نتایج جستجو برای: dacitic
تعداد نتایج: 177 فیلتر نتایج به سال:
Mt. Pinatubo is one of several recent-age volcanoes along the west Luzon volcanic arc. A fumarole near the suminit emits gases with magmatic characteristics. Several thermal springs on the east and west flanks yield various fluid typos, including neutral chloride and bicarbonate. Three wellbores probed the Mt. Pinatubo caldera from elevations of +1230 through -1600 mRSL. Trajectories may be des...
TheOrdovician volcanic and intrusive rocks of the Cadia–Neville region, in the southern Molong Volcanic Belt section of the Macquarie Arc in central-western New South Wales, display a temporal progression from shoshonitic basaltic volcanism (e.g. Mt Pleasant Basalt Member) in the late Darriwilian to Gisbornian (ca 460–453 Ma) to small-volume dacitic medium-K calc-alkaline magmatism (e.g. Copper...
After 11 5 ka of quiescence (24 5–13 ka), the Nevado de Toluca volcano started a 2500 year period of activity. This period was characterized by a dome destruction event at 13 ka, a small Plinian event at 12 1 ka, and a large Plinian eruption at 10 5 ka. About 10 km of magma was erupted that was homogeneous in composition (63 3–65 7 SiO2 wt % whole-rock) and in mineralogy. Pumice consists of pla...
Sulfur is a key element in terrestrial magmatic processes yet its geochemical behavior remains one of the most difficult to model due heterovalent chemistry. The maximum amount sulfur silicate melt can dissolve before saturating with sulfide (e.g., pyrrhotite) or sulfate anhydrite) changes redox state system and has important implications for budget system. Several empirical models have been de...
remains of fossil herbivorous mammal from families like elephantidae, rhinocerotidae, giraffidae, bovidae and equidae have been studied systematically from a new fossiliferous horizon from the ilkhchi area in the southeastern high foothills of sahand. genera such as hipparion, gazella, samotherium, chilotherium and choerolophodon and some undetermined specimens are identified and reported. base...
in the central iranianvolcanic belt (civb), north-west of shahre-babak, in the area of javazm, dehaj and khabr, about 60 subvolcanic porphyritic dacitic to rhyodacitic domes (1-10 km2) are intruded into a variety of rock sequences from mesozoic to early miocene in age. these rocks are a part of dehaj-sardoieh belt. the civb contains intrusive and extrusive rocks of cretaceous-quaternary age. ge...
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