Lisa M. Pratt - US grants

Early diagenetic repartitioning of carbon, sulfur, iron, and manganese in poorly oxygenated to anoxic marine deposits will be studied using new geochemical and stable isotopic data on the Miocene Monterey Formation and the mid-Cretaceous Greenhorn Formation. Our objectives will be 1) to interpret interrela- tionships in the Corg-S-Fe-Mn system in terms of depositional and early diagenetic conditions and 2) to reconstruct the pathways for transfer of sulfur from dissolved and solid inorganic-sulfur species to organic-sulfur compounds in bitumen and kerogen. Organic and inorganic sulfur species will be isolated using a step-wise procedure that will yield seven sulfur fractions (sulphate, elemental, bitumen, acid-volatile, disulfide, barite, and kerogen). Depth and timing of pyrite formation relative to incorporation of sulfur into organic matter will be inferred from the isotopic compositions of the various sulfur fractions in conjunction with the distribution of iron and manganese. The Monterey and Greenhorn both contain interbedded laminated and bioturbated lithofacies that will enable us to sample a wide range of paleoenvironmental and early diagenetic settings. Integration of organic and inorganic sulfur data with manganese and iron data will provide a new basis for interpreting ancient poorly oxygenated to anoxic basins. The geological units selected for this study will permit comparison of sedimentary strata in modern and Miocene coastal upwellings and in modern oceanic and Cretaceous epicontinental settings.

Technical Narrative: This U.S.-Nigeria collaborative research project involving Indiana University and the University of Ibadan, Ibadan, Nigeria is in the area of geochemical and stable isotopic studies of mid- Cretaceous black shales. Project funding will allow a highly qualified researcher from Nigeria to spend an extended period of time in the laboratory of Dr. Lisa M. Pratt at Indiana University. The collaborative research will investigate mid- Cretaceous black shales from the Benue trough in southeastern Nigeria. One of the projected outcomes of the study will be a strategic framework for the Nigerian black shales that can be correlated with standard North American and European stages. This project in geochemistry fulfills the program objective of advancing scientific knowledge by enabling leading experts in the United States and Nigeria to combine complementary talents and pool research resources in areas of strong mutual interest and competence.

9304659 Pratt PIs will develop a high-resolution stratigraphic and geochemical framework for the Lower and middle Cretaceous in northern South America, with focus on the Cenomanian-Turonian boundary interval. These data are needed to establish a regional picture of sea level change, primary marine production, and biologic evolution in the Caribbean gateway between the Pacific and the developing Atlantic oceans. Isotopic and geochemical data will be used to calculate the total quantity of marine organic carbon preserved on this margin, making it possible to assess the degree to which the equatorial region influenced global concentrations of carbon dioxide and oxygen in the Cretaceous atmosphere.

9313546 Hayes This award will allow the University of Indiana to modernize its laboratory space that was originally built to accommodate classical rock analysis in 1962 and now must be adapted for research in isotopic biogeochemistry. New hoods and lob benches will be installed, a computer and data facility will be established, and a core-storage and layout room provided with this renovation project. The biogeochemistry labs at the University of Indiana are used by four senior faculty and serve as an important training center for individuals establishing biogeochemistry research groups at other university locations. Through geoscience research, the focus of this lab is on the cycling of carbon in modern and ancient environments. To provide a basis for interpretation of ancient records, members of this research lab study structured fractionation of stable isotopes in modern environments and microbial cultures, the stabilization of sedimentary chemical systems in contemporary settings, and the distribution and abundance's of molecular structures in modern organisms. The origin and development of fossil fuels, the geochemistry of sedimentary carbon, and the development of instrumentation and techniques for both the analysis of stable isotopes in traces of organic material and organic molecules are additional research themes. The modernization of this laboratory is very important for the training of the next generation of biogeochemists, low-temperature geochemists, and geochemically-oriented geobiologists and sedimentologists who will give us new knowledge about global change issues. ***

Analyses of light stable isotopes in bulk organic matter and major compound classes are widely used by organic geochemists to assess the origin and thermal maturity of fine-grained sedimentary rocks. In the last five years, it has become possible to determine the carbon isotopic composition of individual organic compounds using instruments with a gas chromatograph coupled to an isotope mass spectrometer. Application of isotope ratio monitoring of individual compounds (IRM/GC-MS) to a wide range of geological problems is beginning to emerge. PIs will utilize IRM/GC-MS for a direct comparison of the isotopic composition of lipid biomarkers (organic molecular fossils) between soft tissues and organic matter within mineralized tissues of bivalve shells. Both living shells and fossil shells will be surveyed. If sufficient quantities of lipids can be extracted from shells and if lipids from the shell mimic the isotopic composition of the mantle tissues, then it should be feasible to use shell lipids for studies of molecular paleontology and paleoecology.

9316279 Cobabe Bivalve shells are common fossils in near-shore marine strata from the early Paleozoic to the Recent. The diversity and abundance of bivalves makes them an important research target for molecular paleontology. Based on our preliminary research, the geologically stable and easily extracted class of compounds known as lipids offers a promising new approach to interpreting the biogeochemical record of bivalves. Recent and fossil shells contain a wide variety of mineral-associated lipids, including fatty acids, cholesterol, ketones, phytadienes, and alkanes. The shell-lipid assemblages contain compounds that are 1) present in all of the studied bivalves (recent and fossil), 2) specific to a single taxon, and 3) environmentally specific. In the cases of extraordinary fossil preservation, lipids trapped in the shell may provide a clean molecular and isotopic record of trophic strategy, biosynthetic pathway, and paleoenvironmental conditions. We propose utilizing the molecular structure and 13C content of shell lipids to determine the biogenic source of the compounds. We will then apply these compounds to studies of 1) chemosymbiosis in the fossil record and 2) the use of fatty acid saturation to assess paleotemperature.

9726264 Ripley This grant provides partial support to Indiana University for the costs of acquiring a stable isotope ratio mass spectrometer (SIRMS) with peripheral sample introduction and gas handling devices. The SIRMS will be dedicated to sulfur isotopic analyses, replacing the 19-yr. old Nuclide mass spectrometer currently operated at Indiana University. This new facility will be shared by researchers from Indiana-Bloomington, the University of Illinois at Champaign-Urbana and the University of Missouri- Columbia. State-of-the-art SIRMS allow analyses of much smaller gas samples (< 1 micromole) than currently possible on the Nuclide, thus greatly expanding the analytical possibilities for this regional group. This facility will provide data for a wide range of studies in economic geology, paleoceanography, biogeochemistry and sulfur isotope systematics. Specific studies will include sulfur isotopic investigations of the genesis of hydrothermal ore bodies within the Midcontinent Rift system, species specific sulfur isotopic analyses of organic compounds as proxies of diagenetic processes in anoxic marine sediments, characterization of the biogeochemical pathways of sulfur in Chesapeake Bay sediment pore-water systems, paleoenvironmental studies of pyrite formation in anoxic Black Sea sediments, and experimental studies of sulfur isotope fractionation in sulfosalt systems. ***

0207836
Pratt

The International Continental Scientific Drilling Program (ICDP) is funding the drilling of a 2km hole in the Chicxulub impact crater on the Yucatan Peninsula in Mexico. NSF is funding US investigators to analyze core samples from the Chicxulub Scientific Drilling Project (CSDP). The Chicxulub crater is one of the world's largest impact craters and has been linked to the mass extnction event at the Cretaceous - Tertiary boundary ~65 million years ago. As part of the CSDP Science Team, the Principal Investigators will look at the Sulfur (S) isotopic systematics of the Chicxulub impact site. They will investigate the mixing between target rocks and the bolide at the drill site. This will be an important contribution to the complete characterization of the Chicxulub drill core samples.
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0214265
Schimmelmann

This grant supports the acquisition of a gas source stable isotope ratio mass spectrometer configured for continuous flow operation (CF-irmMS) and with associated sample introduction peripherals that will allow for the analysis of multiple stable isotopic ratios in a wide range of natural materials including, organic matter, carbonates, hydrous minerals and water. Specific sample inlet devices will include an elemental analyzer (EA), a gas chromatograph (GC), and an automated carbonate preparation device. The new CF-irmMS will complement two existing stable isotope ratio mass spectrometers(both late model Finnegan MAT 252s) in the Geological Sciences department at Indiana University. One was recently funded by the EAR/IF program (NSF-9726264) to co-PI Ed Ripley and is dedicated to the analysis of the isotopic composition of sulfide ores and the other is somewhat older (vintage 1991) and is dedicated to analysis of carbonate carbon. The new instrument will greatly expand the current isotopic capabilities of this already well equipped department by adding the ability to make high precision isotopic analyses of hydrogen/deuterium (H/D) ratios in extremely small samples of organic matter and natural waters with high throughput. The requested peripheral devices will also allow for investigation of the stable isotopic signatures of individual compounds of organic materials. The instrument will support the research efforts of numerous IU faculty including Arndt Schimmelmann, Lisa Pratt, Ed Ripley, Peter Sauer and Jeff White and their students for research spanning the fields of paleoclimatology, oceanography, ecology and hydrology. The addition of a CF-irmMS to this lab will undoubtedly serve to further the attraction of this facility to a number of active geoscientists and will likely lead to future productive collaborations with these IU scientists and their students.
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0413575
Ripley


This grant will support a technical position in the Stable Isotope Research Facility (SIRF) at Indiana University over a three-year period. Duties of the research technician will include: 1) training of all users of laboratory facilities, 2) maintenance of mass spectrometers and associated gas preparation systems, 3) development of new analytical techniques, and 4) analyses of non-routine samples, especially those produced by laser ablation methods. The SIRF houses four stable isotope ratio mass spectrometers and a variety of associated on-line sample preparation devices including a laser fluorination system for sulfur isotopic analyses, high-temperature combustion furnaces and related gas chromatographic systems for carbon and hydrogen isotopic analyses, elemental analyzers for sulfur, carbon, oxygen, hydrogen, and nitrogen analyses, water-CO2 equilibration and water to hydrogen conversion devices, and an automated carbonate-CO2 preparation system. In addition to on-line peripheral systems The SIRF contains several traditional vacuum extraction systems. These include a CO2 laser fluorination system, a conventional BrF5 extraction line, SO2 lines for the preparation of large standard samples for both EA and dual inlet analyses, high- and low-temperature sequential carbon extraction lines, a system for the extraction of inclusion fluids and gases, and chromatographic systems for the isolation of various sulfur species. Technician support is essential to ensure that this lab continues as a first-rate national center for stable isotopic analyses and training. Over the past 24 months more than 30 visiting researchers have utilized the SIRF laboratory facilities. The development of new analytical techniques, particularly those aimed at reducing sample size, is critical for advancing our understanding of important earth processes. A dedicated technician provides invaluable support for faculty and student research, and plays a pivotal role in the development of analytical skills that are essential for tomorrow's researchers. The research technician in this position will also supervise part-time, project specific, laboratory technicians who are supported through individual research grants (e.g. NSF, NASA, DOE).
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This grant support acquisition of a new bench-top gas chromatograph-mass spectrometer (GC-MS) for biomarker research at Indiana University. The GC-MS will be dedicated to analyses of molecular constituents in geological samples that can provide invaluable clues to the diverse origins and varied fates of sedimentary organic matter. It will replace aged, high-maintenance GC-MS instrumentation that is at the end of its useful lifespan. Graduate and undergraduate students, and also visiting scientists, will be trained in its operation, learning how to identify organic compounds amid complex mixtures, and will use the results from their analyses in a broad spectrum of projects. Data obtained using this GC-MS instrument, coupled with information on isotopic compositions, will enhance research focused on understanding the numerous controls on molecular and isotopic compositions of earth materials. The results from such biogeochemical research will benefit understanding of the history of global climate and environmental change, the biogeochemical carbon cycle, microbial activity and the deep biosphere, and evolutionary processes.

Title: Microbial Arsenate Reduction Control on Arsenic in Groundwater
Abstract The proposed research addresses natural occurrences of elevated arsenic in aquifers, a compelling public health hazard to a large population in both the United States and areas around the world. We focus on the role of microorganisms in controlling arsenic concentrations in aquifers, particularly at low values but still above the drinking water standards. The proposed study will determine quantitatively the role of microbial arsenate reduction in the bedrock aquifer in the Southern Willamette Basin, Oregon, USA. Arsenic occurs naturally in the aquifer at concentrations as high as 2000 parts per billion (ppb). This aquifer serves as a model for studying arsenic contamination in aquifers of felsic volcanic rocks and related alluvial sediments. We will conduct field biostimulation experiments and biogeochemical reactive transport modeling to test the hypothesis that microbial arsenate reduction controls significantly arsenic attenuation and mobilization in anoxic aquifers. Results of this study will pinpoint quantitatively the significance of different microbial functional groups in regulating arsenic concentrations in the aquifer. The theoretical component of this study will advance biogeochemical reaction modeling that couples microbial metabolisms with geochemical reactions. Results of this study will also provide critical information concerning groundwater microbiology for government agencies in designing effective strategies and regulations for groundwater resource management, monitoring, and protection. We will collaborate with science instructors at high schools near the field site to develop a replicable and sustainable classroom lesson on arsenic into their science curriculum. The teaching portfolio of the arsenic lesson will be distributed to all Oregon K-12 educators to help Oregon public schools better prepared for a new requirement of a science class with laboratory experience by the Oregon State Board of Education.

The multi-collector inductively coupled plasma mass spectrometer (MC-ICP-MS) funded by this MRI award enables a team of scientists at Indiana University to investigate metal isotope fractionation effects and the chemical mechanisms governing metal isotope fractionation in a variety of environmental, biological, geological, and planetary contexts. Undergraduate, graduate, postdoctoral, and faculty researchers in Geological Sciences, Chemistry, and the School of Public and Environmental Affairs, as well as collaborators from two nearby primarily undergraduate institutions (Indiana State University and DePauw University), will use this cutting-edge instrumentation to advance understanding of how metal isotopes trace and record chemical, geological, and biological processes occurring in nature. This understanding will in turn enable application of metal isotope geochemistry to a wide range of important questions, including those related to contaminant metal fate and transport, availability of bioessential metals in natural waters and sediments, origin of ore deposits, and records of early life on Earth and other planets. The MC-ICP-MS will be located in the recently completed Multidisciplinary Science Building II, which also contains a newly constructed, dedicated clean room for experimentation and sample preparation. The instrument shares space with a well-established and internationally recognized gas-source mass spectrometry facility and thus extends the analytical capabilities of that laboratory across the entire periodic table. These facilities and hands-on training from a partially NSF-supported technician will aid in preparation of the current and next generation of young scientists.

1028102
Ripley

This award provides $300,000 in total funding over 24 months to acquire two gas-source isotope ratio mass spectrometers (IRMS) systems for the Stable Isotope Research Facility (SIRF). The instruments will replace current failing ones. The instruments will be used for petrology and ore genesis, geomicrobiology, planetary processes, water-rock interaction, environmental assessment, atmospheric science and archaeology. The instrumentation will support faculty from Chemistry, Biology, Geography/Atmospheric Sciences, Archaeology and the School of Public and Environmental Affairs in addition to the Department of Geological Sciences which manages the SIRF. In addition, outsider users (~ 80 in the past three years) have utilized the facility. An instrument capable of four ion beams simultaneous measurement is requested for SF6 analysis. A more standard instrument is requested which will be used for oxygen, carbon, and nitrogen isotope analysis. The SIRF has users both at Indiana University and outside institutions. Student use is also high. The SIRF provides hands-on training for students. Training includes sample prep and instrument operation. The PI and co-PI have managed the SIRF for more than 20 years. Both Pis have a strong background in advising underrepresented graduate students. The instruments will be housed in the existing SIRF space. The facility has two full-time technical researchers. Technician salary, supplies and maintenance come from grant support and external user fees.

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