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The drilling team worked around the clock in 12-hour-shifts. No light penetrated to the drilling tent on frozen Lake Elgygytgyn in the long polar nights.

(© Universtiy of Cologne)

An international team of researchers from Russia, Germany, the United States and Austria has conducted a deep drilling program in the far northeast of Russia during the last six months to retrieve several hundred meters of lake sediments, impact breccias and permanently frozen soil.

These provide new insights into the climate history of the Arctic, crater formation of Lake El'gygytgyn and what kinds of permafrost dynamics are possible.

A milestone was reached at the beginning of May with the first results of the drilling campaign. The cores gained will help to answer crucial open questions of Arctic geology.

At the far northern fringe of northeastern Siberia, about 900 km (559 miles) west of the Bering Strait and 100 km (62 miles) north of the Arctic Circle (67°30' N, 172°05' E), lies Lake El'gygytgyn which originated 3.6 million years ago from a meteorite impact. The lake has, in contrast to other areas of this latitude, never been glaciated - the sediments which accumulated continually at the bottom of the lake are therefore an invaluable Arctic climate archive.

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To be able to construct the drilling camp on Lake Elgygytgyn, the ice cover of the lake had to be artificially thickened from 50 cm (20 inches) to 2 m (6.6 feet). A snow formation formed by icy polar winds can be seen in the foreground.

(© Alfred Wegener Institute/Kristin Brady)

International researchers from various disciplines have set a goal to retrieve this archive. Preparations took 11 years before the large-scale deep drilling campaign began at the end of 2008. Infrastructure for up to 40 people had to be created in this remote area under the most difficult conditions - accommodations, sanitary installations and supply utilities.

"Humans and technical appliances need sufficient energy in temperatures of down to -45°C (-49°F), for instance for storing the drilling cores above freezing point," says Martin Melles from the University of Cologne, project manager of the El'gygytgyn Drilling Project for the German scientists working at the site.

The drilling equipment employed for drillings in the lake weighs about 70 tons, a great challenge for its safe positioning on the lake ice.

At the end of 2008, permafrost drillings were performed by a Russian construction company from the 260 km (162 miles) distant Pevek. It yielded impressive results: the team reached a drilling depth of 142 meters (466 feet) despite heavy snowstorms and low temperatures. The cores contain information on the permafrost history and its influence on lake sedimentation.

"It is possible to read lake level fluctuations from the cores," reports Georg Schwamborn from the Research Station Potsdam of the Alfred Wegener Institute who headed the permafrost drillings.

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Jochen Kück from the German Research Centre for Geosciences Potsdam prepares borehole measurements. The sail-shaped tent roof extends above him.

(© Alfred Wegener Institute/Kristin Brady)

Of great importance is the installation of a temperature measurement chain in the drilling hole by the researchers from Potsdam, a city located just outside of Berlin. It documents the current changes in the permafrost soil. Its understanding is of great value for climate research since the release of the gases bound in the thawing permafrost might further reinforce the greenhouse effect.

The lake drillings which have just been completed were no less successful: lake sediments were drilled 315 meters (1,033 feet) below the lake bottom; the upper 110 meters (361 feet) overlapped to close the remaining gap of the first drilling in the archive.

Initial results indicate that the climate and environment history of the last 3.6 million years is largely documented. Measurements of the magnetic properties in the upper part of the sediment layers show numerous warm and glacial periods with different intensities and characteristics.

"We can learn from detailed examinations of the transition from a glacial to a warm period that the Arctic reacted to global warming in the past; it is therefore safe to assume that it will also react to it in the future," explains Catalina Gebhardt from the Alfred Wegener Institute in the northern German harbor city of Bremerhaven.

The deepest lake sediment cores reached into the Pliocene of 2.6 million years ago.

"These sediments are of unique importance because the climate of this time was considerably warmer than it is today," says Martin Melles. "The insights gained from these sediments can serve as a perfect example for the Arctic in a few years time, in case the global warming takes place as prognosticated by climate models."

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Grisha Federov from the partner institute AARI St. Petersburg examines a core drilled during the permafrost drillings headed by the Alfred Wegener Institute in November 2008 at the shore of the Lake Elgygytgyn.

(© Alfred Wegener Institute)

An important goal of the lake drilling was the drilling of the impact breccias. This clastic rock created by a meteorite impact was found 315 meters (1,033 feet) below the lake bottom. The cores drawn by drilling 200 meters (656 feet) into the breccias are invaluable.

"We expect new insights not only about the trajectory and composition of the meteorite, but particularly about the reactions of the volcanic rocks to the impact," says Christian Koeberl from the University of Vienna, who coordinates the international team processing the impact rocks.

The insights serve the risk assessments in areas with similar rock formations. The 3.5 tons of cores drilled in 2009 will be brought to the Russian Arctic and Antarctic Research Institute (AARI) in St. Petersburg in early June.

The cores of the whole drilling campaign will thereafter be brought to Germany - the permafrost cores to the Alfred Wegener Institute for Polar and Marine Research, the lake sediments to the University of Cologne and the impact breccias to the ICDP in Potsdam.

The examinations will take two years. Altogether, about 30 additional guest researchers will work alongside German researchers and students on the cores. 

The El'gygytgyn Drilling Project is funded by several participating international government agencies and research institutes, including Germany's Federal Ministry for Education and Research (BMBF), the Helmholtz Association's Alfred Wegener Institute and the German Research Centre for Geosciences.