The Messinian Salinity Crisis in the Adana Basin, (southern Turkey): New Data for the Exploration of the Taurus Petroleum System

Giuditta Radeff, Domenico Cosentino, Paola Cipollari, Taylor F. Schildgen, Manfred R. Strecker, Guldemin Darbas, and Kemal Gürbüz

The Adana Basin (Southern Turkey) is located beside the Central Anatolian Plateau SE margin, very close to the Arabian-Eurasian collision zone; its sedimentary record spans from Late Oligocene to Quaternary. The Burdigalian–Serravallian sandstones and limestones and the Late Tortonian–Messinian shales and evaporites of the Adana Basin have been reported in literature as the reservoir–seal rock combinations in the eastern Taurus petroleum system.

The recently proposed stratigraphy of the Adana Basin allowed us to re-interpret some of the seismic profiles acquired in the basin by the Turkish Petroleum Corporation (TPAO). We interpreted 34 seismic profiles, distinguishing 5 different seismic units, and identifying 4 regional erosional surfaces. We reconstruct the top and bottom surfaces of the different seismic units in order to estimate the spatial continuity and the volumes of the potential reservoir and seal-rock.

From our new interpretation, the geometries of the potential seal rock of the Adana Basin appear to be more complicated than previously reported. The anhydrites and black shales, recording the main evaporative event of the Mediterranean (Primary Lower Gypsum) and conformably lying above the Tortonian-early Messinian marine and continental deposits, are spatially discontinuous. The Resedimented Lower Gypsum, deposited above the first Messinian erosional event (MES1, about 5.59 Ma), outline a spatially confined sedimentary body showing a 3D lobe geometry.

Using the seismic data we reconstruct the subsidence curve and the geohistory of the Adana Basin showing the main events that occurred in the area. At the Middle/Late Miocene transition the stratigraphy of the Adana Basin records an erosional surface which can be related to the collision between Arabian and Eurasian plates coupled with a global sea level drop. An increase in the subsidence rate is shown at about 5.59 Ma: it corresponds to a period of increased sedimentation rate right after the drawdown of the Mediterranean base level and the formation of the MES1. At about 5.45 Ma, above a younger erosional surface (MES2) a major increase in subsidence rate is recorded, with the deposition of up to 1.6 km of fluvial deposit (conglomerates and marls of the Handere Fm) during the latest Messinian Lago-Mare event (5.45-5.33 Ma).

Integrating the seismic data with the reconstruction of the subsidence curve, our study highlights the complexity of the Adana Basin, providing useful data for the exploration of the Taurus petroleum system.

AAPG Search and Discovery Article #90161©2013 AAPG European Regional Conference, Barcelona, Spain, 8-10 April 2013