Browsing by Author "Çiner, A"

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    Late pleistocene cosmogenic 36Cl clacial geochronology and PISM ice flow model of the Central Taurus Range, Turkey
    (International Union for Quaternary Research (INQUA), 2019-07-28) Köse, O; Sarıkaya, MA; Çiner, A; Yildirim, C; Candaş, K; Wilcken, KM
    The glacial geochronology of the Taurus Mountain Range is well-studied thanks to several works that use quantitative methods. Here, we report the timing of deglaciations in the central part of the Taurus Range, in the Mount Karanfil and Aladağlar during the Late Pleistocene. In the light of terrestrial cosmogenic nuclide 36Cl surface exposure ages and glacial geomorphology, we use the Parallel Ice Sheet Model (PISM) to model Last Glacial Maximum (LGM-20 ka) cycle in central Taurus Range. Aladağlar Massif, covers an area of 800 km2, composed mainly of Mesozoic carbonate rocks and shows the evidence of Late Pleistocene glaciations. We carefully carried out glacial geomorphological map of Aladağlar and Karanfil mountains and collected moraine boulder samples for cosmogenic 36Cl surface exposure dating. We collected 21 samples from Karanfil Mountains and 39 from Aladağlar to assess the timing of paleoglaciations. The ages obtained from W-NW-facing Körmenlik Valley indicate a deglaciation starting from ca. 35.000 years (35 ka) in Aladağlar which give substantial evidence regarding ice accumulation before the global LGM. Moraines of ca. 20 ka in age are observed in higher altitudes in Aladağlar and Mount Karanfil. Late Glacial (ca. 15 ka) moraine ages are also well established from Maden Valley. We also present preliminary field observations as 13 samples are still in progress from Eastern Valleys of Aladağlar. The results from the NW-facing valleys in Mount Karanfil indicate deglaciation starting during local Last Glacial Maximum (LGM), ca. 19 ka. Late Glacial (ca. 15 ka) moraine ages are also well established in Mount Karanfil. Additionally, a rock glacier at ca. 2500 m was dated to early Holocene (ca. 11 ka) indicating periglacial conditions in this mountain. The moraine and rock glacier ages are first dates obtained from this part of the Taurus Range, which is compatible with the glacial chronology of southern Turkey and surrounding regions. In order to obtain glacial conditions of the past, we used simulations of nine conditions, in Mount Karanfil, with open-source PISM, which necessitates 9°C decrease in air temperatures and 25% more precipitation compared to today’s conditions. This work was supported by TÜBİTAK 116Y155 project.
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    Late pleistocene cosmogenic 36Cl glacial chronology of the Mount Karanfil, Central Taurus Range, Turkey
    (American Geophysical Union, 2018-12-14) Çiner, A; Köse, O; Sarikaya, MA; Yildirim, C; Candaş, A; Wilcken, KM
    The glacial chronology of the Taurus Mountain Range of Turkey is probably one of the best studied in the world thanks to several works and publications that use quantitative methods during the last decade. Here, we report the timing of deglaciations during the late Pleistocene in the Mount Karanfil (37.36oN, 35.03oE, 3026 m) in the central Taurus Range. Glaciers that originated from N-NW facing cirques at ca. 2500 m asl, deposited lateral, hummocky and terminal moraines that reach down to 2100 m asl. We dated the limestone boulders from these moraines by terrestrial cosmogenic nuclide 36Cl surface exposure method. A total of 20 boulder ages indicate up to 3 phases of deglaciation during the late Pleistocene. Three glaciers that deposited well-developed lateral moraines ca. 1.5 km long and up to 50 m high, yield an average mean age of ∼20 ka corresponding to the local Last Glacial Maximum (LGM). Another moraine, at slightly higher elevations, testifies to the presence of Late Glacial (∼15 ka) in the Mount Karanfil. Finally, a lower cirque moraine, in contact with the upper parts of the Late Glacial moraines at ∼2200 m asl, yielded an age of 10.5 ± 1.0 ka, which indicates that glaciers totally disappeared at the onset of Holocene. A rock glacier at ca. 2500 m was also dated to early Holocene (11.5 ± 1.1 ka) indicating that in early Holocene periglacial conditions dominated in the area. The moraine and rock glacier ages are first dates obtained from this part of the Taurus Range and are compatible with glacial chronology of the southern Turkey and surrounding regions.
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    The Namaras rock avalanche: evidence of mid-to-late Holocene paraglacial activity in the Central Taurus Mountains, SW Turkey
    (Elsevier B. V., 2022-07-01) Hashemi, K; Sarıkaya, MA; Görüm, T; Wilcken, KM; Çiner, A; Žebre, M; Stepišnik, U; Yıldırım, C
    The Namaras rock avalanche (NRA) deposit originated from the northern flank of the glaciokarstic Geyikdağ Mountain in the Central Taurus Range, SW Turkey. The deposit has an area of ~0.430 km2 and an estimated average thickness of 10 m, corresponding to 4.3 million m3 volume. The fan-shaped deposit area consists of house-sized Jurassic-Cretaceous neritic limestone boulders that overlie lateral and hummocky moraines down into the valley. We used geomorphological mapping and 36Cl surface exposure dating to obtain six boulder ages which unravelled the NRA age, the number of events and their geometric features. Our results indicate that the NRA consists of two successive mid-to-late Holocene events; the first high magnitude main event with a weighted average age of 4.59 ± 0.25 ka followed by a second low magnitude event with a weighted average age of 3.77 ± 0.20 ka. 36Cl exposure dating of the lateral moraine covered by the rock avalanche deposit yielded approximately an age of ~12.30 ± 1.20 ka. The older event with a maximum runout distance of 1550 m and 600 m elevation loss yielded in a travel angle of 21°. Similarly, the younger event with 1720 m maximum runout length and 640 m vertical elevation loss resulted in a travel angle of 20°. The bedded limestone with cross-joints in the glacial cirque preconditioned the NRA slope failure. The significant lag time between deglaciation and the rock avalanche indicates that the glacial erosion and debuttressing acted as preparatory factors. Based on the low seismic activity in the Central Taurus Range and the synchronicity of the rock avalanche with mid-to-late Holocene climatic transitions, we propose that climatic factors may have triggered the NRA failure. The age of the older main event coincides with the warm drought period of the mid-Holocene associated with torrential rainfalls in the Taurus Mountains, while the age of the younger event correlates with the long wet period in the late Holocene. Thus, the main NRA event may have been triggered by the influence of warm temperatures and intense rainfall, while the second event may have been triggered by prolonged period of high precipitation. The two events of the NRA are coeval with the enhanced rock slope failures dating back to 5–3 ka in the Alps. © 2022 Elsevier B.V.