Investigating Role of the Hormuz Salt Bodies in Initiation and Evolution of the Strike Slip Faults in the Fars Zone of t
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Pure and Applied Geophysics
Investigating Role of the Hormuz Salt Bodies in Initiation and Evolution of the Strike Slip Faults in the Fars Zone of the Zagros Fold and Thrust Belt: Insights from Seismic Data and Sandbox Modeling REZA SHAMS,1,2 IRAJ ABDOLLAHIE FARD,3 SOHEILA BOUZARI,1 and MOHSEN POURKERMANI1 Abstract—The Zagros Belt has examples of strike-slip faults affected by precursor Hormuz Salt bodies. We attempted to examine the role of salt walls in localizing the strike-slip faults using field observations, seismic profiles and understandings from the sandbox modeling. Setting and performance of the pre-Hormuz features in connection to the salt tectonics are major questions. The inherited topography below the salt is an important parameter which controlled the structuration of the basin. The antecedent troughs provided accommodation for the thick Hormuz Salt. Differential loading above the salt helped generation of salt-related structures. The salt-walls caused formation of elongated highs. These highs were re-shaped in form of strike-slip faults during the Zagros Orogeny. The intersection of the salt walls and the Zagrosinduced deformation fronts are location of potential diapirs needless of bending points along the tear faults. In contrast, the underlying deep-seated basement faults are hardly believed to be strike-slip. Keywords: Salt tectonics, halokinesis, sandbox modeling, Zagros, Hormuz Salt.
1. Introduction Understanding the effects of salt tectonics is important for the hydrocarbon exploration since more than 130 sedimentary basins have been affected by salt bodies (Jackson and Hudec 2017). Influence of mobile salt layers have been investigated for many years and role of thick salt beds in controlling the structural deformation and styles is significant
1
Department of Geology, Islamic Azad University Tehran North Branch, vafadar Blvd., Shahid Sadoughi St., Hakimiyeh Exit, Shahid Babaee Highway, Tehran, Iran. E-mail: geoshams [email protected]; [email protected]; [email protected] 2 Present Address: National Iranian Oil Company, Exploration Directorate, Tehran, Iran. 3 National Iranian Oil Company, Exploration Directorate, Tehran, Iran. E-mail: [email protected]
considering results of surface (outcropped features), subsurface (e.g., well and seismic data), and modeling (numerical or physical) studies. The Zagros Fold Thrust Belt (ZFTB) of SW Iran (Fig. 1a), as the study area, has cases of strike slip faults affecting precursor salt pillows or diapirs (Jackson and Hudec 2017). The Late PrecambrianEarly Cambrian Hormuz Salt (Jahani et al. 2017) (Fig. 1b) uplifting has been reported from Late Permian (Motiei 1995) and mostly since Late Cretaceous (e.g., Motamedi and Gharabeigli 2018) before the Neogene collision (Jackson and Hudec 2017). Magnificent exposures of salt structures have made this region one of the most spectacular halokinetic provinces in the world. On seismic lines from the Persian Gulf or the Fars Arc (e.g., Jahani et al. 2009; Hassanpour et al. 2020), the salt structures sho
