Emplacement Mechanism of Zahedan Granitoidic Pluton with the Aid of AMS Method

Zahedan granitoidic pluton with general NW-SE elongation is located in the middle part of the Zahedan-Saravan granitoidic belt. It includes granites, granodiorites and diorites and it is also cut by numerous of andesitic to dacitic dikes. The regional metamorphic rocks of the area, with the age of Eocene, have been intruded by this pluton. In this research, emplacement mechanism of the northern part of Zahedan pluton has been studied with the aid of anisotropy of magnetic susceptibility (AMS) method. The results show that granitic rocks of the Zahedan pluton belong to paramagenitic granites (µSI) while diorites and granodiorites belong to ferromagentic granites (µSI). The magnetic lineations and foliations of the pluton mainly have low dip or sub-horizontal. In contrast, dioritic rocks which cover a small area, have magnetic lineations and foliations with high dip (sub-vertical). Therefore, dioritic rocks are considered as the feeder zone or the ascent location of the magma for this part of the Zahedan granitoidic pluton. Very low dip magnetic lineations and foliations suggest that Zahedan granitoidic pluton has been emplaced as sill. The activity of a very low dip simple shear movement has an important role in preparing a suitable space for emplacement of this granitoidic pluton.