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., BOES, X., CASTIAUX, J., CHARLET, F., URRUTIA, R.,ESPINOZA, C., CHARLIER, B., LEPOINT, G. & FAGEL, N. (2005), Temporal evolution of sediment supply in Lago Puyehue (Southern Chile) during the last 600 years and its climatic significance, Quaternary Research, 64/2, 163-175

Short-term climate changes in Southern Chile are investigated by a multi-proxy analysis of a 53-cm-long sedimentary sequence selected among eight short cores retrieved in Lago Puyehue (Chile, 40-S). This core contains a 600-yr-long undisturbed record of paleo-precipitation changes. Two measurement methods for sediment density, organic matter and biogenic silica contents are compared and the most appropriate techniques are selected. Together with aluminium and titanium concentrations, grain size and geochemical properties of the organic matter, these proxies are used to demonstrate paleo-precipitation changes around 40-S. Increase of terrigenous particle supply between A.D. 1490 and A.D. 1700 suggests a humid period. Contemporaneously, y13C data show increasing lake productivity, in response to the high nutrient supply. The A.D. 1700–1900 interval is characterized by a decreasing terrigenous supply and increasing y13C values, interpreted as a drying period.The magnetic susceptibility signal, reflecting the terrigenous/biogenic ratio, demonstrates that similar variations occur in all the undisturbed sedimentary environments of Lago Puyehue. The A.D. 1490–1700 wet period is associated with the onset of the European Little Ice Age (LIA) and interpreted as its local signature. This work supports the fact that the LIAwas a global event, not only restricted to the Northern Hemisphere.


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