Deploying depositional and stratigraphic evidence in kinematic investigations along multi-role faults: The case study from the eastern Mosha Fault, central Alborz Range, northern Iran

Abstract

Geological history of the Alborz Mountains in northern Iran is characterized by multiple tectonic events. They account for kinematic changes along the eastern Mosha Fault (EMF), reflected in stratigraphic and sedimentological characteristics of rock units in adjacent sub-basins. Our study highlights the role of the E-W-trending EMF in controlling the depositional pattern of rock units in the southern central Alborz. Syn-sedimentary structures and stratigraphic variations in both blocks of the EMF revealed a number of kinematic changes responsible for deposition of a variety of rock units in either fault blocks. The EMF has evidence of at least 8 inversion events since the Middle Cambrian time, associated with 8 tectonic pulses. The longest interval of non-changing fault activity lasted from the Middle Cambrian (initiation of the fault?) to the Late Triassic, during which the EMF is believed to have been an extensional fault in the northern passive margin of the Iranian microplate. The shortest interval of fault activity is characterized by a Quaternary normal sinistral oblique kinematics resulted from clockwise rotation of the South Caspian Basin.