نتایج جستجو برای: organic geochemical

تعداد نتایج: 212630  

2008
E. Grosjean D. A. Fike

The South Oman Salt Basin (SOSB) is host to the world’s oldest known commercial deposits. Most of the South Oman oils have been proven to be associated with the source rocks of the Neoproterozoic to Cambrian Huqf Supergroup, but the assignment of oils to specific Huqf intervals or facies has been hampered by the geochemical similarity of the organic matter across the entire Huqf sequence, possi...

In this study, the concentrations of heavy metals (Ca, Zn, Cu, Fe, Mn, Ni) in thesediment of Shavoor River in Khuzestan Province in Iran has been investigated. After the library studies and field studies, six samples of water and sediment were taken from the river in order to evaluate heavy metal pollution in sediments. To determine the geochemical phases of metals in sediment samples the 5-ste...

Journal: :زمین شناسی اقتصادی 0
وحیده علیپور علی عابدینی

the zonouz kaolin deposit is located ~15 km northeast of marand, east-azarbaidjan province. based on physical features in field investigations, such as color, five distinct kaolin types including (1) white, (2) lemon, (3) gray, (4) brown, and (5) yellow are distinguished in the deposit. field evidence and petrographic studies indicate that the deposit is genetically close to trachy-andesite roc...

2013
Jessica R. Creveling David T. Johnston Simon W. Poulton Benjamin Kotrc Christian März Daniel P. Schrag Andrew H. Knoll

The fossilization of organic remains and shell material by calcium phosphate minerals provides an illuminating, but time-bounded, window into Ediacaran–Cambrian animal evolution. For reasons that remain unknown, phosphatic fossil preservation declined signifi cantly through Cambrian Series 2. Here, we investigate the phosphorus (P) sources for phosphatic Cambrian carbonates, presenting sediment...

2006
Elsie M. Sunderland Frank A.P.C. Gobas Brian A. Branfireun Andrew Heyes

Methylmercury production by sulfate reducing bacteria in coastal sediments leads to bioaccumulation of mercury in fish, shellfish, and ultimately humans. Sulfur, organic carbon, and sediment structure and composition can all affect methylmercury production by changing the amount of bioavailable inorganic mercury and by stimulating the activity of methylating microbes. This study investigates to...

Journal: :Science 2006
Martin Kennedy Mary Droser Lawrence M Mayer David Pevear David Mrofka

An enigmatic stepwise increase in oxygen in the late Precambrian is widely considered a prerequisite for the expansion of animal life. Accumulation of oxygen requires organic matter burial in sediments, which is largely controlled by the sheltering or preservational effects of detrital clay minerals in modern marine continental margin depocenters. Here, we show mineralogical and geochemical evi...

Journal: :geopersia 2015
mazaher yavari mehdi yazdi hormoz gahalavand mohammad hossein adabi

the investigated section cropping out in kuh-e-banesh, zagros basin (southern iran) is represented by limestone, cherty beds and marllevels bearing abundant planktonic foraminifers, radiolarian microfaunas, and ammonite imprints. for the first time, well to moderatelypreserved forms of planktonic foraminifera have been extracted from black shale and marls levels. extracted biota was studied wit...

Journal: :Applied and environmental microbiology 2008
Dariusz Strapoc Flynn W Picardal Courtney Turich Irene Schaperdoth Jennifer L Macalady Julius S Lipp Yu-Shih Lin Tobias F Ertefai Florence Schubotz Kai-Uwe Hinrichs Maria Mastalerz Arndt Schimmelmann

A series of molecular and geochemical studies were performed to study microbial, coal bed methane formation in the eastern Illinois Basin. Results suggest that organic matter is biodegraded to simple molecules, such as H(2) and CO(2), which fuel methanogenesis and the generation of large coal bed methane reserves. Small-subunit rRNA analysis of both the in situ microbial community and highly pu...

2015
Yassine El Frihmat Dierk Hebbeln EL Bachir Jaaidi Nadia Mhammdi

In order to assess the changes in sea-surface hydrology and productivity signal from the last glacial to the Holocene; a set of isotopic, geochemical and microgranulometric proxies was used for this study. Former studies revealed that the reconstruction of paleoproductivity from ocean sediment gives different results depending the measurement used. The comparison between our productivity proxie...

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