Writers : Atapour, H.; Aftabi, A.
Refference : Scientific Quarterly Journal Geosciences, No. 72, Page:161-172
Publishing Year : 1388

Abstract :

Magmatism in Dehaj- Sarduieh volcanic belt has been occurred in three phases. The first magmatic phase consists of Eocene volcanic rocks (tephrite -phonolite, basalt, trachybasalt, tracyandesite, andesite, dacite, rhyolite and pyroclastic rocks) of Bahraseman, Razak and Hezar complex. With increasing angle of subduction, the acidic (Bahraseman complex), intermediate (Razak complex) and basic volcanism (Hezar complex) occurred in Dehaj - Sarduieh volcanic belt. After ceasing the volcanism, the Oligo-Miocene granitoid rocks (gabbro-diorite, diorite, monzonite, quartz diorite, granodiorite, quartz monzonite and granite) with calcalkaline, potassic calcalkaline and shoshonitic affinity intruded into the volcanic rocks, forming the first phase of porphyry copper mineralization.The second magmatic pulse includes Neogene volcanic rocks (dacite - rhyodacite- rhyolite) and plutonic bodies (diorite - quartz diorite) of flat subduction- related calcalkaline-adakitic affinity, associated with the second phase of porphyry copper and polymetallic vein mineralization. Polymetallic vein type mineralization occurs in volcanic rocks, but genetically is related to porphyry mineralization and tectonomagmatic characteristics of the belt. The occurrence of ignimbrite strongly indicates a continental are subduction setting. The high values of incompatible elements such as K, Rb and Ba show that porphyry copper and their host igneous rocks were developed by partial melting of metamorphosed oceanic crust and mantle wedge (phlogopite eclogite and or phlogopite amphibolite) in a continental arc setting. The third magmatic phase is characterized by the occurrences of postcollisional lamprophyres and basaltic lavas of potassic and alkaline affinity. The final postmagmatic activity was related to the vast occurrences of Quaternary travertine deposits.

Subject List : Copper