نتایج جستجو برای: chemical weathering
تعداد نتایج: 382710 فیلتر نتایج به سال:
CRONO is a new code for simulating chemical weathering. This program allows for the simulation of complex scenarios of interaction in water-rock-gas systems while accounting for mineral dissolution kinetics and solution transport. The thermodynamic calculations are realized using the GEOCHEQ program. CRONO was developed for simulations of regolith formation on the surfaces of early Earth and Ma...
This study investigated weathering effects on polyvinyl chloride (PVC) based wood plastic composites (WPC), with a focus on the color and structure that is attributed to the material composition. It is directed towards quantifying the main chemical modifications, such as carbonyl and vinyl groups which are formed during weathering. These composites were subjected to three weathering regimes: ex...
The strontium isotope composition of seawater is strongly influenced on geological time scales by changes in the rates of continental weathering relative to ocean crust alteration. However, the potential of the seawater 87Sr/86Sr curve to trace globally integrated chemical weathering rates has not been fully realised because ocean 87Sr/86Sr is also influenced by the isotopic evolution of Sr sou...
. introduction weathering is crushing, decomposition and decaying the rocks of outer earth's crust by natural processes such as; running waters, wind blowing and ice creeping and biological actions and so on. the study of weathering is important because this process lead to formation of all known of soil types in outer part of earth crust finally. climate is the most important parameter in crea...
Citation: Yang X, Peng X, Qiang X, Li N, Zhou Q and Wang Y (2016) Chemical Weathering Intensity and Terrigenous Flux in South China during the Last 90,000 Years—Evidence from Magnetic Signals in Marine Sediments. Front. Earth Sci. 4:47. doi: 10.3389/feart.2016.00047 Chemical Weathering Intensity and Terrigenous Flux in South China during the Last 90,000 Years—Evidence from Magnetic Signals in M...
It has been proposed that increased rates of chemical weathering and the related drawdown of atmospheric CO on the 2 Ž . continents may have at least partly contributed to the low CO concentrations during the last glacial maximum LGM . 2 Variations in continental erosion could thus be one of the driving forces for the glacialrinterglacial climate cycles during Quaternary times. To test such an ...
We determined the total mass loss and rate of chemical weathering from three minimally eroded, Hawaiian lava flows that are ∼10, 170, and 350 ka old. Using a backhoe, we sampled the entire weathering zone at 28 sites and measured the depletion or enrichment of each major element in each soil horizon relative to parent material. We were able to assess the influence of both climate and substrate ...
This autobiography covers the past 55 years of my research in geochemistry. I try to show how chemical principles can be applied to a wide variety of geological problems, ranging from iron sulfide mineralogy, to carbonate chemistry in the oceans, to silicate mineral surface chemistry during weathering, to biogeochemical changes during early diagenesis, to plants and weathering, to models for th...
the protoliths of metamorphosed argillaceous rocks from the garmichay area in the east azerbaijan province of nw iran were clay-rich sediments of reworked nature, originating most likely from an andesite to andesite-basalt source and deposited in an active continental margin tectonic setting. the protoliths of the garmichay metapelites experienced low to moderate chemical weathering. andalusite...
[1] The basal regions of continental ice sheets are gaps in our current understanding of the Earth’s biosphere and biogeochemical cycles. We draw on existing and new chemical data sets for subglacial meltwaters to provide the first comprehensive assessment of sub‐ice sheet biogeochemical weathering. We show that size of the ice mass is a critical control on the balance of chemical weathering pr...
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