Patagonian crater lake reveals secrets

Researchers are investigating volcanism and climate change in the south of Argentina

A geoscientific jewel in the South Patagonian dry steppe of Argentina - the Laguna Potrok Aike © Bernd Zoöitschka
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How did the crater lake "Laguna Potrok Aike" originate in southern Patagonia? What are the climate changes in Argentina over the last millennia? These and many other questions will soon be answered by the international PASADO deep drilling program (Potrok Aike Maar Lake Sediment Archive Drilling Project), to be held in autumn 2008 under German leadership in South America.

Already at the end of August 2008, the scientists of the Institute of Geography of the University of Bremen set out to become the largest expedition of their career to date. When Bernd Zolitschka - Professor of Geomorphology and Polar Research - and his staff arrive on site, 21 sea containers with a complete floating drilling platform and extensive scientific equipment are already waiting on the shores of Laguna Potrok Aike. As part of the "International Continental Deep Drilling Program" (ICDP), this lake is only the eighth in the world whose sediment fill is drilled using this technology. The aim is to recover sediment cores up to a depth of 800 meters below the lake level and with a total length of 1.8 kilometers.

A sediment archive in the Argentine dry steppe

The Laguna Potrok Aike was created 700, 000 years ago during volcanic explosions. Over time, the crater filled with sediments and the ash of nearby volcanoes. Today, the Maarsee is the only continuous sediment archive in the Argentine dry steppe due to its depth of 100 meters. It is therefore a particularly well-suited archive that provides accurate information on the development of the environment and climate over the last millennia, as well as volcanological data.

For the first time in the history of volcanic research is drilled in the vent of a young water-covered maares. Maars are volcanic craters that arise when molten rock (magma) gets in contact with groundwater during the ascent to the earth's surface. There are steam explosions. They lead to craters that are common not only in Patagonia but also in the volcanic Eifel.

Climate change in Argentina

Climate information from the southern hemisphere is also important for Germany, because the climate as a global phenomenon affects our lives. In Patagonia, climate change has been an issue for decades. While the first European settlers in the 19th century encountered lush meadows and hundreds of lakes in Argentina, which provided an excellent basis for sheep farming, this situation changed dramatically from the mid-20th century: lakes silted up and the dry steppe expanded, How will the situation change as a result of human accelerated climate change? These and other questions are answered by the sediment core analysis. display

"For such complex scientific projects, we need motivated and committed young scientists who are willing to work on the very forefront of research. This is always associated with a high degree of personal commitment, "explains quarter researcher Zolitschka, who understands months of research expeditions abroad as well as tedious laboratory analyzes.

Logistic strength act

Before this internationally networked project can start, a logistical show of strength has to be mastered first. Since there is no infrastructure in the Patagonian area of ​​operation, overnight accommodation with sanitary facilities as well as a kitchen to supply up to 34 scientists as well as the laboratories have to be set up. The required electricity is produced locally using a diesel generator or a wind turbine. Water is pumped through a specially drilled well 76 meters deep and the connection to the outside world ensures a satellite-supported Internet connection.

International cooperation under German management

The international and interdisciplinary project PASADO is the first ICDP drilling project in a lake under German management. Involved is a team of German, Argentinian, Canadian, Swedish, Swiss and US geographers and geoscientists.

(idw - University of Bremen, 26.08.2008 - DLO)