The Effect of Basement Fault Reactivation on the Triassic – Recent Geology of Kurdistan, North Iraq

Abstract

The Zagros orogenic belt is underlain by a complex faulted Precambrian basement. Major fault trends originating in this basement have been invoked to explain large‐scale structural changes along the strike of the orogen, e.g. the development of the Kirkuk Embayment (Kurdistan, Iraq) and the Lurestan Salient (Iran). However, within the Kirkuk Embayment, these structural trends have not previously been considered as an interacting group of faults which are periodically reactivated. This contribution first presents a revised basement fault map for the Kirkuk Embayment, created from interpreted gravity data, existing fault maps and remote sensing lineament analyses. This map is then compared to surface structure maps, published facies maps and source rock maturity data using GIS techniques. The object is to define the relationship between the basement faults and surface structures, fades and source‐rock maturity through time. Surface anticline orientation and location, as well as a number of major facies changes within the cover sequence, and the maturity of Triassic source rocks, are constrained by the interaction of the Najd and Transverse fault trends. A third basement trend, the Nabitah trend, has a more subtle effect on Phanerozoic geology. The Kirkuk Embayment can be divided into a series of semi‐independent basement blocks, defined by these basement fault trends. The interaction of these semi‐independent blocks has created local but predictable differences in surface structures, sediment thickness and facies, and variations in the maturity of Triassic source units across the Kirkuk Embayment. An understanding of the location and behaviour of basement faults within this hydrocarbon province is therefore a valuable predictive tool in exploration.

Relative Timing of Uplift along the Zagros Mountain Front Flexure Constrained by Geomorphic Indices and Landscape Modelling, Kurdistan Region of Iraq

“…CC BY 4.0 License. seismic data, it was also suggested that contraction has been localized on inherited passive-margin normal faults in the basement, which were inverted during the late stage of deformation since c. 5 Ma (Abdulnaby et al, 2014;Burberry, 2015;Koshnaw et al, 2017). The structural relief across the MFF (Fig.…”

“…An orogenic bend is depicted in the area where the trend of structures changes across the Greater Zab River from NW-SE at the eastern side of the river to nearly E-W at its western side. The course of the Greater Zab River is suggested to overlie a NE-trending transversal basement fault with right-lateral displacement (Ameen, 1992;Burberry, 2015;Jassim and Goff, 2006;15 Omar, 2005) and there is an offset of the High Folded Zone propagation foreland-ward. At the eastern side of the river the deformation has propagated for about 25 km further than on its western side ( Figs.…”

“…1 and 2). The origin of this fault reaches back to the Late Proterozoic tectonic history of the Arabian Plate, and the fault has been reactivated later in subsequent tectonic events (Ameen, 1992;Aqrawi et al, 2010;Burberry, 2015;Jassim and Goff, 2006). This can also be noticed in the thickness of the sedimentary cover, which is thinner to the west of the Greater Zab River (Ameen, 1992;Zebari and Burberry, 2015).…”

Kinematics and surface fracture pattern of the Anaran basement fault zone in NW of the Zagros fold–thrust belt

“…1), including the Foredeep, the Simply Folded Zone and the Imbricate Zone (Stocklin 1968;Falcon 1974;Berberian 1995;Sepehr and Cosgrove 2004). Recent studies (Talbot and Alavi 1996;Bahroudi and Talbot 2003;Bahroudi and Koyi 2004;Sherkati and Letouzey 2004;Farzipour-Saein et al 2009a) show that the geometry of the Zagros deformation front and evolving foreland basin has been controlled by at least two different structural parameters: (1) reactivation of basement faults (Hessami et al 2001a;Bahroudi and Talbot 2003;Sepehr and Cosgrove 2005;Ahmadhadi et al 2007;Mouthereau et al 2007a, b;Farzipour-Saein et al 2009a;Nilfouroushan et al 2013;Burberry 2015) and (2) mechanical nature of the sedimentary layers in the ZFTB (Bahroudi and Koyi 2003;Sherkati and Letouzey 2004;Farzipour-Saein et al 2009b). Different evidences indicate that many of the transverse basement faults involve right-lateral strike-slip displacements with dip-slip components (Baker et al 1993;Berberian 1995;Hessami et al 2001b;Bahroudi and Talbot 2003;Sepehr and Cosgrove 2005;Ahmadhadi et al 2007;Farzipour-Saein et al 2009a;Allen 2010).…”

Fracture and Lineament Patterns across the Midcontinent Indicate Post-Cretaceous Reactivation of Basement-Involved Faults

“…Studies of specific structures (e.g. Gates & Costa, 1998;Molliex et al, 2010;Said et al, 2011;McMechan, 2012;Burberry, 2015) indicate that subsequent structures, facies changes and economic deposits may be affected by the motion of the preexisting fault or faults.…”