Origin and Migration of Sulfur in Active Geothermal         Systems: A Sulfur Isotopic Study Using the SHRIMP Ion Micro-probe
{'Code': '06030103', 'Directorate': {'Abbreviation': 'GEO', 'LongName': 'Directorate For Geosciences'}, 'Division': {'Abbreviation': 'EAR', 'LongName': 'Division Of Earth Sciences'}}
{'SignBlockName': 'Thomas O. Wright', 'PO_EMAI': None, 'PO_PHON': None}
Microbean techniques of stable isotope analysis offer great                insight into petrogenetic processes because minerals contain more               information concerning their origins and subsequent modifications               than can easily be obtained by conventional isotopic sampling and               analytical techniques.  S isotope studies with SHRIMP ion probe                 have revealed dramatic  34S variations within and among minerals                in the Salton Sea geothermal system, identifying sulfides.  The                 isotopic equilibration of sedimentary sulfide and sulfate                       minerals during prograde metamorphism, and the extent of                        recycling of sedimentary S by sulfur poor hydrothermal fluids                   will be examined.  From determinations of  34S for aqueous S                    species the degree of isotopic equilibrium attained between H2S                 and SO4 in saline hydrothermal fluids and the relative                          contributions of H2S to hydrothermal fluids from igneous                        processes and hydrothermal reduction of host rocks evaporites                   will be evaluated.                                                                   It is proposed to extend our studies of S isotope                          systematics to active silicic volcanic-hosted continental                       geothermal systems, making use of new drill cores and fluid                     samples from the Valles Caldera and Coso geothermal systems.  The               proposed study complements our research that are transporting                   precious as well as base metals.  We will continue to use the                   unsurpassed 30 um spatial resolution of the SHRIMP ion microprobe               for studying microscopic   34S variations within and among                      minerals.  Conventional techniques to determine  34S of H2S and                 SO4 in coeval geothermal fluids and to characterize the bulk S                  isotope composition of minerals will be used.  Study of                         microscopic  34S zoning patterns in vein minerals will help                     constrain mechanisms of ore precipitation.  Elucidation of the                  distribution of S isotope geochemistry of sulfur sources in host-               rocks and the degrees of isotopic equilibrium reached between                   minerals and aqueous species at hydrothermal temperatures will                  allow more accurate modeling of metal transport and deposition in               volcanic-hosted hydrothermal systems.
{'FirstName': 'Michael', 'LastName': 'McKibben', 'PI_MID_INIT': 'A', 'PI_SUFX_NAME': None, 'PI_FULL_NAME': 'Michael A McKibben', 'EmailAddress': 'michael.mckibben@ucr.edu', 'NSF_ID': '000468578', 'StartDate': '01/01/1989', 'EndDate': None, 'RoleCode': 'Principal Investigator'}
{'Name': 'University of California-Riverside', 'CityName': 'RIVERSIDE', 'ZipCode': '925210001', 'PhoneNumber': '9518275535', 'StreetAddress': '200 UNIVERSTY OFC BUILDING', 'StreetAddress2': None, 'CountryName': 'United States', 'StateName': 'California', 'StateCode': 'CA', 'CONGRESSDISTRICT': '39', 'CONGRESS_DISTRICT_ORG': 'CA39', 'ORG_UEI_NUM': 'MR5QC5FCAVH5', 'ORG_LGL_BUS_NAME': 'REGENTS OF THE UNIVERSITY OF CALIFORNIA AT RIVERSIDE', 'ORG_PRNT_UEI_NUM': None}
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[{'Code': '157200', 'Text': 'Tectonics'}, {'Code': '912000', 'Text': 'CROSS-DIRECTORATE PROGRAMS'}]
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