Glaciations and paleoclimate of Mount Erciyes, central Turkey, since the Last Glacial Maximum, inferred from Cl-36 cosmogenic dating and glacier modeling

Forty-four boulders from moraines in two glacial valleys of Mount Erciyes (38.53 degrees N, 35.45 degrees E, 3917 m), central Turkey, dated with cosmogenic chlorine-36 (Cl-36), indicate four periods of glacial activity in the past 22 ka (1 ka=1000 calendar years). Last Glacial Maximum (LGM) glaciers were the most extensive, reaching 6 km in length and descending to an altitude of 2150 m above sea level. These glaciers started retreating 21.3 +/- 0.9 ka (1 sigma) ago. They readvanced and retreated by 14.6 +/- 1.2 ka ago (Lateglacial), and again by 9.3 +/- 0.5 ka ago (Early Holocene). The latest advance took place 3.8 +/- 0.4 ka ago (Late Holocene). Using glacier modeling together with paleoclimate proxy data from the region, we reconstructed the paleoclimate at these four discrete times. The results show that LGM climate was 8-11 degrees C colder than today and moisture levels were somewhat similar to modern values, with a range between 20% more and 25% less than today. The analysis of Lateglacial advance suggests that the climate was colder by 4.5-6.4 degrees C based on up to 1.5 times wetter conditions. The Early Holocene was 2.1-4.9 degrees C colder and up to twice as wet as today, while the Late Holocene was 2.4-3 degrees C colder and its precipitation amounts approached to similar conditions as today. Our paleoclimate reconstructions show a general trend of warming for the last 22 ka, and an increase of moisture until Early Holocene, and a decrease after that time. The recent glacier terminates at 3450 m on the northwest side of the mountain. It is a remnant from the last advance (possibly during the Little Ice Age). Repeated measurements of glacier length between 1902 and 2008 reveal a retreat rate of 4.2 m per year, which corresponds to a warming rate of 0.9-1.2 degrees C per century. (c) 2009 Elsevier Ltd. All rights reserved.