A5036074576- Geochemistry and Elemental Analysis
- Geology and Paleoclimatology Research
- Paleontology and Stratigraphy of Fossils
- Geological and Geochemical Analysis
- Geochemistry and Geologic Mapping
- Radioactive element chemistry and processing
- Geomagnetism and Paleomagnetism Studies
- Methane Hydrates and Related Phenomena
- Geological formations and processes
- earthquake and tectonic studies
- Hydrocarbon exploration and reservoir analysis
- Geological and Geophysical Studies
- Geological Studies and Exploration
- Heavy metals in environment
- Extraction and Separation Processes
- Thallium and Germanium Studies
- Clay minerals and soil interactions
- Pacific and Southeast Asian Studies
- Astro and Planetary Science
- Isotope Analysis in Ecology
- Marine Biology and Ecology Research
- Mineralogy and Gemology Studies
- Groundwater and Isotope Geochemistry
- Geological and Tectonic Studies in Latin America
- Underwater Acoustics Research
United States Geological Survey
2015-2024
Pacific Science Center
2013-2023
Pacific Coastal and Marine Science Center
2012-2023
Pacific Island Ecosystems Research Center
2008-2023
California State University Los Angeles
2016-2018
Los Angeles Mission College
2016
The Ohio State University
2012
Menlo School
1979-2010
Institute for Technical Physics and Materials Science
2009
Max Planck Institute for Chemistry
2009
ABSTRACT Diatom ooze and diatomaceous mudstone overlie terrigenous beds at Leg 19 Deep Sea Drilling Project sites. The units are 300‐725 m thick but most commonly about 600 m. Diagenesis of diatom frustules follows a predictable series physical chemical changes that related primarily to temperature (depth burial local geothermal gradient). During the first 300‐400 fragmented undergo mild dissolution. By dissolution opal‐A (biogenic silica) is widespread. Silica reprecipitates abundantly as...
Abstract Iron, manganese, and iron-manganese deposits occur in nearly all geomorphologic tectonic environments the ocean basins form by one or more of four processes: (1) hydrogenetic precipitation from cold ambient seawater, (2) hydrothermal fluids, (3) sediment pore waters that have been modified bottom water compositions diagenetic reactions column (4) replacement rocks sediment. Iron manganese five forms: nodules, crusts, cements, mounds sediment-hosted stratabound layers. Seafloor...
e a seamount Mineral Deposits source of rare Metals for high-techNology iNDustries figure 1. (a,B) two seabed photos showing fe-Mn nodules and crust from horizon guyot.seamount typically have larger nucleus than abyssal are really encrusted pebbles cobbles.(c,D) slabbed samples the Marshall islands.(c) Thick labibjet seamount.(D) nodule lomilik seamount.e-g east Diamante caldera, Mariana islands.(e) active gray-smoker zinc-sulfide chimneys 345-m water depth (hein et al., 2005).(f) inactive,...
Seamount phosphorites have been recognized since the 1950s, but this is first study to provide an in depth exploration of origin and history these widespread deposits. Representative samples from equatorial Pacific Cretaceous seamounts were analyzed for chemical, mineralogical, stable isotope compositions. The occur a wide variety forms, most commonly carbonate fluorapatite (CFA) replaced middle Eocene older sediment deep water environment (>1000 m). Element ratios distinguish seamount...
The intensity of North Atlantic Deep Water (NADW) production has been one the most important parameters controlling global thermohaline ocean circulation system and climate. Here we present a new approach to reconstruct overall strength NADW export from Southern Ocean over past 14 Myr applying deep water Nd Pb isotope composition as recorded by ferromanganese crusts nodules. We first long‐term time series for masses, which are compared with previously published NW Ocean. These data suggest...
As hydrogenous iron-manganese crusts grow, at rates of millimeters per million years, they record changes in the lead isotopic composition ambient seawater. Time-resolved data for cut slabs two central Pacific that have been growing since about 50 years ago were measured situ by laser ablation, multiple-collector, inductively coupled plasma mass spectrometry. The compositions remained remarkably uniform over past 30 but small variations corresponds with other paleoceanographic indicators...