Magma source and the evolution of Early Paleozoic (Silurian) metavolcanic rocks of Maku area (northwest of Iran): An evidence for Paleotethys drifting

A vast part of the Central Iranian and Alborz zones have affected by an extensional tectonic regime in the lower Paleozoic, especially the Silurian period. Due to some clear relation of lithological exposes, similar geochemical and mineralogical as well as the ages, we have compared the early Paleozoic basaltic rocks in the two key areas including Maku in the northwest and Soltan Maidan in the east of Iran. The geochemical properties demonstrate the alkaline nature and intra-plate extensional regime for these rocks. In the Maku area, despite the Soltan Maidan, magma differentiation and crustal contamination had a main role to produce different types of rocks from basalt to rhyolites. Whereas, in the Soltan Maidan, undifferentiated basaltic rocks were floated in a large area probably it infer the fast rises of parent magma comparing to that of the Maku area due to the violent detaching in continental lithosphere led to sudden decompression on the rising mantle plumes, providing conditions for extensive partial melting. This process more highlighted on the Paleotethys drifting rate getting slower from the east to the west. This finding more be useful to understand the Paleotethys evolution and also can explain the variety of ophiolite types along the Paleotethys suture zone in the northern Iran