Featured Research

from universities, journals, and other organizations

North Pole Exploration: Large Sliding Masses Close Beneath The Seafloor Of East-Siberian Continental Shelf Discovered

Date:
October 28, 2008
Source:
Helmholtz Association of German Research Centres
Summary:
RV Polarstern has returned to Bremerhaven from the Arctic Sea. It has cruised both the Northeast and the Northwest Passages and thereby circled the North Pole. The third part of the research vessel's 23rd Arctic expedition started its journey on Aug. 12 in Reykjavik and ended it on Oct. 17 in Bremerhaven. The ship traveled a distance of 20,000 km.

Aerial view of the ice-breaker "Polarstern“
Credit: Alfred Wegener Institute

The German research vessel Polarstern has returned today to Bremerhaven from the Arctic Sea. It has cruised as the first research vessel ever both the Northeast and the Northwest Passages and thereby circled the North Pole. The third part of the research vessel's 23rd Arctic expedition, operated by the Alfred Wegener Institute in the Helmholtz Association, started its journey on August 12th in Reykjavik and ended it on October 17th in Bremerhaven. The ship travelled a distance of 10.800 nautical miles, equivalent to 20.000 kilometres.

On board were 47 researchers from 12 nations, for example from Belgium, Germany, France, Japan, Canada, Korea, the Netherlands, Russia and the USA. Because of the small ice cover, the expedition members were able to research hitherto uncharted waters. The small sea ice cover presents a cause for concern regarding climate change in the Arctic Ocean. The aim of this expedition was to gather data on the development of the geology of the Arctic area.

The researchers around cruise leader Dr. Wilfried Jokat, geophysicist at the Alfred Wegener Institute, have discovered large sliding masses close beneath the seafloor of the East-Siberian continental shelf by means of sediment-acoustic parasound measurements. "Sliding masses are witnesses of great sediment relocations which appear, for instance, when large amounts of sediments are deposited", explains Jokat.

The continental slope becomes instable and sediments slide down. Such a large amount of sediments causing a shift can only have one reason: the sediments were frozen in the ice masses of the East-Siberian mainland, thawed during an interglacial and unloaded their sediments with the melt water into the ocean. "This is a spectacular finding. Large-scale glaciations in eastern Siberia within the younger geological past of 60.000 years and older are so far unknown", explains Prof. Dr. Rόdiger Stein, geologist at the Alfred Wegener Institute. Additional acoustic (seismic) data show that the East-Siberian Shelf was covered with ice over the last three million years only during a few glacial periods.

Further investigations are necessary to confirm this finding and particularly to time the reported events chronologically. The scientists have brought material in the form of sediment cores to Bremerhaven to achieve this. 16 soil samples could be taken on a transect of 700 kilometres from the Canada Basin via the Mendeleev Ridge into the Makarov Basin. The analysis will allow for the first time to compare the glacial history of the Northern USA and Canada with Siberia and to elaborate differences and parallels in detail. Furthermore, the data from the sediment cores can deliver information on the temporal and spatial changes of ocean currents and the extent of sea ice in the central Arctic Ocean. "We expect from these investigations important new insights into the control procedures of long and short term climate changes in the Arctic", says a delighted Stein.

Another focal point of this cruise was on the geological development of the Arctic Ocean during the last 90 million years. Seismic, an acoustic measurement method, allows peeking into the deep layers under the ocean floor down to 4.000 metres depth. "The collected data show that the ocean basin between the two Arctic ridge systems, the Lomonossov and the Mendeleev Ridge, are considerably older than estimated so far. Thus, the basins in the old part of the Arctic Ocean, the Makarov and the Canada Basin, have developed at about the same", reports Jokat. "The following detachment of the Lomonossov Ridge from the East-Siberian Shelf took place 60 million years ago – not without massive changes to the environment. The data present evidence of strong relocation processes in the deep-sea sediments", continues the geophysicist. "Many model representations about the development of the Arctic Ocean must be rethought on the basis of the new data", concludes Jokat.

Oceanographers regularly collect data on water temperature, density and salinity from the ship. Additionally, they brought out buoys on ice floes which autonomously conduct these measurements over one or two years. The oceanographers can thereby better understand how the water masses circulate in the Arctic Ocean. Integrated into long-term measurements, they can describe changing water temperatures and sea ice cover regarding climate change.

Biologists on board investigated the occurrence and distribution of the copepod Oithona similis in the Arctic Ocean. This small crab is an important part of the food web. It feeds, among other things, on small algae and animals and serves on its part as food for fish larvae. Another biological programme is aimed at collecting data on the distribution of birds, seals, whales and polar bears along the route. An almost continuous measurement of the seafloor and a programme for water probes rounded off the interdisciplinary scientific programme.

The measurements contribute to research within the framework of the International Polar Year, the European project DAMOCLES and the North Atlantic project of the German Federal Ministry of Education and Research. After the usual maintenance and repair work, Polarstern will leave on October 31st with the destination Cape town. There begins the Antarctic season 2008/09.


Story Source:

The above story is based on materials provided by Helmholtz Association of German Research Centres. Note: Materials may be edited for content and length.


Cite This Page:

Helmholtz Association of German Research Centres. "North Pole Exploration: Large Sliding Masses Close Beneath The Seafloor Of East-Siberian Continental Shelf Discovered." ScienceDaily. ScienceDaily, 28 October 2008. <www.sciencedaily.com/releases/2008/10/081020120045.htm>.
Helmholtz Association of German Research Centres. (2008, October 28). North Pole Exploration: Large Sliding Masses Close Beneath The Seafloor Of East-Siberian Continental Shelf Discovered. ScienceDaily. Retrieved October 22, 2014 from www.sciencedaily.com/releases/2008/10/081020120045.htm
Helmholtz Association of German Research Centres. "North Pole Exploration: Large Sliding Masses Close Beneath The Seafloor Of East-Siberian Continental Shelf Discovered." ScienceDaily. www.sciencedaily.com/releases/2008/10/081020120045.htm (accessed October 22, 2014).

Share This



More Earth & Climate News

Wednesday, October 22, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Traditional Farming Methods Gaining Ground in Mali

Traditional Farming Methods Gaining Ground in Mali

AFP (Oct. 20, 2014) — He is leading a one man agricultural revolution in Mali - Oumar Diatabe uses traditional farming methods to get the most out of his land and is teaching others across the country how to do the same. Duration: 01:44 Video provided by AFP
Powered by NewsLook.com
How Detroit's Money Woes Led To U.N.-Condemned Water Cutoffs

How Detroit's Money Woes Led To U.N.-Condemned Water Cutoffs

Newsy (Oct. 20, 2014) — The United Nations says water is a human right, but should it be free? Detroit has cut off water to residents who can't pay, and the U.N. isn't happy. Video provided by Newsy
Powered by NewsLook.com
Hey, Doc! Sewage, Beer and Food Scraps Can Power Chevrolet’s Bi-Fuel Impala

Hey, Doc! Sewage, Beer and Food Scraps Can Power Chevrolet’s Bi-Fuel Impala

3BL Media (Oct. 20, 2014) — Hey, Doc! Sewage, Beer and Food Scraps Can Power Chevrolet’s Bi-fuel Impala Video provided by 3BL
Powered by NewsLook.com
White Rhino's Death In Kenya Means Just 6 Are Left

White Rhino's Death In Kenya Means Just 6 Are Left

Newsy (Oct. 20, 2014) — Suni, a rare northern white rhino at Ol Pejeta Conservancy, died Friday. This, as many media have pointed out, leaves people fearing extinction. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:

Strange & Offbeat Stories

 

Plants & Animals

Earth & Climate

Fossils & Ruins

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins