Formation of Collapse Doline Lakes in the Diyarbakir Basin: Morphological Features, Dynamics and Geoarchaeological Significance (original) (raw)
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Journal of Quaternary Science, 2016
Individual palaeoenvironmental records represent a combination of regional-scale (e.g. climatic) and site-specific local factors. Here we compare multiple climate proxies from two nearby maar lake records, assuming that common signals are due to regional-scale forcing. A new core sequence from Nar Lake in Turkey is dated by varves and U-Th to the last 13.8 ka. Markedly dry periods during the Lateglacial stadial, at 4.3-3.7 and at 3.2-2.6 ka BP, are associated with peaks in Mg/dolomite, positive d 18 O, elevated diatom-inferred electrical conductivity, an absence of laminated sediments and low Quercus/chenopod ratios. Wet phases occurred during the early-mid Holocene and 1.5-0.6 ka BP, characterized by negative d 18 O, calcite precipitation, high Ca/Sr ratios, a high percentage of planktonic diatoms, laminated sediments and high Quercus/chenopod ratios. Comparison with the record from nearby Eski Acıgö l shows good overall correspondence for many proxies, especially for d 18 O. Differences are related to basin infilling and lake ontogeny at Eski Acıgö l, which consequently fails to register climatic changes during the last 2 ka, and to increased flux of lithogenic elements into Nar Lake during the last 2.6 ka, not primarily climatic in origin. In attempting to separate a regional signal from site-specific 'noise', two lakes may therefore be better than one.
WIT Transactions on Ecology and the Environment, 2002
Ulubat and Manyas Lakes (Southern Marinara Region, Turkey) and their close surroundings fall into one of the most active tectonic areas of Turkey due to their location on the Norther Anatolia Fault Zone. This location has been a primary reason for important geomorphic environmental changes at this area in Quatemary. This study consists a modelling of geomorphic environmental changes at Uluabat and Manyas Lakes and their close surroundings. In modelling, paleoclimatic, paleomorphologic , paleobotanic, paleopedologic, and archeologic data have been evaluated together, Also, especially, boring data of Quatemmy stratigraphy have been used. Lithological data, earthquake records of historical and instrumental eras, and contemporary geomorphological analysis results have contributed a great deal to this study The study area was probably a Iagoonary environment which was connected to Marrnara Sea during upper Miocene. Tectonical movements which began at that time and continued up to now have caused horizontal and vertical displacements also affecting streams resulting in drainage deformations and base level changes, which conform with such an alteration. Accordingly, six basic stages can be diferentiated belonging to geomorphologic development of sutdy area. In the last section, compare between 1965 and 2001 geomorphological features of area. As the factors and processes are still current at Uluabat and Manyas Lakes, geomorphic environmental changes that took place in a time span of 35 years are an indicator for extinction of these lakes in near future.
The formation of the Upper Pleistocene terraces of Lake Van (Eastern Anatolia, Turkey)
Journal of Quaternary Science, 2010
Sedimentological and geomorphological studies of terraces around Lake Van (1647 m) provided a preliminary framework for lake-level variations. The elevations of terraces and past lake level were measured with a differential global positioning system. A chronology is developed using 234 U/ 230 Th dating of travertines, 39 Ar/ 40 Ar dating of pyroclastites and 14 C dating of organic matter. Facies and stratigraphic correlations identify four transgressions (C1 0 , C1 00 , C2 0 and C2 00), each followed by a regression which ended with low lake levels that caused river incision and terrace formation. Evidence of the oldest transgression (C1 0) is found in the uppermost reaches of valleys up to 1755 m, an altitude higher than the present lake threshold (1736 m). This C1 0 transgression may be related to pyroclastic flows which dammed an outlet located in the western part of the lake basin and which is dated to before 105 ka. After 100 ka, a second transgression (C1 00) reached 1730/1735 m, possibly related to a younger ignimbrite flow, in association with high water inflow (warm and/or wetter conditions). The two younger transgressions reached 1700-1705 m. The first one (C2 0) is dated to 26-24.5 cal. ka BP and the second one (C2 00) to 21-20 cal. ka BP. Available data suggest that the long-term lake-level changes responded mainly to climate oscillations. Additional events such as river captures caused by volcanic falls filling valleys, tectonism, erosion and karstic diversion may have impacted these long-term lake-level changes.
HOLOCENE LAKE EVOLUTION IN THE ELMALI BASIN, SOUTHWEST TURKEY
The spatial coverage of paleoecological research from southwestern Turkey is expanded by reporting on a ca. 12,690 14 C yr BP (14,935 cal yr BP) proxy record recovered from the Elmalı basin. Four AMS radiocarbon age determinations, the litho-stratigraphic analysis of a lake bed core, and the analysis of subsurface sediment samples from 15 shallow auger holes across the basin document sedimentation patterns during the Holocene. Based on the widespread occurrence of Chara gyrogonite, and several species of ostracoda and gastropoda, the Elmalı basin was dominated by lacustrine and palustrine environments but was continually influenced by alluvial fan sedimentation. Contrasting stratigraphy in the Kara Göl and Avlan Gölü sub-basins is a result of basin morphology, and possibly hydrologic control by karst features, and sub-basin isolation due to alluvial fan development. The cyclical deposition of marl/lime mud, gyttja, and peat in the Kara Göl core is indicative of periodic fluctuations in water level across a broad shallow basin, whereas the continuous clay record observed at Avlan Gölü implies deep-water sedimentation within a plugged former karst collapse feature. Calcareous clay deposited between 14,935 and 11,180 cal yr BP signals the growth and expansion of paleo Lake Elmalı, which at its peak during the late Pleistocene, may have inundated over half of the of the 180 km 2 Elmalı basin. [
2013
Different settlement types can be observed all over Anatolia from the Neolithic time onwards. The most common prehistoric settlement form is the mound (höyük). Settlement mounds are usually made up of several meters of habitation deposits which accumulate over a longer period of time. Their specific form is caused by the use of sun-dried mudbricks as the preferred building material which cannot be re-used after the destruction of the buildings. The destroyed houses were usually levelled and new ones built on top of them, thus leading to a steadily rising mound. Settlement mounds are mainly situated in fertile plains, often near fresh water sources. In the Lake District most of the settlement mounds are located at the margins of the plains. The main reason for this seems to be the threat of flooding of the plains which often have no natural water outlet 12 . Settlement mounds can also be located on higher terraces, often on the spurs of natural hills. The site of Kuruçay is a typical example for this kind of location 13 . Besides natural threats like floods, hill-spur sites possess strategic advantages in regard to their defensive situation. This is also a characteristic element of hill-top sites which form another settlement type. Hill-top sites are located on top of natural hills surrounding the fertile plains. With their strategic position they often also control important traffic routes. Whereas most of the settlements mounds are already known today because they are easy to spot in the plains, many hill-top sites still await to be discovered. This is also the case with flat sites, which were usually inhabited for a shorter time period; therefore their habitation deposits are only of minimal height. Flat settlements can be located either in the plains or on the flanks of hills. They are usually found only in intensive surveys. Today many flat sites have been destroyed by modern agriculture. Whereas these kinds of settlements are known from all parts of Anatolia, another settlement type occurs especially in the Lake District: island and lake-shore sites.
Quaternary International, 2005
This study was carried out to elucidate the Holocene development of the valley of the Tigris River between Bismil and Batman, which will be inundated by the reservoir waters of Ilısu Dam to be built in Upper Tigris Valley, and to collect the geoarchaeological data of the mounds located there. In the Tigris Valley +4-5 and +2-3 m terraces were formed in the Holocene. According to geoarchaeological data obtained from the mound located on the +4-5 m terrace, it was determined that the Tigris River has been flowing in the same bed from the Neolithic Age. The floodplains of the +4-5 m terrace occurred as a result of floods which took place in three different cycles. The first caused the formation of Late Pleistocene-Early Holocene channel and floodplain material composed of coarse gravel and sandy silt. On this floodplain with a relative altitude of +2 m above river level, Late Neolithic settlements (6000-5500 BC) were formed. The second cycle is represented by the formation of Early Chalcolithic (5500-4000 BC) floodplain material. There were Late Chalcolithic and Early Bronze Age (4000-2650 BC) settlements formed on this floodplain with a relative altitude of 3-3.5 m above river level. The third and the final cycle is represented by 1-2 m thick yellowish-orange flood deposits which started to form from the end of Early Bronze Age I. These cover the Early Bronze Age I cemetery (2800-2650 BC) and settlements belonging to earlier periods, as in the case of A-sa& gı Salat Mound. r
Quaternary Science Reviews, 1999
Well-developed coarse-grained palaeo-shoreline deposits are found along the rising margins of the Konya basin, marking the former extent of a now desiccated Late Pleistocene lake. This study evaluates the depositional environments and the sequential evolution of a shoreline system that developed at the northern margin of the Konya palaeolake near Go¨iu¨. Several laterally continuous quarry sections provided an excellent opportunity for studying spatial and temporal changes of depositional environments and related lake-level fluctuations. Eight principal sedimentary facies and six major lithostratigaphic units have been identified in these deposits representing progradational and retrogradational episodes of shoreline development. The lowest sequence is an aggradational unit formed by wind-driven currents and waves in a sand-dominant lake bottom above the wave base. It is overlain by a convoluted palaeosol C dated to ca 28,300 BP representing a major lowering of lake levels. Following an unconformity, the next sequence is characterised by large-scale gravelly clinoforms that progressively offlap/downlap onto the underlying sequence, and correspond to progradation of a foreshore resulting from storm-originated oscillating and unidirectional currents, avalanching processes and minor subaqueous debris flows. It is overlain by an areally extensive lensoid body of structureless clays comprising a thin organic layer, abundant rootlets and freshwater mollusc shells, formed from suspension fallout in a quiet, very shallow freshwater lagoonal environment. This phase, representing a more minor lake regression, has been C dated to ca. 21,960-20,730 BP. The final sequences include large-scale sand waves and bars, which developed by storm-originated wave surges and strong shoreline currents, and prograding delta foresets. These sequences indicate a renewed lake transgression to higher water levels, before a final regression after 17,500 BP. Lack of tectonic deformation and the overall sedimentary characteristics of the beach system at Go¨iuc learly suggest that the sedimentary evolution of the system is closely related to lake-level fluctuations resulting from long-and short-term hydro-climatic changes. Successive stages of lake-level rises and large amounts of supply of coarse grained material imply a positive hydrological balance and relatively high rates of sediment discharge from the adjacent hillslopes. 1999 Elsevier Science Ltd. All rights reserved.