Miocene Plutonism In the Sarcheshmeh Region, NW of Kerman, Iran

The granitoid rocks of the Sarcheshmeh region lie in the southern margin of Central Iran block and constitute sizeable outcrops in southeastern part of the Urumieh-Dokhtar magmatic assemblage. The granitoid rocks have been divided into two main groups; plutonic and hypabbysal. The plutonic group, including Mamzar batholith and Chenar stock, has a cathedral granular texture and lacks any copper mineralization. The hypabbysal group which includes Sarcheshmeh (Sarcheshmeh porphyry stock and its related intrusive units), Sarkuh and Nochun areas, shows a diagnostic aporphyritic texture with various degree of copper mineralization ranging from weak to intensive.

The plutonic and hypabbysal rocks exhibit a calc-alkaline and adakitic character respectively. These rocks belong to an arc-setting and formed in a post-collision environment. Geodynamic interpretation of the area and isotopic similarities between plutonic and hypabbysal rocks support this assessment and further suggest that these rocks may have been produced by partial melting of metabasaltic rocks in the lower continental crust and thickened as a consequence of post-collision compressions.

The obtained age (Lower-Middle Miocene) for these rocks in the Sarcheshmeh area and their post-collision nature, suggest a prior Miocene collision time between Arabian plate and Central Iran. The new petrological, geochemical and field observation, therefore, reinterpret the origin of large voluminous Miocene or younger granitoid rocks in the Urumieh-Dokhtar magmatic assemblage which were previously defined and categorized as a pre-collision assemblage. The new assessment is compatible with many interpretations of similar rocks in the other regions of the Alpine-Himalayan orogenic belt.