نتایج جستجو برای: travertine deposits
تعداد نتایج: 28658 فیلتر نتایج به سال:
Ancient historical references consistently describe an intoxicating gas, produced by a cavern in the ground, as the source of the power at the oracle of Delphi. These ancient writings are supported by a series of associated geological findings. Chemical analysis of the spring waters and travertine deposits at the site show these gases to be the light hydrocarbon gases methane, ethane, and ethyl...
We show that Zhang and Li's sedimentological model for the Chusang travertine neglects the three-dimensional information from multiple outcrops and that their optically stimulated luminescence (OSL) age of about 20,000 years for the human imprints is untenable. We highlight the robustness of our chronology and explore reasons why Zhang and Li's OSL age is a gross overestimation of the real depo...
A microstructural investigation by electron microscopy on a travertine specimen collected from Munigou National Park, Sichuan Province, China revealed evidence of a non-classical reversed crystal growth route previously only discovered in synthetic materials. Examination of the travertine specimen suggests that the presence of organic matter initiates the oriented aggregation of calcite nanocry...
Travertine deposits are a kind of continental carbonates that form in specific chemical, physical and biological conditions. Garab travertines in southeast of Mashhad are studied based on field, geochemistry (elemental and stable isotope analysis) and hydro-geochemistry analysis. Field and petrographic characterization led to recognize of crystalline crust, raft, foam, shrub, laminated, black m...
A dynamical theory of geophysical precipitation pattern formation is presented and applied to irreversible calcium carbonate (travertine) deposition. Specific systems studied here are the terraces and domes observed at geothermal hot springs, such as those at Yellowstone National Park, and speleothems, particularly stalactites and stalagmites. The theory couples the precipitation front dynamics...
Lipid biomarkers and C fractionation patterns were used to understand the dynamics of carbon cycling during microbial metabolisms in different environments of travertine precipitation (called facies) at Spring AT-1 on Angel Terrace in the Mammoth Hot Springs complex of Yellowstone National Park, USA. Microbial mats that encrust travertine deposits were collected for analyses of lipid biomarkers...
The south-eastern Gorny Altai is one of the most hazardous seismogenic area in north Central Asia. We present a synthesis field, 230Th-U geochronological, mineralogical and geochemical data collected on seven Quaternary travertines. All travertines occur within zones active faults that border Chuya Kurai intermontane basins. Travertine cement mainly comprises calcite (with minor amounts aragoni...
The Plio-Quaternary Ait Chaib basin occupies the northwestern part of Skoura Syncline, which is northern Middle Atlas Folded Zone. This intracontinental was formed probably in Pliocene after Tortono-Messinian regression sea. deposits are bound by fluvial conglomerates and continental carbonates. They consist barrage travertines; travertine limestones oncholitic silts sands upstream downstream d...
A series of fossil spring deposits are exposed along the Dixie Valley fault just south of the producing geothermal field, in an area now characterized by active fumaroles and steaming ground. These deposits are composed of both travertine and sinter that have trapped pollen and other plant material during their formation. Radiocarbon dates on the organic material indicate that the youngest hot ...
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