Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Behavior of arctic ocean ridge confounds predictions; May lead to new insights into crust formation


The discovery that an ocean ridge under the Arctic ice cap is unexpectedly volcanically active and contains multiple hydrothermal vents may cause scientists to modify a decades-long understanding of how ocean ridges work to produce the Earth’s crust.

The new results, which come from a study of the Gakkel Ridge, one of the slowest spreading ridges on Earth, have broad implications for the understanding of the globe-encircling mid-ocean ridge system where melting of the underlying mantle creates the ocean floor.

In two articles appearing in the June 26 edition of the journal Nature, scientists supported by the National Science Foundation (NSF) and Deutsche Forschungsgemeinschaft (DFG) present striking new results obtained during a nine-week research cruise that lasted from August to October of 2001. NSF is an independent federal agency that supports fundamental research and education across all fields of science and engineering, with an annual budget of nearly $5 billion.

In general, fast-spreading ocean ridges, where the Earth’s crust is produced, are volcanically very active. So scientists on the Arctic Mid-Ocean Ridge Expedition (AMORE) expected the Gakkel, where the spreading rate is one centimeter (.39 inches) per year, to exhibit little, if any, volcanic activity. The spreading rate on the Gakkel is about 20 times slower than that of more-frequently studied ocean ridges, such as the East Pacific Rise.

The Gakkel extends 1770 kilometers (1100 miles) from north of Greenland to Siberia. It is the deepest and most remote portion of the global mid-ocean ridge system. Because the spreading rate decreases progressively towards Siberia, "we expected that the amount of melting and magma production would decrease as we worked our way from Greenland towards the east," said Peter Michael, the AMORE chief scientist from the University of Tulsa.

Instead, the very first sampling station brought up fresh volcanic rock, and the new map published in Nature shows large young volcanoes dominating the part of the ridge nearest Greenland.

"By contrast, the central portions of the ridge showed virtually no volcanism and large faults as pieces of the Earth’s mantle were emplaced directly on the sea floor," noted Henry Dick, who specializes in mantle materials. Even larger volcanic edifices appeared farther to the east.

Scientists aboard the Healy, a U.S. Coast Guard icebreaker specially equipped for research, and a companion vessel, the German research icebreaker, the PFS Polarstern, achieved several scientific "firsts."

They obtained high-resolution, well-navigated maps of the entire portion of the ridge, collected thousands of samples by dredging the sea floor, explored for regional anomalies in the water column that would indicate the amount and location of deep hydrothermal vents surrounded by ecosystems that thrive in the absence of sunlight.

Michael noted that the results obtained at sea continually surprised the research team, which was co-led by Henry Dick, of the Woods Hole Oceanographic Institution, and Charles Langmuir of Harvard University.

Based on the picture the Gakkel data painted, factors other than spreading rate must be taken into account when characterizing the likelihood of a given area’s volcanic activity.

"It’s an interconnected multi-variate system," said Michael. "The level of volcanic activity was higher than that predicted from the spreading rate and did not vary continuously as the spreading rate decreased. The chemical composition and temperature of the mantle that melts to form the magma must also be of substantial importance" to the process of ridge formation.

This is most apparent at the slowest spreading rates.

"At the slowest spreading rates, small changes in the other factors have more dramatic effects, making their importance more visible," noted Langmuir.

The research team, which included more than 30 scientists from U.S. and German research institutions, based their conclusions on the remarkably detailed map of the sea floor and on 200 samples taken on average every five kilometers (3.1 miles) along the ridge.

"To our great surprise, sampling from both vessels in the ice was straightforward," said Langmuir, " and this permitted three to four times more sample recovery than planned. We were able to obtain a regional perspective similar to what has been possible for ridges nearer the equator."

"Our sampling strategy allowed us to cruise along each part of the ridge twice," Michael added. "We were also measuring the chemistry of the rocks in the laboratories aboard the ship. We used that chemistry plus the new bathymetric maps to guide sampling on our second pass."

In the same issue, the European research team reports seismic and magnetic data that indicate the crust along the ridge is extremely thin. That confirms inferences made from gravity data collected by submarine as part of the SCICEX program, an NSF-funded survey of the Arctic Ocean floor.

The Gakkel cruise was the first major research voyage for the Healy.

Michael said the new Gakkel Ridge data highlight how important it is to continue the physical exploration of the planet.

"What we found could not be extrapolated from decades of previous studies of the ocean ridge system," he said. "It shows that there is still much to be discovered from exploratory science, and testing hypotheses in new regions. Discovery often happens when we put ourselves in conditions where we are likely to be surprised."

NSF Program Officer: Jane Dionne, (703) 292-8030,

Principal Investigators:

Peter Michael, University of Tulsa, (918) 631-3017,
Charles Langmuir, Harvard University,
Robert Mitchell, Harvard University, (617) 780-9465,

The National Science Foundation is an independent federal agency that supports fundamental research and education across all fields of science and engineering, with an annual budget of nearly $5 billion. National Science Foundation funds reach all 50 states through grants to nearly 2,000 universities and institutions. Each year, NSF receives about 30,000 competitive requests for funding, and makes about 10,000 new funding awards. The National Science Foundation also awards over $200 million in professional and service contracts yearly.

Receive official National Science Foundation news electronically through the e-mail delivery system, NSFnews. To subscribe, send an e-mail message to In the body of the message, type "subscribe nsfnews" and then type your name. (Ex.: "subscribe nsfnews John Smith")

Peter West | National Science Foundation
Further information:

More articles from Earth Sciences:

nachricht Gas hydrate research: Advanced knowledge and new technologies
23.03.2018 | Helmholtz-Zentrum Potsdam - Deutsches GeoForschungsZentrum GFZ

nachricht New technologies and computing power to help strengthen population data
22.03.2018 | University of Southampton

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Space observation with radar to secure Germany's space infrastructure

Satellites in near-Earth orbit are at risk due to the steady increase in space debris. But their mission in the areas of telecommunications, navigation or weather forecasts is essential for society. Fraunhofer FHR therefore develops radar-based systems which allow the detection, tracking and cataloging of even the smallest particles of debris. Satellite operators who have access to our data are in a better position to plan evasive maneuvers and prevent destructive collisions. From April, 25-29 2018, Fraunhofer FHR and its partners will exhibit the complementary radar systems TIRA and GESTRA as well as the latest radar techniques for space observation across three stands at the ILA Berlin.

The "traffic situation" in space is very tense: the Earth is currently being orbited not only by countless satellites but also by a large volume of space...

Im Focus: Researchers Discover New Anti-Cancer Protein

An international team of researchers has discovered a new anti-cancer protein. The protein, called LHPP, prevents the uncontrolled proliferation of cancer cells in the liver. The researchers led by Prof. Michael N. Hall from the Biozentrum, University of Basel, report in “Nature” that LHPP can also serve as a biomarker for the diagnosis and prognosis of liver cancer.

The incidence of liver cancer, also known as hepatocellular carcinoma, is steadily increasing. In the last twenty years, the number of cases has almost doubled...

Im Focus: Researchers at Fraunhofer monitor re-entry of Chinese space station Tiangong-1

In just a few weeks from now, the Chinese space station Tiangong-1 will re-enter the Earth's atmosphere where it will to a large extent burn up. It is possible that some debris will reach the Earth's surface. Tiangong-1 is orbiting the Earth uncontrolled at a speed of approx. 29,000 km/h.Currently the prognosis relating to the time of impact currently lies within a window of several days. The scientists at Fraunhofer FHR have already been monitoring Tiangong-1 for a number of weeks with their TIRA system, one of the most powerful space observation radars in the world, with a view to supporting the German Space Situational Awareness Center and the ESA with their re-entry forecasts.

Following the loss of radio contact with Tiangong-1 in 2016 and due to the low orbital height, it is now inevitable that the Chinese space station will...

Im Focus: Alliance „OLED Licht Forum“ – Key partner for OLED lighting solutions

Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology FEP, provider of research and development services for OLED lighting solutions, announces the founding of the “OLED Licht Forum” and presents latest OLED design and lighting solutions during light+building, from March 18th – 23rd, 2018 in Frankfurt a.M./Germany, at booth no. F91 in Hall 4.0.

They are united in their passion for OLED (organic light emitting diodes) lighting with all of its unique facets and application possibilities. Thus experts in...

Im Focus: Mars' oceans formed early, possibly aided by massive volcanic eruptions

Oceans formed before Tharsis and evolved together, shaping climate history of Mars

A new scenario seeking to explain how Mars' putative oceans came and went over the last 4 billion years implies that the oceans formed several hundred million...

All Focus news of the innovation-report >>>



Industry & Economy
Event News

New solar solutions for sustainable buildings and cities

23.03.2018 | Event News

Virtual reality conference comes to Reutlingen

19.03.2018 | Event News

Ultrafast Wireless and Chip Design at the DATE Conference in Dresden

16.03.2018 | Event News

Latest News

For graphite pellets, just add elbow grease

23.03.2018 | Materials Sciences

Unique communication strategy discovered in stem cell pathway controlling plant growth

23.03.2018 | Agricultural and Forestry Science

Sharpening the X-ray view of the nanocosm

23.03.2018 | Physics and Astronomy

Science & Research
Overview of more VideoLinks >>>