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Slippery fault unleashed destructive Tohoku-Oki earthquake and tsunami

An international team of scientists has concluded that an unusually thin and slippery geological fault where the North American plate rides over the edge of the Pacific plate caused a massive displacement of the seafloor off the coast of Japan in March 2011, touching off the devastating tsunami that struck the Tohoku region. Credit: JAMSTEC/IODP

For the first time, scientists have measured the frictional heat produced by the fault slip during an earthquake. Their results, published December 5 in Science, show that friction on the fault was remarkably low during the magnitude 9.0 Tohoku-Oki earthquake that struck off the coast of Japan in March 2011 and triggered a devastating tsunami.

 

“The Tohoku fault is more slippery than anyone expected,” said Emily Brodsky, a geophysicist at the University of California, Santa Cruz, and coauthor of three papers on the Tohoku-Oki earthquake published together in Science. All three papers are based on results from the international Japan Trench Fast Drilling Project (JFAST), which Brodsky helped organize.

Because friction generates heat (like rubbing your hands together), taking the temperature of a fault after an earthquake can provide a measure of the fault’s frictional resistance to slip. But that hasn’t been easy to do. “It’s been difficult to get this measurement because the signal is weak and it dissipates over time, so we needed a big earthquake and a rapid response,” said Brodsky, a professor of Earth and planetary sciences at UCSC.

The JFAST expedition drilled across the Tohoku fault in 2012 and installed a temperature observatory in one of three boreholes nearly 7 kilometers below the ocean surface. The logistically and technically challenging operation successfully recovered temperature measurements and other data as well as core samples from across the fault.

The low resistance to slip on the fault may help explain the large amount of slip—an unprecedented 50 meters of displacement—that occurred during the earthquake, according to UC Santa Cruz researcher Patrick Fulton, who is first author of the paper focusing on the temperature measurements. An abundance of weak, slippery clay material in the fault zone—described in the two companion papers—may account for the low friction during the earthquake, he said.

The Tohoku-Oki earthquake occurred in a “subduction zone,” a boundary between two tectonic plates where one plate is diving beneath another—in this case, the Pacific plate dives beneath the Eurasian plate just east of Japan. Fulton explained that the epicenter, where the earthquake started, was much deeper than the shallow portion of the fault examined by JFAST. One of the surprising things about the earthquake, in addition to the 50 meters of slip, was that the fault ruptured all the way to the surface of the seafloor.

“The large slip at shallow depths contributed to the tsumani that caused so much damage in Japan. Usually, these earthquakes don’t rupture all the way to the surface,” Fulton said.

The strain that is released in a subduction zone earthquake is thought to build up in the deep portion of the fault where the two plates are “locked.” The shallow portion of the fault was not expected to accumulate a large amount of stress and was considered unlikely to produce a large amount of slip. The JFAST results show that the frictional stress on the shallow portion of the fault was very low during the earthquake, which means that either the stress was low to begin with or all of the stress was released during the earthquake.

“It’s probably a combination of both—the fault was pretty slippery to begin with, and whatever stress was on the fault at that shallow depth was all released during the earthquake,” Fulton said.

An earlier paper by JFAST researchers, published in Science in February 2013 (Lin et al.), also suggested a nearly total stress drop during the earthquake based on an analysis of geophysical data collected during drilling.

“We now have four lines of evidence that frictional stress was low during the earthquake,” Brodsky said. “The key measure is temperature, but those results are totally consistent with the other papers.”

One of the new papers (Ujiie et al.) presents the results of laboratory experiments on the material recovered from the fault zone. Tests showed very low shear stress (resistance to slip) attributable to the abundance of weak, slippery clay material. The other paper (Chester et al.) focuses on the geology and structure of the fault zone. In addition to the high clay content, the researchers found that the fault zone was surprisingly thin (less than 5 meters thick).

J. Casey Moore, a research professor of Earth sciences at UCSC and coauthor of the Chester et al. paper, said he suspects the clay layer observed in the Tohoku fault zone may play an important role in other fault zones. “Looking for something like that clay may give us a tool to understand the locations of earthquakes that cause tsunamis. It’s potentially a predictive tool,” Moore said.

According to Brodsky, measuring the frictional forces on the fault is the key to a fundamental understanding of earthquake mechanics. “We’ve been hamstrung without in situ measurements of frictional stress, and we now have that from the temperature data,” she said. “It’s hard to say how generalizable these results are until we look at other faults, but this lays the foundation for a better understanding of earthquakes and, ultimately, a better ability to identify earthquake hazards.”

Note : The above story is based on materials provided by University of California – Santa Cruz

Geoengineering Approaches to Reduce Climate Change Unlikely to Succeed

Heavy rainfall events can be more common in a warmer world. (Credit: Annett Junginger, distributed via imaggeo.egu.eu)

Reducing the amount of sunlight reaching the planet’s surface by geoengineering may not undo climate change after all. Two German researchers used a simple energy balance analysis to explain how Earth’s water cycle responds differently to heating by sunlight than it does to warming due to a stronger atmospheric greenhouse effect. Further, they show that this difference implies that reflecting sunlight to reduce temperatures may have unwanted effects on Earth’s rainfall patterns.

The results are now published in Earth System Dynamics, an open access journal of the European Geosciences Union (EGU).

Global warming alters Earth’s water cycle since more water evaporates to the air as temperatures increase. Increased evaporation can dry out some regions while, at the same time, result in more rain falling in other areas due to the excess moisture in the atmosphere. The more water evaporates per degree of warming, the stronger the influence of increasing temperature on the water cycle. But the new study shows the water cycle does not react the same way to different types of warming.

Axel Kleidon and Maik Renner of the Max Planck Institute for Biogeochemistry in Jena, Germany, used a simple energy balance model to determine how sensitive the water cycle is to an increase in surface temperature due to a stronger greenhouse effect and to an increase in solar radiation. They predicted the response of the water cycle for the two cases and found that, in the former, evaporation increases by 2% per degree of warming while in the latter this number reaches 3%. This prediction confirmed results of much more complex climate models.

“These different responses to surface heating are easy to explain,” says Kleidon, who uses a pot on the kitchen stove as an analogy. “The temperature in the pot is increased by putting on a lid or by turning up the heat — but these two cases differ by how much energy flows through the pot,” he says. A stronger greenhouse effect puts a thicker ‘lid’ over Earth’s surface but, if there is no additional sunlight (if we don’t turn up the heat on the stove), extra evaporation takes place solely due to the increase in temperature. Turning up the heat by increasing solar radiation, on the other hand, enhances the energy flow through Earth’s surface because of the need to balance the greater energy input with stronger cooling fluxes from the surface. As a result, there is more evaporation and a stronger effect on the water cycle.

In the new Earth System Dynamics study the authors also show how these findings can have profound consequences for geoengineering. Many geoengineering approaches aim to reduce global warming by reducing the amount of sunlight reaching Earth’s surface (or, in the pot analogy, reduce the heat from the stove). But when Kleidon and Renner applied their results to such a geoengineering scenario, they found out that simultaneous changes in the water cycle and the atmosphere cannot be compensated for at the same time. Therefore, reflecting sunlight by geoengineering is unlikely to restore the planet’s original climate.

“It’s like putting a lid on the pot and turning down the heat at the same time,” explains Kleidon. “While in the kitchen you can reduce your energy bill by doing so, in the Earth system this slows down the water cycle with wide-ranging potential consequences,” he says.

Kleidon and Renner’s insight comes from looking at the processes that heat and cool Earth’s surface and how they change when the surface warms. Evaporation from the surface plays a key role, but the researchers also took into account how the evaporated water is transported into the atmosphere. They combined simple energy balance considerations with a physical assumption for the way water vapour is transported, and separated the contributions of surface heating from solar radiation and from increased greenhouse gases in the atmosphere to obtain the two sensitivities. One of the referees for the paper commented: “it is a stunning result that such a simple analysis yields the same results as the climate models.”

Note : The above story is based on materials provided by European Geosciences Union (EGU). 

New Jersey Shore Likely Faces Unprecedented Flooding by Mid-Century

The amusement pier at Seaside Heights, N.J., under attack by Hurricane Sandy. (Credit: Master Sgt. Mark C. Olsen, New Jersey Air National Guard)

Geoscientists at Rutgers and Tufts universities estimate that the New Jersey shore will likely experience a sea-level rise of about 1.5 feet by 2050 and of about 3.5 feet by 2100 — 11 to 15 inches higher than the average for sea-level rise globally over the century.

That would mean, the scientists say, that by the middle of the century, the one-in-10 year flood level at Atlantic City would exceed any flood known there from the observational record, including Superstorm Sandy.

Ken Miller, Robert Kopp, Benjamin Horton and James Browning of Rutgers and Andrew Kemp of Tufts base their projections in part upon an analysis of historic and modern-day records of sea-level rise in the U.S. mid-Atlantic region. Their research appears in the inaugural issue of the journal Earth’s Future, published this week by the American Geophysical Union. It builds upon a recent study by Kemp, Horton and others that reconstructed a 2,500-year record of sea level at the New Jersey shore. Horton is a professor of marine and coastal sciences in Rutgers’ School of Environmental and Biological Sciences; Kemp, an assistant professor of earth and ocean sciences at Tufts.

“It’s clear from both the tide gauge and geological records that sea level has been rising in the mid-Atlantic region at a foot per century as a result of global average sea-level rise and the solid earth’s ongoing adjustment to the end of the last ice age,” said Miller, a professor of earth and planetary sciences in Rutgers’ School of Arts and Sciences. “In the sands of the New Jersey coastal plain, sea level is also rising by another four inches per century because of sediment compaction — due partly to natural forces and partly to groundwater withdrawal. But the rate of sea-level rise, globally and regionally, is increasing due to melting of ice sheets and the warming of the oceans.”

Sea-level rise in the mid-Atlantic region also results from changes in ocean dynamics, the scientists said. “Most ocean models project that the Gulf Stream will weaken as a result of climate change — perhaps causing as much as a foot of additional regional sea-level rise over this century,” said Kopp, an assistant professor of Earth and planetary sciences and associate director of the Rutgers Energy Institute.

The researchers said sea-level rise could be higher — 2.3 feet by mid-century and 5.9 feet by the end of the century — depending on how sensitive the Gulf Stream is to warming and how fast the ice sheets melt in response to that warming.

Either way, the researchers’ study of past sea-level change also revealed that something remarkable started happening over the last century. It’s not only temperatures that have been veering upward as a result of greenhouse gas emissions. “The geological sea-level records show that it’s extremely likely that sea-level in New Jersey was rising faster in the 20th century than in any century in the last 4300 years,” Kemp said.

The unprecedented 20th-century sea-level rise had a significant human impact. The study found that the eight inches of climate change-related regional sea-level rise in the 20th century exposed about 83,000 additional people in New Jersey and New York City to flooding during 2012’s Superstorm Sandy.

Miller, Kopp, Horton and Browning are affiliated with the Rutgers Climate Institute, whose recent State of the Climate: New Jersey report surveyed the current and future impacts of climate change on the state.

Note : The above story is based on materials provided by Rutgers University. 

Cookeite

Mount Mica Quarry, Paris, Oxford Co., Maine, USA © Van King

Chemical Formula: (Al2Li)Al2(AlSi3O10)(OH)8
Locality: Oxford Co., Maine, USA. Pala, San Diego Co., California, USA.
Name Origin: Named for Josiah B. Cooke, Jr. (1827-1894), American mineralogist and chemist, Harvard University, Cambridge, Massachusetts, USA.

Cookeite (pronounced Cook-ite) is an uncommon member of the Chlorite group, and is best known for its occurrence in granite pegmatites associated with Tourmaline, where it often forms as a growth layer upon the Tourmaline. Cookeite is named in honor of Josiah Parsons Cooke Jr. (1827-1894), a Harvard University scientist who was instrumental in the measurement of atomic weights.

Physical Properties of Cookeite

Cleavage: {001} Perfect
Color: White, Green, Brown, Yellowish white, Pinkish white.
Density: 2.67
Diaphaneity: Transparent to translucent
Fracture: Flexible – Flexible fragments.
Hardness: 2.5 – Finger Nail
Luminescence: Non-fluorescent.
Luster: Vitreous (Glassy)
Streak: white

Photos

Locality: Bennett Quarry, Buckfield, Oxford Co., Maine, USA FOV: 4mm Copyright © Bill Bunn
Locality: Strickland Quarry (Eureka Quarry), Strickland pegmatite (Strickland-Cramer Quarry; Strickland-Cramer Mine; Strickland-Cramer Feldspar-Mica Quarries), Collins Hill, Portland, Middlesex Co., Connecticut, USA FOV: 15 mm Copyright © Harold Moritz
Locality: Tamminen Quarry, Greenwood, Oxford Co., Maine, USA FOV: 1cm Copyright © Bill Bunn
Locality: Bennett Quarry, Buckfield, Oxford Co., Maine, USA Copyright © Peter Cristofono

Functional Importance of Dinosaur Beaks Illuminated

Computer models of the skull of Erlikosaurus andrewsi without (left) and with keratinous beak (right); colour plots resulting from finite element analysis show the degree of deformation in the different skull configurations. (Credit: Image by Dr Stephan Lautenschlager)

Why beaks evolved in some theropod dinosaurs and what their function might have been is the subject of new research by an international team of palaeontologists published this week in PNAS (Proceedings of the National Academy of Sciences).

Beaks are a typical hallmark of modern birds and can be found in a huge variety of forms and shapes. However, it is less well known that keratin-covered beaks had already evolved in different groups of dinosaurs during the Cretaceous Period.

Employing high-resolution X-ray computed tomography (CT scanning) and computer simulations, Dr Stephan Lautenschlager and Dr Emily Rayfield of the University of Bristol with Dr Perle Altangerel (National University of Ulaanbaatar) and Professor Lawrence Witmer (Ohio University) used digital models to take a closer look at these dinosaur beaks.

The focus of the study was the skull of Erlikosaurus andrewsi, a 3-4m (10-13ft) large herbivorous dinosaur called a therizinosaur, which lived more than 90 million years ago during the Cretaceous Period in what is now Mongolia, and which shows evidence that part of its snout was covered by a keratinous beak.

This new study reveals that keratinous beaks played an important role in stabilizing the skeletal structure during feeding, making the skull less susceptible to bending and deformation.

Lead author Dr Stephan Lautenschlager of Bristol’s School of Earth Sciences said: “It has classically been assumed that beaks evolved to replace teeth and thus save weight, as a requirement for the evolution of flight. Our results, however, indicate that keratin beaks were in fact beneficial to enhance the stability of the skull during biting and feeding.”

Co-author Dr Emily Rayfield, Reader of Palaeobiology at Bristol said: “Using Finite Element Analysis, a computer modelling technique routinely used in engineering, we were able to deduce very accurately how bite and muscle forces affected the skull of Erlikosaurus during the feeding process. This further allowed us to identify the importance of soft-tissue structures, such as the keratinous beak, which are normally not preserved in fossils.”

Co-author Lawrence Witmer, Chang Professor of Paleontology at the Ohio University Heritage College of Osteopathic Medicine said: “Beaks evolved several times during the transitions from dinosaurs to modern birds, usually accompanied by the partial or complete loss of teeth and our study now shows that keratin-covered beaks represent a functional innovation during dinosaur evolution.”

This work was funded by a research fellowship to Stephan Lautenschlager from the German Volkswagen Foundation and grants from the National Science Foundation to Lawrence Witmer.

Note : The above story is based on materials provided by University of Bristol.

International Drilling Mission to Lower Crust of Pacific Yields Unexpected Clues to Ocean Mysteries

Jonathan Snow (Co-chief Scientist, University of Houston, USA), Kathryn Gillis (Co-chief Scientist, University of Victoria, B.C., Canada) and Chad Broyles (Curatorial Specialist, IODP-USIO/TAMU) work on a core sample in the splitting room. (Credit: Bill Crawford, IODP/TAMU)

A University of Houston (UH) geoscientist and his colleagues are revealing new discoveries about Earth’s development, following a major international expedition that recovered the first-ever drill core from the lower crust of the Pacific Ocean.

Co-chief scientists Jonathan Snow from UH and Kathryn Gillis from University of Victoria in Canada led a team of 30 researchers from around the world on the $10 million expedition, finding a few surprises upon penetrating the lower crust of the Pacific. Their findings are described in the Dec. 1 issue of Nature in a paper titled “Primitive Layered Gabbros from Fast-Spreading Lower Oceanic Crust.”

“The ocean crust makes up two-thirds of the Earth’s surface and forms from volcanic magma at mid-ocean ridge spreading centers,” Snow said. “The deepest levels of this process are hidden from view due to the miles of upper volcanic crust on top. So, until now we had to make educated guesses about the formation of the lower crust based on seismic evidence and the study of analogous rocks found on land.”

Traveling aboard the Integrated Ocean Drilling Program Expedition 345 to the Hess Deep in the Pacific Ocean, the scientific voyagers recovered core sections of lower crustal rocks, called gabbros, that formed more than two miles beneath the sea floor. A large rift valley in the eastern equatorial Pacific, the Hess Deep is like an onion sliced and pulled apart, revealing its deeper layers.

“Hess Deep is like a window into the lower crust of the ocean, where we can drill directly into these lower crustal levels,” Snow said. “This is where magma rising up from the Earth’s mantle begins to crystallize on its way to eventual eruption at the sea floor.”

The two-month expedition, aboard the drilling vessel JOIDES Resolution, confirmed for the first time the widespread existence of layered gabbros in the lower crust. This observation had been predicted by plate tectonic theory and analogies made to fragments of ocean crust found on land, called ophiolites, but only rarely had actual layered rocks been recovered from the ocean floor.

A second surprise discovered by the explorers was akin to “finding gold in a silver mine,” according to Snow. By studying thin slices of the gabbros under polarizing microscopes, the scientists identified substantial amounts of the mineral orthopyroxene, a magnesium silicate that was thought to be absent from the lower crust.

“Orthopyroxene by itself is nothing special. Traces of it are often found at late stages of crystallization higher in the crust, but we never in our wildest dreams expected a lot of it in the lower crust,” Snow said. “Although this mineral is not economically valuable, the discovery means that basic chemical reactions forming the lower crust will now have to be re-studied.”

A third surprise, Snow says, casts doubt on one of the main theories of the construction of the lower ocean crust. It involved the mineral olivine, also a magnesium silicate. This mineral is known to grow in delicate crystals sometimes found in layered intrusions on land, but never expected in the ocean crust. This is because the separation of the tectonic plates was thought to deform the magma like play dough in a partially molten state that would have broken them up. However, Snow says, the last word isn’t written on this, because the researchers just cored a small section of the crust in one place on this expedition. To know for sure, they will have to explore the lower crust more, which will require drilling.

The fourth phase of ocean drilling, to be called the “International Ocean Discovery Program,” was approved in late November by the National Science Board (NSB). The NSB is the governing board of the National Science Foundation and is responsible for guiding the pursuit of national policies for promoting research and education in science and engineering.

Note : The above story is based on materials provided by University of Houston. The original article was written by Lisa Merkl.

A living desert underground

UA scientists have discovered diverse communities of bacteria, fungi and archaea on the surface of Kartchner stalactites that live off of nutrients from the cave drip water and contribute to the growth of the cave formations through calcite precipitation. Credit: Bob Casavant/Arizona State Park Service

In the perpetual darkness of a limestone cave, UA researchers have discovered a surprisingly diverse ecosystem of microbes eking out a living from not much more than drip water, rock and air

Hidden underneath the hilly grasslands studded with ocotillos and mesquite trees in southeastern Arizona lies a world shrouded in perpetual darkness: Kartchner Caverns, a limestone cave system renowned for its untouched cave formations, sculpted over millennia by groundwater dissolving the bedrock and carving out underground rooms, and passages that attract tourists from all over the world.
Beyond the reaches of sunlight and seemingly devoid of life, the caves are in fact teeming with an unexpected diversity of microorganisms that rival microbial communities on the earth’s surface, according to a new study led by University of Arizona researchers that has been published in the journal of the International Society for Microbial Ecology. The discovery not only expands our understanding of how microbes manage to colonize every niche on the planet but also could lead to applications ranging from environmental cleanup solutions to drug development.

“We discovered all the major players that make up a typical ecosystem,” said Julie Neilson, an associate research scientist in the UA’s College of Agriculture and Life Sciences. “From producers to consumers, they’re all there, just not visible to the naked eye.”

In a long-standing collaboration between Kartchner Caverns State Park and the UA, Neilson and her co-workers have spent years exploring the underground world and its inhabitants. For their latest study, they swabbed stalactites and other cave formations for DNA analysis. Based on the genes they found in their samples, they reconstructed the bacteria and archaea – single-celled microorganisms that lack a cell nucleus – living in the cave. Kept secret for 14 years after its discovery in 1974 by two UA graduate students who were hiking in the Whetstone Mountains just south of Benson, Ariz., Kartchner Caverns has been protected from human impact so that scientists can study the fragile environment and organisms inside the cave.

“We didn’t expect to find such a thriving ecosystem feasting on the scraps dripping in from the world above,” Neilson said. “What is most interesting is that what we found mirrors the desert above: an extreme environment starved for nutrients, yet flourishing with organisms that have adapted in very unique ways to this type of habitat.”

Unlike their counterparts on the surface, cave microbes can’t harness the energy in sunlight to build organic matter from carbon dioxide in the atmosphere. This process, known as photosynthesis, forms the basis of all life on Earth.

In the absence of light, bacteria live off water runoff dripping into the cave through cracks in the overlying rock and harvest the energy locked in compounds leaching out from decaying organic matter in the soils above and minerals dissolved within the rock fissures, Neilson and her team discovered.

Former UA doctoral student Marian Ortiz samples microbes that live on the surface of stalactites and other mineral deposits in Kartchner Caverns. Credit: Photo courtesy of Ginger Nolan/Kartchner Caverns State Park

“Kartchner is unique because it is a cave in a desert ecosystem,” Neilson explained. “It’s not like the caves in temperate areas such as in Kentucky or West Virginia, where the surface has forests, rivers and soil with thick organic layers, providing abundant organic carbon. Kartchner has about a thousand times less carbon coming in with the drip water.”

“The cave microbes make a living off the extremely limited nutrients that are available,” Neilson said. “Instead of relying on organic carbon, which is a very scarce resource in the cave, they use the energy in nitrogen-containing compounds like ammonia and nitrite to convert carbon dioxide from the air into biomass.”

The researchers found evidence of cave microbes engaging in all six known pathways that organisms use to fix carbon from the atmosphere to make food and structural material.

Neilson said although the nitrogen-driven pathway is probably the most dominant in the cave, there might be others. Some microbes even eat rock – to derive energy from chemical compounds such as manganese or pyrite.

Raina Maier, a professor in the Department of Soil, Water and Environmental Science at the College of Agriculture and Life Sciences – the study’s principal investigator – said the team expected to find the overall microbial diversity in the cave to be only a fraction of that found in the soil on the surface.

“We expected the surface community many times more diverse than the cave,” said Maier, who is also a member of the UA’s BIO5 Institute. “Instead, we found the cave is about half as diverse as the terrestrial environment where there is sunlight and soil and vegetation. At the same time, the two ecosystems share only 16 percent of the microbial species. In other words, there is a difference of 84 percent between the two, which is amazing.”

Previous studies had shown that, to the cave microbes, the stalactite they live on is like an island: Restricted to the stalactite they happen to be on, there appears to be little mixing between populations, resulting in different assemblages from one cave formation to another.

To analyze the DNA swabbed from the cave formations, Neilson and her team enlisted the help of the lab of Rod Wing, a professor in the UA’s Department of Plant Sciences and director of the Arizona Genomics Institute at BIO5.

“When you work in extreme starving environments, you barely get enough DNA,” Neilson explained. “In some of our samples we got about half of what is considered the minimum amount for DNA sequence analysis. But, we said, let’s just try it. And the wonderful technicians in Rod Wing’s lab tried all those new techniques and they managed to get us a data set even from the dry rock, where there is no drip water and where there are very few microbes living to begin with.”

In addition to encountering all the major players that make up a complex food web in the cave, the scientists discovered what likely are microbes yet unknown to science.

“Twenty percent of the bacteria whose presence we inferred based on the DNA sequences were not similar enough to anything in the database for us to be able to identify them,” Neilson said. “On one stalactite, we found a rare organism in a microbial group called SBR1093 that comprised about 10 percent of the population on that stalactite, but it represented less than 0.5 percent of the microbes on any of the others.”

According to Neilson, nobody has been able to culture that organism in the lab, and its DNA sequence has

Actively growing cave formations such as thread-like helictites and soda straws crowd the walls of Kartchner Caverns in areas where drip water percolates into the cave. Credit: Bob Casavant/Arizona State Park Service

only ever been found three times in history: in a stromatolite – a special type of sedimentary rock involving microbial communities – in the hypersaline waters of Shark Bay in Australia; in a site contaminated with hydrocarbons in France; and in a sewage treatment plant in Brisbane, Australia.

“This suggests there are many microbes out there in the world that we know almost nothing about,” she said. “The fact that these organisms showed up in contaminated soil could mean they might have potential for applications such as environmental remediation. The most abundant microbe that we found in our taxonomic survey was closely related to a microbe that produces erythromycin, an antibiotic. That is not what it is doing in the cave, but it shows you that not only is there a potential to find microbes that are new to science, but studying them in those extreme and poorly studied environments could lead to new applications.”

The implications of the research reach far beyond Kartchner Caverns, as far as other planets, as the researchers point out.

“There is a lot we have to learn about microbes and how they control processes of global importance, and by studying microbes in extreme ecosystems such as Kartchner Caverns or in the Atacama Desert in Chile, it helps us study some of the capabilities we don’t yet understand in rich ecosystems here on the surface,” Neilson said.

“It shows the flexibility of microbes,” Neilson said. “They have conquered every niche on the planet.”

Maier added: “When you think about exploring Mars, for example, and you look at all those clever strategies that microbes have evolved and tweaked over the past 4 billion years, I wouldn’t be surprised if we found them elsewhere if we just keep looking.”

Note : The above story is based on materials provided by University of Arizona

Lakes discovered beneath Greenland ice sheet

Example of deep pool through which a substantial volume of water appears to have flowed is likely the site of the moulin that formed in 2006. (Credit: Big Ice/Polar Science Center)

The subglacial lakes are the first to be identified in GreenlandThe study, published in Geophysical Research Letters, discovered two subglacial lakes 800 metres below the Greenland Ice Sheet. The two lakes are each roughly 8-10 km2, and at one point may have been up to three times larger than their current size.

Subglacial lakes are likely to influence the flow of the ice sheet, impacting global sea level change. The discovery of the lakes in Greenland will also help researchers to understand how the ice will respond to changing environmental conditions.
The study, conducted at the Scott Polar Research Institute (SPRI) at the University of Cambridge, used airborne radar measurements to reveal the lakes underneath the ice sheet.

Lead author Dr Steven Palmer, formerly of SPRI and now at the University of Exeter, stated: “Our results show that subglacial lakes exist in Greenland, and that they form an important part of the ice sheet’s plumbing system. Because the way in which water moves beneath ice sheets strongly affects ice flow speeds, improved understanding of these lakes will allow us to predict more accurately how the ice sheet will respond to anticipated future warming.”

The lakes are unusual compared with those detected beneath Antarctic ice sheets, suggesting that they formed in a different manner. The researchers propose that, unlike in Antarctica where surface temperatures remain below freezing all year round, the newly discovered lakes are most likely fed by melting surface water draining through cracks in the ice. A surface lake situated nearby may also replenish the subglacial lakes during warm summers.

This means that the lakes are part of an open system and are connected to the surface, which is different from Antarctic lakes that are most often isolated ecosystems.

While nearly 400 lakes have been detected beneath the Antarctic ice sheets, these are the first to be identified in Greenland. The apparent absence of lakes in Greenland had previously been explained by the fact that steeper ice surface in Greenland leads to any water below the ice being ‘squeezed out’ to the margin.

The ice in Greenland is also thinner than that in Antarctica, resulting in colder temperatures at the base of the ice sheet. This means that any lakes that may have previously existed would have frozen relatively quickly. The thicker Antarctic ice can act like an insulating blanket, preventing the freezing of water trapped underneath the surface.

As many surface melt-water lakes form each summer around the Greenland ice sheet, the possibility exists that similar subglacial lakes may be found elsewhere in Greenland. The way in which water flows beneath the ice sheet strongly influences the speed of ice flow, so the existence of other lakes will have implications for the future of the ice sheet.

Note : The above story is based on materials provided by University of Cambridge

What Drives Aftershocks?

Setting up a Creepmeter Station in Southern Central Chile. (Credit: GFZ)

On 27 February 2010 an earthquake of magnitude 8.8 struck South-Central Chile near the town of Maule. The main shock displaced the subduction interface by up to 16 meters. Like usually after strong earthquakes a series of aftershocks occurred in the region with decreasing size over the next months. A surprising result came from an afterslip study: Up to 2 meters additional slip occurred along the plate interface within 420 days only, in a pulse like fashion and without associated seismicity. An international research group lead by GFZ analysed the main shock as well as the following postseismic phase with a dense network of instruments including more than 60 high-resolution GPS stations.

The aftershocks and the now found “silent” afterslip are key to understand the processes occurring after strong earthquakes. The GPS data in combination with seismological data allowed for the first time a comparative analysis: Are aftershocks triggered solely by stress transfer from the main shock or are additional mechanisms active? “Our results suggest, that the classic view of the stress relaxation due to aftershocks are too simple” says Jonathan Bedford from GFZ to the new observation: “Areas with large stress transfer do not correlate with aftershocks in all magnitude classes as hitherto assumed and stress shadows show surprisingly high seismic activity.”

A conclusion is that local processes which are not detectable at the surface by GPS monitoring along the plate interface have a significant effect on the local stress field. Pressurized fluids in the crust and mantle could be the agent here. As suspected previously, the main and aftershocks might have generated permeabilities in the source region which are explored by hydrous fluids. This effects the local stress field triggering aftershocks rather independently from the large scale, main shock induced stress transfer. The present study provides evidences for such a mechanism. Volume (3D) seismic tomography which is sensitive to fluid pressure changes in combination with GPS monitoring will allow to better monitor the evolution of such processes.

The main shock was due to a rupture of the interface between the Nasca and the South American plates. Aftershocks are associated with hazards as they can be of similar size as the main shock and, in contrast to the latter, much shallower in the crust.

Note : The above story is based on materials provided by Helmholtz Centre Potsdam – GFZ German Research Centre for Geosciences. 

Connellite

Locality: Sol Mine, Cerro de los Guardias, Rodalquilar, Níjar, Almería, Andalusia, Spain FOV: 1.5mn Copyright © Christiane & Jean-Robert Eytier

Chemical Formula: Cu19(SO4)(OH)32Cl4 · 3H2O
Name Origin: Named after the Scottish chemist, A. Conell (1794-1863).

Connellite is a rare mineral species, a hydrous copper chloro-sulfate, Cu19(OH)32(SO4)Cl4·3H2O, crystallizing in the hexagonal system. It occurs as tufts of very delicate acicular crystals of a fine blue color, and is associated with other copper minerals of secondary origin, such as cuprite and malachite. Its occurrence in Cornwall, England, was noted by Philip Rashleigh in 1802, and it was first examined chemically by Prof Arthur Connell FRSE in 1847, after whom it is named.

The type locality is Wheal Providence at Carbis Bay in Cornwall. Outside Cornwall it has been found in over 200 locations worldwide including Namaqualand in South Africa and at Bisbee, Arizona (USA).

Physical Properties of Connellite

Cleavage: None
Color: Blue green, Light blue.
Density: 3.4
Diaphaneity: Translucent
Fracture: Uneven – Flat surfaces (not cleavage) fractured in an uneven pattern.
Hardness: 3 – Calcite
Luminescence: Non-fluorescent.
Luster: Vitreous (Glassy)
Magnetism: Nonmagnetic
Streak: light blue green

Photos

Locality: Bleida Mine, Bleida, Bou Azer District (Bou Azzer District), Tazenakht, Ouarzazate Province, Souss-Massa-Draâ Region, Morocco FOV: 2mm Copyright © Pierre Le Roch
Locality: Madonna di Fucinaia (Madonna della Fucinaia) slag heaps, Campiglia Marittima, Campigliese (Campiglia Mountains; Campiglia Ridge), Livorno Province, Tuscany, Italy FOV: 1.2mm Copyright © Tiberio Bardi
Locality: Clara Mine, Rankach valley, Oberwolfach, Wolfach, Black Forest, Baden-Württemberg, Germany Picture width 3 mm. Copyright © Stephan Wolfsried

Locality: Hilarion Mine (Hilarion adit; Hilarion Mine No. 50), Hilarion area, Kamariza Mines (Kamareza Mines), Agios Konstantinos [St Constantine] (Kamariza), Lavrion District Mines, Lavrion District (Laurion; Laurium), Attikí Prefecture (Attica; Attika), Greece FOV; 15mm Copyright ©Fritz Schreiber

Indirect study of Earth’s core

The diamonds are embedded in a steel casing that is used to apply extreme pressure on the rock samples. Studying how surface rocks change under high pressure and temperature helps researchers understand how rocks behave deep within the Earth’s mantle. Credit: Kristen Hwang

The center of the Earth is about 6,371 kilometers or 4, 000 miles away, roughly the distance between Phoenix and the North Pole.

It cannot be seen. It cannot be touched. And it cannot be sampled.

But that doesn’t stop Dan Shim, a mineral physicist in the School of Earth and Space Exploration at ASU, from trying to understand the forces working deep within our world.
“You may wonder why I’m interested in the interior, which is far, far away and sounds like something that is separated from our daily life,” Shim said. “But if you think of the whole planet, the surface is very small volumetrically and the interior represents 99 percent of the planet.”

Studying the interior of the Earth helps scientists answer questions about how the Earth has changed over billions of years and why there are volcanoes and earthquakes, Shim said.

But figuring out what the inside of the Earth is made of is not so easy.

“If you think about geologists, you think about rocks and studying rocks, but in our case there are no rock samples to deal with unfortunately,” Shim said.

There are several different ways to study the Earth’s interior, which cannot be directly probed. Seismologists look at how earthquakes propagate through the Earth and try to construct an image based on the waves’ reflections and refractions.

Shim’s research helps seismologists understand what the images mean.

“If you do an ultrasound of your body, you’re basically looking at contrasts in properties,” Shim said. The reason doctors can say, “This is a tumor,” is because the tumor looks different relative to the image of the body surrounding it, he said.

“But to understand the image, you need to understand the properties of the material that makes up the particular thing you image,” Shim said. “My job is to squeeze the rock up to the pressure you expect for the mantle and the core and observe what kind of processes are going on in the lab.”

Shim and his research team study how the properties of rocks change under extreme pressure and temperature by simulating the conditions in the laboratory.

The laboratory experiments help Shim understand how the deep interior of the Earth operates and helps him interpret seismology data.

“One fancy part of my research is using diamonds,” Shim said.

Diamond is the strongest material known in nature, making it ideal for high pressure experiments.

Using a microscope and a needle, Shim takes pieces of rocks smaller than the width of a human hair and places them in between two quarter-carat diamonds. The diamonds, which are embedded in steel casings, are forced together by four screws to higher and higher pressures.

“If you stack 100 Statue of Liberties, and then apply that weight to one square inch, that’s roughly the pressure at the center of the Earth,” Shim said.

The pressure Shim works with is so great that sometimes the diamonds break, he said.

“We have a joke in my community: How many diamonds do you need to break to get a Ph.D.?” Shim said. “I broke 11.”

Shim has been an associate professor in the School of Earth and Space Exploration since August 2011. He has taught Geology 101, Planetary Materials and will be teaching Dynamic Planet in the spring.

“SESE has a very unique structure bringing astrophysicists, geologists, geophysicists and system engineers all together,” Shim said. “This unique structure presents a lot of new opportunities.”

Note : The above story is based on materials provided by Arizona State University

Ancient Minerals: Which Gave Rise to Life?

The magnesium silicate forsterite was one of the most abundant minerals in the Hadean Eon, and it played a major role in Earth’s near-surface processes. The green color of this mineral (which is also known as the semi-precious gemstone peridot, the birthstone of August) is caused by small amounts iron. The iron can react with seawater to promote chemical reactions that may have played a role in life’s origins. (Credit: Robert Downs, University of Arizona, Ruff Project)

Life originated as a result of natural processes that exploited early Earth’s raw materials. Scientific models of life’s origins almost always look to minerals for such essential tasks as the synthesis of life’s molecular building blocks or the supply of metabolic energy. But this assumes that the mineral species found on Earth today are much the same as they were during Earth’s first 550 million years — the Hadean Eon — when life emerged. A new analysis of Hadean mineralogy challenges that assumption. It is published in American Journal of Science.

Carnegie’s Robert Hazen compiled a list of every plausible mineral species on the Hadean Earth and concludes that no more than 420 different minerals — about 8 percent of the nearly 5,000 species found on Earth today — would have been present at or near Earth’s surface.

“This is a consequence of the limited ways that minerals might have formed prior to 4 billion years ago,” Hazen explained. “Most of the 420 minerals of the Hadean Eon formed from magma — molten rock that slowly crystallized at or near Earth’s surface — as well as the alteration of those minerals when exposed to hot water.”

By contrast, thousands of mineral species known today are the direct result of growth by living organisms, such as shells and bones, as well as life’s chemical byproducts, such as oxygen from photosynthesis. In addition, hundreds of other minerals that incorporate relatively rare elements such as lithium, beryllium, and molybdenum appear to have taken a billion years or more to first appear because it is difficult to concentrate these elements sufficiently to form new minerals. So those slow-forming minerals are also excluded from the time of life’s origins.

“Fortunately for most origin-of-life models, the most commonly invoked minerals were present on early Earth,” Hazen said.

For example, clay minerals — sometimes theorized by chemists to trigger interesting reactions — were certainly available. Sulfide minerals, including reactive iron and nickel varieties, were also widely available to catalyze organic reactions. However, borate and molybdate minerals, which are relatively rare even today, are unlikely to have occurred on the Hadean Earth and call into question origin models that rely on those mineral groups.

Several questions remain unanswered and offer opportunities for further study of the paleomineralogy of the Hadean Eon. For example, the Hadean Eon differs from today in the frequent large impacts of asteroids and comets — thousands of collisions by objects with diameters from a mile up to 100 miles. Such impacts would have caused massive disruption of Earth’s crust, with extensive fracture zones that were filled with hot circulating water. Such hydrothermal areas could have created complex zones with many exotic minerals.

This study also raises the question of how other planets and moons evolved mineralogically. Hazen suggests that Mars today may have progressed only as far as Earth’s Hadean Eon. As such, Mars may be limited to a similar suite of no more than about 400 different mineral species. Thanks to the Curiosity rover, we may soon know if that’s the case.

Note : The above story is based on materials provided by Carnegie Institution. 

When tectonics killed everything

Geostationary Operational Environmental Satellite-11 (GEOS-11) image of the Earth acquired on June 14, 2000. Credit: NOAA

A new paper reveals how the worst extinction in Earth’s history may have been tied to the formation of Supercontinent Pangea. The catastrophe wasn’t triggered by an impact from above—unlike another well-known extinction—but by a geological process below, deep within Earth’s core.

It’s often known as “The Great Dying.”

About 252 million years ago, all life nearly vanished. More than 90 percent of ocean species and 70 percent of land species died. Trees, plants, reptiles, fish, insects, microbes—all nearly wiped out. 

The event marked the end of the Permian period and the beginning of the Triassic, the period that would give rise to the dinosaurs. But unlike the later Cretaceous extinction, the one that’d kill off the dinosaurs 186 million years later, this one wasn’t caused by an asteroid impact, most scientists think. The ultimate trigger, in fact, has remained an ongoing mystery. 

Scientists have unearthed many clues over the last decades, but they’ve yet to reach a final verdict. So far the evidence has pointed toward drastic changes on Earth and in the oceans. Oxygen levels were low in the oceans, making it difficult for many animals to survive. Carbon dioxide and methane levels were unusually high, contributing to major warming of the planet. Acid rain fell, and made sea water so acidic that all coral reefs disappeared. The inland turned into an dry desert, hot and arid, and devastated by major wild fires. The climate also varied between periods of sudden warming and cooling, making it impossible for many species to adjust.

Many of these changes have been tied to the eruption of two major volcanoes—one in southern China 260 million years ago, and one in northern Russia 251 million years ago. These would have released the large amounts of carbon dioxide, leading to greenhouse effects and global warming. The carbon dioxide also made the seawater acidic, killing off many marine organisms. The eruptions would also have led to the catastrophic release of methane, another potent greenhouse gas, stored as methane “ice” nearby under the seabed.

But the drama may have already started earlier, some scientists think. Drastic drops in sea levels had already perturbed ocean currents and wind patterns, inducing climate change.

And yet, all these clues could in fact be related.

When All the World Was One

In a paper published this month in Science China, Earth Sciences, two scientists attempt to pull the curtain further back, to give a fuller picture. According to Dr. Yin Hongfu and Dr. Song Haijun of China University of Geosciences (Wuhan), all the events described above may have been set in motion 50 million years before the climax of the catastrophe.

According to the paper, here’s how the story may have begun.

Some 300 million years ago, at the beginning of the Permian period, all the world’s lands had joined into a single supercontinent, Pangea, and all the world’s sea water had formed a global ocean, Panthalassa.

The formation of Pangea led to higher mountains and deeper oceans. According to an equilibrium principle, a giant continent should have a thicker crust than each scattered continent, and the oceans should become deeper. This recession of water away from the land would have eliminated a lot of the biodiversity that thrives in shallow water near the coasts. This recession would have also led to changes in ocean currents and wind patterns, initiating global climate changes.

What’s more, the inland region of one giant continent would become dry and arid, leading to the disappearance of much vegetation.

But something else also went on, deep within the Earth.

When the lands joined, some tectonic plates moved under others and sunk deep into the Earth’s mantle. That cooler material then may have reached all the way to the Earth’s core layer. Evidence for that includes the reversal of Earth’s magnetic field that occurred around that time, an event called the Illawarra magnetic reversal.

The accumulation of cool material near Earth’s core then could have led to the formation of a large mantle plume (by a process called thermo-convection), other researchers had suggested. That “super-plume” would eventually reach the Earth’s surface in two separate bursts—first with an eruption in China 260 million years ago, and then with the other in Russia 251 million years ago.

By that point, all life had nearly vanished.

In short, the paper argues that the Great Dying may have been an ongoing process tied to the formation of Pangea, which led to sea level change and climate change, but also and ultimately to what went on inside the Earth.

Problems with Pangea

Late Permian (260 million years ago) — All the world’s lands had joined into a single supercontinent, Pangea, and all the world’s sea water had formed a global ocean, Panthalassa. Credit: Ron Blakey, NAU Geology

However, many scientists disagree with the theory that the formation of Pangea played any role in the extinction. Some argue that the formation of Pangaea happened too early, and that the dying happened too rapidly, for the two events to be linked.

Others don’t think that sea level changes played a role in the extinction. “I don’t agree with all the links they propose,” says Paul Wignall, a Professor of Palaeoenvironments at the University of Leeds. “The peak regression [low sea levels] in the late Permian is significantly before the mass extinction and so unlikely to be a factor.”

As for the other factors, most scientists seem to have reached a consensus. “The paper is not really saying anything new but giving an overview of the key factors responsible,” Wignall adds. “Nearly all, including me, blame volcanism.”

But the paper’s real point, it seems, is that both the formation of Pangea and the volcanic eruptions were caused by processes deep inside the Earth—which could have been related, even if one occurred before the other.

The links between inner Earth, Earth’s surface, and the evolution of life is “an important theme of the earth system science that is worthy of further investigation,” wrote the authors.

But they also concede that their hypothesis is just that, an hypothesis, and that more research is needed. They end the paper, perhaps fittingly, with a quote by an ancient Chinese poet named Qu Yuan, who wrote:

“Long as might be the road, keep searching above and below I would.”

Note : The above story is based on materials provided by Astrobio net

Oceanic ‘dead zones’ and Jurassic extinction

The fossil study found a reduction in the size of the 183-million-year-old-clams as oxygen in the water diminished

Data collected by a scientist now at the University of Liverpool has predicted a dramatic decline in the size of marine animals used as food by humans, due to reduced oxygen levels in the oceans.

Dr Bryony Caswell, from the University’s School of Environmental Sciences, in collaboration with Dr Angela Coe at the Open University, studied over 36,000 fossilised clam shells from northern England. These clams date from a short period near the beginning of the Jurassic (183 million years ago) which featured climatic change and declining oxygen levels in the seas, similar to that occurring today.

Ocean dead zones

Over 7% of the world’s oceans are classed as low oxygen zones or ‘ocean dead zones’.  This figure has grown dramatically over the last 50 years, caused by increasing levels of pollution and accelerating climate change. Other recently published studies have shown that low oxygen reduces organism size and have predicted that under our current emissions scenario this will to lead to a decrease in the body size of individual marine animals of around 25% by 2050.

The fossil study, which took place in Whitby, Yorkshire, found a reduction in the size of the 183-million-year-old-clams as oxygen in the water diminished.  These changes affected ocean chemistry, which in turn affected the clams’ algal food supply and the rest of the food chain – leading to a decrease in biodiversity and the average body size of clams.

This process has important ramifications for today’s marine life, and for the humans which feed on it.  Around 14% of the animal protein consumed today comes from the oceans, and with projections from this study foreseeing a decline of mean shellfish size of up to 50%, it could mean a significant food source for a growing population is now in decline.

During the early Jurassic period studied by the researchers, many species became extinct.  However, some flourished, such as the clam Pseudomytiloides dubius which was small, reached sexual maturity quickly, and reproduced in large numbers. Similar patterns can be observed today, with dramatic growth in the populations of the modern-day coot clam in areas which have low oxygen levels.

Declining oxygen levels

Dr Caswell, said: “By examining changes in the oceans that happened millions of years ago we are able to piece together more of the picture of what is likely to happen in our own time as a result of declining oxygen levels.”

“Unfortunately, our research has shown that if ocean oxygen levels continue to decline, within the next few decades to centuries, it is likely that marine molluscs and possibly other seafloor animals will be smaller and there will be fewer species.  This reduction in body-size and biodiversity has profound implications for the animals in our seas and the people who rely on them for food.”

The study was published in the journal Geology.

Note : The above story is based on materials provided by University of Liverpool

Clues to paleoclimate from tiny fossils

paleoclimato
Credit: Wikimedia Commons

New insights into the growth dynamics of minuscule marine organisms could help put the study of Earth’s climate, both present and prehistoric, on a more solid footing.

For hundreds of millions of years, the tiny shells of single-celled marine organisms called foraminifera have been accumulating on the ocean floor. Their shells contain clues about the composition of the seawater they lived in. In a recent cooperation between EPFL and the Alfred Wegener Institute, researchers lay out a new explanation for how these organisms take up the elements they use to grow their shells, offering climatologists a better understanding into a common tool to study the Earth’s climate history. Their results were published in the journal Biogeosciences in late October, and highlighted in the November 22 issue of Science.

Scientists often rely on secondary evidence, from ice or sediment cores, to reconstruct the prehistoric climate. Studying sediment cores containing foraminifera, scientists have reconstructed temperature timelines and analyzed the planet’s ice cover based on the composition of the shells. But as coauthor Anders Meibom explains, because they are the result of complex biological processes, foraminifer from sediment cores cannot be interpreted easily using data from inorganically formed minerals.

Not just passive transport

Foraminifera build their shells by using calcium, carbon, and oxygen that they find in seawater. Until now, scientists thought that the microorganisms used tiny “carrier bubbles,” or vacuoles, to transport seawater into them. There, calcium carbonate would precipitate from the water, forming the shell.

Scientists have long been baffled by the low magnesium concentrations in the shells. Seawater has five times more magnesium than calcium, so if minerals only entered the shells through vacuoles, they would contain large amounts of magnesium – unless it was somehow removed from the organism. Researchers have proposed a number of ways that the magnesium could be removed; yet none of them have ever been proven.

Molecular pumps that select for calcium

Instead of being taken up in vacuoles, the authors of this recent paper hold that most of the calcium is let in through transmembrane transport, which selects for calcium, but block magnesium. The fact that the shells nevertheless contain small amounts of magnesium means that both mechanisms could act in tandem, with non-selective vacuole transport accounting for the traces of magnesium found in the shells.

Based on the magnesium-calcium ratio in the surrounding seawater, the researchers developed a model to predict the magnesium-calcium ratio in the foraminifera shells. “We tested our predictions against three different experiments where foraminifera were grown in an aquarium, and the fit was almost perfect,” says Anders Meibom. According to lead author Gernot Nehrke from the Alfred Wegener Institute, their model is the first to predict the composition of the foraminifera shells without having to resort to unconfirmed theories of magnesium removal.

Beyond ice fields

“Foraminifera can provide all sorts of information on the climate, but until now, they have been treated as a black box. With this research we are beginning to understand, at a sub-cellular level, how these organisms develop, giving us a better idea about both the accuracy and the limits of sediment core measurements to reconstruct the climate of the past,” says Meibom.
Note : The above story is based on materials provided by Ecole Polytechnique Federale de Lausanne

Colossal New Predatory Dino Terrorized Early Tyrannosaurs

This is an illustration of Siats meekerorum. (Credit: Artwork by Jorge Gonzales)

A new species of carnivorous dinosaur — one of the three largest ever discovered in North America — lived alongside and competed with small-bodied tyrannosaurs 98 million years ago. This newly discovered species, Siats meekerorum, (pronounced see-atch) was the apex predator of its time, and kept tyrannosaurs from assuming top predator roles for millions of years.
Named after a cannibalistic man-eating monster from Ute tribal legend, Siats is a species of carcharodontosaur, a group of giant meat-eaters that includes some of the largest predatory dinosaurs ever discovered. The only other carcharodontosaur known from North America is Acrocanthosaurus, which roamed eastern North America more than 10 million years earlier. Siats is only the second carcharodontosaur ever discovered in North America; Acrocanthosaurus, discovered in 1950, was the first.

“It’s been 63 years since a predator of this size has been named from North America,” says Lindsay Zanno, a North Carolina State University paleontologist with a joint appointment at the North Carolina Museum of Natural Sciences, and lead author of a Nature Communications paper describing the find. “You can’t imagine how thrilled we were to see the bones of this behemoth poking out of the hillside.”

Zanno and colleague Peter Makovicky, from Chicago’s Field Museum of Natural History, discovered the partial skeleton of the new predator in Utah’s Cedar Mountain Formation in 2008. The species name acknowledges the Meeker family for its support of early career paleontologists at the Field Museum, including Zanno.

The recovered specimen belonged to an individual that would have been more than 30 feet long and weighed at least four tons. Despite its giant size, these bones are from a juvenile. Zanno and Makovicky theorize that an adult Siats might have reached the size of Acrocanthosaurus, meaning the two species vie for the second largest predator ever discovered in North America. Tyrannosaurus rex, which holds first place, came along 30 million years later and weighed in at more than twice that amount.

Although Siats and Acrocanthosaurus are both carcharodontosaurs, they belong to different sub-groups. Siats is a member of Neovenatoridae, a more slender-bodied group of carcharodontosaurs. Neovenatorids have been found in Europe, South America, China, Japan and Australia. However, this is the first time a neovenatorid has ever been found in North America.

Siats terrorized what is now Utah during the Late Cretaceous period (100 million years ago to 66 million years ago). It was previously unknown who the top meat-eater was in North America during this period. “Carcharodontosaurs reigned for much longer in North America than we expected,” says Zanno. In fact, Siats fills a gap of more than 30 million years in the fossil record, during which time the top predator role changed hands from carcharodontosaurs in the Early Cretaceous to tyrannosaurs in the Late Cretaceous.

The lack of fossils left paleontologists unsure about when this change happened and if tyrannosaurs outcompeted carcharodontosaurs, or were simply able to assume apex predator roles following carcharodontosaur extinction. It is now clear that Siats’ large size would have prevented smaller tyrannosaurs from taking their place atop the food chain.

“The huge size difference certainly suggests that tyrannosaurs were held in check by carcharodontosaurs, and only evolved into enormous apex predators after the carcharodontosaurs disappeared,” says Makovicky. Zanno adds, “Contemporary tyrannosaurs would have been no more than a nuisance to Siats, like jackals at a lion kill. It wasn’t until carcharodontosaurs bowed out that the stage could be set for the evolution of T. rex.”

At the time Siats reigned, the landscape was lush, with abundant vegetation and water supporting a variety of plant-eating dinosaurs, turtles, crocodiles, and giant lungfish. Other predators inhabited this ecosystem, including early tyrannosaurs and several species of other feathered dinosaurs that have yet to be described by the team. “We have made more exciting discoveries including two new species of dinosaur,” Makovicky says.

“Stay tuned,” adds Zanno. “There are a lot more cool critters where Siats came from.”

All fieldwork was conducted under permits through the Bureau of Land Management and funded by the Field Museum. Research was funded by North Carolina State University, North Carolina Museum of Natural Sciences and the Field Museum.

Note : The above story is based on materials provided by North Carolina State University.

Pre-Industrial Rise in Greenhouse Gases Had Natural and Anthropogenic Causes

For years scientists have intensely argued over whether increases of potent methane gas concentrations in the atmosphere – from about 5,000 years ago to the start of the industrial revolution – were triggered by natural causes or human activities. (Credit: © dell / Fotolia)

For years scientists have intensely argued over whether increases of potent methane gas concentrations in the atmosphere – from about 5,000 years ago to the start of the industrial revolution – were triggered by natural causes or human activities.A new study, which will be published Friday in the journal Science, suggests the increase in methane likely was caused by both.
Lead author Logan Mitchell, who coordinated the research as a doctoral student at Oregon State University, said the “early anthropogenic hypothesis,” which spawned hundreds of scientific papers as well as books, cannot fully explain on its own the rising levels of atmospheric methane during the past 5,000 years, a time period known as the mid- to late-Holocene. That theory suggests that human activities such as rice agriculture were responsible for the increasing methane concentrations.

Opponents of that theory argue that human activities during that time did not produce significant amounts of methane and thus natural emissions were the dominant cause for the rise in atmospheric CH4.

“We think that both played a role,” said Mitchell, who is now a post-doctoral researcher at the University of Utah. “The increase in methane emissions during the late Holocene came primarily from the tropics, with some contribution from the extratropical Northern Hemisphere.

“Neither modeled natural emissions alone, nor hypothesized anthropogenic emissions alone, are able to account for the full increase in methane concentrations,” Mitchell added. “Combined, however, they could account for the full increase.”

Scientists determine methane levels by examining ice cores from polar regions. Gas bubbles containing ancient air trapped within the ice can be analyzed and correlated with chronological data to determine methane levels on a multidecadal scale. Mitchell and his colleagues examined ice cores from the West Antarctic Ice Sheet Divide and the Greenland Ice Sheet Project and found differences between the two.

Ice cores from Greenland had higher methane levels than those from Antarctica because there are greater methane emissions in the Northern Hemisphere. The difference in methane levels between the hemispheres, called the Inter-Polar Difference, did not change appreciably over time.

“If the methane increase was solely natural or solely anthropogenic, it likely would have tilted the Inter-Polar Difference out of its pattern of relative stability over time,” Mitchell said.

Since coming out of the ice age some 10,000 years ago summer solar insolation in the Northern Hemisphere has been decreasing as a result of the Earth’s changing orbit, according to Edward Brook, a paleoclimatologist in Oregon State’s College of Earth, Ocean, and Atmospheric Sciences and Mitchell’s major professor. This decrease affects the strength of Asian summer monsoons, which produce vast wetlands and emit methane into the atmosphere.

Yet some 5,000 years ago, atmospheric methane began rising and had increased about 17 percent by the time the industrial revolution began around 1750.

“Theoretically, methane levels should have decreased with the loss of solar insolation in the Northern Hemisphere, or at least remained stable instead of increasing,” said Brook, a co-author on the Science article. “They had been roughly on a parallel track for some 800,000 years.”

Mitchell used previous models that hypothesized reasons for the methane increase – both natural and anthropogenic – and compared them to the newly garnered ice core data. None of them alone proved sufficient for explaining the greenhouse gas increase. When he developed his own model combining characteristics of both the natural and anthropogenic hypotheses, it agreed closely with the ice core data.

Other researchers have outlined some of the processes that may have contributed to changes in methane emissions. More than 90 percent of the population lived in the Northern Hemisphere, especially in the lower latitudes, and the development of rice agriculture and cattle domestication likely had an influence on methane emissions. On the natural side, changes in the Earth’s orbit could have been responsible for increasing methane emissions from tropical wetlands.

“All of these things likely have played a role,” Mitchell said, “but none was sufficient to do it alone.”

The study was supported by the National Science Foundation’s Office of Polar Programs, with additional support from the Oregon National Aeronautics and Space Administration (NASA) Space Grant Consortium.

Note : The above story is based on materials provided by Oregon State University. 

Satellite Trio to Explore the Earth’s Magnetic Field

Swarm in space. (Credit: ESA/AOES Medialab)

In a dense fog, a Russian Rockot rocket on 22 November 2013 cleared the launchpad of the Baikonur Cosmodrome on schedule at 13:02:15 CET. In the tip of the rocket: three identical satellites to measure the Earth’s magnetic field.

A good hour and a half later, at 14:37:48 CET, the report of success: all three satellites separated seamlessly from the carrier rocket and the ground stations Kiruna (Sweden) and Longyearbyen /Svalbard (Norway) were able to establish radio contact with them. GFZ scientists and invited guests observed the start of the mission called SWARM of the European Space Agency in Darmstadt via remote transmission.

 

Professor Johanna Wanka, Federal Minister of Education and Research said on the occasion of the perfect start of the mission: “We are very pleased that this European mission has started so smoothly.The magnetic field of the Earth is our shield against cosmic particle radiation. But it is subject to natural fluctuations, from the Earth’s interior or eruptions on the Sun. Improving the exploration of its function and recording space weather data more accurately allows us to draw conclusions for life on our planet.”

Professor Reinhard Huettl, Chairman of the Board of the GFZ German Research Centre for Geosciences pointed out a Potsdam success story: “The three satellites are direct developments from the CHAMP mission of the GFZ, which was launched in 2000. CHAMP with his followers GRACE and SWARM proves to be the founding father of a whole generation of satellites and space-based measurement methods.”

A trio for the magnetic field

SWARM is an ESA mission as part of its “Living Planet” program. “The satellite swarm — hence the name — is to measure the Earth’s magnetic field from space with unprecedented precision for at least four years,” elaborated Professor Huettl. For this, the three satellites fly in an optimized formation: two satellites (SWARM-A, SWARM-B) fly in an altitude of 450 kilometers with a distance of 150 kilometers alongside one another, the third (SWARM-C) ascends into a higher orbit at 530 km altitude. The reason for this complex formation flight lies in the magnetic field itself: it is generated by the flow of electrically conducting liquid iron in the outer core oft he Earth, 2900 kilometers beneath our feet. It is influenced by the conductivity and the dynamics of the overlying mantle (up to 40 kilometers below the Earth’s surface). Finally, the magnetized rocks of the Earth’s crust contribute to the Earth’s magnetic field. In addition, the sun and currents in near-Earth space influence the Earth’s magnetic field from the outside. In order to study these individual components, the total signal of the magnetic field measured by the satellite needs to be separated into its individual components. “From its distance of 150 kilometers, the lower flying SWARM pair can look at the magnetic field of the Earth’s crust with a stereo view,” explains Professor Hermann Lühr , one of the three Principle Investigators of the mission, member of the SWARM Mission Advisory Group and Head of the German SWARM Project Office at the GFZ. “We can therefore analyze this component with very high accuracy.” The third, upper SWARM satellite can in turn precisely determine the force of the magnetic field as it decreases with increasing altitude. Also, over time this satellite flies in a progressively increasing angle to the path of the lower pair. The total measurement will give a picture of the earth’s magnetic field with a precision never achieved before.

Almost as a side effect, the possibility arises to observe space weather more accurately. What is understood by this are flares of our sun, but also magnetic storms generated by distant stars that can interfere with or even paralyze our technical civilization. For example, a strong solar storm in 1989 caused a breakdown of the electricity supply in Canada.

About the satellites

The three SWARM satellites together cost about 220 million euros, each weighs 500 kg. Inside the carrier rocket, a four-meter long measuring arm is folded on the back of the five meter long satellite body. This boom is folded out several hours after the deployment of the satellite, once the on-board operating system has been initiated. The reason for this is that the surface of the satellite is equipped with solar cells for the power supply. The magnetic field generated by the current, however, would interfere with the measurement, therefore, the magnetic field measuring instruments are mounted on the measuring arm.

At the tip of the boom, the particularly sensitive apparatus for measuring the magnetic field strength is installed, the sensors for determining the direction of the magnetic field are in its center. In the same position, three star sensors allow the satellite to determine and corrected its location.

To begin with, the three satellites fly parallel on a north-south path at about 88° inclination. Swarm-C is then slowly deflected by 30° per year and thus continues to fly at an increasing angle to the orbit of Swarm-A and -B.

Note : The above story is based on materials provided by Helmholtz Centre Potsdam – GFZ German Research Centre for Geosciences. 

Gold rush in space? Asteroid miners prepare, but eye water first

Meteorites sit on a display table at the Deep Space Industries announcement of plans for the world’s first fleet of commercial asteroid-prospecting spacecraft at the Museum of Flying in Santa Monica, California, January 22, 2013. Credit: Reuters/Jonathan Alcorn

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(Reuters) – Mining in space is moving from science fiction to commercial reality but metals magnates on this planet need not fear a mountain of extraterrestrial supply – the aim is to fuel human voyages deeper into the galaxy.

Within three years, two firms plan prospecting missions to passing asteroids. When even a modest space rock might meet demand for metals like platinum or gold for centuries, it is little wonder storytellers have long fantasized that to harness cosmic riches could make, and break, fortunes on Earth.

But with no way to bring much ore or metal down from the heavens, new ventures that have backing from some serious – and seriously rich – business figures, as well as interest from NASA, will focus on using space minerals in interplanetary “gas stations” or to build, support and fuel colonies on Mars.

There may be gold up there, but the draw for now is water for investors willing to get the new industry off the ground.

Governments believe it has a future; NASA has a project that may put astronauts on an asteroid in under a decade and on Mars in the 2030s. And if the costs seem high, grumblers are told that one day the new skills might just save mankind from sharing the fate of the dinosaurs – if we can learn how to stop a massive asteroid smashing into Earth.

“We are dreamers,” declares the web site of Deep Space Industries (DSI), next to an image of a wheel-like metal station hooked up to a giant floating rock. But what the U.S.-based start-up firm calls the first small steps in a “long play” to develop the resources of space are about to happen.

A priority is using hydrogen and oxygen, the components of water locked in compounds on asteroids, to refuel rockets.

Early in 2016, the first of DSI’s exploration satellites, smaller than toasters, will hitch-hike into space on rockets carrying other payloads and start scouting for suitable rocks. The same year, another U.S.-based venture, Planetary Resources, expects to launch prospecting craft hunting viable asteroids.

“They are the low-hanging fruit of the solar system,” said Eric Anderson, an American aerospace engineer and co-founder of Planetary Resources, which lists Google’s Larry Page and Virgin billionaire Richard Branson among its backers.

“They are just there and they are not difficult to get to and they are not difficult to get away from,” he told Reuters.

METALS

Meteorites – chunks that survive and fall to earth after asteroids disintegrate in the atmosphere – yield significant amounts of precious metals like platinum, rhodium, iridium, rhenium, osmium, ruthenium, palladium, germanium and gold.

Planetary Resources estimates some platinum-rich asteroids just 500 meters across could contain more than the entire known reserves of platinum group metals. Studies based on observation and meteorites suggest space is even richer in iron ore.

Wall Street research firm Bernstein notes that a big asteroid called 16 Psyche, in the asteroid belt between Mars and Jupiter and measuring some 200 km (130 miles) across, may contain 17 million billion tones of nickel-iron – enough to satisfy mankind’s current demand for millions of years.

But costs and technical hurdles rule out hauling resources down to Earth in the foreseeable future, experts say. The real value in asteroid mining is for further space travel – and so hydrogen and oxygen reserves are as attractive as any metal.

“It’s ridiculous to believe that asteroid resources will ever compete with terrestrial alternatives and Earth markets,” said Brad Blair, a mining engineer and economist.

Referring to talk of city-sized settlements on Mars, he said: “The reason asteroid mining makes sense is because people might be some day where those resources are. You can’t put an 80,000-person colony on Mars without using the local ‘timber’.

“And if you’re going to use chemical propulsion, it’s going to take a lot of water to get them there.”

The energy released when hydrogen and oxygen combine to make water can power rockets. The presence of both elements in compounds found on asteroids offers scope to set up space factories to make fuel for missions to Mars and beyond as well as offering “pit stops” to extend the lives of satellites.

“We’re going to be looking at propellants for satellites, which is a multi-billion dollar industry to keep them alive,” said Rick Tumlinson, Deep Space Industries’ board chairman and a veteran promoter of commercial space development.

“We’ll eventually be an oasis, a place where you can get air, and we can provide propellants. So we’re a gas station,” Tumlinson told a recent seminar in London.

“You can take the process leftover material, the slag, and use it for shielding, or concrete, and build large structures, and of course there is a percentage of precious metals.”

CAMERAS, LASERS

DSI hopes to launch flying cameras it calls FireFlies early in 2016. Their images will let scientists judge the composition of asteroids they pass. They will use off-the-shelf parts in tried and tested modules, just 10 cm (4 inches) wide.

That first phase should cost some $20 million, DSI chief executive David Gump told Reuters, adding he expects about half to come from government and research institute contracts and half from corporate advertising and corporate sponsorship.

A year later, larger craft would begin two- to three-year missions to land and take samples for analysis. Most dramatic of all, the company sees a “harvester” craft heading out in 2019 to capture and divert the most promising asteroids so that they settle into orbit around Earth by 2021. On these, Gump said, DSI would try to make propellant and mine nickel and iron to make the building components for new structures in space.

“If we are successful producing resources in space then it makes what NASA wants to do, which is going to Mars, that much less expensive,” he said. “It costs a lot of money to launch everything from the ground.”

Planetary Resources plans to send telescopes into space to study asteroids between Earth and the moon. In a later phase, it will send out craft carrying deep-space lasers to gather data on some of the thousands of more distant asteroids.

“By 2020 we will have begun processing asteroidal material in space, and we will have our first interplanetary fuel stop,” Planetary Resources’ Anderson said. “A mission can leave the Earth and stop by the trading post and gas themselves up.”

And while commercial gain from asteroid exploration is drawing investors, the rest of humanity also has an interest.

A shift in climate caused by a big asteroid strike may have killed off the dinosaurs and NASA is taking the risk of another such impact seriously enough to go looking for similar threats.

As mining expert Blair put it: “For survival of the human species, we have to address the asteroids, or they will address us. Because statistically a big enough one will come along that will scrub the planet clean and set it back to zero.”

Note : The above story is based on materials provided by Susan Thomas for Reuters

CT and 3-D Printers Used to Recreate Dinosaur Fossils

3-D print of vertebral body. (Credit: Image courtesy of Radiological Society of North America)

Data from computed tomography (CT) scans can be used with three-dimensional (3-D) printers to make accurate copies of fossilized bones, according to new research published online in the journal Radiology.

Fossils are often stored in plaster casts, or jackets, to protect them from damage. Getting information about a fossil typically requires the removal of the plaster and all the sediment surrounding it, which can lead to loss of material or even destruction of the fossil itself.

German researchers studied the feasibility of using CT and 3-D printers to nondestructively separate fossilized bone from its surrounding sediment matrix and produce a 3-D print of the fossilized bone itself.

“The most important benefit of this method is that it is non-destructive, and the risk of harming the fossil is minimal,” said study author Ahi Sema Issever, M.D., from the Department of Radiology at Charité Campus Mitte in Berlin. “Also, it is not as time-consuming as conventional preparation.”

Dr. Issever and colleagues applied the method to an unidentified fossil from the Museum für Naturkunde, a major natural history museum in Berlin. The fossil and others like it were buried under rubble in the basement of the museum after a World War II bombing raid. Since then, museum staff members have had difficulty sorting and identifying some of the plaster jackets.

Researchers performed CT on the unidentified fossil with a 320-slice multi-detector system. The different attenuation, or absorption of radiation, through the bone compared with the surrounding matrix enabled clear depiction of a fossilized vertebral body.

After studying the CT scan and comparing it to old excavation drawings, the researchers were able to trace the fossil’s origin to the Halberstadt excavation, a major dig from 1910 to 1927 in a clay pit south of Halberstadt, Germany. In addition, the CT study provided valuable information about the condition and integrity of the fossil, showing multiple fractures and destruction of the front rim of the vertebral body.

Furthermore, the CT dataset helped the researchers build an accurate reconstruction of the fossil with selective laser sintering, a technology that uses a high-powered laser to fuse together materials to make a 3-D object.

Dr. Issever noted that the findings come at a time when advances in technology and cheaper availability of 3-D printers are making them more common as a tool for research. Digital models of the objects can be transferred rapidly among researchers, and endless numbers of exact copies may be produced and distributed, greatly advancing scientific exchange, Dr. Issever said. The technology also potentially enables a global interchange of unique fossils with museums, schools and other settings.

“The digital dataset and, ultimately, reproductions of the 3-D print may easily be shared, and other research facilities could thus gain valuable informational access to rare fossils, which otherwise would have been restricted,” Dr. Issever said. “Just like Gutenberg’s printing press opened the world of books to the public, digital datasets and 3-D prints of fossils may now be distributed more broadly, while protecting the original intact fossil.”

Note : The above story is based on materials provided by Radiological Society of North America. 

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