Earth Science
Recent Submissions
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Microstructural Evolution of Porosity and Stress During the Formation of Brittle Shear Fractures: A Discrete Element Model Study
(2018)Brittle fracturing in rocks is a progressive process involving changes in stress, strain, and porosity. Changes in these properties occur heterogeneously within a rock and are manifest at the grain scale, which is difficult ... -
High-resolution and high-precision correlation of dark and light layers in the Quaternary hemipelagic sediments of the Japan Sea recovered during IODP Expedition 346
(2018)The Quaternary hemipelagic sediments of the Japan Sea are characterized by centimeter- to decimeter-scale alternation of dark and light clay to silty clay, which are bio-siliceous and/or bio-calcareous to a various degree. ... -
Volcanic ash as a driver of enhanced organic carbon burial in the Cretaceous
(2018)On greater than million year timescales, carbon in the ocean-atmosphere-biosphere system is controlled by geologic inputs of CO2ﾠthrough volcanic and metamorphic degassing. High atmospheric CO2ﾠand warm climates in the ... -
Deep mantle roots and continental emergence: implications for whole-Earth elemental cycling, long-term climate, and the Cambrian explosion
(2018)Elevations on Earth are dominantly controlled by crustal buoyancy, primarily through variations in crustal thickness: continents ride higher than ocean basins because they are underlain by thicker crust. Mountain building, ... -
Microseismic Monitoring of Stimulating Shale Gas Reservoir in SW China: 2. Spatial Clustering Controlled by the Preexisting Faults and Fractures
(2018)Microseismic monitoring is crucial to improving stimulation efficiency of hydraulic fracturing treatment, as well as to mitigating potential induced seismic hazard. We applied an improved matching and locating technique ... -
Effect of freeze-thaw cycling on grain size of biochar
(2018)Biochar may improve soil hydrology by altering soil porosity, density, hydraulic conductivity, and water-holding capacity. These properties are associated with the grain size distributions of both soil and biochar, and ... -
Permeability During Magma Expansion and Compaction
(2017)Plinian lapilli from the 1060 Common Era Glass Mountain rhyolitic eruption of Medicine Lake Volcano, California, were collected and analyzed for vesicularity and permeability. A subset of the samples were deformed at a ... -
Short‐Term Changes in Physical and Chemical Properties of Soil Charcoal Support Enhanced Landscape Mobility
(2017)Charcoal is a major component of the stable soil organic carbon reservoir, and the physical and chemical properties of charcoal can sometimes significantly alter bulk soil properties (e.g., by increasing soil water holding ... -
Plant species, not climate, controls aboveground biomass O2:CO2 exchange ratios in deciduous and coniferous ecosystems
(2017)The oxidative ratio (OR) is the O2:CO2 ratio associated with photosynthesis, respiration, and other ecosystem gas exchange processes and can be reported on the scale of an individual leaf, an ecosystem, up to the entire ... -
Low oxygen and argon in the Neoproterozoic atmosphere at 815 Ma
(2017)The evolution of Earth's atmosphere on >106-yr timescales is tied to that of the deep Earth. Volcanic degassing, weathering, and burial of volatile elements regulates their abundance at the surface, setting a boundary ... -
Extreme enrichment in atmospheric 15N15N
(2017)Molecular nitrogen (N2) comprises three-quarters of Earth’s atmosphere and significant portions of other planetary atmospheres. We report a 19 per mil (‰) excess of 15N15N in air relative to a random distribution of nitrogen ... -
Coralgal reef morphology records punctuated sea-level rise during the last deglaciation
(2017)Coralgal reefs preserve the signatures of sea-level fluctuations over Earth’s history, in particular since the Last Glacial Maximum 20,000 years ago, and are used in this study to indicate that punctuated sea-level rise ... -
Valuing the Air Quality Effects of Biochar Reductions on Soil NO Emissions
(2017)While it is clear that biochar can alter soil N2O emissions, data on NO impacts are scarce. Reports range from 0 to 67% soil NO emission reductions postbiochar amendment. We use regional air quality and health cost models ... -
Persistent anomalies of the extratropical Northern Hemisphere wintertime circulation as an initiator of El Niño/Southern Oscillation events
(2017)Climates across both hemispheres are strongly influenced by tropical Pacific variability associated with the El Niño/Southern Oscillation (ENSO). Conversely, extratropical variability also can affect the tropics. In ... -
The Malpelo Plate Hypothesis and implications for nonclosure of the Cocos-Nazca-Pacific plate motion circuit
(2017)Using global multiresolution topography, we estimate new transform-fault azimuths along the Cocos-Nazca plate boundary and show that the direction of relative plate motion is 3.3° ± 1.8° (95% confidence limits) clockwise ... -
Post-LGM Grounding-Line Positions of the Bindschadler Paleo Ice Stream in the Ross Sea Embayment, Antarctica
(2017)The West Antarctic Ice Sheet (WAIS) retreated more than 1,000 km since last grounding at the Ross Sea outer continental shelf. Here we show an interpretation of former grounding line positions from a new large-area multibeam ... -
Full-waveform inversion of triplicated data using a normalized-correlation-coefficient-based misfit function
(2017)In seismic full-waveform inversion (FWI), the choice of misfit function determines what information in data is used and ultimately affects the resolution of the inverted images of the Earth's structure. Misfit functions ... -
A perspective on climate model hierarchies
(2017)To understand Earth's climate, climate modelers employ a hierarchy of climate models spanning a wide spectrum of complexity and comprehensiveness. This essay, inspired by the World Climate Research Programme's recent “Model ... -
Planktic foraminiferal response to early Eocene carbon cycle perturbations in the southeast Atlantic Ocean (ODP Site 1263)
(2017)At low latitude locations in the northern hemisphere, striking changes in the relative abundances and diversity of the two dominant planktic foraminifera genera, Morozovella and Acarinina, are known to have occurred close ...
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