On the origin of the Bosphorus

Abstract

The Palaeozoic-Upper Cretaceous basement palaeomorphology of the Bosphorus (the Strait of Istanbul) bears the evidence of a valley of a palaeostream running to the Black Sea in the north, a palaeobasin deeper than -160 m opening to the Sea of Marmara in the south, and a barrier between these two features. This suggest that the northern part of the Bosphorus was formed mainly by fluvial activity, whereas the southern part developed as a basin by faulting. The recent sediment thickness exceeds 130 m in the basin, indicating that the southern part of the Bosphorus was once essentially depositional rather than an erosional.