A. Bahrampour; Gh. Ghadami; H. Atapour; M. Poosti; H. Ahmadipour
Abstract
At 60km north-east of Kerman city,near Sarashk village (Ravar, Kerman province) and along the Kuhbanan fault, several lamprophyric dikes have been intruded into Carboniferous to Cretaceous sedimentary formations. Petrographically these lamprophyres could be classified into two groups: comptonites ...
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At 60km north-east of Kerman city,near Sarashk village (Ravar, Kerman province) and along the Kuhbanan fault, several lamprophyric dikes have been intruded into Carboniferous to Cretaceous sedimentary formations. Petrographically these lamprophyres could be classified into two groups: comptonites and sanaite. Olivine, clinopyroxene, plagioclase and potassium feldspar are the main minerals in all two groups. Mineral chemistry shows that olivines, clinopyroxenes and amphiboles are of chrysolite (Fo = 72.35-79.85)), augite (Wo = 44.3-50.2, En= 37.06-44.4, Fs = 9.24-14.6), and kaersutite (Ca+Na = 2), (Na+K = 0.59-0.95), (Mg/(Mg+Fe2) = 0.63-0.76) composition, respecrively. Geobarometric and geothermometric estimations along with the tectonomagmatic diagrams for clinopyroxenes show that the parental magmas werealkaline in which the clinopyroxenes crystallized at pressure of 11-15 Kbar and temperature of 1150-1300 ◦C.Whole rock chemical analyses of these rocks show that the parental alkaline magma was originated from a metasomatized lithospheric garnet- spinel- lherzolite mantle source and emplaced in a post-collisional environment.
H. Atapour; A. Aftabi
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 ...
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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 arc 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.
