جستجوی مقالات مرتبط با کلیدواژه « نفریت » در نشریات گروه « زمین شناسی »

The Kermanshah ophiolite Complex is located in the structural – tectonic zone of the western Iran in northern part of Zagros main thrust and is a part of highly dismembered Kermanshah – Panjvin ophiolite belt. The poly metamorphic zone in this region is mainly related to the development and tectonic emplacement of the ophiolite. Some of the metamorphic rocks (Jade and its simulants) have so ​​hardness, density and high specific gravity, containing tremolite, actinolite, plagioclase, clinochlore, grossular and hydrogrossular garnet. Metamorphic rocks containing very condensed and compact tremolite and nephrite found in the area, as well as very compact antigoritic serpentinite so called bowenite, clearly proof that the high-pressure metamorphism took place during subduction. Serpentinites also appear in the region which is characterized by the predominance of antigorite and Cr-magnetite, as well as by their relatively low LOI (10.9-12.1 wt.%), corresponding to medium or high temperature blueschist facies metamorphism. These metamorphic conditions are strongly similar to the high-pressure metamorphic appearing in this serpentinites that formed from serpentinization of highly depleted harzburgitic protoliths where they were subjected to extensive partial melting processes (>15%), consistent with a hydrous subduction-related environment. Gabbros in this ophiolite complex have been altered rodingitization, the altered rodingitized gabbros, in the continuation were underwent a de-rodingitization process too.