نتایج جستجو برای: sedimentary model

تعداد نتایج: 2113533  

2015
Shigekazu Kusumoto Yasuto Itoh Keiji Takemura Tomotaka Iwata

In the two-dimensional discrete element modeling of displacement of sedimentary layers caused by faulting within the basement, we attempted to move a rigid basement as if it were an elastic basement by controlling its motion through application of dislocation solutions. An advantage of our modeling procedure is that we can discuss displacement fields of sedimentary layers in connection with fau...

1986
Steven A. Austin John D. Morris

Introduction Evolutionists and creationists have different views on the origin of sedimentary rock strata. Evolutionists, who uphold the uniformitarian doctrine of 19th century geologists, suppose that most sedimentary strata were deposited slowly over millions of years as the Earth evolved gradually to its present configuration. Creationists who uphold the catastrophist doctrine of Scripture p...

Journal: :Science 2014
S M McLennan R B Anderson J F Bell J C Bridges F Calef J L Campbell B C Clark S Clegg P Conrad A Cousin D J Des Marais G Dromart M D Dyar L A Edgar B L Ehlmann C Fabre O Forni O Gasnault R Gellert S Gordon J A Grant J P Grotzinger S Gupta K E Herkenhoff J A Hurowitz P L King S Le Mouélic L A Leshin R Léveillé K W Lewis N Mangold S Maurice D W Ming R V Morris M Nachon H E Newsom A M Ollila G M Perrett M S Rice M E Schmidt S P Schwenzer K Stack E M Stolper D Y Sumner A H Treiman S VanBommel D T Vaniman A Vasavada R C Wiens R A Yingst

Sedimentary rocks examined by the Curiosity rover at Yellowknife Bay, Mars, were derived from sources that evolved from an approximately average martian crustal composition to one influenced by alkaline basalts. No evidence of chemical weathering is preserved, indicating arid, possibly cold, paleoclimates and rapid erosion and deposition. The absence of predicted geochemical variations indicate...

2010
Christopher J. Somes Andreas Schmittner Eric D. Galbraith Moritz F. Lehmann Mark A. Altabet Joseph P. Montoya Ricardo M. Letelier Alan C. Mix Annie Bourbonnais Michael Eby

[1] We present a new nitrogen isotope model incorporated into the three‐dimensional ocean component of a global Earth system climate model designed for millennial timescale simulations. The model includes prognostic tracers for the two stable nitrogen isotopes, N and N, in the nitrate (NO3 ), phytoplankton, zooplankton, and detritus variables of the marine ecosystem model. The isotope effects o...

2003
Scott M. McLennan

Terrestrial planetary surfaces, other than Earth, are overwhelmingly basaltic in character. Because of this, among the most intriguing and significant results from recent studies of Mars are the occurrences of high-silica rocks at the Pathfinder site and orbital thermal emission spectroscopy evidence for a global petrological dichotomy with andesites dominating the entire northern hemispheric p...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2012
Jens Kallmeyer Robert Pockalny Rishi Ram Adhikari David C Smith Steven D'Hondt

The global geographic distribution of subseafloor sedimentary microbes and the cause(s) of that distribution are largely unexplored. Here, we show that total microbial cell abundance in subseafloor sediment varies between sites by ca. five orders of magnitude. This variation is strongly correlated with mean sedimentation rate and distance from land. Based on these correlations, we estimate glob...

Journal: :Astrobiology 2011
John Grotzinger David Beaty Gilles Dromart Sanjeev Gupta Mitch Harris Joel Hurowitz Gary Kocurek Scott McLennan Ralph Milliken Gian Gabrielle Ori Dawn Sumner

Processes that operate at planetary surfaces have the potential to record a history of planetary evolution in the form of sedimentary rocks. This is important because our experience on Earth shows that sediments and sedimentary rocks are the dominant archive of high-resolution proxies of present and past tectonic, climatic, and biological processes. Our understanding of the evolution of Earth’s...

2010
Homa Lee

Our goals are to understand how geotechnical and physical properties develop in marine sedimentary deposits on continental margins and how these properties influence sediment transport processes and the development of geomorphology. Our studies include predicting stability of sediment on the continental shelf and slope, providing input parameters for models of sediment transport and deformation...

Journal: :The Journal of the Acoustical Society of America 1998
A N Ivakin D R Jackson

It is known that marine sediments can support both compressional and shear waves. However, published work on scattering from irregular elastic media has not examined the influence of shear on sea bed scattering in detail. A perturbation model previously developed by the authors for joint roughness-volume scattering is used to study the effects of elasticity for three sea bed types: sedimentary ...

2011
Alessandro Iannace

Sedimentary rocks are one component of the modern threefold classification of rocks. They derive from the lithification of sediments, which are produced in basically two ways: by the mechanical deposition of grains derived from the alteration of other rocks (detrital or clastic rocks), or as chemical precipitates or grains formed organically or inorganically from an aqueous solution. The whole ...

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