Seismic expression and inferred depositional environments of Plio-Pleistocene sedimentary sequences in the southwestern Caspian Sea

Abstract

Eight seismic profiles from the southwestern Caspian Sea were analyzed to establish the sedimentary environments and depositional history in the South Caspian Basin since Pliocene times. Based on reflection terminations, nine sequence boundaries (S1 to S9) were identified and traced across the study area. Consequently, nine depositional sequences (S1–S9) were defined on the basis of seismic facies analysis. The results suggest a transition from non-marine sedimentation in the Lower Pliocene to marine-dominated conditions in the Upper Pliocene (S1–S4). Marine conditions then continued to the present time; however, several sea-level changes led to the formation of sequences S5 to S9. Although no local sea-level curve is available due to a lack of well data, there is good agreement between the seismic stratigraphy of the study area and a published regional sea-level curve.