Petrogenesis of granitoids from Dalfard area (Northwest of Jiroft): Evidence of Volcanic arc tectonic setting in Urumieh – Dokhtar magmatic belt

Dalfard granitoids are located in the south-east of Kerman province and in the margins mainly include quartz diorite. Quartz diorites contain main minerals plagioclase, amphibole and biotite  and this work reveals that the rocks in this area are I type granitoides and they belong to calc-alkaline magmatic series. The enrichment of LREE relative to HREE, high contents of LILE relative to HFSE and anomalies of Nb and Ti in spider diagrams show that the Dalfard quartzdiorites are formed in an arc setting environment. The CaO/(MgO+FeOt) and Al2O3/(MgO+FeOt) ratios (0.55 and 1.36 respectively) show that the parent magmas were formed by the partial melting of basaltic rocks of the lower crust and mantle fluids/melts also participated in their formation. Based on geochemical data such as La/Yb(N) and Th/Yb(N) ratios (4.4 and 6.5 respectively), these magmas are related to pre-plate collision environment and formed in the mature Volcanic arc setting at a depth of about 40 km at the supra subduction zone of the Neothetys oceanic lithosphere and then, they ascent to the higher levels of the crust and passed fractional crystallization.