Development of the Kura delta, Azerbaijan; a record of Holocene Caspian sea-level changes

Four phases of delta progradation alternating with erosional transgressive surfaces have been identified, representing just as many cycles of sea-level fall and rise. The first cycle is represented by lowstand deposits truncated by a transgressive surface (TS1) at ca. 80 m below GSL. TS1 is overlain by several metres of laminated clays and silts, deposited during a Late Holocene forced regression (H1). These deposits are truncated by the prominent reflector (TS2), corresponding to the Derbent lowstand around 1500 yr BP and subsequent transgression. This transgressive surface is overlain by prograding shallowing upwards deposits, H2, in turn truncated by a third transgressive surface (TS3), correlated with a lowstand of ca. 32 m below GSL. The last phase, H3, comprises an onshore progradational unit followed by an aggradational unit with an offshore veneer of clays and silts, corresponding to the formation of the modern Kura delta that started at the beginning of the 19th century.