Groundbreaking Research Changing Geological Map Of Canada

Researchers exploring a remote terrain in Arctic Canada have made discoveries that may rock the world of Canadian geology.

Geologists from the University of Alberta have found that portions of Canada collided a minimum of 500 million years earlier than previously thought. Their research, published in the American journal Geology, is offering new insight into how the different continental fragments of North America assembled billions of years ago.

Lead researcher Michael Schultz, a graduate student at the U of A, took advantage of a rare opportunity to explore the Queen Maud block of Arctic Canada, a large bedrock terrain that is said to occupy a keystone tectonic position in northern Canada.

Because of its remote location, the Queen Maud block has remained understudied – until now. “In terms of trying to figure out how Canada formed, this block held a lot of secrets,” said Schultz.

The U of A team reached the rugged Northern Canadian location in helicopters and discovered – through field work and lab analysis – that the sedimentary basins within the terrain, and the age and timing of high-temperature metamorphism of the rocks found there, challenged previous models.

“Every time we did an analysis, it gave us a new piece of information that was nothing we were expecting, based on what was known in the geological community,” said Schultz.

Schultz credits cutting-edge technology only recently developed in the department of Earth and Atmospheric Sciences at the U of A with the ability to acquire large amounts of data from rocks of the Queen Maud block in record time. The technique, known as in-situ laser ablation, substantially reduces the preparation time for geochronology, the process of dating rocks and minerals.

As the Canadian Arctic starts to gain attention nationally and globally, Schultz believes the time is right to push for more geological exploration in the region.

“All this newly discovered geological information means that large portions of Northern Canada are still very poorly understood, and in fact may contain rocks that nobody knows about. This has many implications, both academically and for mineral resources,” said Schultz. “Given the remote nature of these areas, investigation has to be initiated and funded by federal, provincial or territorial governments, in cooperation with universities for facilities and additional expertise.”

Geologists Compile Longest Ever Record of Atlantic Hurricane Strikes

Graduate student Jonathan Woodruff of the WHOI Geology and Geophysics Department works to sink a coring tube into the sediments beneath Laguna Playa Grande in Vieques, Puerto Rico. - Photo Credit: Jeff Donnelly, Woods Hole Oceanographic Institution
Graduate student Jonathan Woodruff of the WHOI Geology and Geophysics Department works to sink a coring tube into the sediments beneath Laguna Playa Grande in Vieques, Puerto Rico. – Photo Credit: Jeff Donnelly, Woods Hole Oceanographic Institution

The frequency of intense hurricanes in the Atlantic Ocean appears to be closely connected to long-term trends in the El Niño/Southern Oscillation (ENSO) and the West African monsoon, according to new research from the Woods Hole Oceanographic Institution (WHOI). Geologists Jeff Donnelly and Jonathan Woodruff made that discovery while assembling the longest-ever record of hurricane strikes in the Atlantic basin.

Donnelly and Woodruff began reconstructing the history of land-falling hurricanes in the Caribbean in 2003 by gathering sediment-core samples from Laguna Playa Grande on Vieques (Puerto Rico), an island extremely vulnerable to hurricane strikes. They examined the cores for evidence of storm surges—distinctive layers of coarse-grained sands and bits of shell interspersed between the organic-rich silt usually found in lagoon sediments—and pieced together a 5,000-year chronology of land-falling hurricanes in the region.

In examining the record, they found large and dramatic fluctuations in hurricane activity, with long stretches of frequent strikes punctuated by lulls that lasted many centuries. The team then compared their new hurricane record with existing paleoclimate data on El Niño, the West African monsoon, and other global and regional climate influences. They found the number of intense hurricanes (category 3, 4, and 5 on the Saffir-Simpson scale) typically increased when El Niño was relatively weak and the West African monsoon was strong.

“The processes that govern the formation, intensity, and track of Atlantic hurricanes are still poorly understood,” said Donnelly, an associate scientist in the WHOI Department of Geology and Geophysics. “Based on this work, we now think that there may be some sort of basin-wide ‘on-off switch’ for intense hurricanes.”

Donnelly and Woodruff published their latest results in the May 24 issue of the journal Nature.

Donnelly and his colleagues have pioneered efforts to extend the chronology of hurricane strikes beyond what can be found in historical texts and modern meteorological records and previously applied their methods to the New England and the Mid-Atlantic coasts of the United States.

Their research area, Laguna Playa Grande, is protected and separated from the ocean during all but the most severe tropical storms. However, when an intense hurricane strikes the region, storm surges carry sand from the ocean beach over the dunes and into Laguna Playa Grande. Such “over-topping” events leave markers in the geological record that can be examined by researchers in sediment core samples.

The geological record from Vieques showed that there were periods of more frequent intense hurricanes from 5,000 to 3,600 years ago, from 2,500 to 1,000 years ago, and from 1700 AD to the present. By contrast, the island was hit less often from 3,600 to 2,500 years ago and from 1,000 to 300 years ago.

To ensure that what they were seeing was not just a change in the direction of hurricanes away from Vieques—that is, different storm tracks across the Atlantic and Caribbean—the scientists compared their new records with previous studies from New York and the Gulf Coast. They saw that the Vieques record matched the frequency of land-falling hurricanes in New York and Louisiana, indicating that some Atlantic-wide changes took place.

Donnelly and Woodruff, a doctoral student in the MIT/WHOI Joint Graduate Program, then decided to test some other hypotheses about what controls the strength and frequency of hurricanes. They found that periods of frequent El Niño in the past corresponded with times of less hurricane intensity. Other researchers have established that, within individual years, El Niño can stunt hurricane activity by causing strong winds at high altitudes that shear the tops off hurricanes or tip them over as they form. When El Niño was less active in the past, Donnelly and Woodruff found, hurricane cycles picked up.

The researchers also examined precipitation records from Lake Ossa, Cameroon, and discovered that when there were increased monsoon rains, there were more frequent intense hurricanes on the other side of the Atlantic. Researchers have theorized that frequent and stronger storms over western Africa lead to easterly atmospheric waves moving into the Atlantic to provide the “seedlings” for hurricane development.

Much media attention has been focused recently on the importance of warmer ocean waters as the dominant factor controlling the frequency and intensity of hurricanes. And indeed, warmer sea surface temperatures provide more fuel for the formation of tropical cyclones. But the work by Donnelly and Woodruff suggests that El Niño and the West African monsoon appear to be critical factors for determining long-term cycles of hurricane intensity in the Atlantic.

The research by Donnelly and Woodruff was funded by the National Science Foundation, the Risk Prediction Initiative, the National Geographic Society, the WHOI Coastal Ocean Institute, and the Andrew W. Mellon Foundation.

The Woods Hole Oceanographic Institution is a private, independent organization in Falmouth, Mass., dedicated to marine research, engineering, and higher education. Established in 1930 on a recommendation from the National Academy of Sciences, its primary mission is to understand the oceans and their interaction with the Earth as a whole, and to communicate a basic understanding of the ocean’s role in the changing global environment.

Glaciologist Looks To Ice For Clues About Global Warming

Glaciologists extract ice cores, analyze them and determine changes in climate over time.
Glaciologists extract ice cores, analyze them and determine changes in climate over time.

Once or twice a year Keith Mountain, chair of the Department of Geography and Geosciences at the University of Louisville, and colleagues from the Byrd Polar Research Center at Ohio State University spend months hunting for a disappearing treasure: ice.

They travel to a glacier in the mountains of Bolivia, Peru, China, Antarctica or Tanzania. The conditions can be brutal at elevations as high as 20,000 feet, but what they find might help save the planet.

Glacier ice contains thousands of years of the Earth’s climate history. It also provides clues as to how and why global warming is happening today, Mountain said.

The researchers use a portable drilling system to extract from the glaciers cylindrical ice cores about 13 centimeters in diameter and hundreds of meters long. They cut each core into 1-meter segments, then mark and pack it for later analyses.

Like the rings of trees, these ice cores are time capsules which can span tens of thousands of years.

Through mathematical models and other methods, including preliminary test drillings, the team can determine the amount of ice compression and come up with reliable ways to interpret these ice cores, he explained.

“We can reconstruct atmospheric temperatures and ascertain precipitation rates and how much dust there was in the atmosphere,” Mountain said. “We can find out the chemical composition of the atmosphere. You can pick up things like various nitrates-sea salt, for example-and figure out wind directions and the sources of moisture and how those may have changed over time.”

The team has determined from interpreting the ice records over time that, “yes, climate change is global and real,” he said.

Rising temperatures worldwide and local decreases in precipitation are contributing to the decline of the glaciers — which makes their work a race against time.

“When I started out in this field in the late ’70s I never would have thought that the photographs we took of this big ice sheet in southern Peru would become archival records of something lost,” Mountain said. “We photograph the changes there every year now, and the changes are occurring quickly. It’s retreating on the order of 50 meters a year.”

Ice is retreating not only in Peru, but worldwide. The famed white cap of Mt. Kilimanjaro in Tanzania soon will be no more. At its current rate of melting, he said, it will disappear by about 2015.

Glaciologists are just one scientific sector contributing to the mass of evidence on the reality of global climate change, Mountain said, noting that 95 percent of the scientific community believes that global climate change is happening and that humans are a significant causal factor.

Yet somehow, he said, a 95 to 5 percent ratio becomes a yes-no, either-or vote: “Some are trying to turn this into a debate, but there is no debate.”

In his native Australia where years of drought have led to bush fires and dying cattle, global warming is a real issue, Mountain said. That’s also true in other parts of the world.

“For the people in Peru, as the glaciers melt they are losing their irrigation water for farming. In Tibet, as the glaciers recede streams are evaporating and leaving big salt deposits that make the remaining water undrinkable,” he said.

The jury is no longer out on global warming, Mountain said.

“At some point, the jury has to come back and make a decision. What kind of policies are we going to develop to deal with this?”

Fragmented Structure of Seafloor Faults May Dampen Effects of Earthquakes

This bathymetric map of the seafloor shows the Siqueiros transform fault in the eastern Pacific Ocean, illustrating the fragmented structure of the fault line. (Jian Lin, Jack Cook, and Patricia Gregg, Woods Hole Oceanographic Institution)
This bathymetric map of the seafloor shows the Siqueiros transform fault in the eastern Pacific Ocean, illustrating the fragmented structure of the fault line. (Jian Lin, Jack Cook, and Patricia Gregg, Woods Hole Oceanographic Institution)

Many earthquakes in the deep ocean are much smaller in magnitude than expected. Geophysicists from the Woods Hole Oceanographic Institution (WHOI) have found new evidence that the fragmented structure of seafloor faults, along with previously unrecognized volcanic activity, may be dampening the effects of these quakes.

Examining data from 19 locations in the Atlantic, Pacific, and Indian oceans, researchers led by graduate student Patricia Gregg have found that “transform” faults are not developing or behaving as theories of plate tectonics say they should. Rather than stretching as long, continuous fault lines across the seafloor, the faults are often segmented and show signs of recent or ongoing volcanism. Both phenomena appear to prevent earthquakes from spreading across the seafloor, thus reducing their magnitude and impact.

Gregg, a doctoral candidate in the MIT/WHOI Joint Program in Oceanography and Oceanographic Engineering, conducted the study with seismologist Jian Lin and geophysicists Mark Behn and Laurent Montesi, all from the WHOI Department of Geology and Geophysics. Their findings were published in the July 12 issue of the journal Nature.

Oceanic transform faults cut across the mid-ocean ridge system, the 40,000-mile-long mountainous seam in Earth’s crust that marks the edges of the planet’s tectonic plates. Along some plate boundaries, such as the Mid-Atlantic Ridge, new crust is formed. In other regions, such as the western Pacific, old crust is driven back down into the Earth.

If you imagine the mid-ocean ridge as the seams on a baseball, then transform faults are the red stitches, lying mostly perpendicular to the ridge. These faults help accommodate the motion and geometry of Earth’s tectonic plates, cracking at the edges as the different pieces of rocky crust slip past each other.

The largest earthquakes at mid-ocean ridges tend to occur at transform faults. Yet while studying seafloor faults along the fast-spreading East Pacific Rise, Gregg and colleagues found that earthquakes were not as large in magnitude or resonating as much energy as they ought to, given the length of these faults.

The researchers decided to examine gravity data collected over three decades by ships and satellites, along with bathymetry maps of the seafloor. Conventional wisdom has held that transform faults should contain rocks that are colder, denser, and heavier than the new crust being formed at the mid-ocean ridge. Such colder and more brittle rocks should have a “positive gravity anomaly”; that is, the faults should exert a stronger gravitational pull than surrounding seafloor region. By contrast, the mid-ocean ridge should have a lesser gravity field, because the crust (which is lighter than underlying mantle rocks) is thicker along the ridge and the newer, molten rock is less dense.

But when Gregg examined gravity measurements from the East Pacific Rise and other fast-slipping transform faults, she was surprised to find that the faults were not exerting extra gravitational pull. On the contrary, many seemed to have lighter rock within and beneath the faults.

“A lot of the classic characteristics of transform faults didn’t make sense in light of what we were seeing,” said Gregg. “What we found was the complete opposite of the predictions.”

The researchers believe that many of the transform fault lines on the ocean floor are not as continuous as they first appear from low-resolution maps. Instead these fault lines are fragmented into smaller pieces. Such fragmented structure makes the length of any given earthquake rupture on the seafloor shorter—giving the earthquake less distance to travel along the surface.

It is also possible that magma, or molten rock, from inside the earth is rising up beneath the faults. Earthquakes stem from the buildup of friction between brittle rock in Earth’s plates and faults. Hot rock is more ductile and malleable, dampening the strains and jolts as the crust rubs together and serving as a sort of geological lubricant.

“What we learn about these faults and earthquakes underwater could help us understand land-based faults such as the San Andreas in California or the Great Rift in eastern Africa,” said Lin, a WHOI senior scientist and expert on seafloor earthquakes. “In areas where you have strike-slip faults, you might have smaller earthquakes when there is more magma and warmer, softer rock under the fault area.”

The findings by Gregg, Lin, and colleagues may also have implications for understanding the theory of plate tectonics, which says that new crust is only formed at mid-ocean ridges. By traditional definitions, no crust can be created or destroyed at a transform fault. The new study raises the possibility that new crust may be forming along these faults and fractures at fast-spreading ridges such as the East Pacific Rise.

“Our understanding of how transform faults behave must be reevaluated,” said Gregg. “There is a discrepancy that needs to be addressed.”

Funding for this research was provided by the NSF Graduate Research Fellowship Program, the WHOI Deep Ocean Exploration Institute, the NSF Ocean Sciences Directorate, and the Andrew W. Mellon Foundation Awards for Innovative Research.

Explorers to Use New Robotic Vehicles to Hunt for Life and Hydrothermal Vents on Arctic Seafloor

The topographic and bathymetric map of the Arctic Ocean shows the Gakkel Ridge, Nansen Basin, Lomononsov Ridge, and the proposed cruise track of the Oden. (Data from the International Bathymetric Chart of the Arctic Ocean and the National Geophysical Data Center; with graphic enhancements by Jack Cook, Woods Hole Oceanographic Institution)
The topographic and bathymetric map of the Arctic Ocean shows the Gakkel Ridge, Nansen Basin, Lomononsov Ridge, and the proposed cruise track of the Oden. (Data from the International Bathymetric Chart of the Arctic Ocean and the National Geophysical Data Center; with graphic enhancements by Jack Cook, Woods Hole Oceanographic Institution)

Scientists and engineers from the Woods Hole Oceanographic Institution (WHOI) have just completed a successful test of new robotic vehicles designed for use beneath the ice of the Arctic Ocean. The multidisciplinary research team will now use those vehicles to conduct the first search for life on the seafloor of the world’s most isolated ocean.

WHOI researchers have built two new autonomous underwater vehicles (AUVs) and a new tethered, remote controlled sampling system specifically for the difficult challenges of operations in the Arctic ice. They hope to discover exotic seafloor life and submarine hot springs in a region of the ocean that has been mostly cut off from other ecosystems for at least 26 million years.

The 30-member research team will depart on July 1 from Longyearbyen, Svalbard, for a rare expedition to study the Gakkel Ridge, the extension of the mid-ocean ridge system which separates the North American tectonic plate from the Eurasian plate beneath the Arctic Ocean.

The 40-day cruise on the Oden—a 108-meter long (354-foot) icebreaker operated by the Swedish Maritime Administration—will take researchers close to the geographic North Pole.

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.

WHOI geophysicist Robert Reves-Sohn will serve as chief scientist. Fellow principal investigators include: Tim Shank, a hydrothermal vent biologist from WHOI; Hanumant Singh, a WHOI engineer and vehicle developer; marine chemist Henrietta Edmonds of the University of Texas at Austin, who sailed on the last research expedition to the Gakkel Ridge in 2001; Susan Humphris, a WHOI geochemist who has surveyed dozens of hydrothermal vent sites around the world; and Peter Winsor, a WHOI oceanographer who studies Arctic Ocean circulation and its implications for climate.

Major funding for the expedition and for vehicle development was provided by the National Science Foundation (NSF) and the National Aeronautics and Space Administration (NASA).

“This is an exciting opportunity to explore and study a portion of Earth’s surface that has been largely inaccessible to science,” said Reves-Sohn. “Any biological habitats at hydrothermal vent fields along the Gakkel Ridge have likely evolved in isolation for tens of millions of years. We may have the opportunity to lay eyes on completely new life forms that have been living in the abyss beneath the Arctic ice pack.”

Most of the instrumentation that researchers would normally use to study deep sea environments and organisms—such as the human occupied submersible Alvin or tethered vehicles—cannot be safely operated in the Arctic ice, which can easily crush most small vehicles. So researchers asked Singh and colleagues to design and develop three new vehicles from scratch.

During the July expedition, researchers will use the Puma AUV, or “plume mapper,” to sniff out the chemical and temperature signals of hot, mineral-rich fluids venting out of the ocean floor. Once Puma finds the source of venting, Singh and colleagues will send down the Jaguar AUV, which will use cameras and bottom-mapping sonar systems to image the seafloor. Finally, the CAMPER towed vehicle will be lowered to the seafloor to scoop or vacuum up rocks, sediments, and living creatures.

During a 10-day engineering trial in May and June 2007, all three vehicles were lowered through the Arctic ice and driven underwater, while engineers simultaneously tested acoustic communications techniques. The researchers were able to recover their vehicles from beneath the ice, which can be risky in the midst of moving floes that can quickly close the leads around an icebreaker.

“Anyone can deploy an AUV in the Arctic; the trick is getting it back,” said Singh, who will send his vehicles to the seafloor for 10 to 24 hours at a time during the Gakkel expedition. “In order to have a good day with autonomous vehicles, the number of recoveries must equal the number of launches.”

Researchers will use two new autonomous underwater vehicles (AUVs)--Puma and Jaguar--in tandem to locate hydrothermal vent sites on the seafloor of the Arctic Ocean. (Illustration by E. Paul Oberlander, Woods Hole Oceanographic Institution)
Researchers will use two new autonomous underwater vehicles (AUVs)–Puma and Jaguar–in tandem to locate hydrothermal vent sites on the seafloor of the Arctic Ocean. (Illustration by E. Paul Oberlander, Woods Hole Oceanographic Institution)

The Gakkel Ridge extends roughly 1,800 kilometers (1,100 miles) from north of Greenland toward Siberia. It is both the deepest ocean ridge—ranging from 3 to 5 kilometers (1.8 to 3 miles) beneath the ice cap—and the slowest spreading tectonic plate boundary anywhere on Earth. The ridge moves roughly one centimeter (1/3 inch) per year, about 20 times slower than most other ridges.

At most mid-ocean ridges, Earth’s crust spreads apart, allowing hot magma from the mantle to come up and form new ocean crust. The enormous heat sparks chemical reactions between crustal rocks and the seawater that seeps down into them.

These chemical reactions produce hot, mineral-rich fluids that spew like geysers from seafloor vents, as well as massive deposits of minerals, such as copper and zinc. These hydrothermal fluids also contain chemicals that sustain rich communities of unusual life forms, which thrive via chemosynthesis, rather than photosynthesis.

Many geologists believed the Gakkel Ridge region would be too geologically cold to produce hydrothermal vents. And yet during a 2001 expedition, researchers found signs of such venting in the Arctic. Where there are vents, there may be unusual seafloor life forms.

“A few years ago, mid-ocean ridge and hydrothermal vent biologists came together and asked: ‘Where are the key places in the world to go to make big leaps in understanding biodiversity?’ The Gakkel Ridge was one of the top places,” said Shank, who plans to study the genetics of animals found during the expedition.

“The region has been mostly separated from the Atlantic and Pacific oceans for millions of years, so whatever lives there has since been evolving in relative isolation—much the way animals in Australia did,” Shank added. “We know that deep-sea Arctic fauna found away from vents are more than 70 percent different from all others around the world. So at hydrothermal vents we are likely to find completely new suites of species with never-before seen adaptations.”

Some scientists—including program managers and scientists from the NASA Astrobiology Program—have been keenly interested in the possibility that Gakkel Ridge may harbor life forms and environmental conditions consistent with primordial Earth or other watery planets.

“The origin of life discussion comes up because the rocks that are exposed on this very slow spreading ridge are not volcanic, but instead come directly from Earth’s mantle,” said Humphris. “The chemistry is very much like the volcanism that occurred on the primordial Earth. If you are thinking about origins of life, you’d like to have an area that is the closest analog to what was happening on the early Earth.”

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 Gakkel Ridge expedition will be covered live on the web, allowing students, educators, and the general public to follow along with daily dispatches from the Arctic Ocean. The Dive and Discover web site brings students and teachers along on research field trips to read about science in action, while the Polar Discovery project uses photos and live phone calls from the Oden to allow museum visitors and the public to see the Arctic through the eyes of the explorers.

Support for the Gakkel Ridge expedition and for underwater vehicle development has been provided by the National Science Foundation’s Office of Polar Programs and Division of Ocean Sciences; the NASA Astrobiology Program; the WHOI Deep Ocean Exploration Institute; and the Gordon Center for Subsurface Sensing and Imaging Systems, an NSF Engineering Research Center.

Catastrophic Flooding Changes The Course Of British History

Three dimensional perspective view showing details of the Channel valley (pink is shallow; blue is deep).  The erosional scours carved into floor of the valley are clearly evicent. - Image Credit: Imperial College London
Three dimensional perspective view showing details of the Channel valley (pink is shallow; blue is deep). The erosional scours carved into floor of the valley are clearly evicent. – Image Credit: Imperial College London

A catastrophic megaflood separated Britain from France hundreds of thousands of years ago, changing the course of British history, according to research published in the journal Nature today.

The study, led by Dr Sanjeev Gupta and Dr Jenny Collier from Imperial College London, has revealed spectacular images of a huge valley tens of kilometres wide and up to 50 metres deep carved into chalk bedrock on the floor of the English Channel.

Using high-resolution sonar waves the team captured images of a perfectly preserved submerged world in the channel basin. The maps highlight deep scour marks and landforms which were created by torrents of water rushing over the exposed channel basin.

To the north of the channel basin was a lake which formed in the area now known as the southern North Sea. It was fed by the Rhine and Thames, impounded to the north by glaciers and dammed to the south by the Weald-Artois chalk ridge which spanned the Dover Straits. It is believed that a rise in the lake level eventually led to a breach in the Weald-Artois ridge, carving a massive valley along the English Channel, which was exposed during a glacial period.

At its peak, it is believed that the megaflood could have lasted several months, discharging an estimated one million cubic metres of water per second. This flow was one of the largest recorded megafloods in history and could have occurred 450,000 to 200,000 years ago.

The researchers believe the breach of the ridge, and subsequent flooding, reorganised the river drainages in north-west Europe by re-routing the combined Rhine-Thames River through the English Channel to form the Channel River.

The breach and permanent separation of the UK also affected patterns of early human occupation in Britain. Researchers speculate that the flooding induced changes in topography creating barriers to migration which led to a complete absence of humans in Britain 100,000 years ago.

Dr Sanjeev Gupta, from the Department of Earth Science & Engineering at Imperial said: “This prehistoric event rewrites the history of how the UK became an island and may explain why early human occupation of Britain came to an abrupt halt for almost 120 thousand years.”

Project collaborator, Dr Jenny Collier, also from the Department of Earth Science & Engineering, speculates on the potential for future discoveries on the continental shelves.

“The preservation of the landscape on the floor of the English Channel, which is now 30-50 m below sea-level, is far better than anyone would have expected. It opens the way to discover a host of processes that shaped the development of north-west Europe during the past million years or so,” said Dr Collier.

The Imperial research team collaborated with the UK Hydrographic Office and the Maritime Coastguard Agency (MCA) on the project. Data collected by the MCA and archived by the Hydrographic Office was originally sourced for civil safety at sea.

Glaciers and Ice Caps to Dominate Sea Level Rise Through 21st Century

When a glacier with its “toe in the water” thins, a larger fraction of its weight is supported by water and it slides faster and calves more ice into the ocean at the glacier terminus. – Photo Credit: Nicolle Rager Fuller, National Science Foundation

Ice loss from glaciers and ice caps is expected to cause more global sea rise during this century than the massive Greenland and Antarctic ice sheets, according to a new University of Colorado at Boulder study.

The researcher, primarily funded by the National Science Foundation (NSF) and NASA, concluded that glaciers and ice caps are currently contributing about 60 percent of the world’s ice to the oceans and the rate has been markedly accelerating in the past decade, said Emeritus Professor Mark Meier of CU-Boulder’s Institute of Arctic and Alpine Research, lead study author. The contribution is presently about 100 cubic miles of ice annually — a volume nearly equal to the water in Lake Erie — and is rising by about three cubic miles per year.

In contrast, the CU-Boulder team estimated Greenland is now contributing about 28 percent of the total global sea rise from ice loss and Antarctica is contributing about 12 percent. Greenland is not expected to catch up to glaciers and ice caps in terms of sea level rise contributions until the end of the century, according to the study.

A paper on the subject appears in the July 19 issue of Science Express, the online edition of Science magazine. Co-authors include CU-Boulder INSTAAR researchers Mark Dyurgerov, Ursula Rick, Shad O’Neel, Tad Pfeffer, Robert Anderson and Suzanne Anderson, as well as Russian Academy of Sciences scientist Andrey Glazovsky.

“One reason for this study is the widely held view that the Greenland and Antarctic ice sheets will be the principal causes of sea-level rise,” said Meier, former INSTAAR director and professor in geological sciences. “But we show that it is the glaciers and ice caps, not the two large ice sheets, that will be the big players in sea rise for at least the next few generations.”

The accelerating contribution of glaciers and ice caps is due in part to rapid changes in the flow of tidewater glaciers that discharge icebergs directly into the ocean, said the study. Many tidewater glaciers are undergoing rapid thinning, stretching and retreat, which causes them to speed up and deliver increased amounts of ice into the world’s oceans, said CU-Boulder geology Professor Robert Anderson, study co-author.

Water controls how rapidly glaciers slide along their beds, said Anderson. When a glacier with its “toe in the water” thins, a larger fraction of its weight is supported by water and it slides faster and calves more ice into the ocean at the glacier terminus.

“While this is a dynamic, complex process and does not seem to be a direct result of climate warming, it is likely that climate acts as a trigger to set off this dramatic response,” said Anderson, also an INSTAAR researcher.

The human impact of this accelerated sea level rise could be dramatic. The team estimated accelerating melt of glaciers and ice caps could add from 4 inches to 9.5 inches of additional sea level rise globally by 2100. This does not include the expansion of warming ocean water, which could potentially double those numbers. A one-foot sea-level rise typically causes a shoreline retreat of 100 feet or more. The World Bank estimates that about 100 million people now live within about three feet of sea level.

“At the very least, our projections indicate that future sea-level rise may be larger than anticipated, and that the component due to glaciers and ice caps will continue to be substantial,” wrote the researchers in Science Express.

The team summarized satellite, aircraft and ground-based data from glaciers, ice caps, the Greenland ice sheet, the West Antarctic ice sheet and the East Antarctic ice sheet to calculate present and future rates of ice loss for the study.

Meier estimated there are several hundred thousand small glaciers and small, pancake-shaped ice caps in polar and temperate regions. They range from modest, high mountain glaciers to huge glaciers like the Bering Glacier in Alaska, which measures about 5,000 square miles in area and is nearly one-half mile thick in places.

The researchers used a mathematical “scaling” process to estimate more remote glacier volumes, thicknesses and trends by factoring in data like altitude, climate and geography. They used data gathered from around the world, including cold regions in Russia, Europe, China, Central Asia, Canada and South America.

While warming temperatures will likely cause many small high mountain glaciers in North America Europe to disappear by the end of the century, large ice fields and ice caps will continue to produce large amounts of melt water, Meier said. The scientists also believe many “cold” polar glaciers and ice caps will soon warm up enough to begin melting and contributing to sea rise.

The retreat of the Greenland and Antarctic ice sheets also is giving birth to new, smaller glaciers that are prime candidates for study by scientists. “It is incorrect to assume that the small glaciers will simply go away next century — they will continue to play a key role in the sea level story,” said Anderson.

Anderson also said that although the volume of ice locked up in Greenland is equal to roughly 23 feet in sea rise, only a small fraction is likely to be “pulled out” during the next century, most of it through outlet glaciers.

Many smaller “benchmark” glaciers around the world that have been under study for decades are expected to disappear by the end of the century, said Anderson. “We need to start gathering benchmark information on some of the larger glaciers that are unlikely to disappear, so that we can have a long-term record of their behavior.”

Anderson said outlet glaciers in Greenland behave much like tidewater glaciers in Canada and Alaska, making them very relevant for long-term study. “Since the world is becoming increasingly aware that sea-level rise is a very real problem, we need to acknowledge the role of all of the ice masses and understand the physical mechanisms by which they deliver water to the sea.”

Geologists Witness Unique Volcanic Mudflow in Action in New Zealand

This image of the lahar channel shows the area right after the collapse of New Zealand's Crater Lake's walls. - Photo Credit: University of Hawaii
This image of the lahar channel shows the area right after the collapse of New Zealand’s Crater Lake’s walls. – Photo Credit: University of Hawaii

Volcanologist Sarah Fagents from the School of Ocean and Earth Science and Technology (SOEST) at the University of Hawaii at Manoa had an amazing opportunity to study volcanic hazards first hand, when a volcanic mudflow broke through the banks of a volcanic lake at Mount Ruapehu in New Zealand.

Fagents and colleagues were there on a National Science Foundation (NSF)-funded project to study the long-forecast Crater Lake break-out lahar at Mount Ruapehu. A lahar is a type of mudflow composed of water and other sediment that flows down from a volcano, typically along a river valley.

Lahars are caused by the rapid melting of snow and/or glaciers during a volcanic eruption, or as in the case of Mount Ruapehu, the breakout of a volcanic lake.

“Lahars can be extremely hazardous, especially in populated areas, because of their great speed and mass,” said William Leeman, NSF program director for petrology and geochemistry. “They can flow for many tens of miles, causing catastrophic destruction along their path. The 1980 eruptions at Mount St. Helens, for example, resulted in spectacular lahar flows that choked virtually all drainages on the volcano, and impacted major rivers as far away as Portland, Ore.”

Fagents visited stretches of the lahar pathway before the breakout to assess pre-event channel conditions. Although the event was predicted to occur in 2007, the recent decreased filling rate of Crater Lake suggested that the lake bank actually would not be overtopped until 2008.

However, several days of intense rainfall and increased seepage through the bank ultimately caused it to collapse much sooner, on March 18, 2007.

A lahar warning system had been installed at Mount Ruapehu, and was hailed a success after it successfully alerted officials to the onset of the lahar. In total, about 1.3 million cubic meters of water were released from Crater Lake.

“We found a broad area covered in a veneer of mud and boulders,” said Fagents. “It was an unprecedented opportunity to see the immediate aftermath of such an event. It’s particularly motivating for the students who were along to learn first-hand about lahar processes in such a dynamic environment.”

Fagents and colleagues returned to New Zealand a month later to conduct a more detailed analysis of the deposit. “Because the Crater Lake breakout had been long forecast, there was an unprecedented amount of instrumentation installed in the catchment by our New Zealand colleagues to capture the event,” says Fagents.

“The 2007 event is the best studied lahar in the world,” she said.

Prediction of the effects of the events is of critical importance in populated volcanic regions. Many other volcanoes around the world, including Mount Rainier in Washington State, and Galunggung in Indonesia, are also considered particularly dangerous due to the risk of lahars, according to Leeman.

Fagents is developing a computer model to simulate lahar emplacement and to predict the associated hazards. “The intent is to adapt this model to account for different lahar triggering mechanisms, and for different locations, to make it widely applicable,” said Fagents. “The ultimate goal is provide a useful hazards assessment tool for future lahars.”

Geoscientists Investigate Art Rock Movement

A St Andrews researcher is taking part in a major scientific investigation of the ancient Spanish rocks said to inspire the work of surrealist artist Salvador Dali.

Dr Ian Alsop has just returned from fieldwork analysing 500 million year old rocks along the rugged coastline forming the Costa Brava of North East Spain. In a case of art imitating science, the landscape displaying `spectacular and peculiar geometries’ provided the inspiration for some of Salvador Dali’s most famous art works. One of the great 20th century surrealists, Dali – who was born and lived in the area – was said to be inspired by the ‘unrivalled’ rocks at Cap de Creus in his surrealist masterpieces.

Dr Alsop, a senior lecturer at the University’s School of Geography & Geosciences, is collaborating with colleagues from the Universitat Autonoma de Barcelona in a detailed scientific investigation of the rocks and structure of the largely unspoiled area. They hope that the study will reveal new insights into the products and processes responsible for the evolution of the Earth’s crust.

He said, “The rocks were originally deposited about 500 million years ago, but were subsequently compressed and deformed during mountain building or ‘orogeny’ 300 million years ago. The rocks were squeezed into fantastically folded and sheared geometries, and were also injected with molten magma which subsequently cooled into spectacular outcrops.

“It is these strange and sometimes grotesque exposures that are considered to have provided the inspiration for some of the surreal shapes in Dali’s greatest masterpieces such as “The persistence of memory” (known as the ‘melting clocks’ painting), currently on display in the Tate Modern.”

The unrivalled landscape is due to a combination of rock types, waves and wind in the area that provides a unique quality of exposure – resulting in fantastic three-dimensional rock formations.

The rocks now exposed at Cap de Creus provide superb small-scale ‘analogues’ of the behaviour of the Earth’s crust when sedimentary basins and mountain belts are created. The rocks can also tell geoscientists much about the way the Earth behaves during mountain building, when continental masses move towards one another at about the rate fingernails grow.

Dr Alsop explained, “The rocks of Cap de Creus provide an opportunity to collect and analyse an unrivalled data set of folds and fractures. This allows us a perhaps unparalleled glimpse of the products and processes responsible for the evolution of the Earth’s crust.”

The unique geology and weathering patterns observed in Cap de Creus are recognised not just as an inspiration for artists, but also as a special landscape now protected in a national park. The ongoing research by Dr Alsop and colleagues in to the nature of the deformed rocks is funded by grants from the Carnegie Trust and the Spanish Ministry of Science.