Abstract
Shiranish Formation represents the uppermost Cretaceous pelagic sediment unit of the Iraqi segment within the western Zagros fold and the thrust belt. The occurrence of the formation governed by the northern edge of the Neabo-Arabian plate`s tectonic activity and the distribution has now been interpreted according to the modern tectonic concept of the foreland basin system. Field data and Isopach map have shown that two main basins existed on both sides of the Forebulge (Qamchuqa Formation). Currently, the first one has extended north west-southeast within the foredeep depozone, while the second one, which represents the Backbulge Depozone. The influence of the tectonic rise of the Forebulge Depozone leads to a non-existing pelagic sediments unit of the Shiranish Formation in the area restricted from northwest Amadiya town (the south limb of Mateen Anticline) towards southeast areas (Gara Anticline), thereafter to Aqra areas. Thus, the absence of the formation in the Shikhan area (e.g.) refers to inhomogeneity on the backbulge basin causing exposed or submerged areas during the age of upper Cretaceous.
Highlights
The northern and eastern margins of the Nubian-Arabian plate were affected by episodically compressional stresses in the pre collisional orogeny stage
The characteristics of the foreland basin system were manifested, where the accretionary prism and ophiolite thrust slices formed the top-wedge of depozone
The basinal situation of the underfilled trinity in a foredeep depozone of the foreland basin system, affected as the tectonic load thrusts above the craton, the foreland basin depozone migrates at about the same rate (Sinclair, 1997a)
Summary
The northern and eastern margins of the Nubian-Arabian plate were affected by episodically compressional stresses in the pre collisional orogeny stage (during Cretaceous). The stresses increased in the Late Cretaceous. These stresses may attribute to the subduction of the oceanic crust plate and cause the accumulation of accretionary prism of Qulqula Radiolarite serpentinite mélange slices (Ali et al, 2019; Aziz et al, 2011a). According to (Ibrahim, 2009; Agard et al, 2011), ophiolite abducted on the stated NE margin of the continental Arabian plate. The continental crust, flexed due to the overload under the influence of the accretionary prism assemblages. The flexural foreland-Zagros basin system in the Iraqi segment undergoes an under-filled stage.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
