A5013780220- Geology and Paleoclimatology Research
- Paleontology and Stratigraphy of Fossils
- Isotope Analysis in Ecology
- Radioactive element chemistry and processing
- Groundwater and Isotope Geochemistry
- Geological and Geochemical Analysis
- Chemical Synthesis and Characterization
- Methane Hydrates and Related Phenomena
- Metal Extraction and Bioleaching
- Marine and coastal ecosystems
- Field-Flow Fractionation Techniques
- Astro and Planetary Science
- Minerals Flotation and Separation Techniques
- Mine drainage and remediation techniques
- Geochemistry and Geologic Mapping
- Catalysis and Oxidation Reactions
- Catalytic Processes in Materials Science
- Pacific and Southeast Asian Studies
- Pleistocene-Era Hominins and Archaeology
- Chemical Looping and Thermochemical Processes
- Space Exploration and Technology
- Marine and environmental studies
- Zeolite Catalysis and Synthesis
- Radioactive contamination and transfer
- Geological Formations and Processes Exploration
United States Geological Survey
2023
Rice University
2016-2022
Johnson Space Center
2020-2022
National Aeronautics and Space Administration
2021
Louisiana State University
2013-2019
Louisiana State University Agricultural Center
2013-2016
A strongly oxidizing Paleoproterozoic era Two billion years ago, marine sulfate concentrations were around one-third as high modern ones, constituting an capacity equivalent to more than 20% of that the ocean-atmosphere system. Blättler et al. found this by analyzing a remarkable evaporite succession 1 older oldest comparable deposit discovered date. These quantitative results, for time when only qualitative information was previously available, provide constraint on magnitude and timing...
The element oxygen has three stable isotopes: 16 O, 17 and 18 O. For a defined process, change in O/ O scales with the corresponding or fractionation factors α have relationship of θ = ln α/ln α, which triple isotope exponent is relatively fixed but does vary reaction path, temperature, species involved. When small variation interest, distinction concepts—θ, S (a slope through data points δ O–δ space), C (an arbitrary referencing number for degree deviation)—becomes important. Triple...
Research Article| December 12, 2017 Linking paleocontinents through triple oxygen isotope anomalies Peter W. Crockford; Crockford 1Department of Earth and Planetary Sciences, McGill University, Montreal, Quebec H3A 0E8, Canada Search for other works by this author on: GSW Google Scholar Malcolm S.W. Hodgskiss; Hodgskiss Canada2Department Geological Stanford Stanford, California 94305, USA Gabriel J. Uhlein; Uhlein 3CPMTC–IGC (Centro de Pesquisas Professor Manoel Teixeira da Costa–Instituto...
Isotope ratio measurements have become extremely precise in recent years, with many approaching parts-per-million (ppm) levels of precision. However, seemingly innocuous errors signal baselines, which exist only when gas enters the instrument, might lead to significant errors. These "pressure-baseline" (PBL) offsets may a variety origins, such as incoherent scattering analyte, isobaric interferences, or electron ablation from walls flight tube. They are probably present all but...
Abstract The Arosa Zone, Central Alps, represents a Cretaceous to Paleogene fossil subduction interface from paleodepths of 10 >35 km. Metasedimentary schists directly below preserved seismogenic zone exhibit viscous (foliations, folds, and lineations) brittle (crack‐seal quartz ± calcite veins) deformation features. Si‐in‐phengite barometry published temperature estimates yield metamorphism conditions 0.8–0.9 GPa 300–350°C for an albite‐rich pelitic schist 0.9 420°C calcite‐rich...
The ∼635 Ma Marinoan glaciation is marked by dramatic Earth system perturbations. Deposition of nonmass-dependently 17 O-depleted sulfate (SO 4 2− ) in worldwide postglacial sediments is, thus far, unique to this glaciation. It proposed that an extremely high- p CO 2 atmosphere can result highly atmospheric O , or the Oxygen-17 Depletion (MOSD) event. This anomalous signal was imparted oxidative weathering origin. However, occurs limited sedimentary intervals, suggesting surface conditions...
and kinetic isotope effects).The intrinsic relationships among temperature (T), fractionation factor (α), three-isotope exponent (θ) in mass-dependent elemental processes at equilibrium have not been explored theoretically.The first accurate model for predicting the separation of isotopes was published independently by Urey (1947) Bigeleisen Goeppert-Mayer (1947; B-GM-U model).Their development concept reduced partition function ratio (RPFR or (s/s')f ) allowed calculation α between two...
Research Article| January 01, 2021 Climbing to the Top of Mount Fuji: Uniting Theory and Observations Oxygen Triple Isotope Systematics Laurence Y. Yeung; Yeung Department Earth, Environmental Planetary Sciences. Rice University, Houston, TX 77005, U.S.A. * E-mail: lyeung@rice.edu Search for other works by this author on: GSW Google Scholar Justin A. Hayles Jacobs, Astromaterials Exploration Science, Johnson Space Center, National Aeronautics Administration, 77058, justin.a.hayles@nasa.gov...
The 18O/16O ratios of ancient marine minerals show a puzzling increase over geologic time. Long-term changes in temperature, seawater ratios, and post-depositional overprinting can all explain this trend, but few tracers distinguish between these scenarios. Here, we report high-precision 17O/16O cherts through 3.4 Ga Earth′s history. We find that Phanerozoic are consistent with having formed porewaters isotopically indistinguishable from modern (ice-free) seawater. In contrast, Precambrian...