Microfacies and sedimentary environment of the Maastrichtian deposits in Jorbat Stratigraphic section, west of Kopet Dagh
Subject Areas :یداله عظام پناه 1 , عباس صادقی 2 , محمد حسين آدابي 3 , امیرمحمد جمالي 4
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Abstract :
To determine microfacies and depositional subenvironments of the Maastrichtian deposits in the western part of the Kopet-Dagh Basin, one stratigraphic section, has been selected and analysed. In this section which is located 9.5 kms N-NW of Jorbat, Maastrichtian deposits are composed of two formations including Kalat (282 m thickness) and Chakhmaghlo (77 m thickness). The Kalat Formation consists of bioclastic and sandy limestone and the Chakhmaghlo Formation is composed of shale, marl, limestone and argillaceous limestone. Based on field observations and also petrographic studies, the lower boundary of the Kalat Formation with the Abderaz Formation is disconformable. The lower boundary of the Chakhmaghlo Formation with the Kalat Formation is gradual and conformable, while its upper contact with the Paleocene Pesteligh Formation is disconformable. Petrographic studies in Maastrichtian deposits led to recognition of 16 microfacies. These microfacies deposited in 5 facies belts including tidal flat, lagoon, shoal, reef and fore reef subenvironments in a carbonate platform.
