Articles by Tolga ESİRTGEN

The character of the boundary between the tectonic units in the Central Taurides and the Ulukışla Basin is controversial. The contact has been accepted as discordant or tectonic contact by different researchers. The deformation data of the units in the study area provide important information about the Mesozoic - Cenozoic period geological developments of the region. Regional compression in NW - SE direction has caused the development of fold, foliation and reverse fault type structures in the units in the study area. Similar structural deformations are observed in the rock units defined in the Ulukışla Basin as well. In this study, structural data were collected from the field in order to determine the deformation pattern and contact relations of the units in the region. Field data and structural analysis reveal that the contact between the Ulukışla Basin deposits and the Bolkardağı Unit in the study area is of 70° - 80° southeast dipping reverse fault character. These structural data in the region were interpreted as the product of a movement from southeast to northwest. https://doi.org/10.19111/bulletinofmre.868515

The lacustrine units have been deposited in the Ermenek, Bucakkışla, Korucuk and Çamlıyayla basins in the Central Taurides since early Oligocene. In this study, structural features and stratigraphical properties of Oligocene basins have been described in detail and the lacustrine units have been dated. Regional geological interpretations have been made by using tectono-stratigraphic and age data of the basins. Lacustrine Oligocene sedimentation in these basins, which were opened on the tectonic units of Taurides due to normal faults, constitute the first records of the sedimentation occurring under the extensional tectonic regime after the orogeny of the Central Taurides. All the pre-Oligocene units that had been emplaced in the region due to a north-south compressional movement in the Central Taurides, continued to be compressed until the end of Eocene, and completed their orogenic development as napped structures. The bedrock units, reaching the maximum elevation, have been subjected to “orogenic collapse” due to the strain or gravity forces as a result of an interruption or termination of the compression which lasted until the end of Eocene. Thus, “orogenic collapse” basins have started to be formed in the Central Taurides since Oligocene. The orogeny and the compressional tectonic regime forming the Taurides lasted until late Miocene in the Eastern Taurides. On the other hand, extensional basin formation since early Oligocene on the Taurus units, which had been emplaced in the region due to nappe tectonics, indicates that a new tectonic period has started in the Central Taurides. https://doi.org/10.19111/bulletinofmre.681218

Early–middle Miocene reefal limestones are overlain disconformably by late Serravallian– early Tortonian incised valley-fi ll deposits of Dağpazarı formation in the Mut Basin. Dağpazarı formation is composed of mudstone, siltstone, sandstone and conglomerates. Facies associations of the formation are: fl uvial, lagoon, shoal-water delta, shoreface, beach and barrier island deposits. Loxoconcha tumida Brady and Loxoconcha sp. in the gray mudstones indicate the freshwater infl uence and decrease in salinity. Hemicyprideis sp. documents brackish water conditions. The shoreface sandstones alternating with the lagoonal mudstones, and oyster-rich beach deposits in different levels of the sequence indicate episodes of marine connections. The age of the Dağpazarı formation is provided by the planktonic foraminifera from the marine mudstones and marls below and above the formation, and corresponds to the MMi8–MMi10 biostratigraphic interval, which spans the late Serravallian–early Tortonian. Late Serravallian eustatic sea-level fall caused to the quick shallowing of the Mut Basin and subaerial exposure of the reefal limestones at the basin margin. Thus, the incised valley, formed upon the reefal limestones of the Mut formation. This incised valley refl ects a regional forced regression and unconformity. The Dağpazarı formation was deposited within this incised valley following an early Tortonian relative sea-level rise. https://doi.org/10.19111/bulletinofmre.501543

The study area located in Bucakk›flla region in Central Taurides consists of rock units of the melange which form Bozk›r unit of the Tauride units and the overlying cover rocks. There are volcanic, ophiolitic and sedimentary rocks which generated in different environmental conditions. These rock groups comprise units which formed in Middle-Upper Triassic- Paleocene periods in Inner Tauride Ocean that had been opened between Tauride – Anatolide continents. Within the scope of this study, lithostratigraphic characteristics of Hu¤lu, Boyal› tepe (hill), Korualan nappes and cover rocks which form Bozk›r Unit and tectono sedimentary evolution of the study area was built up by paleontological and structural features. Due to rifting, which started in Middle Upper Triassicin the region, the products of the rift volcanism in rifting center and the carbonate deposition on margins of basin have occurred. Thecontinuation of extension which initiated rifting caused collapse in the basin in Middle Upper Triasic – Lower Senonian. Deep marine deposition has occurred at the center of basin, however pelagic and neritic limestones were deposited in basin margins during this time. The region has become compressed by the effect of a new tectonical regime which had been effective starting from Santonian. This compression caused new complexes to take place due to reverse faults and thrust. The formation of these complexes has continued until the end of Eocene period. However, there has not been observed any formation depending on the compression in post Paleocene. The nappes have moved southward by the effect of compression until Eocene. But then, these nappes could not advance forward anymore so, northward back thrusts took place as basin was closured andreached the collisional stage. Sequences which had become imbricated structures by back thrusts were subjected to collapsing by the stop of compression and the gravitational effect. All sequences in the imbricated structure were cut by dip slip normal faults and lacustrine basins were formed on fallen blocks. The formation of Early Oligocene terrestrial deposits in these lakes indicates that the collapse occurred in Oligocene or immediately before this time, and this allows the dating of new tectonical period. Early Oligocene deposits to become tilted by dip slip faults show that new tectonic period in the region has also continued after Oligocene.