Tectonostratigraphic overview of the Zagros Suture Zone, Kurdistan Region, Northeast Iraq

Abstract

The northwestern segment of the Zagros Orogenic Belt of the Kurdistan Region of Iraq includes the Zagros Suture Zone which is consisting of allochthonous Tethyan Triassic–Eocene thrust sheets. The zone is bounded by the Zagros Main Reverse Fault in the northeast, and the Zagros Thrust Front in the southwest. Parts of this zone’s rocks are represented by stacks of thrust megasheets obducted over the autochthonous Cretaceous–Cenozoic sequence of the Arabian Plate margin. Each sheet represents a specific Tethyan tectonostratigraphic facies, and includes (from older to younger): isolated Triassic carbonate platforms (Avroman Limestone), Jurassic carbonate imbricates (Chia Gara, Sargelu and other formations), radiolarites (Qulqula Group), sedimentary mélange (sedimentary-volcanic units of the Qulqula Group), ophiolites (Mawat and Penjwin ultramafics complexes), and Cenozoic fore-arc volcano-sedimentary sequences (Walash Group). Petrography, facies interpretation and lithostratigraphic correlation of these allochthons along four traverses across the Zagros Suture Zone of the examined area indicate that they evolved during the closure of the Neo-Tethys Ocean. Their stacking pattern and tectonic association resulted from two important events: the Late Cretaceous obduction processes, and the Late Miocene–Pliocene collision, uplift, folding and suturing between the Arabian Plate and the Sanandaj-Sirjan Block of Iran. Based on these field observations and by using the model of the Iranian Zagros evolution, a tectonic scenario is proposed to explain the history and evolution of the Zagros Suture Zone in this area.

Petrography and geochemistry of sandstones from the Injana Formation, Hemrin South Mountain, Northern Iraq: Implications for provenance, weathering and tectonic setting

“…These same rock types as well as others like serpentinites, amphibolites, granitoid dikes, chromitite pods and various other volcanic and metamorphic rocks form the ophiolites of northeastern Iraq. The geology and description of the rock units comprising these three tectonic zones of northeastern Iraq are explained by Buday and Jassim (1987), Al‐Qayim et al (2012) and Jassim and Goff (2006). The Lower Miocene Injana Formation possibly represents the first deposited continental fluviolacustrine rock unit in the area following the closure of the Neotethyan Ocean during Early Miocene because the older underlying evaporite‐dominated Middle Miocene Fatha Formation and the limestone‐dominated Upper Eocene Pila Spi Formation are both of lagoonal origin (Jassim & Goff, 2006).…”

“…This ophiolite belt is represented by the Suture Zone, which trends E‐W in Turkey and NW‐SE in Iran and Iraq. The line separating the Suture Zone and the Shalair (Sanandaj‐Sirjan) Terrane is called the Main Zagros Thrust (Mouthereau, 2011) or as the Zagros Main Reverse Fault in the Iraq‐Iranian part and Anatolian Fault in the Turkish part (Al‐Qayim, Omer, & Koyi, 2012). The NE‐SW‐directed pressure of collision resulted in intense deformation and folding of the continental, marine and trench sediments and created a NW‐SE trending fold belt forming the bulk of the geology of Iraq, which is part of the Western Zagros Fold‐Thrust Belt (Figure 2).…”

Depositional Setting of Khurmala Formation (Paleocene-Early Eocene) in Nerwa section, Berat Anticline, Kurdistan Region, Northern Iraq

“…The Paleocene-Lower Eocene succession including the Khurmala Formation located in the foreland basin in Iraq, between the Arabian Craton and the Alpine Orogen proper which is well-known by the Folded Zone of Iraq (Al-Qayim et al, 2012). The latter is mainly formed by Mesozoic and Tertiary formations and display well-exposed anticlinal and synclinal structures (Numan and Al-Azzawi, 1993).…”

“…The Paleogene rocks in northern Iraq are comprised of marine carbonates and clastics (Sissakian and Al-Jibouri, 2012). One of the carbonate units which developed on the shoaling Zagros foreland basin during the Late Paleocene to Early Eocene time is the Khurmala Formation (Al-Qayim et al, 2012). The formation was first reported by Bellen (1953) in Bellen et al (1959) from KirkukWell-114, consisting of dolomite (partly pseudoolitic) and recrystallized limestone.…”

3D Co-Seismic Surface Displacements Measured by DInSAR and MAI of the 2017 Sarpol Zahab Earthquake, Mw7.3

“…Progressive shortening led to the faulting, folding, and imbrication of the Arabian Plate margin sequences conveyed by the over-thrusting of the Tethyan accretionary prism components, which led to the final development of the Zagros Suture Zone ( Figure 1 ). According to [ 10 ], this tectonic history is proved by the development of numerous major tectonic boundaries and zones associated along the Zagros tectonic strike. These boundaries are: (1) the Urumieh-Dokhtar Magmatic, (2) the Zagros Main Reverse Fault, (3) the magmatic Sanandaj-Sirjan zone, (4) the Zagros Thrust Front, (5) the Zagros Imbricate Zone, (6) the High Zagros Reverse Fault, (7) the Zagros Fold Zone, (8) the Zagros Foredeep Fault, and (9) the Mesopotamian Zone.…”