The Miocene of the Hatay area, S Turkey: Transition from the Arabian passive margin to an underfilled foreland basin related to closure of the Southern Neotethys Ocean

Abstract

Miocene sediments of the Hatay area document the distal, southerly, part of an “underfilled” peripheral foreland basin related to the closure of the Southern Neotethys. The basin is underlain by latest Cretaceous and Eocene shallow-marine carbonates, interpreted as the youngest part of the Arabian passive margin succession. Unconformably overlying Lower Miocene conglomerates, sandstones and palaeosols (up to 250 m thick) represent braided river deposits derived from an uplifted area to the south. During the Middle Miocene, carbonate sediments accumulated in a variety of shallow-marine environments dominated by a northward-sloping ramp, with non-marine, peritidal, lagoonal and coral reef deposition in local areas. The Upper Miocene succession is mainly deeper-water hemipelagic marl with clastic interbeds. Messinian evaporites were deposited near the depocentre. The Early Miocene coarse fluvial sediments above the regional unconformity reflect the development of a flexural bulge, or re-activated basement structure. The Middle Miocene carbonates and Upper Miocene marls are interpreted as the lower and middle units of an “underfilled trinity”, considered typical of peripheral foreland basins. Similar Lower Miocene coarse clastic sediments and Mid-Miocene shallow-water carbonates unconformably overlie the Arabian platform succession c. 75 km to the north, where the succession continues upwards into thick shallow-marine to non-marine terrigenous sediments (upper unit of the “trinity”), sourced from the overthrust load. Comparable coarse clastic sediments are absent from the distal foreland basin in the Hatay area, probably reflecting its more southerly position, structural barriers in the foreland and the westward bypassing of sediment towards the Mediterranean Sea. Regional convergence halted by the end of the Miocene and was followed by strike–slip and westward “tectonic escape”. As a result the Miocene foreland basin was dismembered to form the Plio-Quaternary transtensional Hatay Graben. This like many other foreland basins shows some features which are not accommodated by ideal models of foreland basin evolution.