The use of diatom stratigraphy in well-dated sedimentary records is a widely used and excellent tool to characterize past environmental changes. This study investigates the diatoms of Laguna Potrok Aike, a maar lake in Southern Patagonia as part of the Po

RECASENS, C.; ARIZTEGUI, D.; MAIDANA, N. I.; PASADO SCIENCE TEAM

San Francisco, EE UU de Norteamérica

Congreso; 2009-AGU Meeting; 2009

AGU

The use of diatom stratigraphy in well-dated sedimentary records is a widely used and excellent tool to characterize past environmental changes. This study investigates the diatoms of Laguna Potrok Aike, a maar lake in Southern Patagonia as part of the Potrok Aike Maar Lake Sediment Archive Drilling Program (PASADO). Being one of the few permanent lakes in this steppe region, it provides a continuous sedimentary record over an extended time span in this area of the world. Previous works done on a composite core from Laguna Potrok Aike present data about the vegetation and climate history since 16,100 cal yr BP of the drylands in the Patagonian Steppe1. The multi-proxy study carried out on these cores reveal that during the Late Glacial the steppe was cold, humid and with low wind speeds. Towards the Holocene transition, warmer temperatures, lower moisture and stronger winds resulted in falling lake levels. During the PASADO drilling operations, two sites were cored at water depths close to 100 m. More than 500 m of sedimentary cores were recovered, the longest reaching over 100 m. Preliminary estimations suggest the record goes back in time as far the last glaciation. Here are presented the first results on the diatom record of PTA-1D, a 97.3 m long sedimentary core from the central part of the lake. Taxonomical and quantitative analyses have been achieved at low resolution throughout the whole record in order to track changes in lake conditions and tackle the sections where higher resolution will be carried out.The combination of the different diatom assemblages observed, blended with the other proxies and calibrated with a modern training set for Patagonia will provide unique paleoecological information of the Southern Hemisphere.