Petrology, Magnetic susceptibility, Tectonic setting and mineralization associated with Plutonic and Volcanic Rocks, Eastern Bajestan and Taherabad, Iran

Document Type : مقالات پژوهشی

Authors

Mohammad Karimpour

Ali Ashouri

Saeed Saadat

Maliheh Ghourchi

10.22067/sed.facies.v1i1.679

Abstract

The oldest exposed rocks, to the north of intrusive rocks and in Eastern Bajestan, are meta-chert, slate, quartzite, thin-bedded crystalline limestone and meta-argillite. They are exposed, to the north of intrusive rocks and in eastern Bajestan. Since both Sardar Formation (Carboniferous) and Jamal Formation (Permian), close to this association, are not metamorphosed, therefore the regional metamorphism and the rocks must be older than Carboniferous. The sedimentary units are: Sardar Formation (Carboniferous), Jamal Formation (Permian), Sorkh Shale and Shotori Formations (Triassic), K1, K2, K3 (Cretaceous) and lithostratigraph-ically equivalent to Kerman conglomerate (Cretaceous-Paleocene) are exposed in this area. Based on relative age, magmatism in eastern Bajestan and Taherabad started after Late Cretaceous and it has been active and repeated during Tertiary time. At least, three episodes of volcanic activities are recognized in this area. The first stage was mainly volcanic flow with mafic composition and minor intermediate. The second episode was mainly intermediate in composition. The third stage was changed to acid-intermediate in composition. Since the plutonic rocks intruded the volcanic rocks, therefore they may be Oligo-Miocene age. Bajestan intrusive rocks are granite-granodiorite-quartz monzonite. Taherabad intrusive rocks are diorite-quartz diorite- monzonite-latite. Bajestan intrusive rocks with magnetic susceptibility less than 20 ×10-5 SI are reduced type (ilmenite series) and Taherabad with susceptibility more than 100 ×10-5 SI are oxidized type (magnetite series).Based on geochemical analysis including trace elements, REE and (Sr87/Sr86)i = 0.71, Bajestan intrusive rocks formed in continental collision zone and the magma has crustal origin. Taherabad intrusive rocks were formed in subduction zone and magma originated from oceanic crust. Taherabad intrusive rock has exploration potential for Cu-Au.

---