Triassic Carbonate Tidalites and Tempestites in the Khaneh Kat Formation type locality, High Zagros, East Shiraz

The Khaneh Kat Formation represents carbonate development of the Triassic sediments in the Zagros Mountains. This formation with a thickness of 691 m at the type locality in 110 km of east Shiraz was studied for facies analysis and reconstruction of sedimentary environment. Detailed field and laboratory investigations showed that the Triassic sedimentary succession in Khaneh Kat anticline consists of limestones and dolomites deposited in tidal flat setting and shallow, relatively quite portion of a carbonate platform. These deposits are mainly results of shallowing-upward cycles consisting of intertidal-supratidal (sabkha) facies repeated over and over in a tidal system under dry climate. In some horizons, the presence of laterally extensive carbonate storm beds has terminated the normal succession of peritidal facies. All these pieces of evidence suggest that the Khaneh Kat Formation carbonates in the study area were deposited in inner part of an open, storm-dominated platform. Comparison of this situation with the sedimentary environment of equivalent deposits in other parts of the basin confirms the widespread expansion of the platform and also the existence of an epeiric sea in Triassic period of these areas. Significant increase of evaporites and siliciclastics in the southern of High Zagros Fault revealed the paramount role of this bounding fault in controlling basin geometry and facies variations during deposition of the Khaneh Kat Formation. The results also indicated that the southern part of the basin was close to the coast and water circulation was restricted. In contrast, the reduction of evaporites and siliciclastics together with the existence of storm beds in High Zagros region showed a further development of marine environment in northern part and its relation to the Neotethys Ocean.