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

Subject Areas :

Elham Ghaffari ¹ , Vachik Hairapetian ² , Sayed Hassan Hejazi ³

1 - دانشجوی کارشناسی ارشد رسوب شناسی و سنگ شناسی رسوبی دانشگاه آزاد اسلامی واحد خوراسگان
2 - استادیار گروه زمین شناسی دانشگاه آزاد اسلامی واحد خوراسگان
3 - استادیار گروه زمین شناسی دانشگاه آزاد اسلامی واحد خوراسگان

Received: 2016-09-07 Accepted : 2016-09-07 Published : 2011-09-23

Keywords: Depositional environment, upper devonian, sequence stratigraphy, Zefreh,

Abstract :

In order to determination of facies, depositional environment and sequence stratigraphy of carbonate andsiliciclastic sedimentary sequences of upper devonian succession of Kuh-e-Zard (eastern profil) with 378mthickness, field and microscopic studies were performed. Facies analysis and petrographic studies led to therecognition of three silisiclastic facies (sandstone, shale and siltstone), two hybrid subfacies (sandstone micriticand allochemic sandstone) and seventeen carbonate facies were identified. The latter includes lime mudstone andintraclast packstone (representing peritidal environment), wackstone/packstone with molluscs and lime mudstone(representing lagoon environment), ooid grainstone with superfical ooid and intraclast and bioclastic packstonewith 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 restrictedmarine environment), peloidal wackstone/packstone, floatstone, grainstone/ rudestone with various bioclasts,boundstone, bioclastic packstone with abundant echinoderms and brachiopods and lime mudstone (representingopen marine environment) and wackstone with bioclast and limestone conglomerate (representing mid rampenvironment). Lateral and ramp subenvironment vertical variation of facies show that these deposits wereformed on a homoclinal ramp. Sequence stratigraphical studies of the section revealed four 3rd order cycles. Adeepening trend in an ascendig order, sparring frasnian to lower famennian was recorded.