نتایج جستجو برای: diagenetic origin

تعداد نتایج: 200395  

2016
P. J. Tomiak E. K. Potter K. G. Johnson

Past variations in global sea-level reflect continental ice volume, a crucial factor for understanding the Earth’s climate system. The Caribbean coral Acropora palmata typically forms dense stands in very shallow water and therefore fossil samples mark past sea-level. Uranium-series methods are commonly used to establish a chronology for fossil coral reefs, but are compromised by post mortem di...

Journal: :Journal of environmental quality 2010
Xiaoxuan Ma Yong Ran Jian Gong Diyun Chen

Sixteen USEPA priority polycyclic aromatic hydrocarbons (PAHs) extracted by Soxhlet extraction (S-PAHs) with dichloromethane and routine accelerated solvent extraction (A-PAHs) with 1:1 toluene/methanol, respectively, were investigated in 24 soil samples from two cities in the center of the Pearl River Delta, South China. Polycyclic aromatic hydrocarbons, methylphenanthrene and perylene, in two...

Journal: :Applied Geochemistry 2022

In this contribution, the origin of fluids having cemented Jurassic limestones in eastern part Paris Basin is discussed through isotopic composition (δ18O, δ13C, 87Sr/86Sr) authigenic calcite crystals filling vugs and fractures. The Upper Middle limestones, overlying underlying Callovian-Oxfordian claystones, experienced dissolution crystallization leading to a succession cements depleted 18O e...

2012
James J. Wray

Gale crater formed from an impact on Mars *3.6 billion years ago. It hosts a central mound nearly 100 km wide and *5 km high, consisting of layered rocks with a variety of textures and spectral properties. The oldest exposed layers contain variably hydrated sulphates and smectite clay minerals, implying an aqueous origin, whereas the younger layers higher on themound are covered by amantle of d...

Journal: :Environmental science & technology 2005
Natalia Garcia-Reyero Benjamin Piña Joan O Grimalt Pilar Fernández Roger Fonts Oliva Polvillo Belen Martrat

Superficial and bottom sediment samples from 83 European mountain lakes, ranging from Norway to the Pyrenees and East Europe, were tested for estrogenic compounds by the recombinant yeast assay. The results showed widespread potential estrogenic activity arriving at remote lakes. Tatra Mountains (Slovakia) and Scotland Highlands were the regions with the highest prevalence of lakes with high es...

The Chehel Kaman Formation of the upper Paleocene age formed from carbonate and siliciclastic sediments is located, in the Kapeh Dagh Sedimentary Basin. Two sections where considered for the purpose of research into the effective diagenetic processes of this formation. The Cheshmeh Qorban section with a thickness of 270.8m located 140km down the Mashhad – Sarakhs Highway while the Shourlog Sect...

موسوی حرمی, رضا , خانه باد, محمد , محبوبی, اسداله,

The (Early Carboniferous) Shishtu 2 Formation at the study area is composed of a shallowing upward sequence. Skeletal packstones consist of crinoids, brachiopods, bryozoans, trilobites, corals and rare foraminiferas. The carbonates of this formation have undergone a complex diagenetic history and the most diagenetic events are silicification and pyritization. The complexity of silicification in...

2009
M. Dumont N. Zoeger C. Streli P. Wobrauschek G. Falkenberg P. M. Sander A. R. Pyzalla

Sauropod dinosaurs were typically one magnitude larger than any other living or extinct terrestrial animal. This sheer size of the sauropod leads to scale effects in their biology and physiology that still are inadequately understood. The only remnants of the sauropods are their fossilized bones. These fossilized bones have sustained burial for some hundred million years and thus may have exper...

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