نتایج جستجو برای: sedimentary environment

تعداد نتایج: 527372  

Journal: :Frontiers in Earth Science 2023

Reconstructing the Late Pleistocene sedimentary environment history of Houtao Plain has great significance not only for revealing evolution Yellow River but also identifying formation paleolake and northern Ulan Buh Desert. This paper presents results facies framework based on a grain-size multi-parameter analysis optically stimulated luminescence 14 C dating drilling core DKZ06 with length 20....

2015
Guy B. M S. Ono J. Gutzmer Y. Lin

23 24 Large rounded pyrite grains (>1 mm), commonly referred to as ‘buckshot’ pyrites, are a characteristic feature of 25 the auriferous conglomerates (reefs) in the Witwatersrand and Ventersdorp supergroups. Detailed petrographic 26 analyses of the reefs indicated that the vast majority of the buckshot pyrites are of reworked sedimentary origin, 27 i.e., that the pyrite originally formed in th...

Journal: :Science 2014
J P Grotzinger D Y Sumner L C Kah K Stack S Gupta L Edgar D Rubin K Lewis J Schieber N Mangold R Milliken P G Conrad D DesMarais J Farmer K Siebach F Calef J Hurowitz S M McLennan D Ming D Vaniman J Crisp A Vasavada K S Edgett M Malin D Blake R Gellert P Mahaffy R C Wiens S Maurice J A Grant S Wilson R C Anderson L Beegle R Arvidson B Hallet R S Sletten M Rice J Bell J Griffes B Ehlmann R B Anderson T F Bristow W E Dietrich G Dromart J Eigenbrode A Fraeman C Hardgrove K Herkenhoff L Jandura G Kocurek S Lee L A Leshin R Leveille D Limonadi J Maki S McCloskey M Meyer M Minitti H Newsom D Oehler A Okon M Palucis T Parker S Rowland M Schmidt S Squyres A Steele E Stolper R Summons A Treiman R Williams A Yingst

The Curiosity rover discovered fine-grained sedimentary rocks, which are inferred to represent an ancient lake and preserve evidence of an environment that would have been suited to support a martian biosphere founded on chemolithoautotrophy. This aqueous environment was characterized by neutral pH, low salinity, and variable redox states of both iron and sulfur species. Carbon, hydrogen, oxyge...

Journal: :دیرینه شناسی 0
محمد شریفی ابراهیم قاسمی نژاد مریم اختری

the sarcheshmeh formation is a shaly sequence of lower cretaceous age (aptian) which is deposited in koppeh-dagh sedimentary basin and conformably overlies and underlies the tirgan and sanghaneh formations respectively in the toos well # 1. lithologically, this formation has a thickness of 177m and consists mainly of marl, shale and shaly limestone. palynological studies resulted in identificat...

Introduction The territory of central Iran is now affected by the hot and dry climate. But, several evidences, such as the extreme erosion of running waters, huge alluvial fans, wide alluvial terraces, and flood deposits indicate colder and wetter climate in the territory (Ghahroodi Tali, 2011: 3). The rivers belong to the most important parts of the sedimentary basin. In fact, the rivers are...

Journal: :Geobiology 2008
Noah Planavsky Kathleen Grey

The extensive and well-preserved Neoproterozoic Acaciella australica Stromatolite assemblage of Australia is ideal for examining the relative roles of microbial and environmental influences on stromatolite branching and stromatolite macrostructure across a wide geographical area. Detailed sedimentological analyses indicate that the basal hemispheroidal section of bioherms contains abundant sedi...

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