نتایج جستجو برای: weathering pattern
تعداد نتایج: 354090 فیلتر نتایج به سال:
During the 2010 Deepwater Horizon oil well blowout in the Northern Gulf of Mexico (GoM), the application of 6.97 million litres of chemical dispersants was used at the well-head and on the sea surface to promote oil degradation and weathering of the Mississippi Canyon 252 (MC252) crude oil. Chemical dispersants encourage microbial degradation by increasing the surface area of the spilled oil, w...
Quantifying long-term rates of chemical weathering and physical erosion is important for understanding the long-term evolution of soils, landscapes, and Earth’s climate. Here we describe how long-term chemical weathering rates can be measured for actively eroding landscapes using cosmogenic nuclides together with a geochemical mass balance of weathered soil and parent rock. We tested this appro...
The weathering of volcanic rocks contributes significantly to the global silicate weathering budget, effecting carbon dioxide drawdown and long-term climate control. The rate of chemical weathering is influenced by the composition of the rock. Rock-dwelling micro-organisms are known to play a role in changing the rate of weathering reactions; however, the influence of rock composition on bio-we...
We used cosmogenic nuclide and geochemical mass balance methods to measure long-term rates of chemical weathering and total denudation in granitic landscapes in diverse climatic regimes. Our 42 study sites encompass widely varying climatic and erosional regimes, with mean annual temperatures ranging from 2 to 25 jC, average precipitation ranging from 22 to 420 cm year , and denudation rates ran...
Full waveform inversion (FWI) has been used to successfully build high-resolution earth velocity models for marine data. For land data sets, FWI using acoustic wave equation (acoustic-FWI) remains challenging due to the lack of modeling of strong surface waves, converted waves, phase dispersion, and near-surface weathering layer distortion. In addition, for land dynamite surveys, the source wav...
It has been hypothesized that predecessors of today's bryophytes significantly increased global chemical weathering in the Late Ordovician, thus reducing atmospheric CO2 concentration and contributing to climate cooling and an interval of glaciations. Studies that try to quantify the enhancement of weathering by non-vascular vegetation, however, are usually limited to small areas and low number...
Much of the literature that analyzes the effect of various factors on basaltic weathering rates does not assess the synergistic effects of several factors at once. Those studies that do address such synergies generally report their results in formats that are difficult to integrate into geographic analysis. The research outlined in this paper employs multivariate statistics to assess the effect...
Consistent with the weathering hypothesis, many studies have captured racial/ethnic disparities in average functional health trajectories. The same mechanisms of social inequality that contribute to worse average health among minority adults may also contribute to greater fluctuations in their physical function at upper ages. Using panel data from the Health and Retirement Study, we examine pat...
Meteorites are frequently not the pristine record of early solar system processes that we would like them to be. Many unique meteorites, samples that can further our understanding of the environment of the early solar system, are finds, so a knowledge of terrestrial weathering becomes a requirement to accurately interpret their preterrestrial history. This chapter outlines the weathering proces...
Evaluating conflicting theories about the influence of mountains on carbon dioxide cycling and climate requires understanding weathering fluxes from tectonically uplifting landscapes. The lack of soil production and weathering rate measurements in Earth's most rapidly uplifting mountains has made it difficult to determine whether weathering rates increase or decline in response to rapid erosion...
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