Depositional environment and sequence stratigraphy of the Khoshyeilagh Formation in Bojnourd and Jajarm (NE Iran)

Abstract

IntroductionDuring the Silurian and Devonian periods, parts of Iran (central Iran, Alborz, and Sanandaj-Sirjan) along with the Afghan and Turkish plates were attached to the Arabian and African plates and formed the northwestern margin of the Gondwana supercontinent and the southern margin of Paleo-Tethys (Berberian and King, 1981;Al-Husseini, 1991;Ruban et al., 2007;Al-Juboury and Al-Hadidy, 2009). The current structure and geological status of Iranian platuea has been shown in Figures 1a and 1b.The Devonian sedimentary horizons of Alborz-Azarbaijan zone show a variety of rock facies. These facies always display unique shapes, which reveal an independent basin with different sedimentary conditions. Also, the Devonian lithologic units are Juban Formation in Saudi Arabia, Kuwait (partly), and parts of Ora Formation in Iraq, Bahram Formation in central Iran, and parts of the Muli and Zakeen Formations in NW and

Biostratigraphy of the Upper Devonian Khoshyeilagh Formation in NE Iran based on conodonts and other faunas

“…The vertical and lateral changes of the Khoshyeilagh Formation show a shoreface marine depositional environment that begins with alluvial sediments and continues by marine sedimentation. According to these changes, a homoclinal ramp model has been proposed (Jafarbeigloo et al, 2020). This ramp model shows a relatively gentle slope that continues to the basin and is similar to present-day carbonate ramps, like the southern coast of the Persian Gulf and Shark Bay in Australia.…”