Petrology, geochemistry and origin of Hesaruiyeh Granitoid, east of Zahedan, southweast Iran

Hesaruiyeh granitoid is located about 85 Km east of Zahedan city, in the Sistan suture zone. This granitoid occurs as small stocks in Cretaceous ophiolite melange and Eocene Flysch. This granitoid is composed of granite, granodiorite and diorite. Granite and granodiorite consist mainly of quartz, plagioclase, orthoclase, biotite and hornblende and diorite is composed of plagioclase and hornblende.  These rocks have mainly granoular texture. This granitoid has mafic enclaves and cut by dioritic dikes. This enclaves and dikes have similar mineralogy as main pluton but they have microlitic and microlitic porphyry textures. Geochemical studies show that Hesaruiyeh granitoid is calcalkaline, metaluminous and I type, and enrichmed from LREE compared to HREE and LILE to HFSE. Tectono magmatic diagrams show Hesaruiyeh granitoid rocks are related to an active continental margin environment. It seems that this pluton was formed from rising residual melts from partial melting of an oceanic crust (Neo-Tethys) during collision of the Lut and Sistan blocks (especially Sistan oceanic crust and mantle wedge on it) and magma effacted by continental crust (Flysch and greywake metamorphosed deposite).