نتایج جستجو برای: sedimentary environments

تعداد نتایج: 199143  

2015
Douwe J. J. van Hinsbergen Hemmo A. Abels Wolter Bosch Flora Boekhout Alexander Kitchka Maartje Hamers Douwe G. van der Meer Mark Geluk Randell A. Stephenson

The Paleozoic Dniepr-Donets Basin in Belarus, Ukraine, and Russia forms a major hydrocarbon province. Although well- and seismic data have established a 20 km thick stratigraphy, field-studies of its sediments are scarce. The inverted Donbas segment (Ukraine) exposes the middle Carboniferous part of the basin's stratigraphy. Here, we provide detailed sedimentological data from 13 sections that ...

2015
Jena E. Johnson Samuel M. Webb Chi Ma Woodward W. Fischer

Oxidation of manganese (II) to manganese (III,IV) demands oxidants with very high redox potentials; consequently, manganese oxides are both excellent proxies for molecular oxygen and highly favorable electron acceptors when oxygen is absent. The first of these features results in manganese-enriched sedimentary rocks (manganese deposits, commonly Mn ore deposits), which generally correspond to t...

2017
Sandrine Bessette Yann Moalic Sébastien Gautey Françoise Lesongeur Anne Godfroy Laurent Toffin

Sitting at ∼5,000 m water depth on the Congo-Angola margin and ∼760 km offshore of the West African coast, the recent lobe complex of the Congo deep-sea fan receives large amounts of fluvial sediments (3-5% organic carbon). This organic-rich sedimentation area harbors habitats with chemosynthetic communities similar to those of cold seeps. In this study, we investigated relative abundance, dive...

2000
Christopher M. Fedo

Whether or not coarse detrital sedimentary rocks occur within the \3.7 Ga Isua Greenstone Belt (IGB), southern west Greenland, has been debated for some time. Repeated, regional metamorphic, deformational, and metasomatic events have obscured most protolith lithologies leading to misunderstandings about the stratigraphy and environments of deposition. Rocks here interpreted as meta-conglomerate...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2013
William D Leavitt Itay Halevy Alexander S Bradley David T Johnston

Phanerozoic levels of atmospheric oxygen relate to the burial histories of organic carbon and pyrite sulfur. The sulfur cycle remains poorly constrained, however, leading to concomitant uncertainties in O2 budgets. Here we present experiments linking the magnitude of fractionations of the multiple sulfur isotopes to the rate of microbial sulfate reduction. The data demonstrate that such fractio...

2015
Kathleen R. Stoof-Leichsenring Ulrike Herzschuh Luidmila A. Pestryakova Juliane Klemm Laura S. Epp Ralph Tiedemann

Genetic investigations on eukaryotic plankton confirmed the existence of modern biogeographic patterns, but analyses of palaeoecological data exploring the temporal variability of these patterns have rarely been presented. Ancient sedimentary DNA proved suitable for investigations of past assemblage turnover in the course of environmental change, but genetic relatedness of the identified lineag...

Journal: :Anais da Academia Brasileira de Ciencias 2014
Marcos A F Sales Paulo Cascon Cesar L Schultz

The paleobiogeography of the theropod clade Compsognathidae is here reaccessed in order to test the hypothesis of this taxon being adapted specifically to inhabit semi-arid environments. Data about localities where these fossils were collected and their paleoenvironments were gathered from the literature. Compsognathids seem to be found especially in sedimentary deposits known as Fossil Lagerst...

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