نتایج جستجو برای: permian system
تعداد نتایج: 2233955 فیلتر نتایج به سال:
The study area is located at the Soghanchi village (east of Miyandoab city, NW of Iran). The Oligocene age Soghanchi stock is intruded into Permian carbonate rocks during Pyrenean orogenic epoch. Petrographically, the main minerals of this intrusive are plagioclase, biotites, pyroxenes, olivines, hornblendes, and alkali-feldspars. The microscopic and geochemical assessments of intrusive, show g...
Permian stratigraphic sequences are widely distributed throughout Iranian, making this one of the best locations in the world to study15 this geological time interval. Nevertheless, some units lack detailed biostratigraphic characterization which is essential for16 palaeogeographic reconstructions. This preliminary study comprises a palynological assessment of a Permian stratigraphi...
r a 200 .015 : +1 570 qu.edu Summary Stable isotopes, radiogenic isotopes, and major ion chemistry are used to constrain flow paths in a fracture-controlled regional groundwater flow system in far west Texas. The flow system occurs in Permian and Cretaceous sedimentary rocks and Cenozoic alluvial basin fill. Samples from springs and wells in the study area were analyzed for major ions and hydro...
The bulk of Earth's coal deposits used as fossil fuel today was formed from plant debris during the late Carboniferous and early Permian periods. The high burial rate of organic carbon correlates with a significant drawdown of atmospheric carbon dioxide (CO2) at that time. A recent analysis of a high-resolution record reveals large orbitally driven variations in atmospheric CO2 concentration be...
This paper reports the mineralogical and geochemical compositions of the Late Permian C2, C5a, C5b, C6a, and C6b semianthracite coals from the Mahe mine, northeastern Yunnan, China. Minerals in the coals are mainly made up of quartz, chamosite, kaolinite, mixed-layer illite/smectite (I/S), pyrite, and calcite; followed by anatase, dolomite, siderite, illite and marcasite. Similar to the Late Pe...
a sequence of permian rocks crops out in northwest of khur in central alborz, north of iran. this sequence consists of the dorud (asselian-sakmarian), ruteh (artinskian-murgabian) and nesen (early djulfian) formations. the ruteh and nesen formations in alborz range were deposited in a shallow marine environment of the continental margin in the paleo-tethys. the ruteh formation with a thickness ...
Ichniotherium tracks with a relatively short pedal digit V (digit length ratio V/IV < 0.6) form the majority of yet described Late Carboniferous to Early Permian diadectomorph tracks and can be related to a certain diadectid clade with corresponding phalangeal reduction that includes Diadectes and its close relatives. Here we document the variation of digit proportions and trackway parameters i...
The Permian from China has a well-known terrestrial record where approximately 30 tetrapod taxa, including several therapsids, have been described. However, the record of therocephalians in China has remained elusive. Shiguaignathus wangi gen. et sp. nov., discovered in the Member III of the Naobaogou Formation, Nei Mongol, China, is here described. This is the first therocephalian recovered fr...
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