نتایج جستجو برای: mechanical weathering

تعداد نتایج: 242214  

2013
Gaojun Li Henry Elderfield

It is generally accepted that progressive cooling of global climate since the Late Cretaceous results from decreasing partial pressure of atmospheric CO2 (pCO2). However, details on how and why the carbon cycle evolved and how it would affect pCO2 have not been fully resolved. While the long-term decline of pCO2 might be caused by the decrease of volcanic degassing through the negative feedback...

ژورنال: مسکن و محیط روستا 2019
Baghbanan, Alireza, Crosta, Giovanni b., Emami, Sayad Mohammad amin, razani, Mehdi,

Kandovan historical village is one of the most important attractive tourist sites on rocky architectures in East Azerbaijan province from the Skirts of Sahand Volcano NW of Iran. This village with unique landscape and rocky historical architecture is on the surfaces of a tuff layer. Nowadays, natural surface weathering of this architecture and intensity of decay phenomena in Kandovan village ro...

2010
James S. Fabiyi Armando G. McDonald

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...

2012
Mary J. Thornbush

The authenticity of much of the stone-work along Queen’s Lane in central Oxford, UK presented an opportunity to produce a photographic survey from which a weathering index could be established. This represents a site-specific approach to devising a weathering form. Because it is photo-based, weathering forms are visible for comparison and classification purposes across disciplines. Limestone pe...

2015
Joe Quirk Jonathan R. Leake David A. Johnson Lyla L. Taylor Loredana Saccone David J. Beerling

How the colonization of terrestrial environments by early land plants over 400 Ma influenced rock weathering, the biogeochemical cycling of carbon and phosphorus, and climate in the Palaeozoic is uncertain. Here we show experimentally that mineral weathering by liverworts—an extant lineage of early land plants—partnering arbuscular mycorrhizal (AM) fungi, like those in 410 Ma-old early land pla...

2007
G. A. Shields

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...

2007
Leonard F. DeBano Paul H. Dunn

Supervisory Soil Scientist, Rocky Mountain Forest and Range Experiment Station, Tempe, Arizona; and Soil Microbiologist, Pacific Southwest Forest and Range Experiment Station, Glendora, California. The weathering of parent rock may be an important source of some nutrients. The rates of weathering of the different parent rock materials vary and affect the inherent fertility and productivity of a...

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...

2011
Jon D. Pelletier Victor R. Baker

[1] Numerical models of bedrock valley development generally do not include weathering explicitly. Nevertheless, weathering is an essential process that acts in concert with the transport of loose debris by seepage and runoff to form many bedrock valleys. Here we propose a numerical model for bedrock valley development that explicitly distinguishes weathering and the transport of loose debris a...

Journal: :Applied and environmental microbiology 2010
Christophe Calvaruso Marie-Pierre Turpault Elisabeth Leclerc Jacques Ranger Jean Garbaye Stéphane Uroz Pascale Frey-Klett

In acidic forest soils, availability of inorganic nutrients is a tree-growth-limiting factor. A hypothesis to explain sustainable forest development proposes that tree roots select soil microbes involved in central biogeochemical processes, such as mineral weathering, that may contribute to nutrient mobilization and tree nutrition. Here we showed, by combining soil analyses with cultivation-dep...

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