Sedimentary Facies and Sequence Stratigraphy of Cretaceous-Paleocene Sequence in Yazd Block, Chahtorsh Section

Transitional boundary of Cretaceous to Paleocene known as a hiatus due to laramid orogenic activities and is associated with detrital facies. There is an outcrop in the south part of the Yazd block which show continuity of sedimentation at the boundary of Maastrichtian to Paleocene. As a result of the importance of this boundary in Central Iran, the sedimentary sequence of Barremian-Paleocene was studied in the Yazd block, the Chahtorsh Section. Lithostratigraphic studied released the presence of carbonate and detrital sediments in this stratigraphic section. Facies analysis led to recognition of 15 sedimentary facies which deposited on a shallow carbonate ramp in four subenvironments, tidal flat, lagoon, shoal and shallow part of open marine. According to the four type 1 and 2 sequence boundary, four sedimentary sequences was divided in this section. The boundary between fist and second sequences recorded on of the longest discontinuity (Aptian- Maastrichtian) in Central Iran Semi continent while the Maastrichtian to Paleocene boundary, that is discontinue in most parts of Central Iran, is a continue boundary in this section. These results can be used in the paleoenvironmental reconstruction of Central Iran Semicontinent.