اوگاندا: برقراري كمك هزينه براي فقر

Rudistid Reef of Upper Cretaceous Shallow Carbonate platform in East Kopet -Dagh Basin

Kalat Formation (Maestrichtian) in the eastern Kopet- Dagh Basin consists of five members and the fifth member contains thick-bedded rudistid limestone which formed a biostrome in north- east Iran. The impotant types of rudist in this formation include Radiolites and Hippurites. In this study, the distribution of biostrome and different types of rudists have been considered and based on field observation and petrological study, depositions model have been presented. Petrological study indicates that the fifth member of the Kalat Formation consists of three carbonate and marl and shale lithofacies, that have been deposited during a regressive phase of deposition in the study area. Rudistid biostrome formed in a warm, relatively high salinity and low energy shallow marine environment which is coincident with worldwide distribution of rudist in the Maestrichtian and their replacement for the corals and calcareous algae.