Yazar "Ergun, Zeynep" seçeneğine göre listele

Listeleniyor 1 - 2 / 2
  • Küçük Resim Yok
    Öğe
    Geological evolution of a tectonic and climatic transition zone: the Beysehir-Sugla basin, lake district of Turkey
    (Springer, 2021) Gurbuz, Alper; Kazanci, Nizamettin; Hakyemez, H. Yavuz; Leroy, Suzanne A. G.; Roberts, Neil; Sarac, Gercek; Ergun, Zeynep
    Central-west Turkey is a transition zone both tectonically and climatically between the quite different central and western regions of Anatolia. Central Anatolia represents the seismically quiet part of the otherwise highly active Turkey. On the other hand, this region has some of the lowest precipitation and highest evaporation ratios of Turkey. Conversely, west Anatolia is one of the most rapidly extending regions of the world and seismically very active. The climate is very different from the central part of Turkey and more humid. The zone between these two regions is also known geologically as the Isparta Angle. This reverse-V-shaped fold and thrust belt has several lake basins today, which have archived the geological and geomorphological history of this tectonic and climatic transition zone. The Beysehir-Sugla basin is located on the eastern part of this zone. This NW-SE trending basin includes the largest natural freshwater lake of the Mediterranean region: Lake Beysehir. Lakes Beysehir and Sugla are located in this tectonic depression that discharge into an incised river gorge opening to the Konya closed basin. In order to shed light on the development of the Beysehir-Sugla basin, our study was mainly conducted within the Neogene and Quaternary units of the region. Our structural results indicate that the depression was probably formed by a transtensional regime in the middle Miocene, which is controlled by extensional tectonics since the early Quaternary. Also, the current depression has mainly embodied the structures that are the products of these tectonic phases. According to our sedimentary data and palaeoecological interpretation of available palaeontological data, the Beysehir-Sugla basin was developed initially under a humid and warm climate in the middle Miocene; then since the late Miocene-Pliocene it was controlled by a relatively more arid and, at times, humid climate more like the central Anatolian basins. Although the Beysehir-Sugla basin is hydrologically connected to the Konya closed basin in central Anatolia, it was protected from arid climatic conditions for over millions of years as evidenced by the lack of evaporites in the studied basin and surrounding basins located in the interior part of the Isparta Angle. While the regional climate seems to have changed consistently with the geomorphic response to large-scale tectonics (i.e. orographic barrier development), the Beysehir-Sugla basin seems to be protected from hydrological closure by the existence of karstic features in the surrounding carbonate basement rocks.
  • Küçük Resim Yok
    Öğe
    Late Quaternary landscape evolution of the southern Marmara region: paleogeographic implications for settlements, NW Turkey
    (Tubitak Scientific & Technological Research Council Turkey, 2019) Kazanci, Nizamettin; Ergun, Zeynep; Iren, Kaan; Leroy, Suzanne A. G.; Boyraz Arslan, Sonay; Oncel, Salim; Koc, Koray
    This study presents the late Quaternary evolution of the southern Marmara region in northwestern Turkey and discusses the suitability of the area for settlements. It is based on interpretation of sediment analyses together with radiometric dates obtained from drilling cores. As three-fourths of the southern Marmara region (ca. 30,000 km(2)) is covered by the Susurluk Drainage Basin (SDB), the study focuses on this basin. The SDB has a concave surface morphology dipping northward, with highlands in the south (ca. 1300-1700 m a.s.l.) and lowlands in the north (ca. 0-250 a.s.l.). Lake Manyas, Lake Ulubat, and south-north flowing rivers, together with deep gorges and large valleys, are basic elements of the landscape. Quaternary deposits are largely confined to the late Pleistocene and Holocene time interval. Results suggest that, as a whole, the Southern Marmara region has been subjected to intense erosion up to the Late Pleistocene. During the Late Pleistocene and Holocene, depositional dynamics and channel migrations are recorded in river valleys, where sediments evidence occurrences of flooding and backswamps. Landscape analyses show that the SDB was not attractive for human settlements in the Late Holocene, with the exception of the Daskyleion and Appolonia sites, in opposition to other parts of western Anatolia, which have been densely occupied since the Chalcolithic Age. According to our results, the location of Daskyleion on a hill near Lake Manyas was likely chosen for security reasons. Lake water and large permanently wet areas (swamps) may have indeed provided a natural contribution to the defense of this Phrygian town.