نتایج جستجو برای: keywords hydrothermal alteration

تعداد نتایج: 2031716  

بازرگانی‌گیلانی, کمال‌الدّین, دلاوری‌کوشان, مرتضی, طبّاخ‌شعبانی, امیرعلی, کوه فر, سحر,

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...

ملک‌زاده شفارودی, آزاده, مظاهری, سید احمد , کریم‌پور, محمدحسن ,

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...

Journal: :journal of mining and environment 0
a. entezari harsini department of geology, ferdowsi university of mashhad, mashhad, iran s. a. mazaheri department of geology, ferdowsi university of mashhad, mashhad, iran s. saadat department of geology, mashhad branch, islamic azad university, mashhad, iran j. f. santos department of geosciences, geobiotec research unit, university of aveiro, aveiro, portugal

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...

2016
Julie A. Bowles Jeffrey S. Gee Mike J. Jackson Margaret S. Avery

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...

ژورنال: علوم زمین 2018
Ali Asghar Calagari Behnaz Barghi, Mohammad Hossein Zarrinkoub Vartan Simmonds

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...

Journal: :Journal Of Geophysical Research: Solid Earth 2021

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...

2006
Miriam Kastner

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 ...

Journal: :زمین شناسی اقتصادی 0
علیرضا الماسی محمد حسن کریم پور خسرو ابراهیمی نصرآبادی بهنام رحیمی اورس کلوتزلی ژوزه فرانسیسکو سانتوس

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 (...

2003
Evandro Cardoso Cintra

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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