Geothermal Model of the Shallow Crustal Structure across the “Mountain Front Fault” in Western Lurestan, Zagros Thrust Belt, Iran

Matteo Basilici,Stefano Tavani,Stefano Mazzoli,Stefano Santini,Antonella Megna

doi:10.3390/geosciences9070301

Abstract

The Zagros thrust belt is a zone of deformed crustal rocks well exposed along the southwest region of Iran. To obtain a better knowledge of this mountain chain, we elaborated a 2D model reproducing the thermal structure of the “Mountain Front Fault”. This study, which is focused on the Lurestan region, is based on a model made by merging published sections and available information on the depth of the Moho. We present the isotherms and the geotherms calculated using an analytical methodology. The calculation procedure includes the temperature variation due to the re-equilibrated conductive state after thrusting, frictional heating, heat flow density data, and a series of geologically derived constraints. In order to perform the temperature calculations, the crustal structure in the Lurestan region is simplified as composed of two domains: A lower unit made by crystalline basement and an upper unit including all the lithostratigraphic units forming the sedimentary cover. The resulting model is compared with the numerical results obtained by previous studies to improve the description of the thermal structure of this geologically important area.

Highlights

The Zagros thrust belt forms part of the Iranian mountains which are actively deforming due to the convergence between the Arabian and Eurasian plates
This research takes into account the northern part of the Lurestan region, where the Arabian Plate collides with the Central Iranian Block producing high-magnitude seismicity, including the seismic event of 12 November 2017 (Mw = 7.3) [3]
In order to gain a better understanding of the tectonic behavior of this sector of the Zagros orogen, taking into account that crustal/lithospheric rheology depends on the thermal field due to the temperature effect on crustal viscosity, it is fundamental to define the thermal structure of the study area

Summary

Introduction

The Zagros thrust belt forms part of the Iranian mountains which are actively deforming due to the convergence between the Arabian and Eurasian plates. 6–9 mm/yr of the plate convergence are accommodated in the Zagros Mountains, the remaining deformation being located in the Alborz and in the South Caspian basin [1,2]. The Central Iranian block, located between Arabia and Eurasia, does not significantly deform, but rather acts as a backstop for the Zagros thrust belt. The relative velocity between the Arabian plate and the Central Iranian block is ~7 mm/yr in a north–south direction [1]. This research takes into account the northern part of the Lurestan region, where the Arabian Plate collides with the Central Iranian Block producing high-magnitude seismicity, including the seismic event of 12 November 2017 (Mw = 7.3) [3]. Cretaceous to Cenozoic times due to the closure of the Neo-Tethys

Methods

Results

Conclusion