Thermoluminescence dating of an Arctic lake core from Alaska

Abstract

Eight samples were selected from a 14 m core record from Squirrel Lake in the Alaskan Arctic for fine-grain, partial bleach thermoluminescence (TL) dating. Nine radiocarbon ( 14C) ages were available for comparison. Three TL ages of 8.8 to 11.6 ka in the upper 2.5 m do not exceed calendar-corrected 14C ages, suggesting that zeroing of light-sensitive TL in the detrital feldspars has been effective enough in this depositional environment to allow accurate dating of deeper core samples of similar sedimentology. TL ages of 60–65 ka for two samples in the 4.9–7 m depth range are consistent with an ‘infinite’ 14C age of >38.6 ka at 5.8 m. TL ages from 83±11 to 125±31 for three samples in the depth range 11–13.5 m suggest that this core record encompasses the last interglacial period (80–130 ka). These first TL ages for sediments from an Arctic lake core demonstrate the potential of the method for providing a directly measured chronology beyond the radiocarbon dating range in the climatically sensitive Arctic regions.