Cretaceous sedimentation along the Romanian margin of the Black Sea: inferences from onshore to offshore correlations

It is generally believed that the western part of the Black Sea opened during the Early Cretaceous. However, recent data and interpretation from the Turkish margin suggest rifting continued into the Coniacian or Santonian. In this review, the evidence related to the Black Sea rifting on the conjugate Romanian margin is reassessed. Our integrated interpretation of this region, supported by outcrop observations, core and detrital zircon data, suggests that rifting started during the Aptian and continued intermittently until the mid-Turonian in two distinct stages. These stages are bounded by significant unconformities and reflect the progressive widening of the rift system. The first synrift stage started in the Aptian with the deposition of fluvial and lacustrine clastic successions, and locally marine carbonates in semi-isolated depocentres. These sinks began to coalesce during the latest Aptian–Albian with shallow-marine transgression from the east, and deposition of coastal swamp, deltaic and littoral facies. The second phase of rifting during the Cenomanian was marked by transgressive shallow-marine deposits overstepping the earlier Albian depocentres. Continental break-up followed in the mid-Turonian associated with regional uplift and erosion of the basin margin and the local deposition of fluvial conglomerates.