New map uncovers thousands of unseen seamounts on ocean floor

This is a gravity model of the North Atlantic; red dots are earthquakes. Quakes are often related to seamounts. -  David Sandwell, SIO
This is a gravity model of the North Atlantic; red dots are earthquakes. Quakes are often related to seamounts. – David Sandwell, SIO

Scientists have created a new map of the world’s seafloor, offering a more vivid picture of the structures that make up the deepest, least-explored parts of the ocean.

The feat was accomplished by accessing two untapped streams of satellite data.

Thousands of previously uncharted mountains rising from the seafloor, called seamounts, have emerged through the map, along with new clues about the formation of the continents.

Combined with existing data and improved remote sensing instruments, the map, described today in the journal Science, gives scientists new tools to investigate ocean spreading centers and little-studied remote ocean basins.

Earthquakes were also mapped. In addition, the researchers discovered that seamounts and earthquakes are often linked. Most seamounts were once active volcanoes, and so are usually found near tectonically active plate boundaries, mid-ocean ridges and subducting zones.

The new map is twice as accurate as the previous version produced nearly 20 years ago, say the researchers, who are affiliated with California’s Scripps Institution of Oceanography (SIO) and other institutions.

“The team has developed and proved a powerful new tool for high-resolution exploration of regional seafloor structure and geophysical processes,” says Don Rice, program director in the National Science Foundation’s Division of Ocean Sciences, which funded the research.

“This capability will allow us to revisit unsolved questions and to pinpoint where to focus future exploratory work.”

Developed using a scientific model that captures gravity measurements of the ocean seafloor, the map extracts data from the European Space Agency’s (ESA) CryoSat-2 satellite.

CryoSat-2 primarily captures polar ice data but also operates continuously over the oceans. Data also came from Jason-1, NASA’s satellite that was redirected to map gravity fields during the last year of its 12-year mission.

“The kinds of things you can see very clearly are the abyssal hills, the most common landform on the planet,” says David Sandwell, lead author of the paper and a geophysicist at SIO.

The paper’s co-authors say that the map provides a window into the tectonics of the deep oceans.

The map also provides a foundation for the upcoming new version of Google’s ocean maps; it will fill large voids between shipboard depth profiles.

Previously unseen features include newly exposed continental connections across South America and Africa and new evidence for seafloor spreading ridges in the Gulf of Mexico. The ridges were active 150 million years ago and are now buried by mile-thick layers of sediment.

“One of the most important uses will be to improve the estimates of seafloor depth in the 80 percent of the oceans that remain uncharted or [where the sea floor] is buried beneath thick sediment,” the authors state.

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Co-authors of the paper include R. Dietmar Muller of the University of Sydney, Walter Smith of the NOAA Laboratory for Satellite Altimetry Emmanuel Garcia of SIO and Richard Francis of ESA.

The study also was supported by the U.S. Office of Naval Research, the National Geospatial-Intelligence Agency and ConocoPhillips.

The complicated birth of a volcano

Snow storms, ice and glaciers – these are the usual images we associate with the Antarctic. But at the same time it is also a region of fire: the Antarctic continent and surrounding waters are dotted with volcanoes – some of them still active and others extinct for quite some time. The Marie Byrd Seamounts in the Amundsen Sea are in the latter group. Their summit plateaus are today at depths of 2400-1600 meters. Because they are very difficult to reach with conventional research vessels, they have hardly been explored, even though the Marie Byrd Seamounts are fascinating formations. They do not fit any of the usual models for the formation of volcanoes. Now geologists from GEOMAR Helmholtz Centre for Ocean Research Kiel were able to find a possible explanation for the existence of these seamounts on the basis of rare specimens. The study is published in the international journal “Gondwana Research“.

Classic volcanologists differentiate between two types of fire mountains. One type is generated where tectonic plates meet, so the earth’s crust is already cracked to begin with. The other type is formed within the earth’s plates. “The latter are called intraplate volcanoes. They are often found above a so-called mantle plume. Hot material rises from the deep mantle, collects under the earth’s crust, makes its way to the surface and forms a volcano,” said Dr. Reinhard Werner, one of the authors of the current paper. One example are the Hawaiian Islands. But neither of the above models fits the Marie Byrd Seamounts. “There are no plate boundary in the vicinity and no plume underground,” says graduate geologist Andrea Kipf from GEOMAR, first author of the study.

To clarify the origin of the Marie Byrd Seamounts, in 2006 the Kiel scientists participated in an expedition of the research vessel POLARSTEN in the Amundsen Sea. They salvaged rock samples from the seamounts and subjected these to thorough geological, volcanological and geochemical investigations after returning to the home labs. “Interestingly enough, we found chemical signatures that are typical of plume volcanoes. And they are very similar to volcanoes in New Zealand and the Antarctic continent,” says geochemist Dr. Folkmar Hauff, second author of the paper.

Based on this finding, the researchers sought an explanation. They found it in the history of tectonic plates in the southern hemisphere. Around 100 million years ago, remains of the former supercontinent Gondwana were located in the area of present Antarctica. A mantle plume melted through this continental plate and cracked it open. Two new continents were born: the Antarctic and “Zealandia”, with the islands of New Zealand still in evidence today. When the young continents drifted in different directions away from the mantle plume, large quantities of hot plume material were attached to their undersides. These formed reservoirs for future volcanic eruptions on the two continents. “This process explains why we find signatures of plume material at volcanoes that are not on top of plumes,” says Dr. Hauff.

But that still does not explain the Marie Byrd Seamounts because they are not located on the Antarctic continent, but on the adjacent oceanic crust instead. “Continental tectonic plates are thicker than the oceanic ones. This ensures, among other things, differences in temperature in the underground,” says volcanologist Dr. Werner. And just as air masses of different temperatures create winds, the temperature differences under the earth’s crust generate flows and movements as well. Thus the plume material, that once lay beneath the continent, was able to shift under the oceanic plate. With disruptions due to other tectonic processes, there were cracks and crevices which allowed the hot material to rise, turn into magma and then- about 60 million years ago – allowed the Marie Byrd Seamounts to grow. “This created islands are comparable to the Canary Islands today,” explains Andrea Kipf. “Some day the volcanoes became extinct again, wind and weather eroded the cone down to sea level, and other geological processes further eroded the seamounts. Finally, the summit plateaus arrived at the level that we know today,” the PhD student describes the last step of the development.

Based on the previously little investigated Marie Byrd Seamounts, the researchers were able to show another example of how diverse and complex the processes are, that can cause volcanism. “We are still far from understanding all of these processes. But with the current study, we can contribute a small piece to the overall picture,” says Dr. Werner.

Undersea volcano gave off signals before eruption in 2011

A team of scientists that last year created waves by correctly forecasting the 2011 eruption of Axial Seamount years in advance now says that the undersea volcano located some 250 miles off the Oregon coast gave off clear signals hours before its impending eruption.

The researchers’ documentation of inflation of the undersea volcano from gradual magma intrusion over a period of years led to the long-term eruption forecast. But new analyses using data from underwater hydrophones also show an abrupt spike in seismic energy about 2.6 hours before the eruption started, which the scientists say could lead to short-term forecasting of undersea volcanoes in the future.

They also say that Axial could erupt again – as soon as 2018 – based on the cyclic pattern of ground deformation measurements from bottom pressure recorders.

Results of the research, which was funded by the National Science Foundation, the National Oceanic and Atmospheric Administration, and the Monterey Bay Aquarium Research Institute (MBARI), are being published this week in three separate articles in the journal Nature Geoscience.

Bill Chadwick, an Oregon State University geologist and lead author on one of the papers, said the link between seismicity, seafloor deformation and the intrusion of magma has never been demonstrated at a submarine volcano, and the multiple methods of observation provide fascinating new insights.

“Axial Seamount is unique in that it is one of the few places in the world where a long-term monitoring record exists at an undersea volcano – and we can now make sense of its patterns,” said Chadwick, who works out of Oregon State’s Hatfield Marine Science Center in Newport, Ore. “We’ve been studying the site for years and the uplift of the seafloor has been gradual and steady beginning in about 2000, two years after it last erupted.

“But the rate of inflation from magma went from gradual to rapid about 4-5 months before the eruption,” added Chadwick. “It expanded at roughly triple the rate, giving a clue that the next eruption was coming.”

Bob Dziak, an Oregon State University marine geologist, had previously deployed hydrophones on Axial that monitor sound waves for seismic activity. During a four-year period prior to the 2011 eruption, there was a gradual buildup in the number of small earthquakes (roughly magnitude 2.0), but little increase in the overall “seismic energy” resulting from those earthquakes.

That began to change a few hours before the April 6, 2011, eruption, said Dziak, who also is lead author on one of the Nature Geoscience articles.

“The hydrophones picked up the signal of literally thousands of small earthquakes within a few minutes, which we traced to magma rising from within the volcano and breaking through the crust,” Dziak said. “As the magma ascends, it forces its way through cracks and creates a burst of earthquake activity that intensifies as it gets closer to the surface.

“Using seismic analysis, we were able to clearly see how the magma ascends within the volcano about two hours before the eruption,” Dziak said. “Whether the seismic energy signal preceding the eruption is unique to Axial or may be replicated at other volcanoes isn’t yet clear – but it gives scientists an excellent base from which to begin.”

The researchers also used a one-of-a-kind robotic submersible to bounce sound waves off the seafloor from an altitude of 50 meters, mapping the topography of Axial Seamount both before and after the 2011 eruption at a one-meter horizontal resolution. These before-and-after surveys allowed geologists to clearly distinguish the 2011 lava flows from the many previous flows in the area.

MBARI researchers used three kinds of sonar to map the seafloor around Axial, and the detailed images show lava flows as thin as eight inches, and as thick as 450 feet.

“These autonomous underwater vehicle-generated maps allowed us, for the first time, to comprehensively map the thickness and extent of lava flows from a deep-ocean submarine in high resolution,” said David Caress, an MBARI engineer and lead author on one of the Nature Geoscience articles. “These new observations allow us to unambiguously differentiate between old and new lava flows, locate fissures from which these flows emerged, and identify fine-scale features formed as the lava flowed and cooled.”

The researchers also used shipboard sonar data to map a second, thicker lava flow about 30 kilometers south of the main flow – also a likely result of the 2011 eruption.

Knowing the events leading up to the eruption – and the extent of the lava flows – is important because over the next few years researchers will be installing many new instruments and underwater cables around Axial Seamount as part of the Ocean Observatories Initiative. These new instruments will greatly increase scientists’ ability to monitor the ocean and seafloor off of the Pacific Northwest.

“Now that we know some of the long-term and short-term signals that precede eruptions at Axial, we can monitor the seamount for accelerated seismicity and inflation,” said OSU’s Dziak. “The entire suite of instruments will be deployed as part of the Ocean Observatories Initiative in the next few years – including new sensors, samplers and cameras – and next time they will be able to catch the volcano in the act.”

The scientists also observed and documented newly formed hydrothermal vents with associated biological activity, Chadwick said.

“We saw snowblower vents that were spewing out nutrients so fast that the microbes were going crazy,” he pointed out. “Combining these biological observations with our knowledge of the ground deformation, seismicity and lava distribution from the 2011 eruption will further help us connect underwater volcanic activity with the life it supports.”

Scientists from Columbia University, the University of Washington, North Carolina State University, and the University of California at Santa Cruz also participated in the project and were co-authors on the Nature Geoscience articles.

Expedition to undersea mountain yields new information about sub-seafloor structure

This is a map of Atlantis Massif, showing the fault that borders this Atlantic Ocean seamount. -  NOAA
This is a map of Atlantis Massif, showing the fault that borders this Atlantic Ocean seamount. – NOAA

Scientists recently concluded an expedition aboard the research vessel JOIDES Resolution to learn more about Atlantis Massif, an undersea mountain, or seamount, that formed in a very different way than the majority of the seafloor in the oceans.

Unlike volcanic seamounts, which are made of the basalt that’s typical of most of the seafloor, Atlantis Massif includes rock types that are usually only found much deeper in the ocean crust, such as gabbro and peridotite.

The expedition, known as Integrated Ocean Drilling Program (IODP) Expedition 340T, marks the first time the geophysical properties of gabbroic rocks have successfully been measured directly in place, rather than via remote techniques such as seismic surveying.

With these measurements in hand, scientists can now infer how these hard-to-reach rocks will “look” on future seismic surveys, making it easier to map out geophysical structures beneath the seafloor.

“This is exciting because it means that we may be able to use seismic survey data to infer the pattern of seawater circulation within the deeper crust,” says Donna Blackman of the Scripps Institution of Oceanography in La Jolla, Calif., co-chief scientist for Expedition 340T.

“This would be a key step for quantifying rates and volumes of chemical, possibly biological, exchange between the oceans and the crust.”

Atlantis Massif sits on the flank of an oceanic spreading center that runs down the middle of the Atlantic Ocean.

As the tectonic plates separate, new crust is formed at the spreading center and a combination of stretching, faulting and the intrusion of magma from below shape the new seafloor.

Periods of reduced magma supplied from the underlying mantle result in the development of long-lived, large faults. Deep portions of the crust shift upward along these faults and may be exposed at the seafloor.

This process results in the formation of an oceanic core complex, or OCC, and is similar to the processes that formed the Basin and Range province of the Southwest United States.

“Recent discoveries from scientific ocean drilling have underlined that the process of creating new oceanic crust at seafloor spreading centers is complex,” says Jamie Allan, IODP program director at the U.S. National Science Foundation (NSF), which co-funds the program.

“This work significantly adds to our ability to infer ocean crust structure and composition, including predicting how ocean crust has ‘aged’ in an area,” says Allan, “thereby giving us new tools for understanding ocean crust creation from Earth’s mantle.”

Atlantis Massif is a classic example of an oceanic core complex.

Because it’s relatively young–formed within the last million years–it’s an ideal place, scientists say, to study how the interplay between faulting, magmatism and seawater circulation influences the evolution of an OCC within the crust.

“Vast ocean basins cover most of the Earth, yet their crust is formed in a narrow zone,” says Blackman. “We’re studying that source zone to understand how rifting and magmatism work together to form a new plate.”

The JOIDES Resolution first visited Atlantis Massif about seven years ago; the science team on that expedition measured properties in gabbro.

But they focused on a shallower section, where pervasive seawater circulation had weathered the rock and changed its physical properties.

For the current expedition, the team did not drill new holes.

Rather, they lowered instruments into a deep existing hole drilled on a previous expedition, and made measurements from inside the hole.

The new measurements, at depths between 800 and 1,400 meters (about 2,600-4,600 feet) below the seafloor, include only a few narrow zones that had been altered by seawater circulation and/or by fault slip deformation.

The rest of the measurements focused on gabbroic rocks that have remained unaltered thus far.

The properties measured in the narrow zones of altered rock differ from the background properties measured in the unaltered gabbroic rocks.

The team found small differences in temperature next to two sub-seafloor faults, which suggests a slow percolation of seawater within those zones.

There were also significant differences in the speed at which seismic waves travel through the altered vs. unaltered zones.

“The expedition was a great opportunity to ground-truth our recent seismic analysis,” says Alistair Harding, also from the Scripps Institution of Oceanography and a co-chief scientist for Expedition 340T.

“It also provides vital baseline data for further seismic work aimed at understanding the formation and alteration of the massif.”

The Integrated Ocean Drilling Program (IODP) is an international research program dedicated to advancing scientific understanding of the Earth through drilling, coring and monitoring the subseafloor.

The JOIDES Resolution is a scientific research vessel managed by the U.S. Implementing Organization of IODP (USIO). Texas A&M University, Lamont-Doherty Earth Observatory of Columbia University and the Consortium for Ocean Leadership comprise the USIO.

Scientists discover new eruption at undersea volcano, after successfully forecasting the event

A team of scientists just discovered a new eruption of Axial Seamount, an undersea volcano located about 250 miles off the Oregon coast – and one of the most active and intensely studied seamounts in the world.

What makes the event so intriguing is that the scientists had forecast the eruption starting five years ago – the first successful forecast of an undersea volcano.

Bill Chadwick, an Oregon State University geologist, and Scott Nooner, of Columbia University, have been monitoring Axial Seamount for more than a decade, and in 2006 published a paper in the Journal of Volcanology and Geothermal Research in which they forecast that Axial would erupt before the year 2014. Their forecast was based on a series of seafloor pressure measurements that indicated the volcano was inflating.

“Volcanoes are notoriously difficult to forecast and much less is known about undersea volcanoes than those on land, so the ability to monitor Axial Seamount, and determine that it was on a path toward an impending eruption is pretty exciting,” said Chadwick, who was chief scientist on the recent expedition, which was jointly funded by the National Oceanic and Atmospheric Administration and the National Science Foundation.

Axial last erupted in 1998 and Chadwick, Nooner and colleagues have monitored it ever since. They used precise bottom pressure sensors – the same instruments used to detect tsunamis in the deep ocean – to measure vertical movements of the floor of the caldera much like scientists would use GPS on land to measure movements of the ground. They discovered that the volcano was gradually inflating at the rate of 15 centimeters (six inches) a year, indicating that magma was rising and accumulating under the volcano summit.

When Axial erupted in 1998, the floor of the caldera suddenly subsided or deflated by 3.2 meters (10.5 feet) as magma was removed from underground to erupt at the surface. The scientists estimated that the volcano would be ready to erupt again when re-inflation pushed the caldera floor back up to its 1998 level.

“Forecasting the eruption of most land volcanoes is normally very difficult at best and the behavior of most is complex and variable,” said Nooner, who is affiliated with the Lamont-Doherty Earth Observatory. “We now have evidence, however, that Axial Seamount behaves in a more predictable way than many other volcanoes – likely due to its robust magma supply coupled with its thin crust, and its location on a mid-ocean ridge spreading center.

“It is now the only volcano on the seafloor whose surface deformation has been continuously monitored throughout an entire eruption cycle,” Nooner added.

The discovery of the new eruption came on July 28, when Chadwick, Nooner and University of Washington colleagues Dave Butterfield and Marvin Lilley led an expedition to Axial aboard the R/V Atlantis, operated by the Woods Hole Oceanographic Institution. Using Jason, a remotely operated robotic vehicle (ROV), they discovered a new lava flow on the seafloor that was not present a year ago.

“It’s funny,” Chadwick said. “When we first arrived on the seafloor, we thought we were in the wrong place because it looked so completely different. We couldn’t find our markers or monitoring instruments or other distinctive features on the bottom. Once we figured out that an eruption had happened, we were pretty excited.

“When eruptions like this occur, a huge amount of heat comes out of the seafloor, the chemistry of seafloor hot springs is changed, and pre-existing vent biological communities are destroyed and new ones form,” Chadwick added. “Some species are only found right after eruptions, so it is a unique opportunity to study them.”

The first Jason ROV dive of the expedition targeted a field of “black smoker” hot springs on the western side of the caldera, beyond the reach of the new lava flows. Butterfield has been tracking the chemistry and microbiology of hot springs around the caldera since the 1998 eruption.

“The hot springs on the west side did not appear to be significantly disturbed, but the seawater within the caldera was much murkier than usual,” Butterfield said, “and that meant something unusual was happening. When we saw the ‘Snowblower’ vents blasting out huge volumes of white floc and cloudy water on the next ROV dive, it was clear that the after-effects of the eruption were still going strong. This increased output seems to be associated with cooling of the lava flows and may last for a few months or up to a year.”

The scientists will examine the chemistry of the vent water and work with Julie Huber of the Marine Biological Laboratory to analyze DNA and RNA of the microbes in the samples.

The scientists recovered seafloor instruments, including two bottom pressure recorders and two ocean-bottom hydrophones, which showed that the eruption took place on April 6 of this year. A third hydrophone was found buried in the new lava flows.

“So far, it is hard to tell the full scope of the eruption because we discovered it near the end of the expedition,” said Chadwick, who works out of OSU’s Hatfield Marine Science Center in Newport. “But it looks like it might be at least three times bigger than the 1998 eruption.”

The lava flow from the 2011 eruptions was at least two kilometers (1.2 miles) wide, the scientists noted.

“Five years ago, these scientists forecast this eruption, which has resulted in millions of square meters of new lava flows on the seafloor,” said Barbara Ransom, program director in the National Science Foundation’s Division of Ocean Sciences. “The technological advances that allow this research to happen will lead to a new understanding of submarine volcanoes, and of any related hazards.”

The bottom-anchored instruments documented hundreds of tiny earthquakes during the volcanic eruption, but land-based seismic monitors and the Sound Surveillance System (SOSUS) hydrophone array operated by the U.S. Navy only detected a handful of them on the day of the eruption because many components of the hydrophone system are offline.

“Because the earthquakes detected back in April at a distance from the volcano were so few and relatively small, we did not believe there was an eruption,” said Bob Dziak, an OSU marine geologist who monitors the SOSUS array. “That is why discovering the eruption at sea last week was such a surprise.” Both Dziak and Chadwick are affiliated with the Cooperative Institute for Marine Resource Studies – a joint NOAA/Oregon State University institute.

This latest Axial eruption caused the caldera floor to subside by more than two meters (six feet). The scientists will be measuring the rate of magma inflation over the next few years to see if they can successfully forecast the next event.

“The acid test in science – whether or not you understand a process in nature – is to try to predict what will happen based on your observations,” Chadwick said. “We have done this and it is extremely satisfying that we were successful. Now we can build on that knowledge and look to apply it to other undersea volcanoes – and perhaps even volcanoes on land.”

Scientists delve into ‘hotspot’ volcanoes along Pacific Ocean Seamount Trail

Like a string of underwater pearls, the Louisville Seamount Trail is strung across the Pacific. -  IODP
Like a string of underwater pearls, the Louisville Seamount Trail is strung across the Pacific. – IODP

Nearly half a mile of rock retrieved from beneath the seafloor is yielding new clues about how underwater volcanoes are created and whether the hotspots that led to their formation have moved over time.

Geoscientists have just completed an expedition to a string of underwater volcanoes, or seamounts, in the Pacific Ocean known as the Louisville Seamount Trail.

There they collected samples of sediments, basalt lava flows and other volcanic eruption materials to piece together the history of this ancient trail of volcanoes.

The expedition was part of the Integrated Ocean Drilling Program (IODP).

“Finding out whether hotspots in Earth’s mantle are stationary or not will lead to new knowledge about the basic workings of our planet,” says Rodey Batiza, section head for marine geosciences in the National Science Foundation’s (NSF) Division of Ocean Sciences.

Tens of thousands of seamounts exist in the Pacific Ocean. Expedition scientists probed a handful of the most important of these underwater volcanoes.

“We sampled ancient lava flows, and a fossilized algal reef,” says Anthony Koppers of Oregon State University. “The samples will be used to study the construction and evolution of individual volcanoes.”

Koppers led the expedition aboard the scientific research vessel JOIDES Resolution, along with co-chief scientist Toshitsugu Yamazaki from the Geological Survey of Japan at the National Institute of Advanced Industrial Science and Technology.

IODP is supported by NSF and Japan’s Ministry of Education, Culture, Sports, Science and Technology.

Over the last two months, scientists drilled 1,113 meters (3,651 feet) into the seafloor to recover 806 meters (2,644 feet) of volcanic rock.

The samples were retrieved from six sites at five seamounts ranging in age from 50 to 80 million years old.

“The sample recovery during this expedition was truly exceptional. I believe we broke the record for drilling igneous rock with a rotary core barrel,” says Yamazaki.

Igneous rock is rock formed through the cooling and solidification of magma or lava, while a rotary core barrel is a type of drilling tool used for penetrating hard rocks.

Trails of volcanoes found in the middle of tectonic plates, such as the Hawaii-Emperor and Louisville Seamount Trails, are believed to form from hotspots–plumes of hot material found deep within the Earth that supply a steady stream of heated rock.

As a tectonic plate drifts over a hotspot, new volcanoes are formed and old ones become extinct. Over time, a trail of volcanoes is formed. The Louisville Seamount Trail is some 4,300 kilometers (about 2,600 miles) long.

“Submarine volcanic trails like the Louisville Seamount Trail are unique because they record the direction and speed at which tectonic plates move,” says Koppers.

Scientists use these volcanoes to study the motion of tectonic plates, comparing the ages of the volcanoes against their location over time to calculate the rate at which a plate moved over a hotspot.

These calculations assume the hotspot stays in the same place.

“The challenge,” says Koppers, “is that no one knows if hotspots are truly stationary or if they somehow wander over time. If they wander, then our calculations of plate direction and speed need to be re-evaluated.”

“More importantly,” he says, “the results of this expedition will give us a more accurate picture of the dynamic nature of the interior of the Earth on a planetary scale.”

Recent studies in Hawaii have shown that the Hawaii hotspot may have moved as much as 15 degrees latitude (about 1,600 kilometers or 1,000 miles) over a period of 30 million years.

“We want to know if the Louisville hotspot moved at the same time and in the same direction as the Hawaiian hotspot. Our models suggest that it’s the opposite, but we won’t really know until we analyze the samples from this expedition,” says Yamazaki.

In addition to the volcanic rock, the scientists also recovered sedimentary rocks that preserve shells and an ancient algal reef, typical of living conditions in a very shallow marine environment.

These ancient materials show that the Louisville seamounts were once an archipelago of volcanic islands.

“We were really surprised to find only a thin layer of sediments on the tops of the seamounts, and only very few indications for the eruption of lava flows above sea level,” says Koppers.

The IODP Louisville Seamount Trail Expedition wasn’t solely focused on geology.

More than 60 samples from five seamounts were obtained for microbiology research.

Exploration of microbial communities under the seafloor, known as the “subseafloor biosphere,” is a rapidly developing field of research.

Using the Louisville samples, microbiologists will study both living microbial residents and those that were abundant over a large area, but now occupy only a few small areas.

They will examine population differences in microbes in the volcanic rock and overlying sediments, and in different kinds of lava flows.

They will also look for population patterns at various depths in the seafloor and compare them with seamounts of varying ages.

Samples from the Louisville Seamount Trail expedition will be analyzed to determine their age, composition and magnetic properties.

The information will be pieced together like a puzzle to create a story of the eruption history of the Louisville volcanoes.

It will then be compared to that of the Hawaiian volcanoes to determine whether hotspots are on the move.

The IODP is an international research program dedicated to advancing scientific understanding of the Earth through drilling, coring and monitoring the subseafloor.

Seamounts reach a pinnacle in upcoming issue of Oceanography

<IMG SRC="/Images/979091882.jpg" WIDTH="350" HEIGHT="133" BORDER="0" ALT="This part of the back cover of the March 2010 issue of the journal Oceanograhy depicts seven seamounts formed by the Louisville hotspot in the South Pacific that were surveyed during the AMAT02 Expedition in 2006 (Peter Lonsdale, Scripps Institution of Oceanography, chief scientist) using R/V Roger Revelle. As part of the Integrated Ocean Drilling Program (IODP), this site survey provided key data to prepare for IODP Expedition 330 (December 2010) that aims to drill four seamounts in the Louisville seamount trail. Using paleomagnetic and geochronological data from the drilled basalts, this project attempts to answer the question of whether the deep Hawaiian and Louisville mantle plumes, the two longest-lived primary hotspot systems in the Pacific, have moved in concert or independently. – The Oceanography Society”>
This part of the back cover of the March 2010 issue of the journal Oceanograhy depicts seven seamounts formed by the Louisville hotspot in the South Pacific that were surveyed during the AMAT02 Expedition in 2006 (Peter Lonsdale, Scripps Institution of Oceanography, chief scientist) using R/V Roger Revelle. As part of the Integrated Ocean Drilling Program (IODP), this site survey provided key data to prepare for IODP Expedition 330 (December 2010) that aims to drill four seamounts in the Louisville seamount trail. Using paleomagnetic and geochronological data from the drilled basalts, this project attempts to answer the question of whether the deep Hawaiian and Louisville mantle plumes, the two longest-lived primary hotspot systems in the Pacific, have moved in concert or independently. – The Oceanography Society

Lying beneath the ocean is spectacular terrain ranging from endless chains of mountains and isolated peaks to fiery volcanoes and black smokers exploding with magma and other minerals from below Earth’s surface. This mountainous landscape, some of which surpasses Mt. Everest heights and the marine life it supports, is the spotlight of a special edition of the research journal Oceanography.

These massive underwater mountains, or seamounts, are scattered across every ocean and collectively comprise an area the size of Europe. These deep and dark environments often host a world teeming with bizarre life forms found nowhere else on Earth. More than 99 percent of all seamounts remain unexplored by scientists, yet their inhabitants, such as the long-lived deepwater fish orange roughy, show signs of habitat destruction and over exploitation from intense international fishing efforts.

Scientists from Scripps Institution of Oceanography at UC San Diego and colleagues from the National Oceanic Atmospheric Administration, Oregon State University, University of British Columbia and Woods Hole Oceanographic Institution were among those who contributed their expertise in seamount chemistry, physics, geology, hydrology, oceanography, biology and fisheries conservation to this special interdisciplinary effort to delve into the extremely broad research supported by seamounts and to communicate the science and threats facing them to the public.

“One of the key goals of this special issue was to bring together the extremely diverse seamount research community that ranges from fisheries science and conservation all the way to mantle geochemistry,” said Hubert Staudigel a research geologist at Cecil H. and Ida M. Green Institute of Geophysics and Planetary Physics at Scripps and the lead guest editor of the special issue. “In my eyes, this volume of Oceanography goes beyond that by presenting amazing new research in a way that the public can understand and get excited about.”

“This issue of Oceanography offers a broad perspective on seamount research of all major disciplines to raise awareness of the diversity of seamount research and to promote collaboration among seamount scientists,” wrote the editors of the issue, which represents the most comprehensive volume of peer-reviewed research on the subject to date.

“I was pleased to see how many of the contributions in this special issue deal with very practical and societally important issues of seamounts,” said U.S. Geological Survey Director Marcia McNutt.