نتایج جستجو برای: chemical weathering

تعداد نتایج: 382710  

2009
E. B. Rampe M. D. Kraft T. G. Sharp

Introduction: Chemical weathering and petrologic trends of the martian surface have been estimated from thermal infrared (TIR) spectral models from the Thermal Emission Spectrometer (TES) and Mini-TES on the Spirit and Opportunity rovers [1,2]. Interpretations of chemical data from APXS on the MER rovers and TIR data from TES and the Thermal Emission Imaging System (THEMIS) suggest planet-wide ...

2007
Michael T. Hren C. Page Chamberlain George E. Hilley Peter M. Blisniuk Bodo Bookhagen

The Yarlung Tsangpo–Brahmaputra river drains a large portion of the Himalaya and southern Tibetan plateau, including the eastern Himalayan syntaxis, one of the most tectonically active regions on the globe. We measured the solute chemistry of 161 streams and major tributaries of the Tsangpo–Brahmaputra to examine the effect of tectonic, climatic, and geologic factors on chemical weathering rate...

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...

2007
Ronald Amundson Esteban G. Jobbágy Jérôme Gaillardet

The Earth has an average surface temperature of about 15°C, which is, in terms of planetary conditions suitable for life, the equivalent of winning the cosmic lottery. Yet, without an atmosphere filled with biological waste gases capable of retaining heat (O2, N2O, CH4, CO2), the average temperature of the planet would be about −18°C (Smil 2002), making the present diversity and abundance of li...

2011
PATRICIA L. CORCORAN KATRINA PACKER MARK C. BIESINGER

Chemical and mechanical weathering textures on siliciclastic grains have provided important information concerning depositional processes and environments, yet understanding is limited by the multicycle origin of most sedimentary deposits. Sea glass grains sampled from a beach in Port Allen, Kauai, Hawaii, were analyzed for mechanical and chemical weathering features using scanning electron mic...

2000
MAGNUS LAND BJÖRN ÖHLANDER

Chemical weathering rates and erosion rates of granitic till in northern Sweden have been estimated. The present-day chemical weathering rate is compared with the long-term average weathering rate since the last deglaciation approximately 8,700 years ago. Also, the present-day release rates of major and trace elements due to chemical weathering are compared with the mobility of these elements i...

Journal: :Science 2014
Isaac J Larsen Peter C Almond Andre Eger John O Stone David R Montgomery Brendon Malcolm

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...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2011
Xiao-Ming Liu Roberta L Rudnick

Chemical weathering, as well as physical erosion, changes the composition and shapes the surface of the continental crust. However, the amount of continental material that has been lost over Earth's history due to chemical weathering is poorly constrained. Using a mass balance model for lithium inputs and outputs from the continental crust, we find that the mass of continental crust that has be...

2011
Y. Graz

This study relates to the input and fate of fossil organic matter (FOM) in the modern environment, and focuses on two experimental watersheds overlying Jurassic marls: Le Laval and Le Brusquet (1 km 2 in area), located near Digne, Alpes-de-Haute-Provence, France. Considering that FOM delivery is mainly a result of different processes affecting sedimentary rocks [(bio)chemical and mechanical wea...

2008
Masayoshi Shimizu Cristian Taccioli Nicola Zanesi

Continental crust rises higher than oceanic crust because it is less dense: It is rich in Si and poor in Mg. However, basalt, which is derived from magma, is denser and has a higher ratio of Mg to Si than the rock that makes up mature continental crust. Cin-Ty Lee et al. argue that chemical weathering alters the composition of continental crust as it ages and helps give it its more buoyant char...

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