نتایج جستجو برای: alkaline volcanic
تعداد نتایج: 57247 فیلتر نتایج به سال:
Pitchblende mineralization was studied in the younger granite samples collected from Gabal Gattar, north Eastern Desert, Egypt using electron scanning microscope (ESM) and electron probe microanalyses (EPMA). This study revealed that this pitchblende contains significant Zr content reaching up to (66.80% ZrO2), which suggests that volcanic rocks were probably the source of such a deposit. High ...
In north to northeast of Baft city, south Kerman, various outcrops of volcanic rocks, belong to Uromieh-Dokhtar magmatic belt, are observed. This region in Kerman Province situated in east of Dehaj – Sarduiye magmatic belt. Most of volcanic sequences in this area are andesite, andesite-basalt, dacite, and a few basalt and rhyolite with Eocene age that interlayered with pyroclastic and volcano s...
Damavand is a fascinating dormant stratovolcano, 60 km to the ENE of Tehran located in the Alborz Mountains. Damavand volcanic products consist of lava flows and pyroclastic fall, flow and surge deposits from different eruption cycles. The volcanic rocks ranges from trachyandesite to trachyadacite and minor basalt. The mineral assemblage consists of potash feldspar (Or43/7), Plagioclase (An25 t...
Intraplate volcanism initiated shortly after the cessation of Cenozoic seafloor spreading in the South China Sea (SCS) region, but the full extent of its influence on the Indochina block has not been well constrained. Here we present major and trace element data and Sr-Nd-Pb-Hf isotope ratios of late Cenozoic basaltic lavas from the Khorat plateau and some volcanic centers in the Paleozoic Sukh...
The Cenozoic volcanic activity of the Harrat Ash Sham volcanic field in south of Syria is a part of the extensive magmatism that took place in the auxiliary extension faults along the Dead Sea Fault Zone from upper Eocene to Holocene. Pliocene volcanic rocks form an important part of igneous succession in Syrian Part of Harrat as Sham. These rocks vary from basalts flows to scoria. Pliocene bas...
Zavarian epitermal gold (copper) deposit is located in an intracontinental volcanic cone (stratovolcano) with the Early Miocene age, in the middle of the Urmia-Dokhtar magmatic arc. The host rocks of this mineralization include a set of basaltic, andesitic-basaltic, andesitic, dacitic, as well as granodiorite and tonal units that have been exposed in volcanic form (lava and pyroclastic) and sem...
Around The Karik village, east of Meiduk mine, Eocene volcanic rocks (andesitic basalt, andesite, dacite and rhyolite) and pyroclastic rocks (agglomerate and tuff) are exposed. These rocks are cut by several andesitic dikes. The major textures in the volcanic rocks are porphyritic and flow textures. The minerals such as plagioclase, alkali feldspar, quartz, pyroxene, amphibole, biotite and opaq...
Sixteen new K-Ar dates are presented from Tasmanian and Bass Basin basalts, more than doubling the previously published number. Eight volcanic regions are described, based on boundaries established on the range of the basalt types contained in each geographic region. Volcanism occurred within the span from Eocene to Miocene (47 to 13+ Ma), but mainly within the time range Middle Eocene to Early...
Cenozoic volcanic activity in Morocco started the Miocene and proceeded, after a short break, during Pliocene Quaternary. Calc-alkaline magmatic occurred first was accompanied by eruption of transitional lavas, followed Plio-Quaternary alkali basaltic activity, which emplaced within Neogene sedimentary basins Rif belt its foreland. From calc-alkaline to alkaline magmatism, passing through term,...
نمودار تعداد نتایج جستجو در هر سال
با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید