Sedimentary Facies, Architectural Elements and Trace Fossils of Kashkan Formation, Folded Zagros Zone in SW Iran

Abstract

The Kashkan Formation (Paleocene to Middle Eocene), consists of conglomerate, sandstone, and siltstone in the Zagros Folded zone, southwest Iran. Type of the sedimentary facies, architectural elements and trace fossils show that Kashkan deposits were formed in a low sinuosity braided stream system, with north to south flow direction. The formation displays coarsening-upward succession reflects an overall regressive sequence. The clast–supported conglomerate is the major components of the formation. A thinning of the coarser–grained sediments toward the south, and southwest indicates that the source for the Kashkan formation was to the north and northwest from the study area. Trace fossils of Kashkan Formation are related to Scoyenia ichnofacies, include Arenicolites isp., Diplocraterion isp., Ophiomorpha isp., Skolithos isp., Steinichnus isp., Thalassinoides isp., Escape structure and vertebrate footprints. Sedimentological analysis and type of the trace fossils indicate the south the stream was restricted by a shoreface environment. Kashkan Formation becomes thinner and fine–grained in the southern part of the study area.