Cosmogenic 36 Cl geochronology of late Quaternary glaciers in the Bolkar Mountains, south central Turkey

Abstract

Abstract We present the first quantitative late Quaternary cosmogenic 36 Cl glacial geochronology from the Bolkar Mountains of south central Turkey. Thirty samples were collected from three glaciated valleys. The geomorphological investigations indicate that the palaeoglaciers deposited their moraines between 3200 and 2200 m above sea level on the north- and south-facing valleys. We recognize four glacial periods, with the oldest one dating back to about 46.0±7.0 ka in the northern Karagöl Valley. Later, glaciers reached their maximum positions (∼5.5 km from cirque to snout) by 18.9±3.3 ka (during the local Last Glacial Maximum; LGM) in the Karagöl Valley. Late-glacial moraines were dated to between 15.2±1.6 and 12.6±2.3 ka in both northern Alagöl and southern Elmalı Valleys, respectively. The final deglaciation in the mountain commenced in the early Holocene (9.0±0.9 ka in the Karagöl Valley; 8.5±1.8 ka in the Elmalı Valley). A contemporaneous outwash plain dates to 8.4±1.0 ka at the outlet of the Alagöl Valley. Our results agree well with the glacial chronologies obtained from other Turkish and Mediterranean mountains. Supplementary material: Google Earth sample locations of this article are available at http://www.geolsoc.org.uk/SUP18877