Woods Hole Oceanographic Institution

Sebastien Bertrand

»Sequence mapping of Holocene coastal lowlands. The application of the Streif?s classification system in the Belgian coastal plain
»Temporal evolution of sediment supply in Lago Puyehue (Southern Chile) during the last 600 years and its climatic significance
»Climate variability of Southern Chile since the Last Glacial Maximum: a continuous sedimentological record from Lago Puyehue (40°S)
»Reconstruction of the Holocene seismotectonic activity of the Southern Andes from seismites recorded in Lago Icalma, Chile, 39°S
»Nature, origin, transport and deposition of andosol parent material in south-central Chile (36-42?S)
»Tephrostratigraphy of the Late Glacial and Holocene sediments of Puyehue Lake (Southern Volcanic Zone, Chile, 40?S)

BERTRAND, S., CHARLET, F., CHARLIER, B., RENSON, V. & FAGEL, N. , Climate variability of Southern Chile since the Last Glacial Maximum: a continuous sedimentological record from Lago Puyehue (40°S), Journal of Paleolimnology, in press, DOI 10.1007/s10933-007-9117-y

This paper presents a multi-proxy climate record of an 11 m long core collected in Lago Puyehue (southern Chile, 40°S) and extending back to 18,000 cal yr BP. The multi-proxy analyses include sedimentology, mineralogy, grain size, geochemistry, loss-on-ignition, magnetic susceptibility and radiocarbon datings. Results demonstrate that sediment grain size is positively correlated with the biogenic sediment content and can be used as a proxy for lake paleoproductivity. On the other hand, the magnetic susceptibility signal is correlated with the aluminium and titanium concentrations and can be used as a proxy for the terrigenous supply. Temporal variations of sediment composition evidence that, since the last glacial maximum, the Chilean Lake District was characterized by 3 abrupt climate changes superimposed on a long-term climate evolution. These rapid climate changes are: (1) an abrupt warming at the end of the last glacial maximum at 17,300 cal yr BP; (2) a 13,100-12,300 cal yr BP cold event, ending rapidly and interpreted as the local counter part of the Younger Dryas cold period, and (3) a 3400-2900 cal yr BP climatic instability synchronous with a period of low solar activity. The timing of the 13,100-12,300 cold event is compared with similar records in both hemispheres and demonstrates that this southern hemisphere climate change lags behind the northern hemisphere Younger Dryas cold period by 500 to 1000 years.

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