نتایج جستجو برای: hydrothermal alteration
تعداد نتایج: 61420 فیلتر نتایج به سال:
The north western part of volcano-sedimentary complex of Davazdah-Emam mountain in north of Central Iran is located about 135 km SE Tehran. The Eocene to Oligocene volcanic rocks and dikes of intermediate to mainly basic of complex under the influence of hydrothermal fluids, probably associated with the involvement of meteoric water, experienced different degrees of alteration. The alteration o...
MA-II area is one of the most important parts of Cu-Au porphyry mineralization at Maherabad prospect area. Subvolcanic intermediate intrusive rocks (Upper Eocene), monzonite to diorite in compositions, intruded telescopically and are mostly altered. Monzonitic porphyries had major role in mineralization. These intrusive rocks are highly altered, have dense stockwork veinlets, and show highest g...
this paper presents the new geochemical isotopes sr and nd, and the mineralization data for the south neyshabour volcanic rocks located in ne iran. based on the chemical classifications, the studied rocks are basaltic trachy andesite, trachy andesite, trachyte, and trachy dacite in composition. all the analyzed volcanic rocks display enrichment in light rare earth elements (lree) relative to th...
Thellier-type paleointensity experiments were conducted on welded ash matrix or pumice from the 1912 Novarupta (NV) and 1980 Mt. St. Helens (MSH) pyroclastic density currents (PDCs) with the intention of evaluating their suitability for geomagnetic paleointensity studies. PDCs are common worldwide, but can have complicated thermal and alteration histories. We attempt to address the role that em...
Mn-bearing veins of Jonub -ESehchangi are located 200 km southwest of Birjand, Southern Khorasan province (east of Iran). These veins are hosted by andesitic rocks of Eocene to Oligocene ages. Ore minerals identified by XRD method and mineralographic studies and are Pyrolusite, cryptomelane, psilomelane, hollandite, hematite and goethite, displaying colloform and open-space filling textures. G...
Volcanoes are unstable structures that deform laterally and frequently experience mass wasting events. Hydrothermal alteration is often invoked as a mechanism contributes significantly to volcano instability. We present study combines laboratory experiments, geophysical data, large-scale numerical modeling better understand the influence of on stability, using La Soufrière de Guadeloupe (Easter...
Mineralogical and oxygen isotopic analyses of samples from Deep Sea Drilling Project Sites 477, 481, and 477 in the Guaymas Basin indicate the existence of two distinct hydrothermal systems. In the first, at Sites 481 and 478, hot dolerite sills intruded into highly porous hemipelagic siliceous mudstones that were moderately rich in organic matter, thermally altered the adjacent sediments, and ...
introduction the study area is located in central part of the khaf- kashmar-bardeskan belt which is volcano-plutonic belt at the north of the dorouneh fault in the north of lut block. the north of the lut block is affected by tectonic rotation and subduction processes which occur in the east of iran (tirrul et al., 1983). the magmatism of lut block begins in jurassic and continues in tertiary (...
This study deals with application of artificial neural networks (ANNs) on grade control at mine sites inputting both geological and geotechnical variables. Case study is Chapada copper-gold deposit (Goiás, Brazil), located in the neoproterozoic Chapada-Mara Rosa volcano-sedimentary sequence. Ore is closely related to hydrothermal alteration, structurally controlled. The geological and geotechni...
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