نتایج جستجو برای: soil erosion and weathering

تعداد نتایج: 16869234  

2008
Hongbing Sun Carol Natter Pierre Lacombe

Total suspended sediments and the total dissolved solids (TDS) from three river gaging stations, near Delaware Water Gap, Riegelsville and Trenton on the Delaware River measured by the USGS were used to estimate the physical erosion, chemical weathering and total denudation rates of the Delaware River Basin. The denudation rates are 28 and 128 tons/km 2 /yr for the upper stream and downstream s...

2002
Suzanne Prestrud Anderson William E. Dietrich George H Brimhall

In a headwater catchment in the Oregon Coast Range, we find that solid-phase mass losses due to chemical weathering are equivalent in the bedrock and the soil. However, the long-term rate of mass loss per unit volume of parent rock is greater in the soil than in the rock. We attribute this finding to the effects of biotic processes in the soil and to hydrologic conditions that maximize contact ...

2008
Wei Luo Alan D. Howard

6 [1] The role of groundwater in forming Martian valley networks is simulated in a 7 computer model as seepage erosion by contributing to surface runoff and as seepage 8 weathering by causing accelerated weathering of bedrock, which makes its subsequent 9 erosion and removal easier. Simulation results show that seepage erosion cannot mobilize 10 large grain size sediment and is marginally effec...

2008
Wei Luo Alan D. Howard

[1] The role of groundwater in forming Martian valley networks is simulated in a computer model as seepage erosion by contributing to surface runoff and as seepage weathering by causing accelerated weathering of bedrock, which makes its subsequent erosion and removal easier. Simulation results show that seepage erosion cannot mobilize large grain size sediment and is marginally effective at gen...

2014
Sarah J. Ivory Michael M. McGlue Geoffrey S. Ellis Anne-Marie Lézine Andrew S. Cohen Annie Vincens

Tropical climate is rapidly changing, but the effects of these changes on the geosphere are unknown, despite a likelihood of climatically-induced changes on weathering and erosion. The lack of long, continuous paleo-records prevents an examination of terrestrial responses to climate change with sufficient detail to answer questions about how systems behaved in the past and may alter in the futu...

2017
Luc Bastian Marie Revel Germain Bayon Aurélie Dufour Nathalie Vigier

Chemical weathering of silicate rocks on continents acts as a major sink for atmospheric carbon dioxide and has played an important role in the evolution of the Earth's climate. However, the magnitude and the nature of the links between weathering and climate are still under debate. In particular, the timescale over which chemical weathering may respond to climate change is yet to be constraine...

2009
M. Schaller T. A. Ehlers J. D. Blum M. A. Kallenberg

[1] Glacial boulders and soils on moraines are often dated to quantify the timing of glaciations and/or rates of chemical weathering in moraine chronosequences. A common assumption is that moraine crest erosion and soil mixing are unimportant. However, several studies suggest moraine denudation may be substantial. We evaluate the magnitude of moraine denudation and soil mixing in the Pinedale (...

Journal: :جغرافیا و مخاطرات محیطی 0
فرامرز خوش اخلاق علی اکبر شمسی پور مهران مقصودی محمدامین مرادی مقدم

. 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...

2006
P. Louvat C. J. Allegre

As chemical weathering of silicate rocks acts as a sink for atmospheric CO2 and as greenhouse effect gases such as CO2 have a leading role in climate regulation, much of river geochemical studies now focus on chemical and mechanical riverine erosion and on their controlling parameters. Moreover, weathering has probably had a dominating influence in the climatic evolution of the Earth, and studi...

2006
J. Belnap S. L. Phillips J. E. Herrick J. R. Johansen

Recently disturbed and ‘control’ (i.e. less recently disturbed) soils in the Mojave Desert were compared for their vulnerability to wind erosion, using a wind tunnel, before and after being experimentally trampled. Before trampling, control sites had greater cyanobacterial biomass, soil surface stability, threshold friction velocities (TFV; i.e. the wind speed required to move soil particles), ...

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