Writers : Helmi,Faride
Refference : Geosciences Scientific Quarterly Journal,No.:8,P.:34

Abstract :

Coronk section near Coronk village of Gheisar area (W.Birjand) was studied. Rocks In this section were deposited through Upper Cretaceous to Lower Eocene. We considered the specialities of sedimentary environment and paleoecology during their deposition.
During Upper Cretaceous fades variations especially geographical, was relatively large In central Alborz and central Iran. Formations of this period Is developed In W.Birjand but probably due to disturbances these sediments are not very thick and so we can not define exactly the sedimentary environment. This instability can be related to the early stages of Alpine orogenic movements.
During early Tertiary conglomerates, sandstone and subsequently limestones were deposited indicating large variation in sedimentary environment.
Limy, conglomeratic and sandy Microfacies are three original kinds of Microfacies that existed In the Coronk section. Based on specialities of these Microfacies, sedimentary environment and sedimentation models were developed. The sea, where these sediments were deposited through Upper Cretaceous - Lower Eocene had experienced two Perfect retreats.
The rocks of Coronk section have primary and secondary porosities. The primary porosity is comparatively insignificant but the secondary especially Fractural porosity Is abundant. This indicate that this area has been active tectonically.

Subject List : biostratigraphy, Stratigraphy