Neogene Tectonics and Sedimentation in the Adana Basin (Southern Turkey): a Record of the Central Anatolian Plateau SE Margin Uplift

Monday, 15 December 2014: 10:35 AM
Giuditta Radeff1, Taylor F Schildgen1, Domenico Cosentino2, Manfred R Strecker1, Paola Cipollari2, Guldemin Darbaş3 and Kemal Gürbüz4, (1)University of Potsdam, Potsdam, Germany, (2)University of Roma Tre, Rome, Italy, (3)Kahramanmaraş Sütçü İmam Üniversitesi, Kahramanmaraş, Turkey, (4)Çukurova Üniversitesi, Adana, Turkey
With its thick, Oligocene to recent sedimentary filling, the Adana Basin of southern Turkey, located between the SE margin of the Central Anatolian Plateau (CAP) and the SW branch of the East Anatolian Fault, is ideally located to record topographic and tectonic changes in Neogene times. We correlate 34 seismic profiles with corresponding exposed units in the Adana Basin, the age constraints of which have been recently improved through detailed biostratigraphic correlation with the broader Mediterranean stratigraphy. The time-depth conversion of the interpreted profiles allows us to reconstruct the subsidence curve of the Adana Basin, which reveals a major increase in subsidence rate in late Messinian times (5.45 to 5.33 Ma), associated with the deposition of ~1500 km3 of conglomerates and marls. Our provenance and paleocurrent analyses of the exposed conglomerates reveal that most of the sediment is derived from the SE margin of the CAP and the plateau region farther north. A comparison of these results with the composition of recent fluvial conglomerates and the present drainage basins indicates major changes between late Messinian and present-day source areas. We suggest that these changes result from the uplift and ensuing erosion of the SE margin of the plateau. This hypothesis is corroborated by a comparison of the Adana Basin’s subsidence curve with that of the Mut Basin, a mainly Neogene basin located atop the CAP’s southern margin. The Adana Basin’s rapid subsidence event is approximately coeval with an uplift episode at the plateau’s southern margin (after ca. 7 Ma), and its timing provides the first minimum time constraint on the timing of plateau margin uplift. Preliminary results from a structural analysis show that extensional and transtensional structures likely helped accommodate the differential uplift of the source (CAP SE margin) relative to the sink (Adana Basin).