New tectonic configuration in NE Iran: Active strike-slip faulting between the Kopeh Dagh and Binalud mountains

Abstract

In this paper, a combined approach of geomorphic analyses, detailed geological mapping on SPOT 5 satellite images and field surveys, complemented by radiometric dating (40Ar/39Ar) allows proposing a new and consistent tectonic configuration for the northeastern Arabia-Eurasia collision zone. It favors a simple strike-slip faulting mechanism in NE Iran accommodating the northward motion of central Iran with respect to Eurasia between the Binalud and Kopeh Dagh mountains. Our results demonstrate that ∼2 mm/a (∼25%) of this northward motion has been transferred from the Binalud to the Kopeh Dagh through the Meshkan Transfer Zone since ∼5 Ma. The modern state of stress deduced from fault kinematics analyses shows N30E trending maximum stress axis and confirms a dominant strike-slip faulting mechanism. Combining our geological data with other available data, we conclude that kinematics of deformation can be appropriately described by rigid block faulting in NE Iran; instead, the continuous deformation as it has been thought during the last 3 decades. Copyright 2009 by the American Geophysical Union.