نتایج جستجو برای: high pressure metamorphism
تعداد نتایج: 2350877 فیلتر نتایج به سال:
All samples of Shanderman eclogites contain amphibole. Epidote group minerals and chlorite formed during retrograde phases of metamorphism. Amphiboles show zoning with high FeO and Al2O3 content at the rims and high MgO in the cores in some samples. In these samples, the amphibole compositions vary from tremolitic hornblende to tschermakite and edenitic hornblende from core to rim, respectively...
The Northern Dabie Complex in east central China lies between the Sino–Korean plate to the north and the Yangtze plate to the south. The Northern Dabie Complex has been variously proposed to represent a Paleozoic magmatic arc on the Sino–Korean plate, an exhumed piece of subducted Yangtze plate crust, or crust produced almost entirely by Cretaceous extension-related magmatism. Trace element com...
Temperature and pressure of pelitic metamorphic rocks (metapelites), from the Jandaq area in NE Isfahan, are studied using pseudosection approach. The data used in this research are from already published data by other researchers; however the applied method is reported for the first time. The metamorphism temperature is estimated to be about 400 to 670°C and pressure to be 2-6 kbar in the pub...
The Geysour area is located east of Gonabad and is a part of the northern Lut block. The rocks in this area include granitoid and metamorphic rocks. Based on field and mineralogical evidence, the protolith of amphibolite rocks are calc-silicate. The metamorphic rocks of this region are divided into metapelites and amphibolites. Textures, such as post-tectonic garnet and random amphiboles, are i...
The current configuration of the Alpujarride complex (Befic Orogen) comprises a stack of thinned tectonic units, made up mainly of continental crest. P T path modelling in different levels of an Alpujarride unit (the Salobrefia tectonic unit) reveals a high-pressure metamorphic stage followed by subsequent decompression at nearly isothermal conditions. Nevertheless, the P T conditions differ fr...
the cheshin meta-calcareous rocks (permo triassic) in southeast hamedan outcrop in association with a variety of pelitic schists and hornfels rocks. the intrusion of the alvand batholith (jurassic age) into pelitic and calcareous host rocks has produced metamorphic rocks in the hamedan area (cheshin village). on the basis of the dominance of calcite/dolomite, silicate and ore minerals, the calc...
Different models are discussed to interpret the presence of kyanite as a stable phase in contact aureoles especially in the andalusite-, sillimanitebearing aureoles. In such aureoles the polymorphic sequence kyanite → andalusite → sillimanite can be explained in terms of an essentially isobaric path during which kyanite initially crystallises from the breakdown of pyrophyllite or more likely mu...
40 Ar/ 39 Ar analyses were made on maruyamaite (potassium-dominant tourmaline) from tourmaline-quartz-feldspar rocks discovered within the Kumdy-Kol microdiamond deposit (Kokchetav massif, North Kazakhstan). Turmaline yielded well-defined plateau age spectra whose values coincide error - ages of 502.3±8.0, 502.2±8.0, 506.0±8.0 Ma. These are much younger than 530±2 Ma determined for high-pressur...
The Austroalpine nappe stack of the Pohorje Mountains (Mts.) in northeastern Slovenia comprises a suite eclogite facies metamorphic rocks that were partially assigned to Eo-Alpine ultrahigh-pressure metamorphism (UHPM). We selected micaschist, which was previously related this metamorphism, for detailed study including chemical zonation garnet and potassic white mica, identification mineral inc...
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