Icelandic volcano sits on massive magma hot spot

This image shows the Holuhraun fissure eruption on the flanks of the Bárðarbunga volcano in central Iceland on Oct. 4, 2014, showing the development of a lava lake in the foreground. Vapor clouds over the lava lake are caused by degassing of volatile-rich basaltic magma. -  Morten S. Riishuus, Nordic Volcanological Institute
This image shows the Holuhraun fissure eruption on the flanks of the Bárðarbunga volcano in central Iceland on Oct. 4, 2014, showing the development of a lava lake in the foreground. Vapor clouds over the lava lake are caused by degassing of volatile-rich basaltic magma. – Morten S. Riishuus, Nordic Volcanological Institute

Spectacular eruptions at Bárðarbunga volcano in central Iceland have been spewing lava continuously since Aug. 31. Massive amounts of erupting lava are connected to the destruction of supercontinents and dramatic changes in climate and ecosystems.

New research from UC Davis and Aarhus University in Denmark shows that high mantle temperatures miles beneath the Earth’s surface are essential for generating such large amounts of magma. In fact, the scientists found that the Bárðarbunga volcano lies directly above the hottest portion of the North Atlantic mantle plume.

The study, published online Oct. 5 and appearing in the November issue of Nature Geoscience, comes from Charles Lesher, professor of Earth and Planetary Science at UC Davis and a visiting professor at Aarhus University, and his former PhD student, Eric Brown, now a post-doctoral scholar at Aarhus University.

“From time to time the Earth’s mantle belches out huge quantities of magma on a scale unlike anything witnessed in historic times,” Lesher said. “These events provide unique windows into the internal working of our planet.”

Such fiery events have produced large igneous provinces throughout Earth’s history. They are often attributed to upwelling of hot, deeply sourced mantle material, or “mantle plumes.”

Recent models have dismissed the role of mantle plumes in the formation of large igneous provinces, ascribing their origin instead to chemical anomalies in the shallow mantle.

Based on the volcanic record in and around Iceland over the last 56 million years and numerical modeling, Brown and Lesher show that high mantle temperatures are essential for generating the large magma volumes that gave rise to the North Atlantic large igneous provinces bordering Greenland and northern Europe.

Their findings further substantiate the critical role of mantle plumes in forming large igneous provinces.

“Our work offers new tools to constrain the physical and chemical conditions in the mantle responsible for large igneous provinces,” Brown said. “There’s little doubt that the mantle is composed of different types of chemical compounds, but this is not the dominant factor. Rather, locally high mantle temperatures are the key ingredient.”

The research was supported by grants from the US National Science Foundation and by the Niels Bohr Professorship funded by Danish National Research Foundation.

Read the full study at http://www.nature.com/ngeo/journal/vaop/ncurrent/full/ngeo2264.html.

International team maps nearly 200,000 global glaciers in quest for sea rise answers

CU-Boulder Professor Tad Pfeffer, shown here on Alaska's Columbia Glacier, is part of a team that has mapped nearly 200,000 individual glaciers around the world as part of an effort to track ongoing contributions to global sea rise as the planet heats up. -  University of Colorado
CU-Boulder Professor Tad Pfeffer, shown here on Alaska’s Columbia Glacier, is part of a team that has mapped nearly 200,000 individual glaciers around the world as part of an effort to track ongoing contributions to global sea rise as the planet heats up. – University of Colorado

An international team led by glaciologists from the University of Colorado Boulder and Trent University in Ontario, Canada has completed the first mapping of virtually all of the world’s glaciers — including their locations and sizes — allowing for calculations of their volumes and ongoing contributions to global sea rise as the world warms.

The team mapped and catalogued some 198,000 glaciers around the world as part of the massive Randolph Glacier Inventory, or RGI, to better understand rising seas over the coming decades as anthropogenic greenhouse gases heat the planet. Led by CU-Boulder Professor Tad Pfeffer and Trent University Professor Graham Cogley, the team included 74 scientists from 18 countries, most working on an unpaid, volunteer basis.

The project was undertaken in large part to provide the best information possible for the recently released Fifth Assessment of the Intergovernmental Panel on Climate Change, or IPCC. While the Greenland and Antarctic ice sheets are both losing mass, it is the smaller glaciers that are contributing the most to rising seas now and that will continue to do so into the next century, said Pfeffer, a lead author on the new IPCC sea rise chapter and fellow at CU-Boulder’s Institute of Arctic and Alpine Research.

“I don’t think anyone could make meaningful progress on projecting glacier changes if the Randolph inventory was not available,” said Pfeffer, the first author on the RGI paper published online today in the Journal of Glaciology. Pfeffer said while funding for mountain glacier research has almost completely dried up in the United States in recent years with the exception of grants from NASA, there has been continuing funding by a number of European groups.

Since the world’s glaciers are expected to shrink drastically in the next century as the temperatures rise, the new RGI — named after one of the group’s meeting places in New Hampshire — is critical, said Pfeffer. In the RGI each individual glacier is represented by an accurate, computerized outline, making forecasts of glacier-climate interactions more precise.

“This means that people can now do research that they simply could not do before,” said Cogley, the corresponding author on the new Journal of Glaciology paper. “It’s now possible to conduct much more robust modeling for what might happen to these glaciers in the future.”

As part of the RGI effort, the team mapped intricate glacier complexes in places like Alaska, Patagonia, central Asia and the Himalayas, as well as the peripheral glaciers surrounding the two great ice sheets in Greenland and Antarctica, said Pfeffer. “In order to model these glaciers, we have to know their individual characteristics, not simply an average or aggregate picture. That was one of the most difficult parts of the project.”

The team used satellite images and maps to outline the area and location of each glacier. The researchers can combine that information with a digital elevation model, then use a technique known as “power law scaling” to determine volumes of various collections of glaciers.

In addition to impacting global sea rise, the melting of the world’s glaciers over the next 100 years will severely affect regional water resources for uses like irrigation and hydropower, said Pfeffer. The melting also has implications for natural hazards like “glacier outburst” floods that may occur as the glaciers shrink, he said.

The total extent of glaciers in the RGI is roughly 280,000 square miles or 727,000 square kilometers — an area slightly larger than Texas or about the size of Germany, Denmark and Poland combined. The team estimated that the corresponding total volume of sea rise collectively held by the glaciers is 14 to 18 inches, or 350 to 470 millimeters.

The new estimates are less than some previous estimates, and in total they are less than 1 percent of the amount of water stored in the Greenland and Antarctic ice sheets, which collectively contain slightly more than 200 feet, or 63 meters, of sea rise.

“A lot of people think that the contribution of glaciers to sea rise is insignificant when compared with the big ice sheets,” said Pfeffer, also a professor in CU-Boulder’s civil, environmental and architectural engineering department. “But in the first several decades of the present century it is going to be this glacier reservoir that will be the primary contributor to sea rise. The real concern for city planners and coastal engineers will be in the coming decades, because 2100 is pretty far off to have to make meaningful decisions.”

Part of the RGI was based on the Global Land Ice Measurements from Space Initiative, or GLIMS, which involved more than 60 institutions from around the world and which contributed the baseline dataset for the RGI. Another important research data tool for the RGI was the European-funded program “Ice2Sea,” which brings together scientific and operational expertise from 24 leading institutions across Europe and beyond.

The GLIMS glacier database and website are maintained by CU-Boulder’s National Snow and Ice Data Center, or NSIDC. The GLIMS research team at NSIDC includes principal investigator Richard Armstrong, technical lead Bruce Raup and remote-sensing specialist Siri Jodha Singh Khalsa.

NSIDC is part of the Cooperative Institute for Research in Environmental Sciences, or CIRES, a joint venture between CU-Boulder and the National Oceanic and Atmospheric Administration.

Frozen in time: 3-million-year-old landscape still exists beneath the Greenland ice sheet

This is a camp at the edge of the Greenland ice sheet. -  Paul Bierman, University of Vermont
This is a camp at the edge of the Greenland ice sheet. – Paul Bierman, University of Vermont

Some of the landscape underlying the massive Greenland ice sheet may have been undisturbed for almost 3 million years, ever since the island became completely ice-covered, according to researchers funded by the National Science Foundation (NSF).

Basing their discovery on an analysis of the chemical composition of silts recovered from the bottom of an ice core more than 3,000 meters long, the researchers argue that the find suggests “pre-glacial landscapes can remain preserved for long periods under continental ice sheets.”

In the time since the ice sheet formed “the soil has been preserved and only slowly eroded, implying that an ancient landscape underlies 3,000 meters of ice at Summit, Greenland,” they conclude.

They add that “these new data are most consistent with [the concept of] a continuous cover of Summit? by ice ? with at most brief exposure and minimal surface erosion during the warmest or longest interglacial [periods].”

They also note that fossils found in northern Greenland indicated there was a green and forested landscape prior to the time that the ice sheet began to form. The new discovery indicates that even during the warmest periods since the ice sheet formed, the center of Greenland remained stable, allowing the landscape to be locked away, unmodified, under ice through millions of years of cyclical warming and cooling.

“Rather than scraping and sculpting the landscape, the ice sheet has been frozen to the ground, like a giant freezer that’s preserved an antique landscape”, said Paul R. Bierman, of the Department of Geology and Rubenstein School of the Environment and Natural Resources at the University of Vermont and lead author of the paper.

Bierman’s work was supported by two NSF grants made by its Division of Polar Programs, 1023191 and 0713956. Thomas A. Neumann, also of the University of Vermont, but now at NASA’s Goddard Space Flight Center, a co-author on the paper, also was a co-principal investigator on the latter grant.

Researchers from Idaho State University, the University of California, Santa Barbara, and the Scottish Universities Environmental Research Centre at the University of Glasgow also contributed to the paper.

The research also included contributions from two graduate students, both supported by NSF, one of whom was supported by the NSF Graduate Research Fellowships Program.

The team’s analysis was published on line on April 17 and will appear in Science magazine the following week.

Understanding how Greenland’s ice sheet behaved in the past, and in particular, how much of the ice sheet melted during previous warm periods as well as how it re-grew is important to developing a scientific understanding of how the ice sheet might behave in the future.

As global average temperatures rise, scientists are concerned about how the ice sheets in Greenland and Antarctica will respond. Vast amounts of freshwater are stored in the ice and may be released by melting, which would raise sea levels, perhaps by many meters.

The magnitude and rate of sea level rise are unknown factors in climate models.

The team based its analysis on material taken from the bottom of an ice core retrieved by the NSF-funded Greenland Ice Sheet Project Two (GISP2), which drilled down into the ice sheet near NSF’s Summit Station. An ice core is a cylinder of ice in which individual layers of ice, compacted from snowfall, going back over millennia can be observed and sampled.

Summit is situated at an elevation of 3,216 meters (10,551 feet) above sea level.

In the case of GISP2, the core itself, taken from the center of the present-day Greenland ice sheet, was 3,054 meters (10,000 feet) deep. It provides a history of the balance of gases that made up the atmosphere at time the snow fell as well as movements in the ice sheet stretching back more than 100,000 years. It also contains a mix of silts and sediments at its base where ice and rock come together.

The scientists looked at the proportions of the elements carbon, nitrogen and Beryllium-10, the source of which is cosmic rays, in sediments taken from the bottom 13 meters (42 feet) of the GISP2 ice core.

They also compared levels of the various elements with soil samples taken in Alaska, leading them to the conclusion that the landscape under the ice sheet was indeed an ancient one that predates the advent of the ice sheet. The soil comparisons were supported by two NSF grants: 0806394 and 0806399.

Mercyhurst, Vanderbilt research targets supervolcanoes

The National Science Foundation has awarded Mercyhurst and Vanderbilt universities a $354,000 grant to engage students in researching one of Earth’s rarest yet deadliest acts — the eruption of a supervolcano.

The Research Experience for Undergraduates (REU) three-year project will take 10-12 students per year into northwest Arizona to study an extinct supervolcano. Students will select their own research pursuit, follow up with lab work at either Mercyhurst or Vanderbilt and, ultimately, present their findings at a national conference.

“The emphasis of this project is to engage students in scientific research, which is consistent with Mercyhurst’s commitment to hands-on learning,” said principal investigator Nick Lang, Ph.D., an assistant professor of geology at Mercyhurst. His project colleague at Vanderbilt is Lily Claiborne, Ph.D.

Lang said the research initiative targets students from diverse backgrounds. “We are looking for talented students, with a particular emphasis on returning veterans, first-generation college students and minorities who will do original research and contribute to the large body of work on supervolcanoes,” he said.

Comprehending what led to supereruptions in the past is essential to understanding and predicting similar events. A supereruption, Lang said, is a volcanic explosion that erupts a volume of material greater than 1,000 km3. This can be about a thousand times larger than normal volcanic eruptions. The deadly 1980 Mount St. Helens explosion, for instance, ejected only 1 cubic km3 of volcanic material, Lang said.

The 10-12 students chosen to participate in each of the three years will hone their geology field skills by investigating the Silver Creek caldera, which produced the Peach Spring Tuff (PST) supereruption nearly 19 million years ago. The PST is exposed over 32,000 km² of western Arizona, southeastern California and southern Nevada.

Students studying the region’s geologic record will guide their research around questions like: What does a supervolcano look like before it erupts? How and why do large magmatic systems change over time? How does supereruptive magmatism (ex., PST) compare with typical-scale magmatism (ex., Mt.St. Helens)?

Lang said he is eager to get started on the research, which will begin in late December or early January in Arizona followed by another field session in the summer. Students will also complete their lab work during the summer, attending either Mercyhurst or Vanderbilt.

“This is an exciting opportunity for us because these grants (National Science Foundation) are difficult to obtain,” Lang said. “The success rate for a project to be funded is 20 to 25 percent.”

Study shows how early Earth kept warm enough to support life

This is an artist's conception of the Earth during the late Archean, 2.8 billion years ago. Weak solar radiation requires the Earth have increased greenhouse gas amounts to remain warm. CU-Boulder doctoral student Eric Wolf Wolf and CU-Boulder Professor Brian Toon use a three-dimensional climate model to show that the late Archean may have maintained large areas of liquid surface water despite a relatively weak greenhouse. With carbon dioxide levels within constraints deduced from ancient soils, the late Archean may have had large polar ice caps but lower latitudes would have remained temperate and thus hospitable to life. The addition of methane allows the late Archean to warmed to present day mean surface temperatures. -  Charlie Meeks
This is an artist’s conception of the Earth during the late Archean, 2.8 billion years ago. Weak solar radiation requires the Earth have increased greenhouse gas amounts to remain warm. CU-Boulder doctoral student Eric Wolf Wolf and CU-Boulder Professor Brian Toon use a three-dimensional climate model to show that the late Archean may have maintained large areas of liquid surface water despite a relatively weak greenhouse. With carbon dioxide levels within constraints deduced from ancient soils, the late Archean may have had large polar ice caps but lower latitudes would have remained temperate and thus hospitable to life. The addition of methane allows the late Archean to warmed to present day mean surface temperatures. – Charlie Meeks

Solving the “faint young sun paradox” — explaining how early Earth was warm and habitable for life beginning more than 3 billion years ago even though the sun was 20 percent dimmer than today — may not be as difficult as believed, says a new University of Colorado Boulder study.

In fact, two CU-Boulder researchers say all that may have been required to sustain liquid water and primitive life on Earth during the Archean eon 2.8 billion years ago were reasonable atmospheric carbon dioxide amounts believed to be present at the time and perhaps a dash of methane. The key to the solution was the use of sophisticated three-dimensional climate models that were run for thousands of hours on CU’s Janus supercomputer, rather than crude, one-dimensional models used by almost all scientists attempting to solve the paradox, said doctoral student Eric Wolf, lead study author.

“It’s really not that hard in a three-dimensional climate model to get average surface temperatures during the Archean that are in fact moderate,” said Wolf, a doctoral student in CU-Boulder’s atmospheric and oceanic sciences department. “Our models indicate the Archean climate may have been similar to our present climate, perhaps a little cooler. Even if Earth was sliding in and out of glacial periods back then, there still would have been a large amount of liquid water in equatorial regions, just like today.”

Evolutionary biologists believe life arose on Earth as simple cells roughly 3.5 billion years ago, about a billion years after the planet is thought to have formed. Scientists have speculated the first life may have evolved in shallow tide pools, freshwater ponds, freshwater or deep-sea hydrothermal vents, or even arrived on objects from space.

A cover article by Wolf and Professor Brian Toon on the topic appears in the July issue of Astrobiology. The study was funded by two NASA grants and by the National Science Foundation, which supports CU-Boulder’s Janus supercomputer used for the study.

Scientists have been trying to solve the faint young sun paradox since 1972, when Cornell University scientist Carl Sagan — Toon’s doctoral adviser at the time — and colleague George Mullen broached the subject. Since then there have been many studies using 1-D climate models to try to solve the faint young sun paradox — with results ranging from a hot, tropical Earth to a “snowball Earth” with runaway glaciation — none of which have conclusively resolved the problem.

“In our opinion, the one-dimensional models of early Earth created by scientists to solve this paradox are too simple — they are essentially taking the early Earth and reducing it to a single column atmospheric profile,” said Toon. “One-dimensional models are simply too crude to give an accurate picture.”

Wolf and Toon used a general circulation model known as the Community Atmospheric Model version 3.0 developed by the National Center for Atmospheric Research in Boulder and which contains 3-D atmosphere, ocean, land, cloud and sea ice components. The two researchers also “tuned up” the model with a sophisticated radiative transfer component that allowed for the absorption, emission and scattering of solar energy and an accurate calculation of the greenhouse effect for the unusual atmosphere of early Earth, where there was no oxygen and no ozone, but lots of CO2 and possibly methane.

The simplest solution to the faint sun paradox, which duplicates Earth’s present climate, involves maintaining roughly 20,000 parts per million of the greenhouse gas CO2 and 1,000 ppm of methane in the ancient atmosphere some 2.8 billion years ago, said Wolf. While that may seem like a lot compared to today’s 400 ppm of CO2 in the atmosphere, geological studies of ancient soil samples support the idea that CO2 likely could have been that high during that time period. Methane is considered to be at least 20 times more powerful as a greenhouse gas than CO2 and could have played a significant role in warming the early Earth as well, said the CU researchers.

There are other reasons to believe that CO2 was much higher in the Archean, said Toon, who along with Wolf is associated with CU’s Laboratory for Atmospheric and Space Physics. The continental area of Earth was smaller back then so there was less weathering of the land and a lower release of minerals to the oceans. As a result there was a smaller conversion of CO2 to limestone in the ocean. Likewise, there were no “rooted” land plants in the Archean, which could have accelerated the weathering of the soils and indirectly lowered the atmospheric abundance of CO2, Toon said.

Another solution to achieving a habitable but slightly cooler climate under the faint sun conditions is for the Archean atmosphere to have contained roughly 15,000 to 20,000 ppm of CO2 and no methane, said Wolf. “Our results indicate that a weak version of the faint young sun paradox, requiring only that some portion of the planet’s surface maintain liquid water, may be resolved with moderate greenhouse gas inventories,” the authors wrote in Astrobiology.

“Even if half of Earth’s surface was below freezing back in the Archean and half was above freezing, it still would have constituted a habitable planet since at least 50 percent of the ocean would have remained open,” said Wolf. “Most scientists have not considered that there might have been a middle ground for the climate of the Archean.

“The leap from one-dimensional to three-dimensional models is an important step,” said Wolf. “Clouds and sea ice are critical factors in determining climate, but the one-dimensional models completely ignore them.”

Has the faint young sun paradox finally been solved? “I don’t want to be presumptuous here,” said Wolf. “But we show that the paradox is definitely not as challenging as was believed over the past 40 years. While we can’t say definitively what the atmosphere looked like back then without more geological evidence, it is certainly not a stretch at all with our model to get a warm early Earth that would have been hospitable to life.”

“The Janus supercomputer has been a tremendous addition to the campus, and this early Earth climate modeling project would have impossible without it,” said Toon. The researchers estimated the project required roughly 6,000 hours of supercomputer computation time, an effort equal to about 10 years on a home computer.

University of Nevada, Reno’s earthquake lab gets $12 million from Commerce Department

The University of Nevada, Reno recently tested a 110-foot 200 ton concrete bridge in its large-structures earthquake engineering lab, which just received $12.2 million from the US Department of Commerce in a competitive grant process to more than double the size of the facility. -  Photo by Mike Wolterbeek, University of Nevada, Reno.
The University of Nevada, Reno recently tested a 110-foot 200 ton concrete bridge in its large-structures earthquake engineering lab, which just received $12.2 million from the US Department of Commerce in a competitive grant process to more than double the size of the facility. – Photo by Mike Wolterbeek, University of Nevada, Reno.

The University of Nevada, Reno has been awarded $12.2 million from the U.S. Department of Commerce’s National Institute of Standards and Technology, it was announced Wednesday. This will fund the major portion of an expansion of the world-renowned earthquake engineering lab where, for the past 25 years, researchers have conducted successful experiments of building and testing large-scale structures and bridges to advance seismic safety.

The expanded facility will house the largest and most versatile earthquake simulation laboratory in the United States. The $18 million project also received funds from the Department of Energy last year to finance the initial phase of construction of the 23,000-square-foot project, scheduled to begin in October. When completed, the combined area of the new and existing facilities will exceed 30,000 square feet.

The University was one of only five institutions – from more than 100 applicants nationwide – that received grant money from the NIST Construction Grants Program. The project will create short-term construction jobs and have a positive long-term employment and economic impact through other agency and private industry projects.

“Strengthening research and development in the United States is critical to our ability to create jobs and remain competitive,” U.S. Commerce Secretary Gary Locke said. “These construction grants will help the U.S. produce world-leading research in science and technology that will advance our economic growth and international competitiveness.”

“This expansion is a major accomplishment that will make us more competitive and productive,” Manos Maragakis, dean of the College of Engineering, said. “Our facility will be unique worldwide and, combined with the excellence of our faculty and students, will allow us to have even greater contributions to the seismic safety of our state, the nation and the world.

“A good part of why we received this funding is because of the high quality work we do and the high-caliber faculty. The competitive nature of this award adds significantly to the importance and prestige of this accomplishment.”

Buckle, director of the Large-Scale Structures Lab, said the expanded facility will house the University’s four large 14-by-14-foot, 50-ton-capacity shake tables that are capable of replicating, through computer software and massive hydraulically-operated actuators, any recorded earthquake.

“The new building configuration will allow for a fifth shake table and more versatile use of the equipment while freeing up space for additional experiments,” Buckle said. “We have a backlog now, a long list of projects of people and agencies who want to use the lab. For example, our next big project is a 145-foot, curved, 130-ton bridge project that takes up every bit of current space, door-to-door and wall-to-wall.”

The greatly expanded research space will allow for additional experiment configurations for large-scale models of buildings, and experiments that are not possible in the existing facility, such as simulating the effect of seismic waves propagating through layers of soil under foundations.

“This will be a quantum jump in the range and complexity of experiments that can be undertaken in both new and existing laboratories, with advances in state-of-the-art earthquake engineering that are not currently possible,” Buckle said. “Safer buildings, bridges and more resilient communities will be the end result.”

The University’s Center for Civil Engineering Earthquake Research carries out research for federal and state agencies, the private sector and non-profit organizations. In addition to highway bridges, the Center’s current research efforts include the study of non-structural components in buildings and alternative building materials.

“The earthquake research done here at the University and in this laboratory has discovered new knowledge, stretched intellectual boundaries and at the same time provided useful research,” University President Milt Glick said. “So when there’s a bridge problem in San Francisco, they call upon our faculty to help them solve the design problem. And, when they want to design a safer building, where do they come? They come here.”

The facility supports itself financially. In the past 10 years, major research grants and contracts acquired by the Center for Civil Engineering Earthquake Research totaled $38.5 million.

“With the expansion we can accommodate more students and their projects and more of the local construction industry will be able to use it, bringing in multi-thousand dollar specimens,” Buckle said.

Almost 20 academic, research and administrative faculty, scientists and technicians are affiliated with the Center for Civil Engineering Earthquake Research and the earthquake simulation lab. About 30 doctoral and masters students are engaged in research projects under the Center’s umbrella. Total research funding in 2009 was about $3.5 million. In its 25-year history the Center has published more than 160 technical reports that describe the results of these activities.

The University facility is managed as a national shared-use National Earthquake Engineering Simulation site created and funded by the National Science Foundation in 2004 to provide new earthquake-engineering research and testing capabilities for large structural systems. This NEES equipment site is connected to the NEES Consortium of 14 other universities.

“UNR’s earthquake research center is among the best in the nation, providing real-time data that is vital to maintaining safe roadways, bridges and buildings that can endure Nevada’s frequent seismic activity,” said Nevada Sen. Harry Reid. “Thanks to this funding, UNR will have the facility and resources needed to build on the quality work they already perform and help keep Nevadans safe.”

The project is expected to be complete in 2013.