Crustal-scale cross-sections across the NW Zagros belt: implications for the Arabian margin reconstruction
ثبت نشده
چکیده
Quantified balanced and restored crustal cross-sections across the NW Zagros Mountains are presented in this work integrating geological and geophysical local and global datasets. The balanced crustal cross-section reproduces the surficial folding and thrusting of the thick cover succession, including the near top of the Sarvak Formation (∼ 90 Ma) that forms the top of the restored crustal cross-section. The base of the Arabian crust in the balanced cross-section is constrained by recently published seismic receiver function results showing a deepening of the Moho from 42 ± 2 km in the undeformed foreland basin to 56 ± 2 km beneath the High Zagros. The internal parts of the deformed crustal cross-section are constrained by new seismic tomographic sections imaging a ∼ 50◦ NE-dipping sharp contact between the Arabian and Iranian crusts. These surfaces bound an area of 10 800 km that should be kept constant during the Zagros orogeny. The Arabian crustal cross-section is restored using six different tectonosedimentary domains according to their sedimentary facies and palaeobathymetries, and assuming Airy isostasy and area conservation. While the two southwestern domains were directly determined from well-constrained surface data, the reconstruction of the distal domains to the NE was made using the recent margin model of Wrobel-Daveau et al. (2010) and fitting the total area calculated in the balanced cross-section. The Arabian continental–oceanic boundary, at the time corresponding to the near top of the Sarvak Formation, is located 169 km to the NE of the trace of the Main Recent Fault. Shortening is estimated at ∼ 180 km for the cover rocks and ∼ 149 km for the Arabian basement, including all compressional events from Late Cretaceous to Recent time, with an average shortening rate of ∼ 2 mm yr−1 for the last 90 Ma.
منابع مشابه
Crustal scale geometry of the Zagros fold–thrust belt, Iran
Balanced cross-sections across the Zagros fold–thrust belt in Iran are used to analyze the geometry of deformation within the sedimentary cover rocks, and to test the hypothesis of basement involved thrusting throughout the fold–thrust belt. Although the Zagros deformation front is a relatively rectilinear feature, the sinuous map-view morphology of the mountain front is a result of a 6 km stru...
متن کاملFirst record of Gyroconulina columellifera Schroeder & Darmoian, 1977 (larger benthic foraminifera) from the Maastrichtian Tarbur Formation of SW Iran (Zagros Fold-Thrust-Belt)
The larger benthic foraminifera Gyroconulina columellifera Schroeder & Darmoian, 1977 (type-locality: Maastrichtian Aqra Formation of Iraq) is described for the first time from two sections of the Maastrichtian Tarbur Formation of the Zagros Fold-Thrust-Belt, SW Iran. New details on its wall microstructure are provided. The microfacies is represented by bioclastic wacke-/pack-/grainstones with ...
متن کاملThe Role of the Zagros Suture on Three Dimensional Deformation Pattern in Eghlid-Deh Bid Area of Iran
Deformation pattern of the northeastern part of the Iranian-Arabian collision zone (i.e., mainly Sanandaj-Sirjan Belt or Zone) is the main concern of this paper. Here, we investigate the stress distribution and displacement pattern of Eghlid-Deh Bid area as affected by the position of Zagros suture using a three dimensional mechanical model. The modeled area is located between the Zagros Thrust...
متن کاملKinematics of Transpressional Deformation Zones in the Urmia Fault Zone, Northwest Iran
Metamorphic and various intrusive rocks in the Urmia area are located in a transpressed active continental margin. These complexes in the Zagros orogen were deformed during an oblique convergence scenario between the Arabian and Sanandaj–Sirjan blocks in NW Iran. The Urmia area contains both NW-SE striking dextral strike-slip and SW verging NE dipping ductile reverse shear fabrics. Ductile shea...
متن کاملAn Expanding Arabian-Nubian Shield Geochronologic and Isotopic Dataset: Defining Limits and Confirming the Tectonic Setting of a Neoproterozoic Accretionary Orogen
Geologic investigations of the Arabian-Nubian Shield (ANS) are supported by a valuable, expanding dataset of geochronologic ages and isotopic analyses. U-Pb zircon SIMS, TIMS, and evaporation data provide robust temporal control on depositional, volcanic, and intrusive events. Nd, Sr, O and, increasingly, Hf isotopic studies provide insights into magma sources and constraints on crustal recycli...
متن کامل