A5054706180- Geology and Paleoclimatology Research
- Methane Hydrates and Related Phenomena
- Hydrocarbon exploration and reservoir analysis
- Geological and Geophysical Studies
- Radioactive element chemistry and processing
- Geological and Geochemical Analysis
- Geochemistry and Geologic Mapping
- Paleontology and Stratigraphy of Fossils
- Geochemistry and Elemental Analysis
- Geological formations and processes
- Radioactive contamination and transfer
- Reservoir Engineering and Simulation Methods
- Seismic Imaging and Inversion Techniques
- earthquake and tectonic studies
- Pleistocene-Era Hominins and Archaeology
- Marine and coastal ecosystems
- Nuclear Physics and Applications
- Isotope Analysis in Ecology
- Atmospheric and Environmental Gas Dynamics
- Evolution and Paleontology Studies
- Radioactivity and Radon Measurements
- Groundwater and Isotope Geochemistry
- Archaeology and ancient environmental studies
- Maritime and Coastal Archaeology
- Advanced X-ray Imaging Techniques
Woods Hole Oceanographic Institution
2016-2025
International Ocean Discovery Program
2022
Boston University
2013-2018
University of Massachusetts Boston
2015
Abstract During International Ocean Discovery Program (IODP) expeditions, shipboard‐generated data provide the first insights into cored sequences. The natural gamma radiation (NGR) of recovered material, for example, is routinely measured on ocean drilling research vessel DV JOIDES Resolution . At present, only total NGR counts are readily available as shipboard data, although full spectra (counts a function gamma‐ray energy level) produced and archived. These contain unexploited...
Abstract Oxic pelagic clays are an important component of seafloor sediment that may hold valuable information about past ocean chemistry due to their affinity for and accumulation biogeochemically metals. We present a new approach calculating site‐specific sedimentation rates (SRs) by comparing authigenic thorium isotope compositions ( 230 Th/ 232 Th) seawater dissolved Th in suite deep (>3,000 m) core sites. extracted the fraction using HHAc leach protocol, which major element (Al, Mn,...
Authigenic clay minerals formed on or in the seafloor occur every type of marine sediment. They are recognized to be a major sink many elements ocean but difficult study directly due dilution by detrital minerals. The extremely low dust fluxes and sedimentation rates South Pacific Gyre (SPG) provide unique opportunity examine relatively undiluted authigenic clay. Here, using Mg isotopes element concentrations combined with multivariate statistical modeling, we fingerprint quantify abundance...
We examine the 0–100 Ma paleoceanographic record retained in pelagic clay from South Pacific Gyre (SPG) by analyzing 47 major, trace, and rare earth elements bulk sediment 206 samples seven sites drilled during Integrated Ocean Drilling Program Expedition 329. use multivariate statistical analyses (Q-mode factor analysis multiple linear regression) of geochemical data to construct a model composition mass accumulation rates (MAR) six end-members, (post-Archean average Australian shale,...
The Quaternary hemipelagic sediments of the Japan Sea are characterized by centimeter- to decimeter-scale alternation dark and light clay silty clay, which bio-siliceous and/or bio-calcareous a various degree. Each layers considered as deposited synchronously throughout deeper (> 500 m) part sea. However, attempts for correlation age estimation individual limited upper few tens meters. In addition, exact timing depositional onset these its synchronicity sea have not been explored previously,...
Abstract. Barium is widely used as a proxy for dissolved silicon and particulate organic carbon fluxes in seawater. However, these applications are limited by insufficient knowledge of the distribution Ba ([Ba]). For example, there significant spatial variability barium–silicon relationship, ocean chemistry may influence sedimentary preservation. To help address issues, we developed 4095 models predicting [Ba] using Gaussian process regression machine learning. These were trained to predict...
Hydrogen (H2) is produced in geological settings by dissociation of water due to radiation from radioactive decay naturally occurring uranium (238U, 235U), thorium (232Th) and potassium (40K). To quantify the potential significance radiolytic H2 as an electron donor for microbes within South Pacific subseafloor basaltic aquifer, we use radionuclide concentrations 43 basalt samples IODP Expedition 329 calculate production rates basement fractures. The are three sites with very different ages...
Abstract. Climate exerted constraints on the growth and decline of past human societies but our knowledge temporal spatial climatic patterns is often too restricted to address causal connections. At a global scale, inter-hemispheric thermal balance provides an emergent framework for understanding regional Holocene climate variability. As adjusted gradual changes in seasonality insolation, Intertropical Convergence Zone migrated southward accompanied by weakening Indian summer monsoon....
Abstract Water radiolysis continuously produces H 2 and oxidized chemicals in wet sediment rock. Radiolytic has been identified as the primary electron donor (food) for microorganisms continental aquifers kilometers below Earth’s surface. products may also be significant sustaining life subseafloor subsurface environments of other planets. However, extent to which most ecosystems rely on radiolytic poorly constrained, due incomplete understanding chemical yields natural environments. Here we...
Abstract Much uncertainty exists about the state of oceanic and atmospheric circulation in tropical Pacific over last glacial cycle. Studies have been hampered by fact that sediment cores suitable for study were concentrated western eastern parts Pacific, with little information from central Pacific. Here we present a suite collected Line Islands Ridge which show sedimentation rates stratigraphies paleoceanographic investigations. Based on radiocarbon oxygen isotope measurements planktonic...
Abstract Dating pelagic clay can be a challenge due to its slow sedimentation rate, post‐depositional alteration, and lack of biogenic deposition. Co‐based dating techniques have the potential create age models in under assumption that flux non‐detrital Co seafloor is spatially temporally constant, resulting concentrations being inversely proportional rate. We apply method sequences from Sites U1365, U1366, U1369, U1370 drilled during Integrated Ocean Drilling Program (IODP) Expedition 329...
Abstract X‐ray fluorescence (XRF) scanning of marine sediment has the potential to yield near‐continuous and high‐resolution records elemental abundances, which are often interpreted as proxies for paleoceanographic processes over different time scales. However, many other variables also affect XRF measurements convolute quantitative calibrations element abundances comparisons data from labs. Extensive interlab results essential resolve ambiguities understand best way interpret produced. For...
No abstract available. doi:10.2204/iodp.sd.15.05.2013
Subsurface microbial communities undertake many terminal electron-accepting processes, often simultaneously. Using a tritium-based assay, we measured the potential hydrogen oxidation catalyzed by hydrogenase enzymes in several subsurface sedimentary environments (Lake Van, Barents Sea, Equatorial Pacific and Gulf of Mexico) with different predominant electron-acceptors. Hydrogenases constitute diverse family expressed microorganisms that utilize molecular as metabolic substrate, product or...
Abstract We reconstruct the provenance of aluminosilicate sediment deposited in Ulleung Basin, Japan Sea, over last 12 Ma at Site U1430 drilled during Integrated Ocean Drilling Program Expedition 346. Using multivariate partitioning techniques (Q-mode factor analysis, multiple linear regressions) applied to major, trace and rare earth element composition bulk sediment, we identify quantify four components (Taklimakan, Gobi, Chinese Loess Korean Peninsula), model their mass accumulation...
Abstract. The expansion of C4 vegetation during the Neogene was one largest reorganizations Earth's terrestrial biome. Once thought to be globally synchronous in late Miocene, site-specific studies have revealed differences timing and suggest that local conditions play a substantial role. Here, we examine on Indian Peninsula since Miocene by constructing ∼6-million-year paleorecord with marine sediment from Bay Bengal at Site U1445, drilled International Ocean Discovery Program Expedition...
Abstract Geochemical analyses of trace elements in the ocean water column have suggested that pelagic clay‐rich sediments are a major source various to bottom‐waters. However, corresponding high‐quality measurements element concentrations porewaters scarce, making it difficult evaluate contributions from benthic processes global oceanic cycles elements. To bridge this gap, we analyzed porewater and bulk sediment vanadium, chromium, cobalt, nickel, copper, arsenic, molybdenum, barium uranium,...
Abstract The geochemistry of marine sediment is a massive archive (paleo)oceanographic information. Accessing that information requires “unmixing” the various influences on to understand individual sources and geochemical processes. Q‐mode factor analysis (QFA) independent component (ICA) are multivariate statistical techniques have successfully been applied large datasets element concentrations identify number composition or end‐members. In this study, we apply both two geochemistry,...
Abstract. Climate exerted constraints on the growth and decline of past human societies but our knowledge temporal spatial climatic patterns is often too restricted to address causal connections. At a global scale, inter-hemispheric thermal balance provides an emergent framework for understanding regional Holocene climate variability. As adjusted gradual changes in seasonality insolation, Inter-Tropical Convergence Zone migrated southward accompanied by weakening Indian summer monsoon....