microfacies and sedimentary environment of carbonate rocks of the dalichai formation in northeast of shahroud (rey-abad section)

dalichai formation at the rey-abad section (northeast shahroud) along the principal road of the mayamey-jajarm has a thickness of 166 meters .in this section, middle to upper jurassic carbonate rocks are well exposed and is typically composed of massive to medium-bedded limestones with thin shale interbeds. in the studied area and most places of this region, the lower boundary of dalichai formation with shemshak formation is covered, but in some locations, this boundary is exposed. the upper boundary with lar formation is not seen. detailed fieldwork and study of 42 thin sections, using microscope, are done for identification of facies and sedimentary environment of the dalichai formation in the rey-abad section. the results of study lead to identification of 11microfacies, groups into 3 carbonate facies (a, b and c), deposited in tidal flat, lagoon and shoal environments. the microfacies studies pointed to a shallow marine environment. on the bases of facies analysis, the carbonate sediments of the dalichai formation are formed in a carbonate platform of the ramp type.