Kemal Gürbüz

Sand body geometry in a sand-rich, deep-water clastic system, Miocene Cingöz Formation of southern Turkey

Abstract Three types of sandstone bodies, canyon-fill, tongues and lobes are recognized, and their geometry and spatial organization described within an elongate, W–E trending deep-water clastic system. The canyon-fill comprises sheet-like, fining upward packages that pinch-out rapidly (over 20 m laterally) where they onlap against the basin margin slope to the north. To the south, bed packages pinch-out more gradually over 400–500 m where they are confined by basin floor topography that forms one margin to the canyon. Down-system from the canyon, tongues form narrow and elongate (0.5–1 km wide and 25 km long) sandstone bodies. They are non-erosive, and are thus not channels, but sedimentation is focused within palaeotopographic lows formed by basement structure and differential compaction. Lobes occur close to the mouth of the canyon, overlying the tongues. Packages of lobes (net sandstone ∼80%) and interlobe deposits (net sandstone ∼40%) are cut by distributary channels that allow sediment to bypass the lobes. The overall asymmetric geometry and elongate nature of this sand-rich deep-water clastic system, and consequently sandstone distribution and architecture, are controlled by the basin margin slope and basin floor palaeotopography.

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

Abstract 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 of the 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 a−1 since c. 1.8 Ma (total uplift of 30–230 m) from subsurface data. Supplementary material: Microphotographs of foraminifers, ostracods, and calcareous nannofossils, plots of the calcareous nannofossil frequencies, occurrence of foraminifers and ostracods in the study sections, results of Sr isotopic analysis, and a complete list of fossils are available at www.geolsoc.org.uk/SUP18535.

Down-channel variations in stratal patterns within a conglomeratic, deepwater fan feeder system (Miocene, Adana Basin, Southern Turkey)

Abstract The proximal, channelized section of a deepwater fan in the Adana Basin, southern Turkey, provides an opportunity to study down-channel changes in stratal patterns. This is a multisourced, bypass fan with at least four feeder channels. The downdip changes within one of these channels are described along a 10 km transect. Down-channel changes in grading and organization of clasts are observed for non-grading disorganized facies in the most proximal locations to more organized, inverse-normal and normal graded conglomerates midway down the transect. Bedding style changes from scoured and more sheet-like beds updip into a pattern of small channels and bars midway along the transect, and into thick-bedded and structureless conglomerates in the more distal locations within the channel. These changes in stratal patterns coincide with observed changes in depositional gradient of the channel. The gradient changes are interpreted to be a contributing factor in controlling hydrodynamics within the gravity flows and thus the depositional stratal patterns.

An example of river course changes on a delta plain: Seyhan Delta (Çukurova plain, southern Turkey)

The three-dimensional sedimentary architecture of wind- and wave-dominated deltas fed by more than one major river system is poorly documented in the scientific literature. The Seyhan–Ceyhan–Tarsus delta in southern Turkey, described in this paper, presents a detailed layer-cake model for such a system. It further documents the planform evolution of the system over the past 4000 years using aerial photography and field mapping together with a series of transects of commercial sedimentary cores with a maximum vertical penetration of 300 m. This latter high-density dataset is unique and affords the opportunity (i) to examine the evolution of this clastic system; (ii) to demonstrate how large-scale erosional truncations in wind- and wave-dominated deltas may be incorrectly interpreted as transgressive surfaces in analogue ancient systems; (iii) to show how major changes in drainage pattern can occur in this environment; and (iv) to sound a note of caution for the interference of man in an area particularly prone to erosion, in this case by the erection of major dams. Copyright

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 ofthe 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 thiswork 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, inthe 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 containinga 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 theMediterranean, 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 oligohalinedepositional environment for the RLE. In terms of hydrocarbon prospecting, the Messinian evaporates 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 evaporates 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.