**7. Tectonosedimentary evolution**

The depositional evolution of the Kolosh formation was mainly controlled by continuous subduction of continental and oceanic crust in the Zagros Tethyian basin and was indirectly related to the sea level changes. The Kolosh successions can be classified into four stratigraphic sequences, representing the certain depositional system. Successive facies associations are arranged from bottom to top cf. slope/submarinechannel fan FA1, inner fan/channel levee FA2, outer fan FA3, and pelagic/hemipelagic basin plane FA4 refer to progressive deepening from slope apron to the basin plain in the top of the formation (**Figures 3** and **4**).

#### **7.1 Stage 1**

The first tectonosedimentary stage comprises slope/submarine channels that flows down the slope and comprised of F4, F5, F6, F8, F9, and F10. These are evident from

the bed geometry, sedimentary structures, and facies types. FA1 is characterized by muddy, pebbly coarse-grained turbidite sandstone F6, chaotic mud-rich facies, with harder horizons of F1/F2 facies in a mud-rich matrix F8, and muddy, pebbly, and bioclastic-sandstone F10. These facies are typically originated from relatively dense turbidity currents, in slope margins via the submarine channel.
