In order to frame the recent global climatic changes, climate and oceanic models need to be tested against known climatic variations in the past. Recently, deglacial and Holocene paleo-environmental related research has shifted its main focus from the North-Atlantic region to the Southern Hemispheric high latitudes, as Antarctica and the Southern Ocean have shown to play an important role in global climate regulation (e.g. Knorr & Lohman, 2003). Very recently, the tropical (mainly Pacific) latitudes have been evenly recognized as potentially playing a large role in global climate modulation, both at interannual- decadal (e.g. El Niño Southern Oscillation) and century to millennial time scales (e.g. long-term changes in ENSO variability; Shulmeister et al., 2006; Pena & Cacho, 2009). Pacific tropical and Antarctic climate anomalies are physically linked with each other through the strength and the position of the Antarctic Circumpolar Current (ACC) and Southern Westerly Wind belt (SWW). Therefore, recent climate reconstructions are focused on past changes in position and strength of these winds, which have a direct impact on local and/or regional weather patterns along the westcoast of South America, and the Antarctic Peninsula. In this thesis, lake sediments were analyzed for biological, sedimentological and geochemical proxies, in order to infer past climatic changes at two key sites along a latitudinal transect from southern South America (40°S) through the Antarctic Peninsula (63°S). The first two chapters of this thesis are dedicated to postglacial paleoenvironmental and related paleoclimatic changes, inferred from an 11.22 m sediment core from Lake Puyehue (Chilean Lake District, 40°S), located at the northern boundary of the Southern Westerly Wind belt. |
