Sedimentary environment and sequence stratigraphy of the upper devonian rocks in Zefreh area (eastern section) northeast of Isfahan

In order to determination of facies, depositional environment and sequence stratigraphy of carbonate and siliciclastic sedimentary sequences of upper devonian succession of Kuh-e-Zard (eastern profil) with 378m thickness, field and microscopic studies were performed. Facies analysis and petrographic studies led to the recognition of three silisiclastic facies (sandstone, shale and siltstone), two hybrid subfacies (sandstone micritic and allochemic sandstone) and seventeen carbonate facies were identified. The latter includes lime mudstone and intraclast packstone (representing peritidal environment), wackstone/packstone with molluscs and lime mudstone (representing lagoon environment), ooid grainstone with superfical ooid and intraclast and bioclastic packstone with a few dominant skeletal grains (representing shoal environment) wackstone/ packstone with brachiopods, echinoderm and ooids and wackstone with intraclast and oncolith and lime mudstone (representing restricted marine environment), peloidal wackstone/packstone, floatstone, grainstone/ rudestone with various bioclasts, boundstone, bioclastic packstone with abundant echinoderms and brachiopods and lime mudstone (representing open marine environment) and wackstone with bioclast and limestone conglomerate (representing mid ramp environment). Lateral and ramp subenvironment vertical variation of facies show that these deposits were formed on a homoclinal ramp. Sequence stratigraphical studies of the section revealed four 3rd order cycles. A deepening trend in an ascendig order, sparring frasnian to lower famennian was recorded.