Earth’s core deprived of oxygen

The composition of the Earth’s core remains a mystery. Scientists know that the liquid outer core consists mainly of iron, but it is believed that small amounts of some other elements are present as well. Oxygen is the most abundant element in the planet, so it is not unreasonable to expect oxygen might be one of the dominant “light elements” in the core. However, new research from a team including Carnegie’s Yingwei Fei shows that oxygen does not have a major presence in the outer core. This has major implications for our understanding of the period when the Earth formed through the accretion of dust and clumps of matter. Their work is published Nov. 24 in Nature.

According to current models, in addition to large amounts of iron, the Earth’s liquid outer core contains small amounts of so-called light elements, possibly sulfur, oxygen, silicon, carbon, or hydrogen. In this research, Fei, from Carnegie’s Geophysical Laboratory, worked with Chinese colleagues, including lead author Haijun Huang from China’s Wuhan University of Technology, now a visiting scientist at Carnegie. The team provides new experimental data that narrow down the identity of the light elements present in Earth’s outer core.

With increasing depth inside the Earth, the pressure and heat also increase. As a result, materials act differently than they do on the surface. At Earth’s center are a liquid outer core and a solid inner core. The light elements are thought to play an important role in driving the convection of the liquid outer core, which generates the Earth’s magnetic field.

Scientists know the variations in density and speed of sound as a function of depth in the core from seismic observations, but to date it has been difficult to measure these properties in proposed iron alloys at core pressures and temperatures in the laboratory.

“We can’t sample the core directly, so we have to learn about it through improved laboratory experiments combined with modeling and seismic data,” Fei said.

High-speed impacts can generate shock waves that raise the temperature and pressure of materials simultaneously, leading to melting of materials at pressures corresponding to those in the outer core. The team carried out shock-wave experiments on core materials, mixtures of iron, sulfur, and oxygen. They shocked these materials to the liquid state and measured their density and speed of sound traveling through them under conditions directly comparable to those of the liquid outer core.

By comparing their data with observations, they conclude that oxygen cannot be a major light element component of the Earth’s outer core, because experiments on oxygen-rich materials do not align with geophysical observations. This supports recent models of core differentiation in early Earth under more ‘reduced’ (less oxidized) environments, leading to a core that is poor in oxygen.

“The research revealed a powerful way to decipher the identity of the light elements in the core. Further research should focus on the potential presence of elements such as silicon in the outer core,” Fei said.

Interactive map of sea level changes launched

A new interactive map that allows users to explore changes in sea level worldwide over five decades has been launched by the UK’s Permanent Service for Mean Sea Level (PSMSL).

The PSMSL, operated by the National Oceanography Centre under the auspices of the International Council for Science, is the global databank for sea-level change information. Established in 1933, it is largely thanks to PSMSL’s dataset that we are able to assess the sea-level changes of the last century.

The Anomalies Map, generated from a worldwide network of tide gauges, demonstrates how sea level varies from year to year when compared with the long-term average at a particular site, calculated over the period from 1960 to 1990. Moving a slider along the time line at the bottom of the map shows how, at some locations, sea level can vary by over 20 centimeters from year to year.

On first loading the web page showing the sea level anomalies, the background trend at each tide gauge is not removed, so a majority of the early years shown (the 1950s) are dominated by blue colors showing negative anomalies and the later years by red colors showing positive anomalies as the average global sea level rises.

There are some notable exceptions to this pattern; for example, the land along the Baltic coasts of northern Sweden and Finland is uplifting as the Earth continues to recover from the collapse of the large ice sheets that covered the region during the last ice age. This causes sea level, measured by tide gauges, to decrease. Thus, the anomalies in that region go from red to blue over the time span of the data. This background trend can be removed at each site, using a tick box below the map.

The trends can be explored more thoroughly using the PSMSL’s Trend Explorer released earlier this year.

PSMSL’s Director, Dr Lesley Rickards, said: “This map lets users see how the estimate of a constant change in time or, in other words, a trend, for each tide gauge record depends upon the period of the data used in the calculation. Zooming out to show the world, it becomes clear that the vast majority of the sites are red, indicating a sea level rise.”

It is interesting to note the change in geographic coverage of the data over time. By choosing the entire time span available – from 1900 to 2010 – users can observe the lack of data covering this period in the Southern Hemisphere and western Pacific. More data is available if the start date is moved up to 1950, but unfortunately there is still a lack of geographic coverage in the Southern Hemisphere.


  1. PSMSL’s Mean Sea Levels Anomalies Map.

  2. and the Trends Explorer.

Carbon cycling was much smaller during last ice age than in today’s climate

Atmospheric carbon dioxide (CO2) is one of the most important greenhouse gases and the increase of its abundance in the atmosphere by fossil fuel burning is the main cause of future global warming. In past times, during the transition between an ice age and a warm period, atmospheric CO2 concentrations changed by some 100 parts per million (ppm) – from an ice age value of 180 ppm to about 280 ppm during warm periods.

Scientists can reconstruct these changes in the atmospheric carbon stock using direct measurements of atmospheric CO2 trapped in air bubbles in the depth of Antarctica’s ice sheets. However explaining the cause of these 100ppm changes in atmospheric CO2 concentrations between glacial and interglacial climate states – as well as estimating the carbon stored on land and in the ocean – is far more difficult.

The researchers, led by Dr Philippe Ciais of the Laboratoire des Sciences du Climat et l’Environnement near Paris, ingeniously combined measurements of isotopes of atmospheric oxygen (18O) and carbon (13C) in marine sediments and ice cores with results from dynamic global vegetation models, the latter being driven by estimates of glacial climate using climate models.

Dr Marko Scholze of the University of Bristol’s School of Earth Sciences, co-author on the paper said: “The difference between glacial and pre-industrial carbon stored in the terrestrial biosphere is only about 330 petagrams of carbon, which is much smaller than previously thought. The uptake of carbon by vegetation and soil, that is the terrestrial productivity during the ice age, was only about 40 petagrams of carbon per year and thus much smaller: roughly one third of present-day terrestrial productivity and roughly half of pre-industrial productivity.”

From these results, the authors conclude that the cycling of carbon in the terrestrial biosphere – that is, the time between uptake by photosynthesis and release by decomposition of dead plant material – must have been much smaller than in the current, warmer climate.

Furthermore there must have been a much larger size of non-decomposable carbon on land during the Last Glacial Maximum (the period in the Earth’s history when ice sheets were at their maximum extension, between 26,500 and 19,000 years ago).

The authors suggest that this inert carbon should have been buried in the permanently frozen soils and large amounts of peat of the northern tundra regions.

Great Plains river basins threatened by pumping of aquifers

Suitable habitat for native fishes in many Great Plains streams has been significantly reduced by the pumping of groundwater from the High Plains aquifer – and scientists analyzing the water loss say ecological futures for these fishes are “bleak.”

Results of their study have been published in the journal Ecohydrology.

Unlike alluvial aquifers, which can be replenished seasonally with rain and snow, these regional aquifers were filled by melting glaciers during the last Ice Age, the researchers say. When that water is gone, it won’t come back – at least, until another Ice Age comes along.

“It is a finite resource that is not being recharged,” said Jeffrey Falke, a post-doctoral researcher at Oregon State University and lead author on the study. “That water has been there for thousands of years, and it is rapidly being depleted. Already, streams that used to run year-round are becoming seasonal, and refuge habitats for native fishes are drying up and becoming increasingly fragmented.”

Falke and his colleagues, all scientists from Colorado State University where he earned his Ph.D., spent three years studying the Arikaree River in eastern Colorado. They conducted monthly low-altitude flights over the river to map refuge pool habitats and connectivity, and compared it to historical data.

They conclude that during the next 35 years – under the most optimistic of circumstances – only 57 percent of the current refuge pools would remain – and almost all of those would be isolated in a single mile-long stretch of the Arikaree River. Water levels today already are significantly lower than they were 40 and 50 years ago.

Though their study focused on the Arikaree, other dryland streams in the western Great Plains – comprised of eastern Colorado, western Nebraska and western Kansas – face the same fate, the researchers say.

Falke said the draining of the regional aquifers lowers the groundwater input to alluvial aquifers through which the rivers flow, creating the reduction in streamflow. He and his colleagues estimate that it would require a 75 percent reduction in the rate of groundwater pumping to maintain current water table levels and refuge pools, which is “not economically or politically feasible,” the authors note in the study.

Dryland streams in the Great Plains host several warm-water native fish species that have adapted over time to harsh conditions, according to Falke, who is with the Department of Fisheries and Wildlife at Oregon State University. Brassy minnows, orange-throat darters and other species can withstand water temperatures reaching 90 degrees, as well as low levels of dissolved oxygen, but the increasing fragmentation of their habitats may impede their life cycle, limiting the ability of the fish to recolonize.

“The Arikaree River and most dryland streams are shallow, with a sandy bottom, and often silty,” Falke said. “The water can be waist-deep, and when parts of the river dry up from the pumping of groundwater, it is these deeper areas that become refuge pools. But they are becoming scarcer, and farther apart each year.”

Falke said the changing hydrology of the system has implications beyond the native fishes. The aquifer-fed stream influences the entire riparian area, where cottonwood trees form their own ecosystem and groundwater-dependent grasses support the grazing of livestock and other animals.

Pumping of regional aquifers is done almost entirely for agriculture, Falke said, with about 90 percent of the irrigation aimed at corn production, with some alfalfa and wheat.

“The impact goes well beyond the Arikaree River,” Falke said. “Declines in streamflow are widespread across the western Great Plains, including all 11 headwaters of the Republican River. Ultimately, the species inhabiting these drainages will decline in range and abundance, and become more imperiled as groundwater levels decline and climate changes continue.”

Underground water reservoirs for the Jordan Valley

The Jordan spring is rich in water, while water is lacking in the lower Jordan valley. -  Photo: Nico Goldscheider
The Jordan spring is rich in water, while water is lacking in the lower Jordan valley. – Photo: Nico Goldscheider

The catchment area of the lower Jordan river between the Sea of Galilee and the Dead Sea is characterized by a very dry climate. Evaporation by far exceeds the amount of precipitation. The team of international experts of various disciplines is developing an integrated water resources management (IWRM) concept taking into account all water resources available. Apart from groundwater, these resources also include processed wastewater, desalinated brackish water, and, after strong rainfall in winter, flood water that flows via wadis into the Jordan river and then into the Dead Sea. Among the academic partners participating in the project funded by the Federal Ministry of Education and Research (BMBF) are the Ben Gurion University of the Negev, the University of Tel Aviv, the Palestinian Al-Quds University, and the Jordanian University of Amman. In addition, ministries, water supply companies, and authorities as well as local decision-makers are involved.

One of five German and three Jordanian young scientists writing their PhD theses at KIT within the framework of the SMART project is the geoecologist Moritz Zemann. His diploma thesis at the KIT Institute of Applied Geosciences already focused on the possibility of storing flood water after rare, but sometimes abundant precipitation in the geological underground. This “managed aquifer recharge ” in natural reservoirs protects the water against evaporation. The scientists use their geological and hydrological knowledge to explore suitable natural reservoirs in sediments and rock and to develop technical solutions for storing water in the underground. Zemann’s PhD thesis now deals with the question of how the quality of the groundwater can be evaluated and protected. “The willingness to cooperate is high, the project contributes to reducing mutual prejudices,” he says. In total, 20 PhD students are involved in the project. Among the German partners are the University of Göttingen and the Helmholtz Centre for Environmental Research (UFZ), Halle. Apart from the acquisition of engineering competence, it is also aimed at finding out which technology is politically feasible and affordable.

The project started in 2006 and has now entered its second phase, namely, practical implementation of research findings. At KIT, several institutes and scientists are involved in SMART apart from the coordinating Chair for Hydrogeology of Professor Nico Goldscheider. The Chair for Water Chemistry of the Engler-Bunte Institute (EBI), for instance, focuses on the desalination of brackish water. “This brackish spring water or groundwater is less salty than seawater, as a result of which energy expenditure for desalination is smaller. Moreover, brackish water can also be found inland,” says Goldscheider. The processed water does not have to be transported from the coastal region, but can be made available for drinking purposes and agriculture in a decentralized manner.

Among others, the dramatic scarcity of water in the lower Jordan valley is related to the population development. “In Jordan, population has grown from about 500,000 people in 1952 to six million today. This means that ten times more people need drinking water,” explains Goldscheider. The KIT professor adds that “the SMART project so far has survived all crises, even in times of major political tensions. On both sides, there probably is a silent, peaceloving majority and obviously, many of these reasonable people are scientists and researchers.”

Massive volcanoes, meteorite impacts delivered one-two death punch to dinosaurs

Princeton University researchers found that massive, prolonged eruptions of the Deccan Traps in India gradually eliminated species and resulted in the Cretaceous-Tertiary mass extinction that killed the dinosaurs 65 million years ago. Marine sediment trapped between Deccan lava flows revealed that a species known as planktonic foraminifera -- widely used to gauge the severity of prehistoric disasters -- succumbed to lava mega-flows and volcano-induced environmental stress such as acid rain and drastic climate changes. As conditions on Earth worsened, large, variedspecies (left) were eliminated. The no more than seven or eight smaller species (right) that remained dwarfed further. -  Courtesy of Gerta Keller
Princeton University researchers found that massive, prolonged eruptions of the Deccan Traps in India gradually eliminated species and resulted in the Cretaceous-Tertiary mass extinction that killed the dinosaurs 65 million years ago. Marine sediment trapped between Deccan lava flows revealed that a species known as planktonic foraminifera — widely used to gauge the severity of prehistoric disasters — succumbed to lava mega-flows and volcano-induced environmental stress such as acid rain and drastic climate changes. As conditions on Earth worsened, large, variedspecies (left) were eliminated. The no more than seven or eight smaller species (right) that remained dwarfed further. – Courtesy of Gerta Keller

A cosmic one-two punch of colossal volcanic eruptions and meteorite strikes likely caused the mass-extinction event at the end of the Cretaceous period that is famous for killing the dinosaurs 65 million years ago, according to two Princeton University reports that reject the prevailing theory that the extinction was caused by a single large meteorite.

Princeton-led researchers found that a trail of dead plankton spanning half a million years provides a timeline that links the mass extinction to large-scale eruptions of the Deccan Traps, a primeval volcanic range in western India that was once three-times larger than France. A second Princeton-based group uncovered traces of a meteorite close to the Deccan Traps that may have been one of a series to strike the Earth around the time of the mass extinction, possibly wiping out the few species that remained after thousands of years of volcanic activity.

[Images can be seen at http://www.princeton.edu/main/news/archive/S32/14/62G75

Researchers led by Princeton Professor of Geosciences Gerta Keller report this month in the Journal of the Geological Society of India that marine sediments from Deccan lava flows show that the population of a plankton species widely used to gauge the fallout of prehistoric catastrophes plummeted nearly 100 percent in the thousands of years leading up to the mass extinction. This eradication occurred in sync with the largest eruption phase of the Deccan Traps – the second of three – when the volcanoes pumped the atmosphere full of climate-altering carbon dioxide and sulfur dioxide, the researchers report. The less severe third phase of Deccan activity kept the Earth nearly uninhabitable for the next 500,000 years, the researchers report. A substantially weaker first phase occurred roughly 2.5 million years before the second-phase eruptions.

Another group based in Keller’s lab found evidence in Indian sediment of a meteorite strike from the time of the mass extinction that would have been sufficient to finish off the few but weakened species that survived the Deccan eruptions, according to a report in the journal Earth and Planetary Science Letters (EPSL) in October. This same sediment — located in Meghalaya, India, more than 600 miles east of the Deccan Traps — portrayed the Earth during this period as a harsh environment of acid rain and erratic global temperatures.

Taken together, Keller said, the Princeton findings could finally put to rest the theory that the mass-extinction event — known as the Cretaceous-Tertiary, or KT, for the periods it straddles — was triggered solely by a large meteorite impact near Chicxulub in present-day Mexico. That impact — which occurred around the time of the second-phase Deccan eruptions — is thought to have been 2 million times more powerful than a hydrogen bomb and generated an enormous dust cloud and gases that radically altered the climate. Keller has long held that the Chicxulub impact was not catastrophic enough to cause the KT mass extinction — the newest work from her lab, however, shows that the largest Deccan eruptions were.

“Our work in Meghalaya and the Deccan Traps provides the first one-to-one correlation between the mass extinction and Deccan volcanism,” said Keller, who is lead author of the Geological Society paper and second author of the EPSL paper after lead author Brian Gertsch, who earned his Ph.D. from Princeton in 2010. Gertsch is now a postdoctoral researcher at the Massachusetts Institute of Technology.

“We demonstrate a clear cause-and-effect relationship that these massive volcanic eruptions were far more destructive than previously thought and could have caused the KT mass extinction even without the addition of large meteorite impacts,” Keller said. “But given the environmental instability caused by the massive Deccan eruptions, an impact could easily have killed off the few survivor species at the end of the Cretaceous. It would have been a double whammy.”

Vincent Courtillot, a geophysicist and professor at Paris University Diderot, said that the Princeton papers are based on a closer examination of Deccan volcanism and its aftermath than has been conducted previously. As such, he said, the researchers’ “impressive analysis” confirms the timing of the Deccan eruptions and environmental fallout reported in recent years by various research teams, including his own.

Courtillot, who is familiar with the Princeton work but had no role in it, led the team that reported in the Journal of Geophysical Research in 2009 that Deccan volcanism occurred in three phases, the second and largest of which coincides with the Cretaceous-Tertiary mass extinction; the Keller-led study published in the Journal of the Geological Society of India confirms the second and third phases, he said.

“The significance of this recent work is that the analysis was conducted in important sections near the volcanic action, and not thousands of kilometers away as had been the case previously,” Courtillot said. “They provide support for the idea that carbon and sulfur dioxide emissions were the principal agents of environmental change and stress, and conclude that the characteristics of the second-phase eruptions were such that it could alone have caused the mass extinction.”

In addition, Courtillot said, the approach the teams used could prove valuable to understanding the part volcanoes played in other extinction events in Earth’s history. “Exceptional, massive volcanism, I am now quite sure, is the general cause of mass extinctions,” he said. “But in order to be considered as proven and quantitatively explained, we need the kind of extensive, detailed work described by these teams to be conducted for all other extinctions.”

The case for Deccan over the Chicxulub impact as the cause of the KT extinction

Keller is prominent among scientists who reject the Chicxulub impact’s role in the end-Cretaceous mass extinction. She is well known for leading a team of researchers who announced in 2003 that a sediment core from the Chicxulub crater revealed that the impact predated the mass-extinction event by about 300,000 years.

Keller and her co-authors published their findings in the journal Proceedings of the National Academy of Sciences in 2004 and suggested that the Chicxulub meteorite was instead one of several meteorite strikes that occurred in the several hundred thousand years leading up to the mass-extinction event. They concluded that while destructive, the Chicxulub impact was not powerful enough to have caused widespread annihilation. Keller and her collaborators have since supported these findings with additional evidence from Texas and northeastern Mexico published in EPSL in 2007 and the Journal of the Geological Society of London in 2009, respectively.

Keller has joined other scientists in focusing her research on the 30-year-old idea first championed by Virginia Tech geologist Dewey McLean that Deccan volcanism was the root of the Cretaceous mass extinction. Until recently, the theory was in question because the eruptions were thought to have been stretched out over a period of more than 1 million years, leaving plenty of time for the Earth to recover between eruptions, Keller said.

Improved dating technology, however, allowed scientists — particularly the team led by Courtillot — to narrow the time of the largest eruptions to a few hundred thousand years at the end of the Cretaceous. Known as Deccan phase-2, this period accounted for 80 percent of the total volcanism. The first and weakest phase of activity occurred about 67.5 million years ago; the third and final eruption phase began about 300,000 years after the KT mass extinction.

In 2008, Keller and her team reported in EPSL the first direct link that the KT extinction coincided with the end of the second phase of Deccan eruptions. She explained that marine sediments preserved between lava flows from the second- and third-phase eruptions contained evidence of the KT boundary, a thin, worldwide geological layer that marks the mass-extinction event.

Deccan volcanism behind the mass extinction, so say the plankton

The work published Nov. 1 by the Geological Society of India builds on Keller’s 2008 paper in EPSL. She and her co-authors examined cores from Deccan lava flows near Rajahmundry in the Krishna-Godavari Basin, the remnant of an ancient sea on the Bay of Bengal coast, and found that lava flows from the second and third Deccan phases are separated by marine sediments.

Keller worked with P.K. Bhowmick, H. Upadhyay, A. Dave, A.N. Reddy and B.C. Jaiprakash, scientists with India’s government-operated Oil and Natural Gas Corporation, which owns the sediment cores. Also included is Thierry Adatte, a geologist with the University of Lausanne in Switzerland, who is Keller’s long-time collaborator and a co-author on the papers challenging the time of the Chicxulub impact, as well as previous papers on Deccan volcanism.

The team examined the basin’s sediment layers to determine the size and number of a species known as planktonic foraminifera that remained following each eruption phase. These plankton are single-celled micro-organisms ranging in size from the point of a needle to a pinhead that are highly sensitive to changes in oxygen, salinity, temperature and nutrients, Keller said. Their sensitivity to environmental changes and their near extinction at the end of the Cretaceous makes the species key to determining the timespan, pace and severity of the mass extinction.

After studying microplankton remains in sediment from below, between and above the second-phase lava flows, the researchers observed that the number of living species dropped 50 percent at the onset of eruptions. The species count plunged by another 50 percent after the first of what would be four lava mega-flows. No more than seven to eight of the species that were most tolerant to environmental changes survived after the first mega-flow, and no recovery occurred between subsequent mega-flows. By the end of the fourth mega-flow the mass extinction was complete, the researchers wrote.

The vast amounts of carbon dioxide and sulfur dioxide poured into the atmosphere by the end of the second volcanic phase — estimated to be 30-times more than the levels produced by the Chicxulub impact — resulted in, among other crises, heavy acid rain, acidic oceans and global temperatures that swung between scorching and frigid, the researchers report. The third eruption phase prolonged these conditions.

Thus, the number of species evolving remained low, and existing species dwarfed during the 500,000-year period after the mass extinction, although no significant extinctions occurred again, Keller and her co-authors found. New, larger marine species did not appear until after the third phase when Deccan eruptions went dormant, suggesting that life began to recover as the atmosphere became less poisonous.

“In my work, I had always observed evidence of marked changes in species abundance with gradually higher levels of stress and extinction during the last several hundred thousand years, rather than one single instantaneous annihilation,” Keller said. “For lack of better evidence, scientists had interpreted this steady decline as the result of climate and sea-level changes.”

Evidence that a large meteorite helped finish the job

For the paper published Oct. 15 in EPSL, Keller and her co-authors provide a supporting and more nuanced depiction of conditions during the Deccan period. They examined sediments from an ancient shallow sea in Meghalaya where rock layers are known to contain among the clearest fossil records of the Cretaceous-Tertiary mass extinction, Keller said. She worked with lead author Gertsch; the geologist Adatte; Rahul Garg and Vandana Prasad from the Birbal Sahni Institute of Palaeobotany in India; Zolt Berner from the Karlsruhe Institute of Technology in Germany; and Dominik Fleitmann at the University of Bern in Switzerland.

Analysis of the Meghalaya sediment revealed an inhospitable planet rife with high humidity, severe storms and massive blooms of the plankton species Guembelitria cretacea, a disaster opportunist that flourished in devastated environments when few other species survived.

At the same time, the team detected large amounts of iridium, an element typically associated with meteorite impacts, Keller said. Iridium is rare on Earth yet is found in high concentrations in the KT boundary, a phenomenon known as the iridium anomaly. Remnants of iridium at the KT boundary in Meghalaya coincide with the global KT boundary iridium anomaly, she said.

The new evidence of a meteorite strike at Meghalaya that coincides with the KT mass extinction supports the theory Keller proffered in 2003 that multiple meteorites struck the Earth around the time of the Deccan eruptions, adding to the volcano-fueled misery of the mass-extinction era.

“Our data suggest that the mass extinction of the dinosaurs and other species was caused by the harsh conditions resulting from massive Deccan eruptions and the coincidence of multiple meteorites,” Keller said. “In light of this new evidence, the single-impact story seems more like an article of faith at this point.”

Study offers 7 safeguards for hydraulic fracturing

A new report by Duke University researchers offers several health and environmental measures for North Carolina lawmakers to consider as they debate legalizing horizontal drilling and hydraulic fracturing for natural gas.

The study, which has been accepted for publication in the Duke Environmental Law and Policy Forum journal, looks at potential environmental hazards and how lawmakers in other states are factoring health and environmental risks into regulatory approaches targeting the natural gas extraction method.

“If North Carolina legalizes shale gas extraction, we need to consider what’s worked best in other states and avoid what hasn’t,” said Rob Jackson, Nicholas professor of global environmental change at the Nicholas School of the Environment. “That’s the only way to get it right.”

Legislation passed earlier this year has moved North Carolina closer to producing shale gas, and is directing the Department of Environment and Natural Resources to complete a study on the effects of hydraulic fracturing, often called “fracking,” by May, 2012.

The authors of Duke’s own study say if North Carolina legislators allow natural gas production through hydraulic fracturing, they should consider seven measures to help avoid and mitigate any possible negative effects. These include:

  • Securing baseline data on groundwater prior to shale gas production and at each stage of the drilling process
  • Funding for regulatory programs and an agency to carry them out
  • Planning for withdrawals from area water supplies related to the production
  • Minimizing the risks of spills and contamination caused by equipment failure and human error by implementing safety requirements
  • Thinking through options for the disposal and treatment of wastewater resulting from the hydraulic fracturing process
  • Assessing the impacts on air quality and assuring attainment of federal ground-level ozone standards
  • Requiring some degree of disclosure regarding the chemicals used in fracturing fluid

“Lawmakers have the unique opportunity to decide whether or not hydraulic fracturing is appropriate for the state,” said Jonas Monast, director of the climate and energy program for the Nicholas Institute for Environmental Policy Solutions. “Before making a decision, we need to understand the full range of potential economic, environmental and health impacts.

Study: Ozone from rock fracture could serve as earthquake early warning

Researchers the world over are seeking reliable ways to predict earthquakes, focusing on identifying seismic precursors that, if detected early enough, could serve as early warnings.

New research, published this week in the journal Applied Physics Letters, suggests that ozone gas emitted from fracturing rocks could serve as an indicator of impending earthquakes. Ozone is a natural gas, a byproduct of electrical discharges into the air from several sources, such as from lightning, or, according to the new research, from rocks breaking under pressure.

Scientists in the lab of Raúl A. Baragiola, a professor of engineering physics in the University of Virginia School of Engineering and Applied Science set up experiments to measure ozone produced by crushing or drilling into different igneous and metamorphic rocks, including granite, basalt, gneiss, rhyolite and quartz. Different rocks produced different amounts of ozone, with rhyolite producing the strongest ozone emission.

Some time prior to an earthquake, pressures begin to build in underground faults. These pressures fracture rocks, and presumably, would produce detectable ozone.

To distinguish whether the ozone was coming from the rocks or from reactions in the atmosphere, the researchers conducted experiments in pure oxygen, nitrogen, helium and carbon dioxide. They found that ozone was produced by fracturing rocks only in conditions containing oxygen atoms, such as air, carbon dioxide and pure oxygen molecules, indicating that it came from reactions in the gas. This suggests that rock fractures may be detectable by measuring ozone.

Baragiola began the study by wondering if animals, which seem – at least anecdotally – to be capable of anticipating earthquakes, may be sensitive to changing levels of ozone, and therefore able to react in advance to an earthquake. It occurred to him that if fracturing rocks create ozone, then ozone detectors might be used as warning devices in the same way that animal behavioral changes might be indicators of seismic activity.

He said the research has several implications.

“If future research shows a positive correlation between ground-level ozone near geological faults and earthquakes, an array of interconnected ozone detectors could monitor anomalous patterns when rock fracture induces the release of ozone from underground and surface cracks,” he said.

“Such an array, located away from areas with high levels of ground ozone, could be useful for giving early warning to earthquakes.”

He added that detection of an increase of ground ozone might also be useful in anticipating disasters in tunnel excavation, landslides and underground mines.

New project will study ‘deep carbon’

Studying the behavior of carbon – the essential element in oil and natural gas – deep within the Earth is the aim of a new initiative co-directed by a UC Davis chemistry professor and funded by a two-year, $1.5 million grant from the Alfred P. Sloan Foundation.

“We don’t know how much carbon is stored in the deep Earth, and we don’t know how it affects fluxes of carbon towards the Earth’s crust or the carbon cycle at the surface,” said Giulia Galli, professor of chemistry at UC Davis, who will lead the Physics and Chemistry of Carbon Directorate initiative with Professor Craig Manning of UCLA.

Geologists believe that commercially produced crude oil and natural gas, or hydrocarbons, are formed by the decomposition of the remains of living organisms buried under layers of sediments in the Earth’s crust, a region that extends five to 10 miles below the Earth’s surface. But there is increasing interest in “abiogenic” hydrocarbons from much deeper in the Earth, which might make their way to the surface in some places.

A fundamental understanding of “deep carbon” could therefore affect both our thinking about energy supplies, and about how carbon moves through the air, soil and water at the surface – a key factor in climate change.

That puts the project at the intersection of energy and environmental research – areas of intense interest at UC Davis, known as a leader in both fields.

Galli and Manning will lead an international team of scientists working on practical experiments, computer simulations and theoretical studies of carbon, carbon compounds like natural gas, oil and diamond, water and other liquids under the enormous temperatures and pressures of the Earth’s depths.

Those conditions are difficult to reproduce in a lab at the surface, Galli noted. But they can be simulated with computers.

“We know very little, so we are starting with the basic physics and chemistry,” she said.

Gamburtsev Mountains enigma unraveled in East Antarctica

The birth of the Gamburtsev Subglacial Mountains buried beneath the vast East Antarctic Ice Sheet – a puzzle mystifying scientists since their first discovery in 1958 – is finally solved. The remarkably long geological history explains the formation of the mountain range in the least explored frontier on Earth and where the Antarctic Ice Sheet first formed. The findings are published this week in the journal Nature.

A seven-nation team of scientists explored the Gamburtsev Subglacial Mountains – buried beneath up to 3km of ice – during the International Polar Year (2007- 09) by using two twin-engine aircraft equipped with ice penetrating radars, gravity meters and magnetometers.

By analyzing the new data, the researchers describe the extraordinary processes – which took place over the last billion years – that created and preserved a root beneath the mountains and the East Antarctic rift system – a 3,000km long fracture in the earth’s surface that extends from East Antarctica across the ocean to India.

One billion years ago, before animals and plants evolved on Earth, several continents (or micro-continents) collided, crushing the oldest rocks of the mountain range together. This event formed a thick crustal root extending deep beneath the mountain range. Over time these ancient mountains were eroded but the cold dense root was left behind.

Around 250-100 million years ago – when dinosaurs walked the Earth – rifting paved the way for the supercontinent Gondwana to break apart, which included Antarctica, causing the old crustal root to warm. This rejuvenated crustal root, together with the East Antarctic Rift forced the land upwards again reforming the mountains. Rivers and glaciers carved deep valleys and this helped uplift the peaks to create the spectacular landscape of the Gamburtsevs, which resemble the European Alps. The East Antarctic Ice Sheet, which formed 34 million years ago and covers 10 million km² of our planet (an area the size of Canada), protected the mountains from erosion.

Lead author, Dr Fausto Ferraccioli from British Antarctic Survey says,

“Understanding the origin of the Gamburtsevs was a primary goal of our International Polar Year expedition. It was fascinating to find that the East Antarctic rift system resembles one of the geological wonders of the world – the East African rift system – and that it provides the missing piece of the puzzle that helps explain the Gamburtsev Subglacial Mountains. The rift system was also found to contain the largest subglacial lakes in Antarctica.”

Co-author, Dr Carol Finn from US Geological Survey says,

“Resolving the contradiction of the Gamburtsev high elevation and youthful Alpine topography but location on the East Antarctic craton by piecing together the billion year history of the region was exciting and challenging. We are accustomed to thinking that mountain building relates to a single tectonic event, rather than sequences of events. The lesson we learned about multiple events forming the Gamburtsevs may inform studies of the history of other mountain belts.”

Co-author, Dr Robin Bell of Columbia University’s Lamont-Doherty Earth Observatory says,

“The next steps will be to assemble a team to drill through the ice into the mountains to obtain the first rock samples from the Gamburtsevs. Amazingly, we have samples of the moon but none of the Gamburtsevs. With these rock samples we will be able to constrain when this ancient piece of crust was rejuvenated and grew to a magnificent mountain range.”

“It is very fitting that the initial results of Antarctica’s Gamburtsev Province (AGAP) project are coming out 100 years after the great explorers raced to the South Pole,” said Alexandra Isern, Programme Director at the National Science Foundation. “The scientific explorers of the AGAP project worked in harsh conditions to collect the data and detailed images of this major mountain range under the East Antarctic Ice Sheet. The results of their work will guide research in this region for many years to come.”

These discoveries in central East Antarctica have significant implications for understanding mountain building and ice sheet evolution within continental interiors.