نتایج جستجو برای: dacitic
تعداد نتایج: 177 فیلتر نتایج به سال:
Nodushan Zn-Pb deposit at the western margin of Urumieh-Dokhtar volcano-plutonic belt resulted from granitoid intrusion into Eocene dacitic to andesitic rocks. Pyrite, sphalerite, galena and chalcopyrite are the main sulfide minerals. The chemical composition of sphalerites and pyrites indicates two different type of sphalerite (high Fe types demonstrating chalcopyrite disease and low Fe type) ...
The Arvaneh volcanic cone at eastern part of the Sahand volcanic complex is located on SW of Bostanabad city. This cone having lava composition as dacite, dacitic andesite and rhyodacite, is formed eletted to young volcanic activity of the Sahand volcanism. Having various colours and textures form dominant composition of the lavas in the Petrographycally phenocrysts are plagioclase+hornblende+b...
The bentonites of Aftar region, with average of 15 meters thickness and about 10 km long, are volcanoclastic sequence of Semnan Formation that formed in a shallow sea water environment. Based on the field, XRD data, microscopic and scanning electron microscopic (SEM) studies, as well as chemistry, the bentonite beds contain zeolites (clinoptilolite and mordenite), gypsum, calcite, celestine, op...
Taftan volcano, is located in about 100 Km South to Southeast of Zahedan, Sistan and Baluchestan province in southeast of Iran. On geological point of view, it is located at the end of Nehbandan-Khash flysch and North Makran structural zones. Field, petrographic and geochemical studies from different samples of rocks show that the volcano mostly composed of andesitic and dacitic rocks. These ro...
The Baharieh kaolin deposit (east Kashmar, Khorasan Razavi Province) is the product of alteration of dacitic rocks (Eocene) and is located in the Khaf-Kashmar-Bardaskan metallogenic belt. Field observations show that the development of this deposit was controlled by the tectonic system of the area and the presence of silica cap is the most important geological feature of this deposit. Mineralog...
Noble gas isotopic composition of fluid inclusions was analyzed in amphibole, plagioclase and clinopyroxene phenocrysts from the shoshonitic dacitic volcanic products Ciomadul dome field, youngest system within Carpathian-Pannonian Region. The highest Rc/RA ratios (3.0–3.8 RA) were obtained for high-mg Malnaş shoshonite. High-Al amphiboles Bixad pumices have between 1.16 2.11 RA. These values o...
Abstract The Los Humeros Volcanic Complex has been characterized as a suitable target for developing super-hot geothermal system (> 350 °C). For the interpretation of geophysical data, development and parametrization numerical geological models, an extensive outcrop analogue study was performed to characterize all relevant key units from basement cap rock regarding their petrophysical proper...
Porphyry and epithermal deposits are important sources of base precious metals. Most actively mined have been exhumed such that ore bodies relatively close to the surface therefore locatable economic extract. Identifying characterizing concealed deposits, particularly more deeply buried porphyry represents a far greater challenge for mineral exploration, will become progressively as near-surfac...
Abstract Mocho-Choshuenco volcano has produced several highly explosive eruptions during its history, which make it one of the most hazardous volcanoes in southern volcanic zone Chile, although is still relatively little studied to date. We present a geochemical study products sub-Plinian, andesitic, Enco eruption that occurred about 1600 years ago. determined major and trace elements compositi...
The Permian marks the transition between end of accretion supercontinent Pangea and beginning its dislocation. In Eastern intertropical domain (i.e. present-day Western Europe), late-Paleozoic uppermost Carboniferous–Permian) history remains poorly constrained due to lack precise radiometric data. This is particularly true for basins from southern part French Massif Central, making it difficult...
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