Timing of Opening of the Black Sea: Sedimentological Evidence from the Rhodope-Pontide Fragment

Abstract

Sedimentologic evidence from the late Jurassic through the Cretaceous sequences of the Rhodope-Pontide fragment (Northern Turkey) indicate that the present Black Sea basin began opening as an originally ensialic ‘back-arc’ basin concurrently with the onset of north-dipping subduction of the floor of the northern branch of Neo-tethys. In late Jurassic-Neocomian time both the present Rhodope-Pontide fragment and the northern shores of the Black Sea were parts of a south-facing Atlantic-type continental margin (shelf). In Aptian to Cenomanian time interval the Rhodope-Pontide fragment began rifting from the southern U.S.S.R. coevally with the onset of moderate intensity subduction-related magmatism. In post-Cenomanian time rift-related normal fault activity ceased, thermal subsidence along the northern, rifted margin of the Rhodope-Pontide fragment commenced, and subduction-related magmatism intensified.

The Black Sea is not a Jurassic structure as maintained by some. It is a late Cretaceous back-arc basin that began opening almost in a pre-arc spreading mode as most present-day extensional arcs.