Andean Snowline Evidence for Cooler Subtropics at the Last Glacial Maximum

摘要: A common perception exists that glacier snowlines were depressed about 1000 m in American alpine regions during the Last Glacial Maximum (dated marine sediments between 23 and 14 kyr BP by δ18O proxy for ice volume) as a result of temperature reduction equivalent to lapse rate 5°–6°C/km (e.g. Broecker Denton, 1989). This contradicts reconstructions sea-surface temperatures are <2°C cooler low-latitude (CLIMAP, 1981; Webster Streten, 1978; Rind andPeteet, 1985; Rind, 1990). In this work I show not uniformily Andean sub tropics revised estimates closer CLIMAP findings. However, glaciation tropical-subtropical latitudes Americas probably culminated twice late Pleistocene, more than 20 just prior deglaciation BP, making direct comparison snowline evidence findings potentially misleading.