Review of age, Rb-Sr geochemistry and petrogenesis of Jurassic to Quaternary igneous rocks in Lut Block, Eastern Iran

Abstract

The Lut Block (Eastern Iran) extends over 900 km in a north-south direction and is only 200 km wide in an east-west direction. It is confined by the Nayband fault and Shotori Range on the west. The eastern edge is bordered by the Sistan suture zone and Nehbandan Fault. The northern termination of Lut Block is the depression of Kavir-e-Namak and the Great Kavir Fault. The Makran arc, including the Bazman volcanic complex and the Jaz-Murian-Depression, define the southern edge. Sixty-five percent of the exposed rocks within the Lut Block are volcanic and plutonic rocks. Klateh Ahani, Shah Kuh and Surkh Kuh granitoids (Middle Jurassic,165-162 Ma) are among the oldest rocks exposed within the Lut Block. Based on mineralogy, low values of magnetic susceptibility [(1 to 50) × 10-5 SI], and high initial 87Sr/86Sr = 0.7073-0.709, Klateh Ahani, Shah Kuh and Surkh Kuh granitoids are classified as belonging to the ilmenite-series of reduced S-type granitoids. They formed in a continental collision tectonic setting and the magma originated from with the continental crust. The next episode of magmatism was in the Late Cretaceous. .