Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Studying evidence from Ice Age lakes

04.09.2007
UST NEM, northern Russia: During the last Ice Age, the ice dammed enormous lakes in Russia. The drainage system was reversed several times and the rivers flowed southwards. A group of geologists is now investigating what took place when the ice melted and the lakes released huge volumes of fresh water into the Arctic Ocean.

”The ice-dammed lakes in Russia were larger than the largest lakes we know today,” Eiliv Larsen, a geologist at the Geological Survey of Norway (NGU), tells me. He is in charge of the important SciencePub International Polar Year project that is studying natural climate changes in the Arctic and the ways in which man has adapted to them.

Moving glaciers

”The entire drainage system in Russia has been reversed several times during the past 130 000 years. The heavy ice cap covering the land area in the north dammed up lakes and forced the large rivers, the Dvina, Mezen, Pechora and Vychegda, to flow southwards to the Caspian Sea, the Black Sea and on to the Mediterranean,” Eiliv Larsen continues.

However, the ice margin in the north shifted; the ice cap varied in extent, sometimes suddenly advancing eastwards, sometimes retreating. When the plug was released as the ice melted, the water poured from the huge lakes into the Kara Sea and the White Sea, causing the sea level to rise.

The sum total of all these dramatic changes greatly influenced the climate and the circulation in the seas in the Barents Region. SciencePub scientists are trying to find answers to where, when and how often this took place.

Digging down

”We drive vehicles and boats along the large valleys and rivers,” Maria Jensen, a group leader and geologist at NGU, tells me. “Where sediments are exposed along the coast and rivers, we study the sequence of their deposition. It’s here, in the transportation of clay, silt and sand out into the marine system, that we find evidence of the major events,” she points out.

In a cutting beside the River Vychegda, a few kilometres from the village of Ust Nem in the Komi Republic, geologists from Norway, Denmark, Russia and Germany are digging their way down through layers that were deposited during the last Ice Age.

Astrid Lyså, another NGU geologist, explains: ”We remove the outermost layer to get at undisturbed sediments. Then we clean the section, measure it, and photograph, draw and describe the structures in every single layer. We also take samples to date the beds using luminescence, a technique that reveals, for example, when a sand grain was last exposed to the light.”

Reading the history

By investigating a given section, geologists can, for instance, find out what types of deposits are present in the area. They may be moraine, peat, mire, or sediments deposited in the sea, rivers and ice-dammed lakes. The scientists can also find out in which environment these sediments were deposited; was it deep, still or shallow water, beneath the ice, or were the sediments deposited by the wind?

It is thus actually possible to read the history of an ice-dammed lake by studying the succession of layers dug out with a spade, a scraper, a knife and a trowel.

That is precisely what they are doing here at Ust Nem. There seems to have been two ice-dammed lakes here. The patterns of patches of coloured clay and the remains of crushed clay in the sediments suggest, for example, a strong increase in pore pressure and that this particular lake was tapped extremely rapidly.

A big jigsaw puzzle

The scientists are also investigating the landscape around the river, searching for old, dry valleys and small depressions that may explain the drainage system. After driving for just a couple of hours and walking a bit in the forest, they find small valleys which drained into the present course of the river.

The pieces in the jigsaw puzzle are thus gradually falling into place.

”When we fit everything together, we can see the details in and around the enormous lakes which the Russian rivers drained southwards on several occasions and at other times emptied into the Arctic Ocean when the ice melted,” Eiliv Larsen explains.

By Gudmund Løvø

Eiliv Larsen | alfa
Further information:
http://www.ngu.no/sciencepub

More articles from Earth Sciences:

nachricht Monitoring lava lake levels in Congo volcano
16.05.2018 | Seismological Society of America

nachricht Ice stream draining Greenland Ice Sheet sensitive to changes over past 45,000 years
14.05.2018 | Oregon State University

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Explanation for puzzling quantum oscillations has been found

So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics

Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...

Im Focus: Dozens of binaries from Milky Way's globular clusters could be detectable by LISA

Next-generation gravitational wave detector in space will complement LIGO on Earth

The historic first detection of gravitational waves from colliding black holes far outside our galaxy opened a new window to understanding the universe. A...

Im Focus: Entangled atoms shine in unison

A team led by Austrian experimental physicist Rainer Blatt has succeeded in characterizing the quantum entanglement of two spatially separated atoms by observing their light emission. This fundamental demonstration could lead to the development of highly sensitive optical gradiometers for the precise measurement of the gravitational field or the earth's magnetic field.

The age of quantum technology has long been heralded. Decades of research into the quantum world have led to the development of methods that make it possible...

Im Focus: Computer-Designed Customized Regenerative Heart Valves

Cardiovascular tissue engineering aims to treat heart disease with prostheses that grow and regenerate. Now, researchers from the University of Zurich, the Technical University Eindhoven and the Charité Berlin have successfully implanted regenerative heart valves, designed with the aid of computer simulations, into sheep for the first time.

Producing living tissue or organs based on human cells is one of the main research fields in regenerative medicine. Tissue engineering, which involves growing...

Im Focus: Light-induced superconductivity under high pressure

A team of scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg investigated optically-induced superconductivity in the alkali-doped fulleride K3C60under high external pressures. This study allowed, on one hand, to uniquely assess the nature of the transient state as a superconducting phase. In addition, it unveiled the possibility to induce superconductivity in K3C60 at temperatures far above the -170 degrees Celsius hypothesized previously, and rather all the way to room temperature. The paper by Cantaluppi et al has been published in Nature Physics.

Unlike ordinary metals, superconductors have the unique capability of transporting electrical currents without any loss. Nowadays, their technological...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Save the date: Forum European Neuroscience – 07-11 July 2018 in Berlin, Germany

02.05.2018 | Event News

Invitation to the upcoming "Current Topics in Bioinformatics: Big Data in Genomics and Medicine"

13.04.2018 | Event News

Unique scope of UV LED technologies and applications presented in Berlin: ICULTA-2018

12.04.2018 | Event News

 
Latest News

Supersonic waves may help electronics beat the heat

18.05.2018 | Power and Electrical Engineering

Keeping a Close Eye on Ice Loss

18.05.2018 | Information Technology

CrowdWater: An App for Flood Research

18.05.2018 | Information Technology

VideoLinks
Science & Research
Overview of more VideoLinks >>>