نتایج جستجو برای: dacite
تعداد نتایج: 251 فیلتر نتایج به سال:
The present study aimed to evaluate the ability of a mixture gabbro powder and dacite promote plant growth, provide nutrients alter soil chemical characteristics. Two experiments were conducted under different field conditions, in which black oat beans added with increasing doses (0 10 t ha-1) rock blend. grain yield (beans), dry matter production (oats) nutritional status crops evaluated. At e...
The Indian Peak volcanic field is representative of the more than 50,000 km3 of ashflow tuff and tens of calderas in the Great Basin that formed during the Oligocene-early Miocene "ignimbrite flareup" in southwestern North America. The field formed about 32 to 27 Ma in the southeastern Great Basin and consists of the centrally positioned I n d i Peak caldera complex and a surrounding blanket of...
New analytical and experimental data constrain the storage and equilibration conditions of the magmas erupted in 1912 from Novarupta in the 20th century’s largest volcanic event. Phase relations at H2O+CO2 fluid saturation were determined for an andesite (58.7 wt% SiO2) and a dacite (67.7 wt%) from the compositional extremes of intermediate magmas erupted. The phase assemblages, matrix melt com...
sahand volcanic-sub-volcanic dome, along with several other magmatic domes in northwest iran and the southern part of tabriz fault show adakitic geochemical characteristics. sahand dome has mainly dacitic composition. the sio2 content and mg number of sahand dome range from 64 to 73 wt% and 27 to 57 respectively. sahand dome can be classified as high silica adakitic (hsa) type. the rocks studie...
Volcán San Pedro in the Andean Southern Volcanic Zone (SVZ) Consequently, the role of young, unradiogenic hydrous gabbro in Chile, comprises Holocene basaltic to dacitic lavas with trace generating dacite and contaminating basalt may be underappreciated element and strontium isotope ratios more variable than those of in the SVZ. most Pleistocene lavas of the underlying Tatara–San Pedro complex....
behaviour characterized by nearly steady extrusion of a solid dacite plug and nearly periodic shallow earthquakes. Diverse data motivate the hypothesis that these earthquakes resulted from stick-slip motion along the margins of the plug as it was forced incrementally upward by ascending, solidifying, gas-poor magma. We formalize this hypothesis with a dynamical model that reveals a strong analo...
we present new whole major and trace elements data for a suite of adakitic dacite to rhyolite rocks from the sahand region. these rocks formed in the pliocene to pleistocene during the the collision between the arabian and eurasian plates following subduction of neo–tethys ocean. these subvolcanic intrusions were emplaced into late cretaceous and eocene sedimentary، volcano–clastic and volcanic...
The Wadi Hodein area contains a wide variety of late Precambrian igneous and metamorphic rocks, represented by gneisses, serpentinites, metagabbros, metasediments, metavolcanics, metagabbro-diorite, granodiorite and granitoids. The Wadi Hodein metavolcanics (WHV), including G. Khashab and G. El Anbat, represent one of the significant metavolcanic suites in the southern part of the Nubian Shield...
The Ela Mountain area is located at the easternmost point of East Kunlun Orogen, in which voluminous igneous rocks developed Triassic period, and it a good place to investigate tectonic evolution Paleo-Tethys Ocean. In this study, petrological, geochemical, zircon U-Pb geochronology Hf isotope studies were carried out on volcanic area. Dacite (239.3 ± 1.4 Ma) exhibits calc-alkaline I-type chara...
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