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- MakaleAçık Erişim2024Scopus SJRQ1Morphometric characteristics of glacial cirques and former glaciers in the Geyik Mountains, Western Taurus, Türkiye
Çılğın, Zeynel; Evans, Ian S.; Keserci, Ferhat; Canpolat, Ergin; Bayrakdar, Cihan
Using the Glacier reconstruction (GlaRe) toolbox, reconstructions of former glaciers in the Geyik Mountains, part of the Taurus Mountain system in southern Türkiye, show that an area of 132.5 km2 was glaciated in the last major glaciation, which left clear terminal and hummocky moraines. Glaciers were 1.4 to 12 km long and those from 49 cirques merged to form a broad 75 km2 piedmont glacier in the Namaras Valley, up to 400 m thick. A thorough analysis of morphometry of the 98 Geyik cirques, using the revised Automated Cirque Metric Extraction version 2 (ACME2) toolbox, shows that they are relatively small, with limited widths: the median length/width ratio of 1.29 is unusually high. With size, length and width increase faster than depth, demonstrating strong static allometry. Maximum slope averages 59°, minimum 3.3° and axial 25°. A combination of low hypsometric integral, high axial profile closure and high axial height-length integral is proposed as a measure of cirque development. The main summits are on sharp ridges on cirque crests, showing that they have been lowered by glacial erosion (by cirque development). Glaciation was strongly asymmetric, with cirque vector mean aspect between northeast and north-northeast. This shows the dominance of solar radiation effects, with some modification from westerly winds. Glacier palaeo- Equilibrium Line Altitudes (pELAs) rise northeastwards and cirque floor minimum altitudes (CFAs) rise toward east-northeast, both showing the importance of moist air from the Mediterranean, 38–55 km to the southwest. pELA averages 2208 m above sea level (a.s.l.) (2277 m area-weighted); CFA averages 2234 m. CFA varies mainly with summit altitudes; where related palaeoglaciers are short CFA is somewhat below pELA, but for longer ones it is above. The most likely palaeoclimate to form these glaciers involves a precipitation increase of 53–72 % with a temperature fall of 8 °C compared with present-day. The cirques formed under similar or less severe conditions.
AtıfScopus7OpenAlex15
İncele - MakaleYalnız künye2021Scopus SJRQ1The form, distribution and palaeoclimatic implications of cirques in southwest Turkey (Western Taurus)
Evans, I.S.; Çılğın, Z.; Bayrakdar, C.; Canpolat, E.
The Taurus Mountains of southwest Turkey are split into numerous separated ranges, of which eleven supported former glaciers. We describe cirques and related moraines in four new locations, as well as those in seven ranges where glaciation was previously known. This gives a complete inventory of the 85 cirques in southwest Turkey. These are comparable in size to those elsewhere, but narrower and often less developed. Lengths averaging 672 m are high relative to widths of 542 m. Overall axial gradients average 22.4°. Cirque floor altitudes are controlled largely by altitudes of the mountains above, but they also vary in relation to precipitation, in sympathy with ELAs (Equilibrium Line Altitudes) of former glaciers. In most ranges where glaciers were short (extending little beyond cirques), ELA can be predicted from mean mid-floor altitude. Our observations demonstrate lower ELAs than in previous literature. Both ELAs and cirque floors rise eastward in the west, and northward inland from the coast. This supports the importance of winds from the west and southwest, off the Mediterranean Sea, bringing LGM (Last Glacial Maximum) conditions wetter than present to mountains near the coast. Cirques face on average a little east of north, showing the effects of shade and differential solar radiation receipt.
AtıfScopus21OpenAlex31
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