A5053933860- Paleontology and Stratigraphy of Fossils
- Geology and Paleoclimatology Research
- Methane Hydrates and Related Phenomena
- Hydrocarbon exploration and reservoir analysis
- Geological and Geochemical Analysis
- Isotope Analysis in Ecology
- Groundwater and Isotope Geochemistry
- Geological formations and processes
- Geological and Geophysical Studies
- Geochemistry and Elemental Analysis
- Microbial Community Ecology and Physiology
- Astro and Planetary Science
- CO2 Sequestration and Geologic Interactions
- High-pressure geophysics and materials
- Archaeology and Natural History
- earthquake and tectonic studies
- Marine Biology and Ecology Research
- Geochemistry and Geologic Mapping
- Planetary Science and Exploration
- Water Quality and Resources Studies
- Radioactive element chemistry and processing
- Drilling and Well Engineering
- Coral and Marine Ecosystems Studies
- Atmospheric and Environmental Gas Dynamics
- Building materials and conservation
California State University, Fullerton
2015-2024
University of California, Los Angeles
2011-2021
Planetary Science Institute
2015-2021
Fullerton College
2016
Southern California Earthquake Center
2007-2015
University of Southern California
2007-2015
Carbonate-d 18 O paleothermometry is used in many diagenetic studies to unravel the thermal history of basins.However, this approach generally requires an assumed pore-water d (d pw ) value, a parameter that difficult quantify past regimes.In addition, processes can change original isotopic composition pore water, which further complicates assignment initial and lead erroneous temperature estimates.Here, we use clumped-isotope thermometry, proxy based on 13 C-18 bond abundance carbonate...
Our understanding of the evolutionary transitions leading to modern endothermic state birds and mammals is incomplete, partly because tools available study thermophysiology extinct vertebrates are limited. Here we show that clumped isotope analysis eggshells can be used determine body temperatures females during periods ovulation. Late Cretaceous titanosaurid yield similar large endotherms. In contrast, oviraptorid lower than most endotherms but ∼ 6 °C higher co-occurring abiogenic...
Abstract Methane cold seep systems typically exhibit extensive buildups of authigenic carbonate minerals, resulting from local increases in alkalinity driven by methane oxidation. Here, we demonstrate that modern carbonates anomalously low clumped isotope values (Δ 47 ), as much ∼0.2‰ lower than expected values. In seeps, this range disequilibrium translates into apparent temperatures are always warmer ambient temperatures, up to 50 °C. We examine various mechanisms may induce behaviour...
Major hydrocarbon accumulations occur in traps associated with salt domes. Whereas some of these hydrocarbons remain to be extracted for economic use, significant amounts have degraded the subsurface, yielding mineral precipitates as byproducts. Salt domes Gulf Mexico Basin typically exhibit extensive deposits carbonate that form cap rock atop structures. Despite previous efforts model formation, details subsurface reactions (including role microorganisms) largely unknown. Here we show...
Research Article| September 01, 2014 Widespread contamination of carbonate-associated sulfate by present-day secondary atmospheric sulfate: Evidence from triple oxygen isotopes Yongbo Peng; Peng 1Department Geological Sciences, Indiana University, Bloomington, 47405, USA Search for other works this author on: GSW Google Scholar Huiming Bao; Bao 2Department Geology & Geophysics, Louisiana State Baton Rouge, 70803, Lisa M. Pratt; Pratt Alan J. Kaufman; Kaufman 3Department and Earth System...
Clumped isotope geochemistry examines the pairing or clumping of heavy isotopes in molecules and provides information about thermodynamic kinetic controls on their formation. The first clumped measurements carbonate minerals were published 15 years ago, since then, interlaboratory offsets have been observed, laboratory community practices for measurement, data analysis, instrumentation evolved. Here we briefly review historical recent developments measurements, share Tripati Lab four...
Authigenic carbonate (AC) forms in siliciclastic marine sediments part as a result of the degradation organic matter and methane. Degradation pathways vary considerably each impact chemical evolution porewater differently. The relative importance these reactions contributing to authigenesis are poorly understood, especially from global perspective. Modern geochemical data authigenic carbon isotope compositions (δ13Cac) globally distributed sediment sites allow direct assessment diagenetic...
Hot spring environments can create physical and chemical gradients favorable for unique microbial life. They also include authigenic mineral precipitates that may preserve signs of biological activity on Earth possibly other planets. The abiogenic or biogenic origins such be difficult to discern, therefore a better understanding formation processes is critical the accurate interpretation biosignatures from hot springs. Little Creek (LHC) complex located in Long Valley Caldera, California,...
Algal blooms in lakes are often associated with anthropogenic eutrophication; however, they can occur without the human introduction of nutrients to a lake. A rare bloom alga Picocystis sp. strain ML occurred spring 2016 at Mono Lake, hyperalkaline lake California, which was also apex multiyear-long drought. These conditions presented unique sampling opportunity investigate microbiological dynamics and potential metabolic function during an intense natural algal bloom. We conducted...
Compared with Phanerozoic strata, sulfate minerals are relatively rare in the Precambrian record; this is probably due to lower concentrations of dominantly anoxic oceans. Here, we present a compilation that stratigraphically associated Ediacaran Shuram excursion (SE) – largest negative <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mi>δ</mml:mi> </mml:math> 13 C Earth history. We evaluated 15 SE sections, all which reveal presence and/or enriched...
Abstract Ancient putative microbial structures that appear in the rock record commonly serve as evidence of early life on Earth, but details their formation remain unclear. The study modern mat can help inform properties ancient counterparts, mineralizing systems with morphological similarity to are rare. Here, we characterize partially lithified mats containing cm-scale dendrolitic coniform from a geothermal pool (“Cone Pool”) at Little Hot Creek, California, if fully lithified, would...
Early diagenesis of marine organic matter dramatically impacts Earth's surface chemistry by changing the burial potential carbon and promoting formation authigenic mineral phases including carbonate concretions. Marine sediment-hosted concretions tend to form as a result microbial anaerobic diagenetic reactions that degrade methane, some which require an external oxidant. Thus, temporal changes in oxidation state oceans may impart first-order control on concretion authigenesis mechanisms...
The thermal evolution of Earth is governed by the rate secular cooling and amount radiogenic heating. If mantle heat sources are known, surface flow at different times may be used to deduce efficiency convective ultimately temporal character plate tectonics. We estimate global from 65 Ma present using seafloor age reconstructions a modified half-space model, we find that has decreased approximately 0.15% every million years during Cenozoic. By examining geometric trends in since 120 Ma, show...
Septarian concretions exhibit multiple generations of cements that include body, fringe, and spar phases.Classic paragenetic interpretations initial precipitation the body followed by fringe(s) then in more or less discrete events.Traditional approaches (e.g., carbon oxygen isotope analyses) are generally unable to distinguish trends as they relate specific formation environments during burial with meteoric influx).Here we present carbonate clumped-isotope, d 13 C (d carb ), 18 O ) values...
Abstract The Neoproterozoic lower Beck Spring Dolomite exhibits a prominent, millimeter-scale, light–dark, planar lamination commonly interpreted as primary depositional fabric. Microscopic examination reveals that the dark laminae are composed of micrite and contain micrometer-scale, wavy fabric, whereas light relatively coarse-crystalline pseudospar engulfs, surrounds, crosscuts laminae. Nearly all surround, or occur in proximity to, elongate (long axis fabric-parallel), spar-filled cavity...
The continued release of fossil fuel carbon into the atmosphere today means it is imperative to understand Earth system response CO2 rise, and geologic record offers unique opportunities investigate such behavior. Stomatal paleosol proxies demonstrate a large change in atmospheric pCO2 across Triassic-Jurassic (T-J) transition, concomitant with eruption emplacement Central Atlantic Magmatic Province (CAMP) splitting Pangea. As one “big 5” mass extinctions—when so-called modern fauna was...