world situations involving mineral-environmental issues. This task will focus on sulfide oxidation, acid mine drainage, and metal fluxes in geologically and climatically diverse natural settings.
Studies will be carried out in transitional marine settings, in acid mine drainage systems, and in pit lakes. Overall objectives are to relate our experimental results to real natural setting.
Work will focus on analysis and publication of data from Prince William Sound (PWS), Alaska, including the role of microbes and macrofauna in metal distribution within the intertidal and offshore zones. Analyses and intrepretation of chemical, isotopic, mineralogical, and DNA data for microbe, macrofauna, sulfide, sediment, precipitate, seawater, ground water, and pore water samples from Prince William Sound will be completed and submitted for publication. Studies of sulfide alteration will be conducted by reflected light microscopy, scanning electron microscopy, and laser ablation techniques. Chemical and mineralogical data and field observations will be compiled and synthesized; a generalized process model for metal flux in the Ellamar intertidal zone will be developed. A manuscript for publication as a journal article describing results from the Ellamar site investigation will be prepared.
Combined onshore and offshore field studies in coastal areas of eastern Prince William Sound during June, 2003 and 2005, investigated the distribution and oxidation characteristics of sulfide-rich rock debris related to early 20th century mining activity.
These are the first study of the environmental effects of oxidizing sulfides within intertidal environments of Prince William Sound. Our findings indicate that acidic water laden with potentially toxic metals are generated intertidal sulfide waste during tidal cycles. The acidic fluids are enriched in numerous metals including Fe, Al, Ba, Tl, Ag, Cd, Co, Ni, Mn, Mn, Pb, Zn, and Hg. The apparent extent of these acid waters and flux of metals is surprising given the buffering capacity of seawater. Elevated Hg in interstitial waters of the intertidal zone is also unexpected in that the massive-sulfide deposits have no known mercury minerals. Precipitates formed from these acidic fluids are enriched in a similar suite of metals plus As and W. Together, these sites represent an opportunity to learn more about sulfide oxidation, fluid flow, and contaminant distribution in this dynamic marine environment. The results have implications for past and future mining activities along coastal zones of the Pacific Northwest and the disposal of mine tailings in shallow marine settings.
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Mineral Resources |
Eastern / Central / Western / Alaska / Minerals Information |
| Crustal Imaging & Characterization / Spatial Data |
U.S. Department of the Interior |
U.S. Geological Survey
URL: http://crustal.usgs.gov
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