A5017713485- Methane Hydrates and Related Phenomena
- Geology and Paleoclimatology Research
- Atmospheric and Environmental Gas Dynamics
- Paleontology and Stratigraphy of Fossils
- Hydrocarbon exploration and reservoir analysis
- Isotope Analysis in Ecology
- Geological and Geochemical Analysis
- Geochemistry and Elemental Analysis
- Astro and Planetary Science
- Planetary Science and Exploration
- Groundwater and Isotope Geochemistry
- earthquake and tectonic studies
- Marine and coastal ecosystems
- Geological and Geophysical Studies
- Geological formations and processes
- Chemical Reactions and Isotopes
- Radioactive element chemistry and processing
- Nuclear Physics and Applications
- Microbial Community Ecology and Physiology
- Geochemistry and Geologic Mapping
- High-pressure geophysics and materials
- Plant Water Relations and Carbon Dynamics
- Geological and Tectonic Studies in Latin America
- Cultural Heritage Materials Analysis
- Climate change and permafrost
Planetary Science Institute
2016-2024
University of California, Berkeley
2017-2024
Lawrence Berkeley National Laboratory
2017-2024
University of Wisconsin–Madison
2023
Earth Island Institute
2020
California Institute of Technology
2008-2017
Princeton University
2015-2016
University of Southern Denmark
2010-2012
University of Rochester Medical Center
2011
University of Minnesota
2011
The Microscopic Imager (MI) on the Mars Exploration Rover Opportunity has returned images of with higher resolution than any previous camera system, allowing detailed petrographic and sedimentological studies rocks soils at Meridiani Planum landing site. Designed to simulate a geologist's hand lens, MI is mounted Opportunity's instrument arm can resolve objects 0.1 mm across or larger. This paper provides an overview operations, data calibration, analysis during first 900 sols (Mars days)...
Methane is an important greenhouse gas and energy resource generated dominantly by methanogens at low temperatures through the breakdown of organic molecules high temperatures. However, methane-formation in nature are often poorly constrained. We measured formation thermogenic biogenic methane using a "clumped isotope" technique. Thermogenic gases yield between 157° 221°C, within nominal window, consistent with their comparatively lower-temperature formational environments (<50°C). In...
Carbonate clumped-isotope geothermometry is a tool used to reconstruct formation or (re)equilibration temperatures of carbonate bearing minerals, including groups substituted into apatite. It based on the preference for isotopologues with multiple heavy isotopes (for example, ^13^C^16^O~2~^18^O^2−^ groups) be more abundant at equilibrium than would expected if all were randomly distributed amongst groups. Because this only function temperature, excesses multiply species can calculate without...
Molecular oxygen (O 2 ) is the second most abundant gas in Earth’s atmosphere, but many natural environments, its concentration reduced to low or even undetectable levels. Although low-oxygen-adapted organisms define ecology of low-oxygen their capabilities are not fully known. These also provide a framework for reconstructing critical period history life, because low, negligible, atmospheric levels could have persisted before “Great Oxidation” surface about 2.3 2.4 billion years ago. Here,...
The million-year variability of the marine nitrogen cycle is poorly understood. Before 57 million years (Ma) ago, 15N/14N ratio (δ15N) foraminifera shell-bound organic matter from three sediment cores was high, indicating expanded water column suboxia and denitrification. Between 50 Ma δ15N declined by 13 to 16 per mil in North Pacific 3 8 Atlantic. decline preceded global cooling appears have coincided with early stages Asia-India collision. Warm, salty intermediate-depth forming along...
Carbonate mud represents one of the most important geochemical archives for reconstructing ancient climatic, environmental, and evolutionary change from rock record. Mud also a major sink in global carbon cycle. Yet, there remains no consensus about how where carbonate is formed. Here, we present stable isotope trace-element data constituents Bahamas, including ooids, corals, foraminifera, algae. We use fingerprinting to demonstrate that cannot be sourced abrasion mixture any combination...
The history of atmospheric O2 partial pressures (Po2) is inextricably linked to the coevolution life and Earth's biogeochemical cycles. Reconstructions past Po2 rely on models proxies but often markedly disagree. We present a record reconstructed using O2/N2 ratios from ancient air trapped in ice. This indicates that declined by 7 per mil (0.7%) over 800,000 years, requiring sinks were ~2% larger than sources. decline consistent with changes burial weathering fluxes organic carbon pyrite...
Abstract Methane clumped-isotope compositions provide a new approach to understanding the formational conditions of methane from both biogenic and thermogenic sources. Under some conditions, these can be used reconstruct temperatures gas, this capability applied common subsets systems. Additionally, there are examples in which do not reflect gas-formation but instead mixing effects kinetic phenomena; such also occur recognizable subtypes gases. Here we review use measurements for origin...
A rise in atmospheric O2 levels between 800 and 400 Ma is thought to have oxygenated the deep oceans, ushered modern biogeochemical cycles, led diversification of animals. Over same time interval, marine sulfate concentrations are also increased near-modern levels. We present compiled data that indicate Phanerozoic island arc igneous rocks more oxidized (Fe3+/ΣFe ratios elevated by 0.12) vs. Precambrian equivalents. propose this elevation due increases deep-ocean Ma, which oceanic crust on...
Methane is produced and consumed via numerous microbial chemical reactions in atmospheric, hydrothermal, magmatic reactions. The stable isotopic composition of methane has been used extensively for decades to constrain the source environment. A recently introduced parameter study formation temperature formational conditions measurement molecules with multiple rare, heavy isotopes ("clumped") such as 13CH3D 12CH2D2. In order place methane-clumped isotope measurements into a thermodynamic...
Research Article| October 19, 2017 Deciphering the diagenetic history of El Abra Formation eastern Mexico using reordered clumped isotope temperatures and U-Pb dating Michael Lawson; Lawson † 1ExxonMobil Upstream Company, Spring, Texas 77389, USA †michael.lawson@exxonmobil.com Search for other works by this author on: GSW Google Scholar Brock J. Shenton; Shenton Daniel A. Stolper; Stolper 2Department Earth Planetary Science, University California, Berkeley, 94720, John M. Eiler; Eiler...
Abstract The release of long‐stored carbon from thawed permafrost could fuel increased methanogenesis in northern lakes, but it remains unclear whether old substrates released are metabolized as rapidly by methanogenic microbial communities recently produced organic carbon. Here, we apply methane (CH 4 ) clumped isotope (Δ 18 and 14 C measurements to test rates related substrate age. Results culture experiments indicate that Δ values negatively correlated with CH production rate....