Insights in to the overprinting of the dextral shearing on the Deh Zaman mylonitic granite, Kuh-e-Sarhangi Area, northwest edge of the Lut Block

Document Type : Original Article

Authors

1 1Department of Geology, Tarbiat Modares University, Tehran, Iran.

2 Department of Geology, Tarbiat Modares university, Tehran, Iran

3 2School of Geology, College of Science, University of Tehran, Iran

Abstract

Abstract:
SE trending (S62E) and NE dipping (80NE) mylonitic foliation is the main structural feature developed in ~557-561Ma Deh-Zaman mylonitic granite in the N70˚E trending Kuh-e-Sarhangi shear zone at the northwest of the Lut Block. 35˚ plunge of the stretching lineation on this mylonitic foliation in combined with microstructural evidence, especially on feldspar crystals confirmed dominant sinistral shear with the little compressional component. Sinistral shear proposed to initiate after emplacement of the granitic body and deformed it at ~300-500˚C during Early Cambrian. Our new and detailed microstructural analysis indicates considerable overprinting of dextral shear on the former older sinistral shear in the Deh-Zaman mylonitic granite. There is no radiometric age constraint on the timing of the shearing shift from sinistral to dextral kinematics; however, based on the structural and stratigraphic evidence, we propose post-Late Cretaceous- Paleocene age of the kinematic change. This shear sense change matches with Structural evolution of the Kuh-e-Sarhangi region in which sense of shear has been changed several times during its evolution.

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Journal of Tectonics
Volume 2, Issue 8
March 2019
Pages 5-15

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