نتایج جستجو برای: regional metamorphism

تعداد نتایج: 207800  

احمدی, احمدرضا , حسینی, بهناز ,

The Almaghoulagh antiform in north of Asadabad, Hamedan, is one of the areas where the Paleozoic rocks are exposed in the Sanandaj-Sirjan zone. The antiform comprises two metamorphosed units. The Almaghoulagh unit in the lower part is overlain by the Chenar Sheikh unit, whereas the former derived from a volcanic protolith, the latter had a protolith with a significant sedimentary component. The...

2008
I. Gyollai

Introduction We investigated two processes in a series of the Hungarian L-chondrites: shock and thermal metamorphism. Thermal metamorphism transforms the textures in the relatively small chondritic planetary body. Shock metamorphism is caused by hypervelocity impact processes transforming texture and mineral structure mainly in the outermost layers of the chondritic planetary body [1,2]. The pu...

Mashhad Metamorphic Complex (MMC) with metamorphic, granitic intrusions and ophiolite units is situated in the suture zone of Paleotethys in NE Iran. Triassic staurolite-garnet schist of Khalaj represents the highest grade of metamorphism in MMC. In this study EPMA analyses of garnet and biotite used to determine the maximum temperature for regional metamorphism. The pattern of zoning in garnet...

مجرد, منیر, موذن, محسن, موید, محسن,

Contact metamorphism in the Shahindezh Metamorphic Core (SMC), which is occurred due to intrusion of Pichaghchi granodiorite during Laramian orogeny (Upper Cretaceous), is studied here. The well deve loped mineral parageneses at the aureo le is quatz + plagioclase + biotite + cordierite ± chlorite ± K-feldspar ± muscovite ± andalusite ± sillimanite ± garnet. Pressure and temperature of the...

2003
JOCHEN E. MEZGER CEES W. PASSCHIER

The Bossòst dome is an E–W-trending elongated structural and metamorphic dome developed in Cambro-Ordovician metasedimentary rocks in the Variscan Axial Zone of the central Pyrenees. A steep fault separates a northern half-dome, cored by massif granite, from an E–W-trending doubly plunging antiform with granitic sills and dykes in the core to the south. The main foliation is a flat-lying S1/2 s...

2007
D. K. Holm D. A. Schneider S. Rose C. Mancuso M. McKenzie K. A. Foland K. V. Hodges

Metamorphism along the southern margin of the Archean Superior Province has been historically attributed to the Penokean orogeny. A narrow corridor of amphibolite facies rocks north of the main suture does record 1.83–1.80 Ga metamorphic monazite U–Th–Pb ages that mark the culmination of arc accretion. However, subsequent widespread amphibolite facies metamorphism and associated magmatism is re...

M. Ahangari M. Moazzen R. Michaeli U. Altenberger

Metapelitic rocks in the Gasht area include micaschist, kyanite schist, andalusite schist, garnet schist, staurolite schist, cordierite schist and sillimanite schist. Tourmaline occurs as accessory mineral in all of these rock types. These schists are metamorphosed regionally and are affected by contact metamorpism subsequently. Based on the textural relations and the fact that CaO and TiO2 con...

1998
Xiaoming Zhai Howard W. Day

The Qinling orogen (Fig. 1) extends for over 2000 km across central China, separating the Archean and Proterozoic Sino-Korean block in the north from the Proterozoic Yangtze block in the south. Although the orogen has been recognized as a continental collision zone for some time, the nature, age, and duration of the collision have been the subject of considerable debate (see review in Hacker et...

Modjarrad , Monir ,

The purpose of this study is to explore the influence of whole rock chemistry of metamorphic protolith on the crystal size distribution curve of garnet in metapelites. With this aim, perfect mosaical photograph from two groups of metapelites have been prepared: regional (Shahindezh schists) and contact (Dorbeh Oshnavieh aureole) metamorphic rocks image processed and their patterns illustrated. ...

Journal: : 2023

Stratigraphic complexes of the Lower Precambrian are everywhere metamorphosed. Therefore, stratigraphic subdivision has always been inextricably linked with study metamorphism. For some time, degree metamorphism was even used as an indication their relative age. With beginning use isotopic dating, this sign not confirmed, after which no longer taken into account in dismemberment shields basemen...

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