نتایج جستجو برای: sillimanite

تعداد نتایج: 179  

Journal: :Journal of Asian Earth Sciences 2021

The North Tianshan Belt (NTB) formed by the subduction and accretion of Junggar Ocean is a key area for reconstructing Paleozoic tectonic evolution southern Central Asian Orogenic (CAOB). Despite numerous studies, interpretation late NTB meets no consensus yet. We conducted field investigations LA-ICP-MS zircon U-Pb dating on metamorphic rocks from Julideneng Metamorphic Complex (JMC) in Harlik...

Journal: :Mineralogical Magazine 2023

Abstract The Maršíkov–Schinderhübel III pegmatite in the Hrubý Jeseník Mountains, Silesian Domain, Czech Republic, is a classic example of chrysoberyl-bearing LCT granitic beryl–columbite subtype. This thin dyke, (up to 1 m thickness biotite–amphibole gneiss characterised by symmetrical internal zoning. Tabular and prismatic chrysoberyl crystals (≤3 cm) occur typically intermediate albite-rich ...

Journal: :Journal of Metamorphic Geology 2021

Eclogites hosted in sillimanite-bearing migmatites the Montagne Noire dome (French Massif Central) have an oceanic protolith and recorded a prograde P–T path from ~19.5 kbar, 700°C to pressure peak at ~21 750°C (pseudosection modelling), suggesting metamorphism subduction setting. Subsequent exhumation low-P high-T (LP–HT) conditions (~6 730°C) is constrained by equilibration of embedding migma...

آلیانی, فرهاد, سپاهی, علی اصغر, معانی‌جو, محمد, میری, میرمحمد,

Garnet amphibolite is a member of the Hamedan regional metamorphic rocks (the Sanandaj-Sirjan zone). The present study is the first report of mineral compositions and P-T condition of the Hamedan region area garnet amphibolites. The garnet amphibolites can be divided into two varieties based on their mineral assemblages including epidote garnet amphibolite and biotite garnet amphibolite.  Elect...

سپاهی, علی اصغر ,

: Despite that, in the Alvand complex, the mafic-intermediate rocks (gabbros, diorites and tonalites) are mostly older than felsic rocks (granodiorites and monzogranites), and mineralogical and geochemical discontinuity is seen between them, there are evidence that indicate they have sometimes been co-existed. With the studies on field relationship of rocks, xenocrysts assemblages, synplutonic ...

جعفری, سیده راضیه , سپاهی, علی اصغر , مانی کاشانی, سارا ,

Metamorphic rocks of the Hamadan region have experienced regional and also contact metamorphism (due to intrusion of gabbro, diorite and granitic bodies), therefore, their mineral assemblages have formed in multiple stages. Evidence of regional metamorphism (M) and contact metamorphisms at the contact of gabbros (M’1) and porphyroid granites (M’2) are separatable, hower At the contact of h...

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...

Journal: :Geological Society of America Bulletin 2022

Abstract In this contribution, we present new structural, microstructural, fabrics, and geochronological data from the southern Chong Shan complex, one of metamorphic complexes in southeastern Tibetan Plateau that were sheared exhumed during India-Eurasia convergence. The NW-SE–striking complex is comprised a central high-grade zone (Unit I) flanked by two low-grade zones (units II III) on nort...

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