Integrated Stratigraphy and Facies Analysis of the Upper Albian-Turonian (Cretaceous) Debarsu Formation (Yazd Block, Central Iran)

The upper Albian-Turonian Debarsu Formation in its type area around Haftoman, south of Khur (Central Iran), has been investigated using an integrated approach of detailed logging, biostratigraphic and sequence-stratigraphic dating, and facies analysis based on field observations and microfacies studies. The formation was deposited on a homoclinal carbonate ramp with a basinal area situated towards the north. Numerous shallowing-upward cycles from offshore marl to shallow-water limestones are capped by palaeokarst surfaces, providing evidence of significant relative sea-level changes. Based on the stratigraphic positions of the sequence-bounding unconformities, a predominantly eustatic control of the sedimentary cyclicity is inferred. The major unconformity at the base of the overlying Coniacian-Campanian Haftoman Formation, however, is of tectonic origin.