Tectonic stress model for the zagros fold–thrust belt and classification of tectonic stress regimes

Title : Tectonic stress model for the zagros fold–thrust belt and classification of tectonic stress regimes

Abstract:

Stress measurement in rocks is an essential parameter in Earth and petroleum sciences. In hydrocarbon explo ration and production from oilfields, a lack of sufficient knowledge on the initial stress field for the fracturing of formations limits proper simulation of the production process. To date, only a limited number of studies have investigated the state of stress in the Zagros Mountains. In this paper, well-established analytical techniques were used to determine the stress state in the Zagros Mountains. First, the Angelier method was used to invert earthquake data in different structural domains. Second, the pattern of crustal stresses was analyzed, and four classes of stress regimes were identified. The stress patterns were reconstructed for five distinct structural domains (zones 1–5). In all five zones, the compressive stress was normal to the main structures (fold axis and fault trace with NW-SE strike). It can be inferred that the structural pattern in the sedimentary cover of the Zagros fold-and-thrust belt (ZFTB) is controlled by R1 (Regime 1) and R4 for zones 1 and 2; R3 for zone 3; R1 and R2 for zone 4; and zone 5. The reconstructed stress patterns are consistent with the observed strike-slip faulting and compressional tectonic deformation regimes. The patterns indicate that deformation in the ZFTB can be explained by a dextral transpressional tectonic model. First-order NE–SW compression stress controls the main convergence tectonics within the Zagros Mountains. Two subordinate compression directions were also identified: one oriented in a dextral main compression direction (N 241 and another in a sinistral (N135° – 177°) and minor extension (N201° – 229° – 243°) ). Classification and modeling of the stress regimes identified both thrusting and strike-slip systems; the former controls the Main Zagros Reverse Fault (hereinafter MZRF), and the latter results in a transpressional tectonic regime.

Biography:

Dr. Zamani studied Tectonics at the University of Shiraz, Iran and graduated as MS in 2002. He then joined the research group of Prof. Jacque Angelier at the Institute of GeoAzur of Pierre et Merrie Cori University of paris 6, France. He received his PhD degree (dual) in 2008 at the University of Shiraz. After 5 year postdoctoral fellowship supervised by Dr. Fredric Masson at the ITES (CNRS), University of Strasbourg, France, he obtained the position of an Associate Professor at the University of Tabriz. He has published more than 60 research articles in SCI (E) journals.