Arctic Ridge of Fire

Surprise: Explosive volcanic eruption under the Arctic ice found
June 25, 2008

Figure (click to enlarge): Gakkel Ridge. From Wikipedia, the free encyclopedia

Entry: I posted on a similar story about volcanic eruptions under Antarctic ice earlier this year. What is unique about this situation is that it was a large eruption that went completely undetected, and under pressures that they thought not possible.

The big question is then; where did the heat from the volcano go, and what effect did it have on the sea ice environment? Another question is how much CO2 would such an eruption emit, and how long would it take to outgas? Research has been going on looking at volcanism in the ridge but this discovery of a significant eruption in 1999 is new and unexpected.

Essence: From Science and The Sea: “In the last few years, for example, scientists have found that a long ridge beneath the north polar ice cap is dotted with volcanoes, and with vents of superheated water that could be home to many new species.”

An international team of researchers was able to provide evidence of explosive volcanism in the deeps of the ice-covered Arctic Ocean for the first time. Researchers from an expedition to the Gakkel Ridge, led by the American Woods Hole Oceanographic Institution (WHOI), report in the current issue of the journal Nature that they discovered, with a specially developed camera, extensive layers of volcanic ash on the seafloor, which indicates a gigantic volcanic eruption.

Far away in the Arctic Ocean, at 85° N 85° E, a similarly violent volcanic eruption happened almost undetected in 1999 – in this case, however, under a water layer of 4,000 m thickness.” So far, researchers have assumed that explosive volcanism cannot happen in water depths exceeding 3 kilometres because of high ambient pressure. “These are the first pyroclastic deposits we’ve ever found in such deep water, at oppressive pressures that inhibit the formation of steam, and many people thought this was not possible,” says Robert Reves-Sohn, staff member of the WHOI and lead scientist of the expedition carried out on the Swedish icebreaker Oden in 2007.

NSM remark: I hope my next Edu Path adventure will not be boring. The maps showing underwater volcanoes or seafloor features come in form of bathymetric maps. The data used for their rendering are being gathered from satellite altimeters and sonar measurements performed by ships, icebreakers, submarines, and submersibles. Due to the lack of detailed data the maps are not that good as topographic maps (land maps).




Figure (click to enlarge): NOAA > NESDIS > NGDC > MGGD > marine geology & geophysics


Figure (click to enlarge): Gakkel Ridge. Zoomed out screenshot of PDF file (ibcaoposter.pdf) from INTERNATIONAL BATHYMETRIC CHART OF THE ARCTIC OCEAN (IBCAO)


Figure (click to enlarge): Gakkel Ridge screenshot from above PDF file. Find a square ~85N/85E on the map and compare the place with the topographic map below. That's were our area of interest lies.


Figure (click to enlarge): Screenshot taken from image IBCAO_ver1map_letter.jpg you can found on UNH-NOAA Ocean Mapping Expedition Yields New Insights into Arctic Depths website.


Figure (click to enlarge): Bathymetric chart of the Gakkel Ridge at 85°E. Photographic bottom surveys were conducted along profiles shown as thin, black lines. The photo showing volcanic ashes on the sea bed were taken at the site, which is marked with a red star and the letter a.


Figure (click to enlarge): From SELECTIVE COMPARISONS OF GEBCO (1979) AND IBCAO (2000) MAPS.

NSM remark: I think it is worth to acquaint with limits of bathymetric maps. Read the text carefully then. I presented only a small excerpt.

Before we start to study other maps of Gakkel Ridge let's read a few articles on earlier expeditions to the region (in chronological order).

Arctic Gakkel Ridge Eruption Reveals Magma from Earth's Mantle
December 3, 2001


Figure (click to enlarge): Dale Chayes, left, and Jay Ardai, Lamont-Doherty senior staff associates, in front of the submarine USS Hawkbill, surface at the North Pole. A sailor and an officer keep watch for polar bears from the top of the sail.

Entry: Boulder, Colo. — It's exciting to be the first scientist to observe a volcanic eruption on an ultraslow-spreading mid-ocean ridge, an event in and of itself that rarely occurs. Even better is discovering that the USS Hawkbill, a submarine equipped with scientific mapping tools, just happened to have passed by at the same time and recorded the event while the scientists on board were completely unaware of the eruption. (see the picture - NSM)

Intense seismic activity began in Gakkel Ridge in January of 1999 and continued for seven months. Gakkel Ridge, the slowest spreading ridge in the world, is located in the Arctic Basin. Initial reports, such as the one published in the February 15, 2001 issue of NATURE magazine, have sparked much interest in the area culminating in the recent excursion of the U.S. Coast Guard icebreaker Healy.

Essence: Maya Tolstoy, an Associate Research Scientist at the Lamont-Doherty Earth Observatory at Columbia University, was the first scientist to discover these volcanic eruptions and she was a co-author of the NATURE article.

More recently, she discovered that the magma body, which was the source of the eruption, might have come from the mantle of the Earth and not the crust. She reports these new findings in the December issue of GEOLOGY.

Excerpts: Tolstoy happened to discover the Gakkel eruptions in the summer of 1999 when she was looking at Arctic seismic data for a hydroacoustic monitoring project.

NSM remark: Please read additional article from the same source entitled Evidence of Recent Volcanic Activity Found Along the Slow-Spreading Gakkel Ridge and look over additional scientific images (two of them are presented below).


Figure (click to enlarge): Seismicity plotted on the most recently active volcano. From Evidence of Recent Volcanic Activity Found Along the Slow-Spreading Gakkel Ridge, by Kristen Watson.


Figure (click to enlarge)

Figure (click to enlarge): Eastern Gakkel (Click to get the view in 17 MB PDF format.)

NOAA SCIENTIST AND COLLEAGUES FIND HOT SPRINGS IN COLD WATERS
January 15, 2003


Figure (click to enlarge): The new U.S. icebreaker Healy performed splendidly on its maiden voyage to the Arctic Ocean in 2001 to explore the Gakkel Ridge—the deepest and slowest-spreading ridge on Earth. (Henry Dick.) From Oceanus published by Woods Hole Oceanographic Institution.

Entry: One of the last places that NOAA scientist Ed Baker thought he would discover a dozen hydrothermal vents was in the icy cold Arctic Ocean, but that’s just where an international team of scientists found them.

“On the Gakkel Ridge, which is in the Arctic Ocean between Greenland and Siberia, we found evidence of nine to 12 hydrothermal vents along about 680 miles of the rift valley,” said Baker, a supervisory oceanographer at the NOAA Pacific Marine Environmental Laboratory in Seattle, Wash. Baker, who has been studying hydrothermal vents for almost 20 years, said the discovery was among the most remarkable and unexpected of his career.

Essence: The findings of Baker and his colleagues, including H.N. Edmonds of the University of Texas at Austin, and P.J. Michael of the University of Tulsa, will be published in the Jan. 16 issue of the science journal Nature. Using a combination of temperature and light measurements, along with an actual fresh sulfide chimney acquired in a dredging operation, the scientists present the first evidence for hydrothermal venting on the Gakkel Ridge.

“This discovery is significant because it is so unexpected,” Baker said. “The tectonic plates on either side of the Gakkel Ridge spread apart, or open, very slowly. In fact, it’s the planet’s slowest spreading ridge, moving at about a half an inch a year or less. We expected to find no more than four or five vent sites because this sluggish spreading rate creates far less volcanic activity than on most mid-ocean ridges.”

Excerpts: Hot spring water rises and forms a plume above the vent, somewhat like smoke rising from a house chimney into the air. These plumes can be detected by oceanographic instruments, like Miniature Autonomous Plume Recorders (MAPRs), a self-contained instrument developed at PMEL to record temperature and light scattering caused by tiny mineral grains suspended in the water—clues that hydrothermal vents are on the seafloor below. (

(...) The unusual marine life found in Atlantic Ocean vent sites are “markedly different” from those found in the Pacific Ocean vent sites. Baker and his colleagues suggest that since the Gakkel Ridge is not connected to other parts of the mid-ocean ridge system south of Iceland, it is likely that new species of vent marine life await discovery.


Figure (click to enlarge): (Click NOAA image for larger view of Miniature Autonomous Plume Recorder or MAPR.)

The Fiery Face of the Arctic Deep
July 18th, 2003


Figure (click to enlarge): Fig. 1: The American research ice-breaker "USCGC Healy" and the German research ship "PFS Polarstern" on expedition in the Arctic Ocean. Image: Henry Dick, Woods Hole Oceanographic Institution / NSF

Entry: Results from a German-American Arctic expedition to the Gakkel Ridge have implications for the understanding of the generation of new seafloor

Essence: The Gakkel ridge is a gigantic volcanic mountain chain stretching beneath the Arctic Ocean. With its deep valleys 5,500 meter beneath the sea surface and its 5,000 meter high summits, Gakkel ridge is far mightier than the Alps. This is the site of seafloor spreading that is actively separating Europe from North America, and was the goal of the international expedition AMORE (Arctic Mid-Ocean Ridge Expedition) (see the entry after the next one) with two research icebreakers, the "USCGC Healy" from USA and the German "PFS Polarstern". Aboard were scientists from the Max Planck Institute for Chemistry and other international institutions. The scientists had expected that the Gakkel ridge would exhibit "anemic" magmatism. Instead, surprisingly strong magmatic activity in the West and the East of the ridge and one of the strongest hydrothermal activities ever seen at mid-ocean ridges were found. These results require a fundamental rethinking of the mechanisms of seafloor generation at midocean ridges (Nature, January 16 and June 26).

Excerpts: The Gakkel ridge extends about 1800 kilometers beneath the Arctic Ocean from north of Greenland to Siberia. It is the northernmost portion of the mid-ocean ridge system, the global 75,000 kilometer long volcanic chain where the ocean crust is generated by erupting magma. Because of its extremely slow spreading rate of about one centimeter per year, the slowest rate of any mid-ocean ridge and 20 times slower than the better explored East Pacific ridge, Gakkel ridge is of particular interest for scientists. It shows a number of unique phenomena that could give more information about the generation of new oceanic crust.

(...) Current theories of oceanic crustal production predict that volcanic activity deminishes as the spreading rate of the tectonic plates decreases and only little or no hydrothermal activity. Instead, the scientists found high levels of volcanic activity. "We expected the volcanic activity to gradually decrease from West to East as the magmatic systems shut down. Instead, approximately in the middle of the survey area, the magmatism shut down completely, then dramatically increased," says Dr. Jonathan Snow, the leader of the research group from the Max Planck Institute. This group was responsible for the petrological and geochemical investigations.

Excerpts: The central region without magmatic activity is unique in the worlds mid-ocean ridges, having no volcanic crust whatsoever. Here, scientists can directly sample rocks belonging to the Earths upper mantle, which is covered on every other part of the globe by thousands of meters of crustal rocks. Some of these mantle rocks were unusually well preserved,

Abstract: The Gakkel Ridge: Bathymetry, gravity anomalies, and crustal accretion at extremely slow spreading rates
JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 108, NO. B2, 2116, doi:10.1029/2002JB001830, 2003


Figure (click to enlarge): From Henrietta N. Edmonds' website. See the chapter "Hydrothermal vents in the Arctic Ocean" ( quote - Read about our discovery of the first hydrothermal vents on the Gakkel Ridge, published in Nature on January 16, 3003: Download the Nature paper and the Supplementary Information. (These are available as PDF files.) (This image is not bound to the Abstract - NSM.)

Essence: Abstract: The Gakkel Ridge in the Arctic Ocean is the slowest spreading portion of the global mid-ocean ridge system. Total spreading rates range from 12.7 mm/yr near Greenland to 6.0 mm/yr where the ridge disappears beneath the Laptev Shelf.

The ridge axis is very deep, generally 4700–5300 m, within a well-developed rift valley. The topography is primarily tectonic in origin, characterized by linear rift-parallel ridges and fault-bounded troughs with up to 2 km of relief. Evidence of extrusive volcanic activity is limited and confined to specific locations.

Excerpts: Swath bathymetry and gravity data for an 850 km long section of the Gakkel Ridge from 5°E to 97°E were obtained from the U.S. Navy submarine USS Hawkbill.

(...) East of 32°E, isolated discrete volcanoes are observed at 25–95 km intervals along the axis. Abundant small-scale volcanism characteristic of the Mid-Atlantic Ridge (MAR) is absent. It appears that the amount of melt generated is insufficient to maintain a continuous magmatic spreading axis. Instead, melt is erupted on the seafloor at a set of distinct locations where multiple eruptions have built up central volcanoes and covered adjacent areas with low relief lava flows.

AMORE - Arctic Mid Ocean Ridge Expedition to Gakkel Ridge



Figure (click to enlarge): The morphology of the Gakkel Ridge can be subdivided into three regions, A, B, C. (NSM - look at the violet or plum or magenta color in region A, it marks a deep valey.) A quote - Region A: The morphology of the Gakkel Ridge in region A is characterised by structures, that are typical for a slow spreading MOR. Here, the ridge exhibits a typical valley (see chart below, profile A), that is located at 4°E. The width of the valley is about 25 km. The inner valley is about 1 km wide and 5500 m deep.

Entry: Processing, Visualisation and Analysing of Multibeam Data from different systems gathered during the AMORE expedition 2001

The Gakkel Ridge is situated in the central Arctic Ocean and was object of an international expedition in the boreal summer 2001. This part of the world´s mid-ocean ridge system is of particular geo-scientific interest because of its slow spreading rate and the variety in morphology. Therefore, multibeam bathymetric measurements are of special importance regarding the scientific targets of the exploration of this deep-sea ridge. The data were acquired during a two-ship expedition by RV "Polarstern" and USCGC "Healy", the first vessel is equipped with the multibeam system Hydroseep DS-2, the latter with Seambeam 2112.

Essence: In this presentation the bathymetric data of the western part of the ridge (see Geographical Settings) were edited in order to remove the outliers and systematic errors under the use of CARIS HIPS. The processed data were used to compute a Digital Terrain Model (DTM) in the GIS ArcInfo, using a grid spacing of 100 m. This DTM covers an area of approx. 9900 km² subdivided in three bathymetric map sheets, that illustrate the topography of the seabed by contour lines (interval: 50 m, scale: 1:150,000).

The morphology of spreading systems is formed by magmatic and tectonic processes. Due to the young age of the crust of the Gakkel Ridge the spreading axis is sparsely covered by sediments. The topography is of special interest, since it makes a contribution to the understanding of the geological processes on and within the solid Earth.


Figure (click to enlarge): Bathymetric profiles across the Gakkel Ridge at Profile A: ~4°E and Profile B: ~1°W.


Figure (click to enlarge): (a) Bathymetry of IBCAO and (b) Comparison of the new high-resolution DTM of the Gakkel Ridge with IBCAO data. A quote - The International Bathymetric Chart of the Arctic Ocean (IBCAO) is a digital database, that contains all available bathymetric data north of 64° N prior to 2001 (Jacobsson et al., 2001). The figures a and b show the IBCAO grid (resolution is 2.5 km) in comparison with the DTM of the Gakkel Ridge using the newly acquired multibeam data. Fig. a shows the data of IBCAO only, while Fig. b reveals the improvements of the new high-resolution DTM compared to IBCAO data.


Figure (click to enlarge): Bathymetric cross sections across the Gakkel Ridge. The black line indicates data from the DTM of this study. The red line shows the same transect using IBCAO data (location of the profiles A and B see Fig. 6).

Exploring the Arctic abyss
By Doug O'Harra, Sunday, June 24th, 2007


Figure (click to enlarge): Autonomous underwater vehicle Puma will “sniff out” the source of hot, mineral-rich fluids venting from the seafloor, and vehicle Jaguar will use cameras and bottom-mapping sonar to image the location. Credit: E. Paul Oberlander/ WHOI

Entry: The dim, frigid floor of the Arctic Ocean is more mysterious than the dark side of the moon. It’s got primordial life and unknown thermal vents. Less explored than Mars, this high-pressure world far beneath the ice may be as remote from human knowledge as some exotic habitat on another planet.

But a team of scientists and engineers from the Woods Hole Oceanographic Institution (WHOI) plan to penetrate the Arctic’s abyss. With new robotic submarines and other tricky technology, they will roam this unseen world for signs of new forms of life, some possibly stewed into existence by hot magma and boiling sea water.

Essence: With funding from NASA and the National Science Foundation, the 30-member team has successfully tested two underwater vehicles and a new tethered sampling system, and now plans to launch the expedition on July 1 from the Norwegian island of Svalbaard, according to a story posted on-line.

Destination will be the little-known Gakkel Ridge, a mid-ocean ridge formed by the inexorable spreading of the North American tectonic plate from the Eurasian plate — and helps cut off the Arctic Ocean from the world’s other seas.

Excerpts: In July 2001, WHOI researchers were part of the Arctic Mid-Ocean Ridge Expedition (AMORE) that produced the first detailed maps of the Gakkel Ridge and made the unexpected discovery that the ridge is volcanically active. Scientists also found that large sections of Earth’s mantle appear to be deposited directly onto the seafloor along the Gakkel Ridge.

(...) The research team for the Arctic Gakkel Vents Expedition (AGAVE) includes specialists in each field of deep-sea exploration, with scientists and engineers from the United States, Norway, Germany, Japan, and Sweden.


Figure (click to enlarge): The Puma, or “plume mapper,” vehicle uses sonar, lasers, and chemical sensors to search wide areas near the ocean floor to detect the telltale temperature, chemical, and turbidity signals from hydrothermal vent plumes. Credit: Hanumant Singh/WHOI

Earth's Complex Complexion
Henry J.B. Dick, Senior Scientist, Geology and Geophysics Department, Woods Hole Oceanographic Institution, Oceanus (magazine) Saturday, Posted: May 13, 2004


Figure (click to enlarge): The 2001 AMORE (Arctic Mid-Ocean Ridge Expedition) collected SeaBEAM sonar data to create this detailed 1,000-kilometer (620-mile) bathymetric map of the Gakkel Ridge.

Entry: Several generations of scientists have dredged rock samples from the seafloor, employed submarines and robots to study it, and even drilled into it to learn a considerable amount about the shallow oceanic crust. We’ve analyzed seismic waves that penetrate and reflect off rock layers deep in the crust in an effort to decipher its characteristics—similar to the way physicians use an MRI to peer below the skin. We’ve also studied ophiolites—isolated portions of the seafloor that tectonic forces have thrust up and exposed on continental margins.

From early studies, a simple picture emerged: It seemed the ocean crust was relatively homogenous in composition, structure, and thickness—sort of a geological three-layer cake about 6 to 7 kilometers (3.7 to 4.3 miles) thick. On top was lava that spilled out and cooled rapidly into a glassy substance called basalt, which carpeted the ocean bottom. Below were great, vertical sheets of molten rock called dikes—the pathways by which magma was injected to the surface from deeper layers. Finally, lying atop the mantle itself, was a lower layer composed of magma that rose directly from the mantle, cooled more slowly, and crystallized into a rock known as gabbro.

This was a neat picture and a great first step, but nature, like life, usually turns out not to be so simple. And so it is with seafloor crust.

Essence: These discoveries have now led to the realization that instead of two great classes of ocean ridges—slow and fast—there is a third category, ultraslow, which may make up as much as one-third of the global ocean ridge system. These ultraslow ridges—so unlike the more explored and better known Atlantic and Pacific Ocean ridges—represent a new frontier.


Figure (click to enlarge): Volcanic activity at mid-ocean ridges creates new seafloor crust that spreads outward to cover 70 percent of Earth's surface. Recent expeditions have led to the discovery of an entirely new type of mid-ocean ridge. Instead of two classes of ridges—fast-spreading and slow-spreading—there is now a third, ultraslow. Ultraslow-spreading ridges, which may make up one-third of the global ocean ridge system, have distinctive characteristics. Like other mid-ocean ridges, ultraslow ridges have areas where magma rises from the mantle and erupts at the seafloor to create new ocean crust. But in between, there are also amagmatic zones, where solid slabs of mantle rock rise directly to the seafloor.

NSM remark: This text ends up our tour in time presenting Gakkel Ridge discoveries. Let's see some other illustrations concerning the Ridge and its underwater volcanic activities.


Figure (click to enlarge): FIGURE 4. Correlation of spreading rate and incidence of hydrothermal plumes. From Nature.


Figure (click to enlarge): From Submarine Volcanism.


Figure (click to enlarge): Depth profile through the Arctic Ocean. Gakkel Ridge is an active spreading zone with a central valley in the middle; Lomonosov Ridge is supposed to be a remanent of the Siberian Shelf. (own work, data from POLARSTERN Expedition ARK-VIII/3 in 1991, Date 2007-06-20, Author Hannes Grobe, Alfred Wegener Institute)


Figure (click to enlarge): Volcanic ashes on the sea bed of Gakkel Ridge (Photo: WHOI)


Figure (click to enlarge): Image : Scientists Report New Type of Mid-Ocean Ridge in Remote Parts of the Earth. A 3-D image of the ultraslow spreading Southwest Indian Ridge, where the seafloor is cracking apart forming a deep trough. (H. B. Dick, J. Lin, and H. Schouten, WHOI). Last updated: June 26, 2008. From News Release : Scientists Report New Type of Mid-Ocean Ridge in Remote Parts of the Earth.


Figure (click to enlarge): SeaBED, the prototype for JAGUAR, entering the water (Photograph by Mike Naylor, SSL). From Dexterous Robotics at the Space Systems Laboratory.


Figure (click to enlarge): JAGUAR undersea vehicle with arm (Model by Stephen Roderick, SSL). From Dexterous Robotics at the Space Systems Laboratory.


Figure (click to enlarge): Tube worms are one life form that may live on the Gakkel Ridge (Courtesy of WHOI). From Dexterous Robotics at the Space Systems Laboratory.


Figure (click to enlarge): This cross-section of the Gakkel Ridge as compiled by Henry Dick, co-chief scientist on the Arctic Mid-Ocean Ridge Expedition, contains a drawing of the USCGC Healy for scale. Credit: Paul Oberlander / Woods Hole Oceanographic Institution. You are in: NSF Home > OLPA Home > Newsroom > > NSF PR 03-67 > Images


Figure (click to enlarge): Researchers about the USCGC Healy pore over a map of the Gakkel Ridge produced during the Arctic Mid-Ocean Ridge Expedition. Credit: Henry Dick Woods Hole Oceanographic Institution / NSF. TIFF of Photo 3 (9.47MB). You are in: NSF Home > OLPA Home > Newsroom > > NSF PR 03-67 > Images


Figure (click to enlarge): Dive and Discover contains a lot of illustration explaining seafloor morphology.