Abstract

• The study area is located in the west of Tatkon Township, Mandalay Region. This area is well exposed of the Kyaukkok Formation (Burdiagalian), the Obogon Formation (Vindobonian) and the Irrawaddy Formation (Pontian to Pliocene). In the study area, the Kyaukkok Formation is well exposed in the Sinthe Chaung. The Kyaukkok Formation is mainly composed of thin to medium bedded, gray, yellowish brown, fine to medium grained sandstone. Micaceous sandstone hard band are locally exposed. In some place, concretions, ripples and cross-laminations are common in the Kyaukkok Formation. In the present research, primary sedimentary structures are used for the facies scheme. The lithology, nature of the bed base and paleocurrent direction is also used to perform facies analysis to interpret the sedimentary environments. The Kyaukkok Formation of the Sinthe Chaung are divided into seven lithofacies such as thick bedded bluish gray shale facies, sandstone and shale alternation facies, thin to medium bedded sandstone facies, massive sandstone facies, trough cross- bedded sandstone facies, hummocky cross- stratification sandstone facies, and sand- mud interlayer facies. These facies can be grouped as prodelta/ offshore facies association, delta front facies association, delta plain facies association and outer shelf facies association.The Kyaukkok Formation is deposited in subtidal, intertidal, and offshore/ shelf environment.