Spatio-temporal evolution of intraplate strike-slip faulting: the Neogene-Quaternary Kuh-e-Faghan Fault, Central Iran

Calzolari, G., Rossetti, F., Della Seta, M., Nozaem, R., Olivetti, V., Balestrieri, M. L., Cosentino, D., Faccenna, C., Stuart, F. M. and Vignaroli, G. (2016) Spatio-temporal evolution of intraplate strike-slip faulting: the Neogene-Quaternary Kuh-e-Faghan Fault, Central Iran. Geological Society of America Bulletin, 128(3/4), pp. 374-396. (doi:10.1130/B31266.1)

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Abstract

Central Iran provides an ideal region to study the long-term morphotectonic response to the nucleation and propagation of intraplate faulting. In this study, a multidisciplinary approach that integrates structural and stratigraphic field investigations with apatite (U+Th)/He (AHe) thermochronometry is used to reconstruct the spatio-temporal evolution of the Kuh-e-Faghan Fault (KFF) in northeastern Central Iran. The KFF is a narrow, ca. 80 km long, deformation zone that consists of three main broadly left stepping, E-W trending, dextral fault strands that cut through the Mesozoic-Paleozoic substratum and the Neogene-Quaternary sedimentary cover. The AHe thermochronometry results indicate that the intra-fault blocks along the KFF experienced two major episodes of fault-related exhumation at ~18 Ma and ~4 Ma. The ~18 Ma faulting/exhumation episode is chiefly recorded by the structure and depositional architecture of the Neogene deposits along the KFF. A source-to-sink scenario can be reconstructed for this time frame, where topographic growth caused the synchronous erosion/exhumation of the pre-Neogene units and deposition of the eroded material in the surrounding fault-bounded continental depocenters. Successively, the KFF gradually entered a period of relative tectonic quiescence and, probably, of regional subsidence during which a thick pile of fine-grained onlapping sediments were deposited. This may have caused resetting of the He ages of apatite in the pre-Neogene and the basal Neogene successions. The ~4 Ma faulting episode caused the final exhumation of the fault system, resulting in the current fault zone and topography. The two fault-related exhumation episodes fit with the regional early Miocene collision-enhanced uplift/exhumation, and the late Miocene–early Pliocene widespread tectonic reorganization of the Iranian plateau. The reconstructed long term, spatially and temporally punctuated fault system evolution in intraplate Central Iran during Neogene-Quaternary times may reflect states of far-field stress changes at the collisional boundaries.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Stuart, Professor Finlay
Authors: Calzolari, G., Rossetti, F., Della Seta, M., Nozaem, R., Olivetti, V., Balestrieri, M. L., Cosentino, D., Faccenna, C., Stuart, F. M., and Vignaroli, G.
College/School:College of Science and Engineering > Scottish Universities Environmental Research Centre
Journal Name:Geological Society of America Bulletin
Publisher:The Geological Society of America
ISSN:0016-7606
ISSN (Online):1943-2674
Copyright Holders:Copyright © 2015 The Geological Society of America
First Published:First published in Geological Society of America Bulletin 128(3/4): 374-396
Publisher Policy:Reproduced in accordance with the copyright policy of the publisher.

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