Sedimentary evidence for late Messinian uplift of the SE margin of the central Anatolian Plateau: Adana Basin, Southern Turkey

The Adana Basin of southern Turkey, located at the SE margin of the Central Anatolian Plateau in the vicinity of the Arabia-Eurasia collision zone, is ideally suited to record Neogene and Quaternary topographic and tectonic changes in the easternmost Mediterranean realm. On the basis of our correlation of 34 seismic reflection profiles with corresponding exposed units along the margins of the Adana Basin, we identify and characterize the seismic facies that corresponds to the upper part of the Messinian Handere Formation (ca. 5.45 to 5.33 Ma), which consists mainly of fluvial conglomerates and marls. The seismic reflection profiles indicate that ca. 1100 km3 of the Handere Formation upper sub-unit is distributed over ca. 3000 km2, reflecting local sedimentation rates of up to 12.5 mm year1. This indicates a major increase in both sediment supply and subsidence rates at ca. 5.45 Ma. Our provenance analysis of the Handere Formation upper sub-unit based on clast counting and palaeocurrent measurements reveals that most of the sediment is derived from the Taurus Mountains at the SE margin of the Central Anatolian Plateau and regions farther north. A comparison of these results with the composition of recent fluvial conglomerates and the present-day drainage basins indicates major changes between late Messinian and present-day source areas. We suggest that these changes in drainage patterns and lithological characteristics result from uplift and ensuing erosion of the SE margin of the plateau. We interpret the tectonic evolution of the southern flank of the Anatolian Plateau and the coeval subsidence and sedimentation in the Adana Basin to be related to deep lithospheric processes, particularly lithospheric delamination and slab break-off

Sedimentary evidence for late Messinian uplift of the SE margin of the Central Anatolian Plateau: Adana Basin, southern Turkey

The Adana Basin of southern Turkey, located at the SE margin of the Central Anatolian Plateau in the vicinity of the Arabia-Eurasia collision zone, is ideally suited to record Neogene and Quaternary topographic and tectonic changes in the easternmost Mediterranean realm. On the basis of our correlation of 34 seismic reflection profiles with corresponding exposed units along the margins of the Adana Basin, we identify and characterize the seismic facies that corresponds to the upper part of the Messinian Handere Formation (ca. 5.45 to 5.33 Ma), which consists mainly of fluvial conglomerates and marls. The seismic reflection profiles indicate that ca. 1100 km3 of the Handere Formation upper sub-unit is distributed over ca. 3000 km2, reflecting local sedimentation rates of up to 12.5 mm year-1. This indicates a major increase in both sediment supply and subsidence rates at ca. 5.45 Ma. Our provenance analysis of the Handere Formation upper sub-unit based on clast counting and palaeocurrent measurements reveals that most of the sediment is derived from the Taurus Mountains at the SE margin of the Central Anatolian Plateau and regions farther north. A comparison of these results with the composition of recent fluvial conglomerates and the present-day drainage basins indicates major changes between late Messinian and present-day source areas. We suggest that these changes in drainage patterns and lithological characteristics result from uplift and ensuing erosion of the SE margin of the plateau. We interpret the tectonic evolution of the southern flank of the Anatolian Plateau and the coeval subsidence and sedimentation in the Adana Basin to be related to deep lithospheric processes, particularly lithospheric delamination and slab break-off. © 2015 The Authors. Basin Research © 2015 John Wiley & Sons Ltd, European Association of Geoscientists & Engineers and International Association of SedimentologistsTA.P05.009.003, TA.P05.009 California Department of Fish and Game: STR373/21-2 European Science Foundation Deutscher Akademischer Austausch Dienst Kairo: GR Genome Institute of SingaporeThis work was supported by the Vertical Anatolian Movements Project (VAMP), funded by the TOPO-EUROPE initiative of the European Science Foundation to DC (IGAG-CNR, com. TA.P05.009, mod. TA.P05.009.003) and MS (DFG project STR373/21-2), and a student grant by the DAAD (Deutscher Akademischer Austausch Dienst) to GR. We are grateful to the national oil and Gas Company of Turkey (T?rkiye Petrolleri Anonim Ortakl???, TPAO) for allowing access to the seismic lines of the Adana Basin and granting permission to publish this data set. Particular thanks to J. Sayago for assistance with the Petrel software, to G. Zeilinger for assistance with GIS software, to C. Yildirim for helpful discussions, to E. Giachetta for the suggestions on the minimum eroded volume calculation and to R. Kutzner for help with fieldwork. We thank D. Pearson, A. Robertson and P. Umhoefer for constructive reviews

Easternmost Mediterranean evidence of the zanclean flooding event and subsequent surface uplift: Adana basin, southern Turkey

According to the literature, the Adana Basin, at the easternmost part of the Mediterranean Basin in southern Turkey, records the Pliocene stage with shallow-marine to fluvial deposits. Our micropalaeontological analysis of samples from the Adana Basin reveal Late Lago-Mare biofacies with Paratethyan ostracod assemblages pertaining to the Loxocorniculina djafarovi zone. Grey clays rich in planktonic foraminifera lie above the Lago-Mare deposits. Within the grey clays, the continuous occurrence of the calcareous nannofossil Reticulofenestra zancleana and the base of the Reticulofenestra pseudoumbilicus paracme points to an Early Zanclean age (5.332-5.199 Ma). Both ostracod and benthic foraminifera indicate epibathyal and bathyal environments. 87Sr/86Sr measurements on planktonic and benthic foraminifera fall below the mean global ocean value for the Early Zanclean, indicating potentially insufficient mixing of low 87Sr/86Sr Mediterranean brackish 'Lago-Mare' water with the global ocean in the earliest Pliocene.We utilize the ages and palaeodepths ofthe marine sediments together with their modern elevations to determine uplift rates of the Adana Basin of 0.06 to 0.13 mm a-1 since 5.2-5.3 Ma (total uplift of 350-650 m) from surface data, and 0.02-0.13 mm a21 since c. 1.8 Ma (total uplift of 30-230 m) from subsurface data. © The Geological Society of London 2013

Stratigraphic architecture of the upper Messinian deposits of the Adana Basin (Southern Turkey): Implications for the Messinian Salinity Crisis and the Taurus petroleum system

This paper is mainly based on field work carried out on the Messinian deposits of the Adana Basin (southern Turkey), as well as on the interpretation of seismic reflection profiles to understand 3D geometries of the basin fill. Chronostratigraphic constraints for the Messinian deposits are from micropaleontological studies on foraminifera, ostracods, and calcareous nannofossils, recently carried out on the Messinian deposits of the Adana Basin. Our results indicate that this basin developed in a marginal area strictly related to the Mediterranean realm. The Messinian deposits of the Adana Basin record all the main steps of the Messinian Salinity Crisis (MSC) that affected the Mediterranean area at the end of the Miocene. The new stratigraphic model for the Messinian deposits of the Adana Basin provided in this work gives new insights into both the MSC and the Taurus petroleum system. Despite their complete correspondence with the MSC, the Messinian deposits of the Adana Basin show some differences with respect to the current conceptual model for the MSC. For example, in the current conceptual model for the MSC, only one regional erosional surface (MES) characterizes the MSC deposits. In the Adana Basin, two regional erosional surfaces, named MES1 and MES2, separate the Messinian deposits related to the MSC in Lower Evaporites, Resedimented Lower Evaporites (RLE), and upper Messinian continental deposits containing a late Lago-Mare ostracod assemblage (mainly fluvial coarse-grained and fine-grained sediments). In some places, Brecciated Limestones lie just above the MES1 and beneath the RLE. In addition, the RLE are thought to be related to the same step that brought to the Messinian halite deposition throughout the Mediterranean, pointing to a hyperhaline environment. In contrast, the fine-grained deposits of the RLE of the Adana Basin show the occurrence of Parathetyan brackish ostracod fauna (early Lago-Mare ostracod assemblages), which defines an oligohaline depositional environment for the RLE. In terms of hydrocarbon prospecting, the Messinian evaporites of the Adana Basin have been considered as a perfect seal for the active Taurus petroleum system. Our results show that due to the complex stratigraphic architecture of the basin fill and the occurrence of two regional erosional surfaces (MES1 and MES2), the Messinian evaporites are discontinuously present both in surface and in the subsurface of the Adana Basin. However, seal properties in the Adana Basin could be found in the Lower Pliocene deep marine clays of the Avadan Formation. This work leads to suggest a new stratigraphical model for the Messinian deposits of the Adana Basin, allowing us to amend the classical scheme with respect to the Messinian, and to officially define some new formations within the stratigraphy of the Adana Basin. © Società Geologica Italiana, Roma 2016

Effects of slab-window, alkaline volcanism, and glaciation on thermochronometer cooling histories, Patagonian Andes

International audienceSouthern Patagonia is a prime example of ongoing oceanic ridge collision and slab-window formation sustained over several million years. The impact of these phenomena on the thermal structure and exhumation of the crust have been mainly assessed with low-temperature thermochronology of bedrock samples. Here, we infer thermal histories from new and existing thermochronological data from the region of most recent ridge collision. In particular, we evaluate the potential far-reaching thermal effects of the evolving slab window, which have previously been considered responsible for patterns of late Miocene reheating associated with back-arc alkaline volcanism. Our model results define protracted cooling since ∼15 Ma and stepwise exhumation since the late Miocene. The pattern of stepwise exhumation closely matches the onset of Patagonian glaciation at 7 Ma and the successive pulse of glacial incision coeval with neotectonic activity since 3–4 Ma that are also documented by independent geological and geomorphological evidence in the region. Importantly, our findings challenge the recently suggested lack of glacial erosion and incision since 5 Ma in this region. Furthermore, in contrast to previous modelling studies, we find that the available data do not evidence a previously proposed northward-propagating heating event associated with alkaline volcanism. We hypothesize that the anomalous alkaline volcanism in the Patagonian back-arc might be related to trench-orthogonal tears aligned with transform faults in the subducting plate. The substantial differences from the previous modelling procedure on some of the same samples is demonstrated to result from an important lack of convergence in model runs

Morphometric assessment of uplifting coral reef sequences, Sumba Island, Indonesia.

International audienc

Morphometric assessment of uplifting coral reef sequences, Sumba Island, Indonesia.

International audienc

Sea level and climate forcing of the Sr isotope composition of late Miocene Mediterranean marine basins

Sr isotope records from marginal marine basins track the mixing between seawater and local continental runoff, potentially recording the effects of sea level, tectonic, and climate forcing in marine fossils and sediments. Our 110 new 87Sr/86Sr analyses on oyster and foraminifera samples from six late Miocene stratigraphic sections in southern Turkey, Crete, and Sicily show that 87Sr/86Sr fell below global seawater values in the basins several million years before the Messinian Salinity Crisis, coinciding with tectonic uplift and basin shallowing. 87Sr/86Sr from more centrally located basins (away from the Mediterranean coast) drop below global seawater values only during the Messinian Salinity Crisis. In addition to this general trend, 55 new 87Sr/86Sr analyses from the astronomically tuned Lower Evaporites in the central Apennines (Italy) allow us to explore the effect of glacio-eustatic sea level and precipitation changes on 87Sr/86Sr. Most variation in our data can be explained by changes in sea level, with greatest negative excursions from global seawater values occurring during relative sea level lowstands, which generally coincided with arid conditions in the Mediterranean realm. We suggest that this greater sensitivity to lowered sea level compared with higher runoff could relate to the inverse relationship between Sr concentration and river discharge. Variations in the residence time of groundwater within the karst terrain of the circum-Mediterranean region during arid and wet phases may help to explain the single (robust) occurrence of a negative excursion during a sea level highstand, but this explanation remains speculative without more detailed paleoclimatic data for the region

Plio-Quaternary extensional tectonics of the Central Anatolian Plateau: A case study from the Tuz Gölü Basin, Turkey

The Tuz Gölü Basin is the largest sedimentary depression located at the center of the Central Anatolian Plateau, an extensive, low-relief region with elevations of ca. 1 km located between the Pontide and Tauride mountains. Presently, the basin morphology and sedimentation processes are mainly controlled by the extensional Tuz Gölü Fault Zone in the east and the transtensional ?nönü–Eski?ehir Fault System in the west. The purpose of this study is to contribute to the understanding of the Plio-Quaternary deformation history and to refine the timing of the latest extensional phase of the Tuz Gölü Basin. Field observations, kinematic analyses, interpretations of seismic reflection lines, and 40Ar/39Ar dating of a key ignimbrite layer suggest that a regional phase of NNW–SSE to NE–SW contraction ended by 6.81 ± 0.24 Ma and was followed by N–S to NE–SW extension during the Pliocene–Quaternary periods. Based on sedimentological and chronostratigraphic markers, the average vertical displacement rates over the past 5 or 3 Ma with respect to the central part of Tuz Gölü Lake are 0.03 to 0.05 mm/year for the fault system at the western flank of the basin and 0.08 to 0.13 mm/year at the eastern flank. Paleo-shorelines of the Tuz Gölü Lake, vestiges of higher lake levels related to Quaternary climate change, are important strain markers and were formed during Last Glacial Maximum conditions as indicated by a radiocarbon age of 21.8 ± 0.4 ka BP obtained from a stromatolitic crust. Geomorphic observations and deformed lacustrine shorelines suggest that the main strand of the Tuz Gölü Fault Zone straddling the foothills of the ?ereflikoçhisar–Aksaray range has not been active during the Holocene. Instead, deformation appears to have migrated towards the interior of the basin along an offshore fault that runs immediately west of ?ereflikoçhisar Peninsula. This basinward migration of deformation is probably associated with various processes acting at the lithospheric scale, such as plateau uplift and/or microplate extrusion.Geoscience & EngineeringCivil Engineering and Geoscience