CHRONOLOGY OF THE LAST GLACIATION IN CENTRAL STRAIT OF MAGELLAN AND BAHÍA INÚTIL, SOUTHERNMOST SOUTH AMERICA

摘要: Glacier fluctuations in the Strait of Magellan tell climatic changes that affected southern latitudes at c. 53-55°S during Last Glacial Maximum (LGM) and Late-glacial/Holocene transition. Here we present a revised chronology based on cosmogenic isotope analysis, 14 C assays, amino acid racemisation tephrochronology. We unpick effect bedrock-derived lignite which has many dates past synthesise new constrain five glacier advances (A to E). Advance A is prior LGM. LGM represented by B reached largely formed arcuate peninsula Juan Mazia. Carbon-14 10 Be dating show it occurred after 31 250 cal yrs BP culminated 25200-23 100 was then followed slightly less extensive advance sometime before 22 400-20 300 BP. This pattern an early maximum found elsewhere South America more widely. Stage D, considerably extensive, 17700-17600 rapid widespread retreat. E, dammed lake, spanned 15500-11770 latter overlaps Bolling-Allerod interstadials retreat occurs peak Younger Dryas stadial northern hemisphere. However, stage E coincides with Antarctic Cold Reversal (c. 14800-12700 BP) may indicate some millennial-scale Late-glacial period are out phase between hemispheres.