QUATERNARY POLLEN RECORDS FROM THE ARCHIPIELAGO DE CHILOE IN THE CONTEXT OF GLACIATION AND CLIMATE

Quate mary vegetation, climate and glaciation of the Archipielago Chil oeare interp reted from five fossil pollen sequences, chronologically controlled by 35 radiocarbon dates. The earliest one from Punta Tenten , representing open Subantarctic-North Patagonian Rain Forest and Mage llanic Moorland during a cold interstade is dated >49,700 yr B.P. The late-glacial and Holocene sequences at Mayol, Estero Huitanque, Dichan , and Puchilco postdate recession of the Castro lobe of the Chiloe pie dmont glacier before 14,350 yr B.P. These sites at 14,350-12,000 yr B. P., at first, reflect cold, humid Subantarctic Parkland, followed by w arming and forest development; later, at 1 2,000-10,000 yr B,P. coolin g is inferred by changing taxa belonging to North Patagonian Rain Fore st communities. Holocene sequences, indicating moderated conditions wi th Valdivian-type forest and later cooling with North Patagonian-type, are of vegetation considerably disturbed by Paleoindian burning and b y European settlement. Holocene sites consistently contain a tephra la yer variously dated between 9,760 and 8,820 yr B.P. Data from the late -glacial of this study and from the full-glacial studied previously at Dalcahue show two glacial maxima and final multistep wastage of the C astro robe. The first step follows a maximum of the ice, dated at clos e 21,000 yr B.P., during late Llanquihue glaciation; a second step fol lows another maximum dated at between 14,700 and 14,350 yr B.P., and a third step is implied from pollen data after 12,000 yr B. P. Each ste p, following long-term cooling on a millennial time scale, is recogniz ed in other geographic regions in the polar hemispheres and may be glo bally imprinted.