Abstract:
Fossils give information that unveil the geologic past including
paleoenvironment, paleogeographic conditions and depositional settings. Samana Suk
Formation is well exposed near Shah Alla Ditta in Islamabad. It is section of Margalla
Hill ranges which is the part of lesser Himalayas. It is located in western margin of
Main Boundary Thrust. The Samana Suk Formation consists of medium to thick bedded
limestone with intercalations of calcareous shale. The limestone contains fragments of
Brachiopods, Bivalves, Ammonoids, Gastropods and Crinoids fauna. The petrographic
study revealed different microfacies including bioclastic facies, dolomitic facies and
quartz rich dolomitic facies. These microfacies were identified on the basis of faunal
content e.g., bivalve fragments, ooids, peloids, intraclasts, algae and other
sedimentological characteristics. The identified microfacies are consistent with the
lagoonal to middle ramp depositional setting.
