Writers : R. Monazzami Bagherzadeh; M.H. Karimpour; B. Rahimi; M.R. Heydarian
Refference : 2nd National Symposium of Iranian Society of Economic Geology
Publishing Year : 1390

Abstract :

Study area is situated in middle part of Taknar structural zone in north of middle Iranian microcontinentent. In the area, metamorphosed volcanic rocks (rhyolite, rhyodacite and dacite) together with sedimentary units (sandstone, schist, slate, sandstony tuff, limestone) and small outcrops of current basalt, have formed the complex that named Taknar formation. In this complex has intruded by Bornavard granite to late Neoproterozoic age. The complex of intermediate and basic rocks has formed gabbro, diorite and quartzdiorite and their fine grain (micro type) that these rocks cut the Bournavard granitoid rocks. Major texture in mafic and intermediate rocks is granular texture (coarse and middle grains). This complex rocks, specially in central part is intruded by one diabasic dykes series with intersertal texture and microdioritic dykes and also aplitic dykes.
Magmatic series of the complex is calc-alkalin. Based on the alumina saturation index, samples set in meta-alumina series. These are medium-K rocks and on
basis of geochemical investigations enriched in the LILE such as Rb, Cs and Th and depleted in the Nb and Ti. Therefore, it shows that these rocks resulted from the mixing by the lower crust.
The rocks of this complex have formed at the continental margin and VAG environment which it is related to the subduction of the Neotethys oceanic crust that exists between Iranian microcontinent and Sabzevar zone. From view of mineralography characteristic, the some of intermediate and basic intrusive rocks of Taknar complex show magnetite-series (oxidan).

Subject List : Geochemical Exploration