نتایج جستجو برای: oil weathering processes

تعداد نتایج: 666843  

2017
Jiangtao Li Jiamei Cui Qunhui Yang Guojie Cui Bingbing Wei Zijun Wu Yong Wang Huaiyang Zhou

When its hydrothermal supply ceases, hydrothermal sulfide chimneys become inactive and commonly experience oxidative weathering on the seafloor. However, little is known about the oxidative weathering of inactive sulfide chimneys, nor about associated microbial community structures and their succession during this weathering process. In this work, an inactive sulfide chimney and a young chimney...

2008
G. M. Marion

Research Professor of Ecology, Systems Ecology Research Group, San Diego State University, San Diego, California 92182 Abstract: The objective of this paper is to assess the role of mineralization processes (pyrolysis, decomposition, and weathering) on nutrient (N, P, K, Ca, Mg, and S) release in mediterranean-type ecosystems. Decomposition is the most important process for N release. Decomposi...

2016
Christian Schröder Phil A. Bland Matthew P. Golombek James W. Ashley Nicholas H. Warner John A. Grant

Spacecraft exploring Mars such as the Mars Exploration Rovers Spirit and Opportunity, as well as the Mars Science Laboratory or Curiosity rover, have accumulated evidence for wet and habitable conditions on early Mars more than 3 billion years ago. Current conditions, by contrast, are cold, extremely arid and seemingly inhospitable. To evaluate exactly how dry today's environment is, it is impo...

2014
M. R. Salvatore

a r t i c l e i n f o a b s t r a c t Classic low-albedo regions of the martian surface are investigated using combined reflectance and emission (" pan-spectral ") data to constrain the types of alteration mineral phases that are present at spectrally significant abundances (>10–15%). The lack of hydrated mineral species observed using near-infrared data suggests that anhydrous chemical alterat...

2017
Cheng Xu Jindřich Kynický Martin P. Smith Antonin Kopriva Martin Brtnický Tomas Urubek Yueheng Yang Zheng Zhao Chen He Wenlei Song

Heavy rare earth elements (HREE) are dominantly mined from the weathering crusts of granites in South China. Although weathering processes occur globally, no economic HREE resources of this type have yet been found outside China. Here, we report the occurrence of unidentified REE minerals in the granites from South Chinese deposits. They contain high levels of both HREE and light REE, but are s...

2014
M. S Thompson T. J Zega

Introduction and Motivation: Mineral grains on the surfaces of airless planetary bodies like the Moon are subjected to continuous radiation processing from solar energetic ions and also experience micrometeorite impact events. Together these processes alter the morphology, chemistry, and microstructure of surface particles and are collectively known as space weathering [1]. The optical properti...

2016
Ute Schoknecht Helena Mathies Robby Wegner

BACKGROUND Biocidal products can be sources of active substances in surface waters caused by weathering of treated articles. Marketing and use of biocidal products can be limited according to the European Biocidal Products Regulation if unacceptable risks to the environment are expected. Leaching of active substances from treated articles was observed in field experiments to obtain information ...

2004
R. Van Grieken F. Delalieux K. Gysels

Air pollution can have a significant influence on the weathering of monuments and on the deterioration of museum objects and prehistoric cave paintings. Three important mechanisms of stone weathering will be discussed, and an overview of analysis techniques invoked for the assessment of the degradation processes will be given. The effects of several air pollutants on works of art are reviewed, ...

2004
T. Meixner J. R. Shaw R. C. Bales

A reaction set of possible mineral weathering reactions is proposed to explain observed cation and silica export for the Emerald Lake watershed, a small Sierra Nevada, California catchment. The reaction set was calculated through a stoichiometric mole-balance method, using a multiyear record of stream flow and snowpack chemical analyses and site-specific mineral compositions. Reaction-set calcu...

Journal: :Current Biology 2012
Nicholas Clipson Deirdre B. Gleeson

Fungi play major roles in biogeochemistry and are responsible for many metal transformations during mineral weathering. A recent finding that fungi transform lead to chloropyromorphite highlights the importance of fungi in biogeochemical processes.

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