نتایج جستجو برای: andesite rocks
تعداد نتایج: 22534 فیلتر نتایج به سال:
Karapınar-Karacadağ Volcanic Rocks (KKVR) have very complex magmatic history and outcropped the southwestern part of Cappadocia Province (Central Anatolia). Here we present petrography whole-rock chemistry enclave-bearing rocks to constrain their source evolution history. These petrographic observation geochemical data reveal that enclaves in volcanic are magma mixing/mingling (MME), segregatio...
The study area is located about 20 km north-west of Hashjin, SW of Ardebil Province and is a part of Kejal-Shamsabad zone in the Tarom-Hashjin volcanic belt. Zeolite and associated minerals, such as quartz and calcite, are formed in cavities and fractures of trachy-andesitic country rock. Studies of zeolitic alteration zones show that stilbite is the main mineral and illite, sanidine, chlorite,...
سنگهای آتشفشانی با ترکیب تفریتی و فونوتفریتی با سن ائوسن بالایی در رشته کوه بزقوش، شمال غرب ایران گسترش قابل ملاحظهای دارند. این سنگهای آتشفشانی هم به صورت گدازههایی با حجم زیاد که عمدتاً در قسمت شمالی رشته کوه بزقوش قرار گرفتهاند و با یک روند شرقی-غربی بر روی آندزیتهای مگاپورفیری ائوسن میانی قرار گرفته اند، دیده میشوند و هم به صورت لنزهایی کوچک در بین سنگهای ولکانی کلاستیکی جای گرفتهان...
Since underground structures such as tunnels are inevitably surrounded by rocks, their long-term safety and stability primarily governed the comportment of these materials. Being able to express time-dependent behavior creep is one most interesting mechanical properties considered in study tunnels. Based on relevant research efforts, this article aims provide a comprehensive review pertinent in...
A remarkable record of early arc volcanism in the Izu–Bonin–Mariana (IBM) arc is exposed in and around the Bonin Islands, an uplifted segment of the IBM forearc. New Ar/Ar dating results imply that the boninitic volcanism on Chichijima Island occurred in a brief period during Eocene time, between 46–48 Ma. A slightly younger volcanic succession is identified along the Bonin Ridge, including 44....
Roshtkhar Iron deposit is located in southeast of Khorasan Razavi Province about 48 Km east of Roshtkhar. This deposit is geologically located in the northeast of the Lut block in the Khaf-Bardaskan volcanic- plutonic belt. Intermediate igneous rocks such as stock, dyke, lava and pyroclastic deposits are host rock. Igneous rocks are dioritic porphyry, monzosyenitic porphyry, andesite, basalt an...
gomish-tappeh zn-pb-cu (ag) deposit is located 90 km southwest of zanjan, in northwestern part of urumieh-dokhtar volcano-plutonic zone. exposed rocks at the area include oligo-miocene volcano-sedimentary and sedimentary sequences as well as pliocene volcano-plutonic sequence (andesite porphyry dykes, dacitic subvolcanic dome and rhyodacitic volcanics). alteration in the deposit developed as si...
The Siluro-Ordovician Southern Uplands terrane occupies a key position in the Caledonian Orogen, yet its genesis is controversial. Marginal basin, back-arc and forearc tectonic regimes, operative at the Laurentian margin of the Iapetus Ocean, have all been invoked. Fresh andesitic detritus within turbidite sandstones has, until now, been assumed to provide evidence for an Ordovician, supra-subd...
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