Analysis of diamonds from the Denver Museum of Nature & Science collection provide a look inside the earth’s mantle. Credit: Denver Museum of Nature & Science
Researchers at the Denver Museum of Nature & Science and University of British Columbia recently analyzed diamonds from the Museum’s collection and learned how an unusual chunk of Africa formed.
It takes incredible heat and pressure to form a diamond. And when these diamonds were formed, microscopic minerals were trapped inside. The chemistry of these minerals, or inclusions, provides a rare look at the processes that led to the formation of Earth’s crust. Inclusions found in the Museum’s diamonds from the Congo craton in central southern Africa illustrate an incredible 3-billion-year journey through tectonic collisions and volcanic eruptions.
The international scientific team, led by author Charles W. Kosman, used an electron microprobe, an infrared spectrometer and a secondary ion mass spectrometer to analyze these diamonds.
“These diamonds are special,” Kosman said. “They’re the ultimate time capsules from deep Earth.”
The researchers determined that the diamonds formed as thinner continental fragments and began their journey beneath the thick, buoyant continental crust of central Africa. Over 2.8 billion years, this part of the African continent repeatedly rammed into smaller and thinner fragments. These fragments slid downward back toward Earth’s core where they were dehydrated by extreme heat and pressure, triggering the formation of diamonds. The diamonds were then brought to the surface in volatile eruptions, which pierced the hide of the ancient African continent and eventually deposited the diamonds on the surface.
“The circumstances that led to the formation of these diamonds trapping invaluable information inside are incredible,” said James Hagadorn, Museum’s curator of geology. “Grueling conditions – temperatures five times hotter than your oven, and pressure 10 times that found below Mount Everest—are what it takes to freeze clues to Earth’s evolution for studies such as this one.”
By knowing how and where diamonds like these are formed, it also informs the ability to predict where to find future diamond deposits. Museum collections are often overlooked as a resource for clues to Earth’s delicate atmospheric history.
“Diamonds are a key part of our culture and industry. Not all diamonds end up on a ring or a saw-blade’s edge. The ugly ones often have the coolest scientific stories to tell,” said Hagadorn.
The results appear in the journal Lithos.
Reference:
Charles W. Kosman et al, Cretaceous mantle of the Congo craton: Evidence from mineral and fluid inclusions in Kasai alluvial diamonds, Lithos (2016). DOI: 10.1016/j.lithos.2016.07.004
Upper left. Kaikaifilu was found in late cretaceous rocks from Seymour island, Antarctica. Upper right. An estimated size comparison of Kaikaifilu with a human. The size of the skull remains suggest it could have been as long as 12-14 mt. Bottom left: The terrain where the remains of Kaikaifulu were found turns mostly into mud under bad weather conditions like those encountered by the Chilean expedition (bottom right). Credit: Image courtesy of University of Chile
Kaikaifilu is a new species of giant sea lizard (mosasaur) discovered in 66-million-year-old rocks of Antarctica. At about 10 m long, it is the largest known top marine predator from this continent. It lived near the end of the dinosaur age, when Antarctica was a much warmer ecosystem, and fed on filter-feeding marine reptiles.
Because of its harsh conditions, Antarctica is probably one of the toughest places to work for palaeontologists. However, precisely because of this, information is scarce, and new discoveries can be highly rewarding. In 2010, an expedition of Chilean scientists to Seymour Island encountered particularly bad weather. Only during their last days in the field, after dreadful walks through knee-deep mud, they made a truly exciting discovery in 66 million year-old rocks: The fossil remains of a particularly large skull of a Mosasaur, a giant sea lizard.
According to Rodrigo Otero, one of the authors of the study, “The increasing diversity of endemic Cretaceous marine reptiles in the southern hemisphere are slowly changing an historical paradigm. Since the 19th century many southern fossil reptiles had been assigned to species from the northern hemisphere. In this sense, Kaikaifilu adds to this paradigm shift. The southern record has scarce informative mosasaur skulls, most of them found in New Zealand. However, in southern South America and Antarctica, mosasaur remains are especially scarce. Hence the relevance of the new specimen, which shows a distant kinship with respect to the northern hemisphere mosasaurs.”
Previous to the discovery of Kaikaifilu, isolated teeth had been frequently found in Late Cretaceous rocks of Antarctica. Anatomical features led scientists to refer them to several mosasaur species previously known in the Northern Hemisphere. Remarkably, the jaws of Kaikaifilu now reveal that many of these teeth co-existed as different tooth types in the mouth of this species, a condition known as heterodonty. Therefore, in all probability, the diversity of Antarctic mosasaurs has been overestimated. The case nicely illustrates the difficulties that palaeontologists may encounter when discovering unique but isolated body parts.
During the dinosaur age, antarctic climate was much warmer and the continent harboured a diverse ecosystem, that included several unusual reptiles. Kaikaifilu probably fed on an abundant “buffet” of contemporaries, especially the unique aristonectine plesiosaurs, robust, long-necked forms that did not feed on fish but rather were filter-feeders of much smaller prey, using fine, narrow teeth and whale-like adaptations in their skulls.
“Prior to this research, the known mosasaur remains from Antarctica provided no evidence for the presence of very large predators like Kaikaifilu, in an environment where plesiosaurs were especially abundant. The new find complements one expected ecological element of the Antarctic ecosystem during the latest Cretaceous” says Otero.
These ecosystems existed shortly before the ultimate demise of the dinosaurs, a time in which temperatures and sea levels experimented significant changes. Scientists continue to discuss how these changes may have affected extinction and evolution in these southernmost marine ecosystems. Without a doubt, they will continue to explore for new data as Antarctica, an entire continent,
Reference:
Rodrigo A. Otero, Sergio Soto-Acuña, David Rubilar-Rogers, Carolina S. Gutstein. Kaikaifilu hervei gen. et sp. nov., a new large mosasaur (Squamata, Mosasauridae) from the upper Maastrichtian of Antarctica. Cretaceous Research, 2016; DOI: 10.1016/j.cretres.2016.11.002
Note: The above post is reprinted from materials provided by University of Chile.
Associate Professor Alexis Templeton and Dr. Stephen Grasby prospecting for sulfur biominerals in a yellow sulfur deposit forming on a glacier surface in the High Arctic. Credit: John Spear
Self-assembling carbon microstructures created in a lab by University of Colorado Boulder researchers could provide new clues — and new cautions — in efforts to identify microbial life preserved in the fossil record, both on Earth and elsewhere in the solar system.
The geological search for ancient life frequently zeroes in on fossilized organic structures or biominerals that can serve as “biosignatures,” that survive in the rock record over extremely long time scales. Mineral elements such as sulfur are often formed through biological activity. Microbes can also produce a variety of telltale extracellular structures that resemble sheaths and stalks.
However, according to new findings published in the journal Nature Communications, carbon-sulfur microstructures that would be recognized today by some experts as biomaterials are capable of self-assembling under certain conditions, even without direct biological activity. These “false” biosignatures could potentially be misinterpreted as signs of biological activity due to their strong resemblance to microbial structures.
“Surprisingly, we found that we could create all sorts of biogenic-like materials that have the right shape, structure and chemistry to match natural materials we assume are produced biologically,” said Associate Professor Alexis Templeton of CU Boulder’s Department of Geological Sciences and senior author of the new study.
The study arose from field research in the Canadian High Arctic, where a team of scientists working with Templeton had identified sulfur-metabolizing organisms that live in shopping mall-sized mineral deposits that form on ice surfaces. Some of these sulfur deposits were returned to CU Boulder to determine whether they contained “biosignatures” that could be relevant to the search for life on Mars or Europa, one of Jupiter’s moons.
Templeton and CU-Boulder Research Associate Julie Cosmidis then set out to study the underlying mechanisms of biological sulfur mineral formation before realizing that some of the “extracellular structures” and associated sulfur minerals could be reproduced in the lab without any organisms present.
“It was very disconcerting- at first to see that the carbon-sulfur structures appear in our tests without biological activity, as they looked very microbial,” said Cosmidis, the lead study author.
“But the fact that these structures self-assemble makes their discovery even more exciting. They challenge our conception of what a biosignature is, and they can teach us about unexpected interactions between carbon and sulfur,” said Cosmidis.
The findings indicate that carbon-sulfur microstructures may no longer be surefire microbial indicators, but they are still useful for reconstructing environmental processes anywhere there is active sulfur cycling.
“We’re interested to learn how organisms mediate mineralization and commonly it is challenging to demonstrate that a mineral was produced by living organism,” said Templeton. “This research is another step forward in understanding fundamental self-assembly processes that are important to materials scientists, biologists and chemists alike.”
But while carbon-sulfur microstructures could confound efforts to identify ancient life, they may provide a roadmap to an entirely different innovation: Next-generation lithium-sulfur (Li-S) batteries.
Rechargeable Li-S batteries are considered to be a promising successor to the lithium-ion batteries that power most of today’s consumer electronics. Li-S batteries can contain up to five times the energy of lithium-ion batteries, but present a number of manufacturing hurdles that have yet to be overcome on a commercial scale.
The carbon-sulfur microstructures created in the new study, however, may solve one of the key challenges by encasing the sulfur in conductive carbon, potentially creating more electrically efficient Li-S batteries.
“We’re making materials that have the desired properties and we’re doing it by mimicking a natural environmental process,” said Templeton. “It’s a promising new pathway to battery design.”
Reference:
Julie Cosmidis, Alexis S. Templeton. Self-assembly of biomorphic carbon/sulfur microstructures in sulfidic environments. Nature Communications, 2016; 7: 12812 DOI: 10.1038/ncomms12812
Today the Barberton Mountains in northeastern South Africa are covered by rocky grasslands; these hills are made of some of the oldest rocks on Earth (3.2 – 3.5 billion years old). At 3.2 billion years ago a shallow ocean covered most of this area, where rivers draining into this ocean provided favorable environment for life to start colonizing the flood planes. Credit: Sami Nabhan/FSU Jena
Life took hold on land at least as early as 3.2 billion years ago, suggests a study by scientists from Berlin, Potsdam and Jena (Germany). The team led by Sami Nabhan of the Freie Universität Berlin studied ancient rock formations from South Africa’s Barberton greenstone belt.
These rocks are some of the oldest known on Earth, with their formation dating back to 3.5 billion years. In a layer that has been dated at 3.22 billion years old, tiny grains of the iron sulfide mineral pyrite were discovered that show telltale signs of microbial activity.
These signs are recorded both in trace element distributions as well as in the ratio between the sulfur isotopes 34S and 32S in the pyrite.
Using instrumentation installed in Potsdam in 2013, the scientists showed that the fraction of 34S in the core of some crystals differ characteristically from that of the same crystal’s rim, indicating that the exterior of the grain involved a processing of sulfur by microbes, so-called biogenic fractionation. The determination of the 34S/32S ratio, using sample masses less than one billionth of a gram, was carried out at the GFZ German Research Centre for Geosciences by Michael Wiedenbeck of the GFZ’s secondary ion mass spectrometry (SIMS) lab.
The composition of the rock, the shape of the crystals, and the layering visible in the field all indicate that the studied rock sequence was derived from an ancient soil profile; this so-called paleosol developed on a river flood plain 3.22 billion years ago.
Field data collected during this study imply that a braided river system transported the sediment containing the iron sulfide crystals. It is interpreted that microbes living in the soil, at a level that was continually shifting between wet and dry conditions, subsequently produced the rim overgrowths on the pyrite crystals.
Based on this evidence, the scientists conclude in their publication in the journal Geology that they found evidence for biological activity on land at this very early date. Their research pushes back the date for the oldest evidence of life on land to some 300 million years earlier than previously documented.
Reference:
Sami Nabhan et al, Biogenic overgrowth on detrital pyrite in ca. 3.2 Ga Archean paleosols, Geology (2016). DOI: 10.1130/G38090.1
Since the 1980s, air pollution has increased worldwide, but it has increased at a much faster pace in regions close to the equator. Research from the University of North Carolina at Chapel Hill now reveals that this changing global emissions map is creating more total ozone worldwide compared to the amount of pollution being emitted, signaling an effect that could be difficult to reign in without strategic policy planning.
“Emissions are growing in places where there is a much greater effect on the formation of ozone,” said Jason West, who led the research at UNC-Chapel Hill with former graduate student and first author Yuqiang Zhang. “A ton of emissions in a region close to the equator, where there is a lot of sunlight and intense heat, produces more ozone than a ton of emissions in a region farther from it.”
The work, to appear in the Nov. 7 advance online issue of Nature Geoscience, provides a much-needed path forward on where in the world to strategically reduce emissions of pollutants that form ozone, which when present in the lower atmosphere, or troposphere, is one of the primary causes of air pollution-related respiratory problems and heart disease. (In the upper atmosphere, or stratosphere, ozone helps protect against the sun’s ultraviolet rays.)
To drive home the point, West explained that China’s emissions increased more than India’s and Southeast Asia’s from 1980 to 2010, but Southeast Asia and India, despite their lower growth in emissions during this period, appear to have contributed more to the total global ozone increase due to their proximity to the equator.
The reason is that ozone, a greenhouse gas and toxic air pollutant, is not emitted but forms when ultraviolet light hits nitrogen oxides (basically combustion exhaust from cars and other sources). When these pollutants interact with more intense sunlight and higher temperatures, the interplay speeds up the chemical reactions that form ozone. Higher temperatures near the equator also increase the vertical motion of air, transporting ozone-forming chemicals higher in the troposphere, where they can live longer and form more ozone.
“The findings were surprising,” said West. “We thought that location was going to be important, but we didn’t suspect it would be the most important factor contributing to total ozone levels worldwide. Our findings suggest that where the world emits is more important than how much it emits.”
Zhang, West and colleagues, including Owen Cooper and Audrey Gaudel, from the University of Colorado Boulder and NOAA’s Earth System Research Laboratory, used a computer model to simulate the total amount of ozone in the troposphere, the part of the atmosphere where ozone is harmful to humans and agriculture, between 1980 and 2010. Since emissions have shifted south during this period, they wanted to answer, what contributed more to the increased production of ozone worldwide: the changing magnitude of emissions or location?
To find out, the team used a unique European data set of ozone observations from commercial aircraft to confirm the strong increases in ozone above Asia. Then they superimposed a map of how much pollution the world was emitting in 1980 onto where the world was emitting it in 2010, and vice versa, in addition to another scenario of the growth of methane gas, to determine what is driving the world’s increase in ozone production.
“Location, by far,” said West, associate professor of environmental sciences in the UNC Gillings School of Global Public Health.
The findings point to several strategies for reducing ground-level ozone across the world, such as decreasing emissions of ozone precursors in regions close to the equator, particularly those with the fastest growth of emissions. However, concerns exist for policy makers.
“A more challenging scenario is that even if there is a net reduction in global emissions, ozone levels may not decrease if emissions continue to shift toward the equator,” said Cooper. “But continuing aircraft and satellite observations of ozone across the tropics can monitor the situation and model forecasts can guide decision making for controlling global ozone pollution.
Reference:
Tropospheric ozone change from 1980 to 2010 dominated by equatorward redistribution of emissions, Nature Geoscience, DOI:10.1038/ngeo2827
Insect galls on a fossil leaf from the latest Cretaceous Lefipán Formation (67-66 Ma) in Patagonia, Argentina. Credit: Michael Donovan/Penn State
Ancient feeding marks from hungry insects in South American leaf fossils are shedding new light on the mass extinction that wiped out the dinosaurs.
Scientists analyzed insect feeding damage to thousands of leaf fossils from Patagonia, Argentina, over the Cretaceous-Paleogene boundary, and found evidence that ecosystems there recovered twice as fast as in the United States.
The findings, published today (Nov. 7) in the new journal Nature Ecology & Evolution, offer important evidence of how terrestrial ecosystems outside the U.S. responded after an asteroid struck Chicxulub, Mexico, some 66 million years ago, marking the end of the Cretaceous period.
“Most of what we know about terrestrial recovery comes from the western interior United States, relatively close to the Chicxulub crater, which has limited our knowledge of recovery in the rest of the world,” said Michael Donovan, doctoral student in geosciences, Penn State and lead author on the paper. “We are giving another view of what was happening during that time, far away from the impact site.”
Donovan and his international team found leaf-mining insects completely disappeared in Patagonia during the extinction event, as previous studies show happened in the U.S. But unlike the U.S., where it took 9 million years to return to pre-impact insect diversity, recovery happened in just 4 million years in Patagonia.
“Insects and plants are the most diverse multicellular organisms in the world, and they are known to respond to major environmental changes,” Donovan said. “So they make a great resource to study our past.”
The team analyzed 3,646 fossils from Patagonia searching for signs of leaf miners—insect larvae named for the type of damage they cause tunneling though leaves for food. These feeding paths, and the insects’ droppings, both create distinctive patterns and can be compared among fossils at different sites.
“Michael developed this technique of very detailed examination of leaf miners, and new methods for looking at the critical differences among these feeding trails in fossil leaves,” said Peter Wilf, professor of geosciences, Penn State and paper co-author. “He’s teased apart this huge story from the tiny differences in how baby insects did their business in leaves that lived 66 million years ago.”
The scientists found no evidence that individual leaf miner species from the Cretaceous survived the extinction event in Patagonia, indicating the far south did not offer a refuge for the insects as Donovan’s team first hypothesized.
“There was no evidence of survival, which is similar to what I found when working on my master’s research at the Mexican Hat site in Montana,” Donovan said. “But what we do find in Patagonia is a pretty diverse group of novel leaf miners that appear much sooner than in the western U.S.”
The researchers suggested Patagonia’s further distance from the impact crater in Mexico and its ground zero effects could be responsible for insect diversity returning more rapidly to the southern location.
“The richness of plant-insect associations that we observed during the recovery may be a contributing factor to insect biodiversity in modern South America,” Donovan said. “We can look far into the past and see these patterns that influence life on Earth as it is today.”
Wilf said the study, the first of its kind outside the western U.S., can help scientists answer questions about modern global biodiversity.
“Our modern world is the legacy of this disaster,” Wilf said. “As we try to understand how today’s biodiversity evolved and why Earth’s millions of species live where they do, the global impact of this major catastrophe is a big sleeping elephant in a dark room—we can’t see much of it and just don’t know enough about it. As we turn on the lights, we see more of the elephant and understand our world better. This paper is a welcome step in that direction.”
Reference:
Michael P. Donovan et al. Rapid recovery of Patagonian plant–insect associations after the end-Cretaceous extinction, Nature Ecology & Evolution (2016). DOI: 10.1038/s41559-016-0012
The shape of the ribcage in more than 120 tetrapods — from prehistoric times up to the present day. Credit: UZH
As an international study conducted by the University of Zurich based on 3D reconstructions of animal skeletons reveals for the first time: Herbivorous mammals have bigger bellies than their usually slim carnivorous counterparts. In dinosaurs, however, there is no notable difference between carnivores and herbivores.
What do enormous dinosaurs have in common with tiny shrews? They are both four-legged vertebrates, otherwise known as tetrapods. In the course of evolution, tetrapods developed various body shapes and sizes — from the mouse to the dinosaur — to adapt to different environments. Their feeding habits range from pure herbivory to fierce carnivory, and their body structure reflects this feeding diversity. As plants are usually more difficult to digest than meat, herbivores are thought to need larger guts and more voluminous bellies. Nevertheless, this hypothesis had never been tested scientifically.
No difference in dinosaurs
A European team of researchers headed by the University of Zurich and the Technical University Berlin has now studied the shape of the ribcage in more than 120 tetrapods — from prehistoric times up to the present day. With the aid of photogrammetry and computer imaging techniques, the scientists produced a 3D database for skeletons of dinosaurs, reptiles, birds, mammals and fossil synapsids (mammal-like reptiles). Using the computer-based visual evaluation of this data, they reconstructed the volume of the body cavity, which is delineated by the spinal column, the ribcage and the pelvis.
The result: On average, herbivorous mammals have a body cavity that is twice as big as carnivores of a similar body size. “This is clear evidence that plant-eating mammals actually have larger guts,” explains Marcus Clauss, a professor of comparative digestive physiology in wild animals at UZH. Far more surprising, however, is the fact that this pattern is not evident among the remaining tetrapods. “We were amazed that there wasn’t even the slightest indication of a difference between herbivores and carnivores in dinosaurs,” explains the first author. Numerous fossilized species were examined in the study — from the earliest amphibians to the largest herbivorous dinosaurs and mammoths.
Fundamental difference in morphology
On the one hand, the results can indicate that it is difficult to reconstruct dinosaur skeletons reliably. “On the other hand,” explains Clauss, “the discovery reveals that there’s a fundamental difference in morphological principles between mammals and other tetrapods.” For instance, the scientist suspects that a different respiratory system might be responsible for the divergent effect of the diet on the body structure in mammals and dinosaurs.
Reference:
Marcus Clauss, Irina Nurutdinova, Carlo Meloro, Hanns-Christian Gunga, Duofang Jiang, Johannes Koller, Bernd Herkner, P. Martin Sander, Olaf Hellwich. Reconstruction of body cavity volume in terrestrial tetrapods. Journal of Anatomy, 2016; DOI: 10.1111/joa.12557
This map shows the changing US CO2 footprint around the world between 1970 and 2008. Red hotspots illustrated where the US carbon footprint has increased, and in blue, decreased. The carbon footprint has gone down in some parts of the US, UK, and other places in Africa and Eastern Europe, while new emissions hotspots have emerged in growing US cities, Mexico, Europe, and throughout Asia. Credit: Daniel Moran, NTNU
A new model creates global hot spot maps to illuminate how what we buy pollutes the planet and where. The idea is to help governments, industries and individuals target areas for cleanup.
Global trade has changed the way the goods we buy are made: in the 1970s, a majority of goods were purchased in the same country where they were produced. Today, cheap shipping and global outsourcing mean that more and more of what Western consumers buy is produced far away.
Environmental footprints already include global supply chains when they show us the impacts of a purchase. But what if in addition to showing you how many kilos of CO2 or other pollutants your purchase causes, the footprint came with a map showing where that purchase is driving environmental impacts?
Two recent articles from researchers at the Norwegian University of Science and Technology (NTNU), Shinshu University in Japan and Yale University in the US try to do precisely that. The researchers show how the environmental footprint of the goods we purchase can be mapped out to find places where that footprint actually falls.
The articles map out “hot spots” for greenhouse gases and unhealthy air, and connect these hot spots to consumers in many countries.
“What we are trying to do is to connect economic activity and global supply chains with environmental impacts. That has not been done before,” said Daniel Moran, a postdoctoral researcher at NTNU’s Industrial Ecology Programme, who was one of the lead authors. “We tried to spatially locate environmental impacts on the production side and link that to global supply chains” on the consumer side.
Finding the where and the what
Solving environmental problems like climate change or air pollution is extremely difficult because they result from many small actions.
Think of your mobile phone. You as a consumer buy one. A company (almost certainly in Asia) makes it. Companies across the globe supply materials to those phone manufacturers so they can assemble them into a mobile phone. All of these individual actions have environmental impacts in all those different countries.
Governments and regulators can pass laws to control pollution from the phone manufacturer, but if you really want to clean up the impact of your phone, you’d have to figure out exactly what and where in the world all those other impacts actually are.
Putting the pieces together
Environmental economists try to calculate the environmental impacts from making products by using tools called life-cycle assessments or “multi-regional input-output” models, abbreviated MRIO.
Simply stated, MRIO models allow researchers to look at one item — your mobile phone — and calculate the environmental impacts caused by producing all its component parts, called the supply chain.
They can also use a different model to calculate the carbon or environmental “footprint” of different activities, which shows by country or region where these environmental impacts are generated.
The next step — combining the two and refining the resolution, to figure out where those environmental impacts actually occur, and linking those impacts to the consumers who actually bought the product — hasn’t been so easy.
Mapping actual locations
Now, Moran and his colleagues have developed a way to put all of the pieces together by combining maps of observed environmental impacts with an economic MRIO model. That means “a company, individual, or government can find the actual locations where their supply chain emissions occur, thus creating new opportunities to participate in reducing the emissions at that place,” the researchers wrote in their paper on mapping carbon footprint hot spots.
The same approach also allowed them to locate hotspots for air pollution more generally and species threats.
Connecting environmental problems to economic activity
Moran says making this connection offers an important opportunity for governments, companies, and individuals to look at their effects on the environment — and find ways to counteract those effects.
“Connecting observations of environmental problems to economic activity, that is the innovation here,” he said. “Once you connect the environmental impact to a supply chain, then many people along the supply chain, not only producers, can participate in cleaning up that supply chain.”
As an example, he said, government regulators can only control the producers whose products cause environmental problems in Indonesia. But if the EU wanted to look at its role in causing those problems in Indonesia, they could look at the maps produced by the researchers and see what kind of impacts EU consumers are having on that country, and where they are falling.
The EU “could decide to adjust their research programmes or environmental priorities to focus on certain hot spots Southeast Asia,” Moran said. “Companies could also use these maps to find out where their environmental impact hot spots are, and make changes.”
Reference:
Daniel Moran, Keiichiro Kanemoto. Tracing global supply chains to air pollution hotspots. Environmental Research Letters, 2016; 11 (9): 094017 DOI: 10.1088/1748-9326/11/9/094017
Stromatolites have been discovered beyond the well-researched south-east corner of Hamelin Pool, in Shark Bay Western Australia, according to a researcher from Bush Heritage.
Erica Suosaari donned a wetsuit and spent three years being dragged behind a boat to investigate the entire pool for the first time.
She found stromatolites around almost the entire 135km margin.
“Stromatolites are a big deal,” says Erica.
“They are remnants of the oldest known life form. These structures dominate the fossil record for more than 80 per cent of the Earth’s history. The microbes that built them produced the oxygen that made animal life possible on earth,” she says.
“They represent a huge leap in our understanding of the diversity of modern and ancient life at the site. They effectively offer us a window into early life on Earth.”
Hamelin Pool is a World Heritage Area based partly on the fact that it is home to the largest and most diverse modern assemblage of stromatolites on the planet.
Stromatolites are the remains of living mats of bacteria that trap and bind surrounding sediments or precipitated carbonate cements, leaving behind a rock fabric that causes the structure to grow vertically.
And the bacteria that formed those ancient structures are the reason we’re alive. Their busy photosynthesis for the first few billion years of Earth’s history produced the oxygen that made animal life possible.
They were first discovered in the 1950s but, until now, research on the ancient structures has been concentrated in the south-eastern region of the bay.
Erica was determined to look further and investigated the entire pool for the first time.
She discovered distinct ‘provinces,’ where each has a different and distinct assemblage of stromatolite forms – a result of depth gradient and local environmental pressures.
She estimates there are 100 million stromatolites at the site, including fossils similar to those that existed long before modern times.
Since the 18th century, geologists have struggled to explain how big magma chambers form in Earth’s crust. In particular, it has been difficult to explain where the surrounding rock goes when the magma intrudes. Now a team of researchers from Uppsala University and the Goethe University in Frankfurt have found the missing rocks — and they look nothing like what they expected.
Researchers have previously proposed that the roofs and walls of magma chamber were either melted and assimilated into the magma, or that they would sink to the bottom of the magma chamber. However, enough evidence for either of these hypotheses have not been forthcoming, and researchers now propose a third possibility.
“We show that rock fragments from the roof of the magma chambers could have been expelled, similar to popcorn that is thrown out of a hot pan! We have found them in rocks that have been ejected in volcanic eruptions. The rock fragments are full of bubbles and have very low densities, and they look a lot like popcorn,” says Steffi Burchardt, researcher at the Department of Earth Sciences, Uppsala University.
When rock fragments fall into the magma chamber, they are rapidly heated by several hundred degrees, and all fluids inside boil instantly. This is similar to what happens when a grain of corn is put into the pan and the water inside boils — and we get popcorn.
Steffi and her colleagues have now managed to show how the popcorn-effect makes the rock fragments float and rise to the top of magma chambers rather than sink to the bottom. The floating rock fragments are then found among the erupted volcanic rocks, instead of inside the frozen magma chambers as previously expected. Furthermore, the gases released from the rock fragments as they boil also contribute to a higher pressure in the magma which can help explain some of the more explosive eruptions.
“Sometimes you can find the solution to age-old puzzles by looking in new places — in this case literally looking outside the box! The frozen magma chambers proved to be the wrong place to look,” Steffi explains.
Reference:
Steffi Burchardt, Valentin R. Troll, Harro Schmeling, Hemin Koyi, Lara Blythe. Erupted frothy xenoliths may explain lack of country-rock fragments in plutons. Scientific Reports, 2016; 6: 34566 DOI: 10.1038/srep34566
Sludge from Metro Vancouver’s wastewater treatment plant has been dewatered prior to conversion to biocrude oil at Pacific Northwest National Laboratory. Credit: WE&RF
It may sound like science fiction, but wastewater treatment plants across the United States may one day turn ordinary sewage into biocrude oil, thanks to new research at the Department of Energy’s Pacific Northwest National Laboratory.
The technology, hydrothermal liquefaction, mimics the geological conditions Earth uses to create crude oil, using high pressure and temperature to achieve in minutes something that takes Mother Nature millions of years. The resulting material is similar to petroleum pumped out of the ground, with a small amount of water and oxygen mixed in. This biocrude can then be refined using conventional petroleum refining operations.
Wastewater treatment plants across the U.S. treat approximately 34 billion gallons of sewage every day. That amount could produce the equivalent of up to approximately 30 million barrels of oil per year. PNNL estimates that a single person could generate two to three gallons of biocrude per year.
Sewage, or more specifically sewage sludge, has long been viewed as a poor ingredient for producing biofuel because it’s too wet. The approach being studied by PNNL eliminates the need for drying required in a majority of current thermal technologies which historically has made wastewater to fuel conversion too energy intensive and expensive. HTL may also be used to make fuel from other types of wet organic feedstock, such as agricultural waste.
Using hydrothermal liquefaction, organic matter such as human waste can be broken down to simpler chemical compounds. The material is pressurized to 3,000 pounds per square inch — nearly one hundred times that of a car tire. Pressurized sludge then goes into a reactor system operating at about 660 degrees Fahrenheit. The heat and pressure cause the cells of the waste material to break down into different fractions — biocrude and an aqueous liquid phase.
“There is plenty of carbon in municipal waste water sludge and interestingly, there are also fats,” said Corinne Drennan, who is responsible for bioenergy technologies research at PNNL. “The fats or lipids appear to facilitate the conversion of other materials in the wastewater such as toilet paper, keep the sludge moving through the reactor, and produce a very high quality biocrude that, when refined, yields fuels such as gasoline, diesel and jet fuels.”
In addition to producing useful fuel, HTL could give local governments significant cost savings by virtually eliminating the need for sewage residuals processing, transport and disposal.
“The best thing about this process is how simple it is,” said Drennan. “The reactor is literally a hot, pressurized tube. We’ve really accelerated hydrothermal conversion technology over the last six years to create a continuous, and scalable process which allows the use of wet wastes like sewage sludge.”
An independent assessment for the Water Environment & Reuse Foundation calls HTL a highly disruptive technology that has potential for treating wastewater solids. WE&RF investigators noted the process has high carbon conversion efficiency with nearly 60 percent of available carbon in primary sludge becoming bio-crude. The report calls for further demonstration, which may soon be in the works.
PNNL has licensed its HTL technology to Utah-based Genifuel Corporation, which is now working with Metro Vancouver, a partnership of 23 local authorities in British Columbia, Canada, to build a demonstration plant.
“Metro Vancouver hopes to be the first wastewater treatment utility in North America to host hydrothermal liquefaction at one of its treatment plants,” said Darrell Mussatto, chair of Metro Vancouver’s Utilities Committee. “The pilot project will cost between $8 to $9 million (Canadian) with Metro Vancouver providing nearly one-half of the cost directly and the remaining balance subject to external funding.”
Once funding is in place, Metro Vancouver plans to move to the design phase in 2017, followed by equipment fabrication, with start-up occurring in 2018.
“If this emerging technology is a success, a future production facility could lead the way for Metro Vancouver’s wastewater operation to meet its sustainability objectives of zero net energy, zero odours and zero residuals,” Mussatto added.
In addition to the biocrude, the liquid phase can be treated with a catalyst to create other fuels and chemical products. A small amount of solid material is also generated, which contains important nutrients. For example, early efforts have demonstrated the ability to recover phosphorus, which can replace phosphorus ore used in fertilizer production.
Michael Sandstrom collects samples from corals embedded in an ancient reef in the Cape Range region of Australia. He will use isotopes from the samples to determine the age of the reef to help figure out how sea level rose in the past. Credit: Dan Marone
Figuring out how far sea level rose during past warm periods in Earth’s history starts with a walk on the beach, a keen eye for evidence of ancient shorelines, and a highly accurate GPS system. The math isn’t as simple as subtracting the distance from the old shoreline to the water’s edge, though. As massive ice sheets retreated during past ice ages, their weight on the land below lifted and the land rebounded. On longer time scales, circulation within the Earth’s mantle has changed the shape and height of the crust, as well.
Lamont-Doherty Earth Observatory marine geologist Maureen Raymo has been at the forefront of the discovery of these forces and of efforts to account for them. Her goal – working in collaboration with Robin Bell’s Polar Geophysics Group through their joint Changing Ice, Changing Coastlines Initiative – is to answer two critical questions: how far will sea level rise as the planet warms now, and how fast?
The answers require knowledge of how the ice sheets are changing now and how sea level rose long ago when global temperatures were warmer than today. While Bell’s team focuses on the ice sheets, Raymo and her colleagues and graduate students have been mapping old shorelines and collecting samples around the world, from Australia’s Cape Range to Argentina’s rocky coast.
From beaches to clean labs
Scientists can spot changes in the fossil structures along the shoreline by using drones and planes equipped with lidar. But to figure out the age of ancient stranded reefs, they need to hike in with rock hammers and GPS.
In Western Australia, Lamont graduate student Michael Sandstrom, with colleagues from both Columbia University and the University of Western Australia, spent weeks walking the coast with heavy packs this summer, documenting the height and location of old shorelines and chipping off samples to take back to the lab.
“In a modern beach environment there are a lot of indicators of where current-day sea level is – tidal notches, subtidal bedding, articulated bivalves (unopened shells can be indicators of intertidal zones). Once we get an idea of what the modern environment looks like, we hike inland looking for the same assemblages and indicators, and we can say that when this past shoreline formed, sea level was at this point,” Sandstrom said.
Back at Lamont, home to one of the most advanced clean labs in geochemistry, Sandstrom uses a thermal ionization mass spectrometer to narrow down the ages of old shoreline samples. One test separates out the isotopes strontium-86 and strontium-87. The isotopes’ relative levels in seawater have changed over millions of years, creating something of a timestamp that scientists can use to determine when the shells were alive. Sandstrom also uses cosmogenic dating techniques with beryllium-10 to determine how long ancient reefs have been above the water level where they would be exposed to cosmic rays. The test provides a minimum age for checking against the strontium results. With younger corals, Sandstrom can also use uranium-thorium dating, by which he compares levels of uranium-234 to thorium-230 to determine how long the uranium-234 has been decaying.
The GPS data paired with the dates allow the scientists to track the rise and fall of old shorelines and calculate the influence of other forces.
“All of these shorelines were deposited basically horizontally when they were formed. Any sort of local deformation is an indication of either tectonics or dynamic topography,” Sandstrom said. “If we’re able to get really accurate ages, we can tell the relative uplift rates and can calculate roughly what elevation local sea level was. Then we can start to look at other climate records and figure out how sea level relates to things like atmospheric CO2 concentration, what climate was like, what the ocean currents were doing.”
Rebounding land and mantle movement
Raymo, a Bruce C. Heezen Lamont Research Professor at Lamont, was drawn to sea level research by a paradox. Fossil evidence from the mid-Pliocene warm period, about 3 million years ago, indicates that temperatures were 1 to 2 degrees Celsius warmer than today. However, sea level estimates from that time varied widely, ranging from 10 meters to about 40 meters above the present level, implying very different polar ice sheet responses for a small amount of warming. Why did different studies come to such different conclusions about the height of past sea levels?
“It turns out, the answer was twofold: no one had corrected their field observations for isostasy, or the deformation of the crust in response to the addition or removal and ice and ocean water—we figured out how to do that; and no one had recognized the really strong influence of dynamic topography, which also deformed ancient shorelines,” Raymo said.
While working along the U.S. East Coast a few years ago, Raymo and Alessio Rovere, then a postdoctoral research scientist at Lamont, noticed that the calculations of mid-Pliocene sea levels 3 million years ago were still too varied, even when they accounted for isostasy. They realized then that dynamic topography – the patterns of uplift and subsidence of the crust induced by movement in Earth’s mantle over time scales of hundreds of thousands of years – was playing an important role.
Raymo’s team is now working on isolating the influence of dynamic topography on ancient shorelines around the world.
Today, global sea level is rising at about 3 millimeters per year as rising temperatures cause the oceans to expand and glaciers to melt. At the end of the last glacial period, about 15,000 years ago, it rose much faster, reaching about 40 mm per year. Understanding what happened then and in other periods past is allowing scientists to make better estimates of the risk ahead.
Reference:
Maureen E. Raymo et al. Departures from eustasy in Pliocene sea-level records, Nature Geoscience (2011). DOI: 10.1038/ngeo1118
Looking into the summit crater from the north side. Along one of the many canyons that have managed to carve their way into the 1980 eruption deposits. Credit: University of New Mexico
It’s been more than 35 years since the last major eruption of Mount St. Helens. Since that blast, much research has been conducted with scientists learning a great deal about one of the most active volcanoes within the Cascade arc, a North-South chain of volcanoes in the Pacific Northwest that formed above the subducting Juan de Fuca plate.
Mount St. Helens is known as a composite volcano or stratovolcano, a term for steep-sided symmetrical cones that are constructed of alternating layers of lava flows, ash and other volcanic debris. Composite volcanoes tend to erupt more explosively and pose considerable danger to nearby life and property such as Mount St. Helens did in the 1980 eruption. Its location, however, is unusual because it lies approximately 30 miles due west of Mount Adams and the main axis of arc volcanism.
Much has been learned since that eruption. Petrologic and geophysical research at Mount St. Helens that suggests most of the eruptive products were derived from one or more upper-crustal magma chambers located between depths of three to 12 kilometers (approximately two to 7 miles).
Volcanic eruptions are caused by magma, a mixture of liquid rock, crystals and dissolved gases. Arc magmas are the end result of complex series of processes involving the interaction between the overlying crust and melts that ascend from the mantle wedge source region.
Despite the previous research, the structure of the deep magmatic plumbing system beneath Mount St. Helens and its context within the broader Cascadia subduction system remain poorly resolved despite the genetic link between subduction and arc volcanism.
Recently, researchers including postdoctoral researcher Steven Hansen, along with mentor and Assistant Professor Brandon Schmandt at The University of New Mexico, have been searching for additional answers surrounding the magmatic system of Mount St. Helens as part of a multi-year collaborative research project involving several institutions.
The overarching goal of the research, released today in Nature Communications, is to illuminate the architecture of the greater Mount St. Helens magmatic system from slab to surface.
The collaboration, titled iMUSH (Imaging Magma Under St. Helens), supported by the GeoPrisms and the EarthScope Programs of the US National Science Foundation, also involves researchers from the Department of Earth Science at Rice University, the Department of Earth and Space Sciences from the University of Washington, and the Department of Earth and Atmospheric Sciences from Cornell.
“Thermal models of the subduction zone indicate the down-going slab is decoupled from the overriding mantle wedge beneath the forearc,” said Hansen. “This results in a cold mantle wedge that is unlikely to generate melt. Given the unusual location of Mount St Helens, we think that this raises questions regarding the extent of the cold mantle wedge and the source region of melts that are ultimately responsible for volcanism.”
In an ambitious attempt to constrain the deep structure of the crust and mantle below Mount St. Helens, which has proven tough to resolve in previous seismic studies, the researchers, along with a handful of students from the collaborating institutions, conducted a large-scale, active-source seismic experiment as part of the iMUSH collaboration to determine where the melt is located in the subsurface and where it is sourced from.
Hiking more than 20 miles a day while carrying up to 12, five-pound seismic sensors at a time, the group deployed an array consisting of 900 autonomous seismographs all within 15 kilometers of the Mount St. Helens summit crater. Active source explosions followed to create seismic energy similar to that produced by small 2.0 magnitude earthquakes.
“All sensors were deployed along the road and trail system at Mount St. Helens with an average spacing of 250 meters,” said Hansen. “After deploying the seismographs, 23 active source explosions were conducted by the Rice group, headed by Alan Levander and Eric Kiser.”
The resulting tremors were recorded by three arrays of vertical-component geophones deployed in two phases which together contained about 4,800 individual channels. The resulting dataset provides a unique opportunity for high-resolution seismic imaging of deep crustal structure beneath this active arc volcano.
“Using high-resolution active-source seismic data, we show that Mount St. Helens sits atop a sharp lateral boundary in Moho reflectivity,” Hansen said. “Weak-to-absent PmP reflections to the west are attributed to serpentine in the mantle-wedge, which requires a cold hydrated mantle wedge beneath Mount St. Helens (<~700°C).” These results suggest that the melt source region lies east towards Mount Adams where there are strong reflections “There’s a stark contrast across Mount St. Helens. In the west, it’s weak or non-existent.”
“This is a nice result because it shows a very sharp boundary between where you have reflectivity and where you don’t, and that boundary between strong and weak reflectivity is pretty much directly beneath Mount St. Helens,” added University of Washington Professor Ken Creager. “The density of data lets us see that this boundary between where there is reflectivity, and where there isn’t, is very sharp. Presumably what it’s telling us is the temperature of the mantle.”
The change in reflectivity is interpreted as low-velocity serpentine in the mantle wedge which requires cold temperatures and thus inhibits melting. The ocean (to the west) adds water to the subduction zone where fluids that drive volcanism are released from the subducting slab. The subducting slab is inherently cold (because it starts at the surface) and slowly warms as it subducts into the hotter mantle. As this happens, water is released from the slab and this water then rises towards the surface and interacts with the overlying mantle wedge.
The effect of the water on the mantle wedge is controlled by the temperature of the wedge rather than the temperature of the water. Water lowers the melting temperature of the mantle wedge which is what causes melting; assuming that the wedge is hot enough.
Where the mantle wedge is cold (<700C, forearc), this water can form serpentine instead of causing melting. This is why finding serpentine in the wedge below Mount St. Helens is so interesting, because we know that melt is making it to the surface there.
Researchers hypothesize that the mantle under the west is a different composition. The change in the mantle composition is right under Mount St. Helens and they speculate that the mantle is cold and hydrated in the west.
“The research suggests the cold mantle wedge extends to Mount St. Helens. The subduction trench is where the plate goes down, which is about 170 miles west of Mount St. Helens,” said Hansen. “The melt that supplies Mount St. Helens is probably formed to the east in the mantle wedge below Mount Adams and then moves west through the magmatic system somehow.”
“This adds to a variety of other experiments that suggest that where it’s cold this water is basically getting soaked into the mantle and turning into serpentine and not going anywhere, so it can’t get up into the crust to form volcanoes,” said Creager. “When you get up into where there is olivine the temperature is hotter, serpentine isn’t stable, so the water can play its role in the volcanic process.”
The location of the volcanic arc relative to the trench is thought to be controlled by the thermal structure of the mantle wedge, which presents a thermal paradox for Mount St. Helens because it lies directly adjacent to the cold mantle wedge and yet still produces arc derived magmatism which requires elevated temperatures.
“It is important to note that we have just finished collecting all of the different types of geophysical data associated with the iMUSH experiment and that these data will provide important additional constraints on the deep structure at Mount St. Helens,” said Hansen.
Reference:
S. M. Hansen et al. Seismic evidence for a cold serpentinized mantle wedge beneath Mount St Helens, Nature Communications (2016). DOI: 10.1038/ncomms13242
This polished fossil slab used in the study dates to more than 210 million years ago and contains well-preserved symbiotic corals. The fossils were collected in a mountainous region in Antalya, Turkey, and originated in the Tethys Sea, a shallow sunlit body of water that existed when the Earth’s continents were one solid land mass called Pangea. Credit: Jaroslaw Stolarski, Polish Academy of Sciences
The mutually beneficial relationship between algae and modern corals—which provides algae with shelter, gives coral reefs their colors and supplies both organisms with nutrients—began more than 210 million years ago, according to a new study by an international team of scientists including researchers from Princeton University.
That this symbiotic relationship arose during a time of massive worldwide coral-reef expansion suggests that the interconnection of algae and coral is crucial for the health of coral reefs, which provide habitat for roughly one-fourth of all marine life. Reefs are threatened by a trend in ocean warming that has caused corals to expel algae and turn white, a process called coral bleaching.
Published in the journal Science Advances, the study found strong evidence of this coral-algae relationship in fossilized coral skeletons dating back more than 210 million years to the late Triassic period, a time when the first dinosaurs appeared and Earth’s continents were a single land mass known as Pangea. Although symbiosis is recognized to be important for the success of today’s reefs, it was less clear that that was the case with ancient corals.
“It is important to know how far back in time symbiosis evolved because it gives insight into how important symbiosis is to the health of coral reefs,” said Daniel Sigman, Princeton’s Dusenbury Professor of Geological and Geophysical Sciences and a member of the Princeton Environmental Institute. “It appears that the origin of symbiosis corresponds to the rise of coral reefs in general.”
In addition to confirming that symbiosis dates back to the Triassic, the study found that the corals inhabited nutrient-poor marine environments—not unlike today’s subtropical waters—where algae-coral symbiosis played a major role in driving reef development.
“The onset of symbiosis with algae was highly profitable for corals,” said lead author Jaroslaw Stolarski, a professor of biogeology at the Institute of Paleobiology at the Polish Academy of Sciences. “It allowed them to survive in very nutrient-poor waters, and at the same time grow and expand.”
Algae belonging to the group known as dinoflagellates live inside the corals’ tissues. The algae use photosynthesis to produce nutrients, many of which they pass to the corals’ cells. The corals in turn emit waste products in the form of ammonium, which the algae consume as a nutrient.
This relationship keeps the nutrients recycling within the coral rather than drifting away in ocean currents and can greatly increase the coral’s food supply. Symbiosis also helps build reefs—corals that host algae can deposit calcium carbonate, the hard skeleton that forms the reefs, up to 10 times faster than non-symbiotic corals.
Finding out when symbiosis began has been difficult because dinoflagellates have no hard or bony parts that fossilize. Instead, the researchers looked for three types of signatures in the coral fossils that indicate the past presence of algae: fossil microstructures, levels of different types of carbon and oxygen, and levels of two forms of nitrogen.
First author Katarzyna Frankowiak of the Institute of Paleobiology at the Polish Academy of Sciences conducted the microstructural analysis with assistance from Marcelo Kitahara of the Federal University of Sao Paulo in Brazil, Maciej Mazur of the University of Warsaw, and Anders Meibom of the Ecole Polytechnique Federale de Lausanne and the Universite de Lausanne. Their analysis revealed regularly spaced patterns of growth consistent with the symbiotic corals’ reliance on algal photosynthesis, which only takes place during daylight.
Frankowiak and Anne Gothmann, who earned her Ph.D. from Princeton’s Department of Geosciences in 2015 and is now a postdoctoral researcher at the University of Washington, measured the ratios of different types of oxygen and carbon and found that the results matched what would be expected when symbiosis occurs.
The third approach, determining the forms of nitrogen—which derive in part from the ammonium the corals had excreted—was conducted by Xingchen (Tony) Wang, who earned his doctoral degree in geosciences from Princeton in 2016 and is now a postdoctoral research fellow working with Sigman.
The nitrogen atoms, which are trapped in the fossil’s calcium-carbonate matrix, come in two forms, or isotopes, that vary only by how many neutrons they have: 14N has seven neutrons while 15N has eight neutrons, making it slightly heavier. By studying modern corals, researchers knew that symbiotic corals contain a lower ratio of 15N to 14N compared to non-symbiotic corals. The team found that the fossilized corals also had a low 15N-to-14N ratio, indicating they were symbiotic.
“Although algae were not present in the fossils, they left behind chemical signatures,” Wang said. “We found strong evidence that the fossilized coral were symbiotic and that they lived in a nutrient-poor environment. We were able to link the environmental conditions from 200 million years ago to the evolution of corals.”
George Stanley, a professor of geosciences at the University of Montana, had earlier explored the question of when symbiosis first evolved in corals. “This confirms a hypothesis that my colleagues and I put forth 20 years ago,” said Stanley, who is familiar with the research but had no role in it. “It is really exciting to see this confirmation.”
The fossils used in the study were collected in a mountainous region in Antalya, Turkey. During their lifetime, they lived in a shallow sunlit body of water called the Tethys Sea.
Stanley said the work would not have been possible without the coral fossils, which were remarkably well-preserved. “These corals are such a wonderful resource because they are as if you picked them up off the beach yesterday, and this is because they were sealed in deposits for centuries.”
The fossil record also shows a significant reef expansion occurred around 205 million years ago, and this fits with a boost in coral growth due to the development of symbiosis, Stanley said.
Reference:
Katarzyna Frankowiak, Xingchen T. Wang, Daniel M. Sigman, Anne M. Gothmann, Marcelo V. Kitahara, Maciej Mazur, Anders Meibom and Jarosław Stolarski1. Photosymbiosis and the expansion of shallow-water corals. DOI: 10.1126/sciadv.1601122
Cracks on the road outside the centre of Norcia, central Italy pictured a day after a 6.5-magnitude earthquake struck on October 30, 2016 . Credit: AFP/Alberto Pizzoli
Areas hit by Italy’s 6.5-magnitude quake displaced the ground by up to 70 centimetres (27.5 inches), Italian scientists reported on Tuesday.
Satellite images found that Sunday’s tremor deformed the landscape over 130 square kilometres (50 square miles), the Italian National Research Council said in a statement.
The biggest displacement was in the Castelluccio region, near the small town of Norcia, which lay only six kilometres (3.7 miles) from the epicentre, it said. The ground in this region was pushed up or sank by up to 70cm.
The quake, measuring a powerful 6.5-magnitude according to Italian monitors, struck at a very shallow depth. It was the latest in a string of seismic shocks to hit central Italy this year.
The event was followed by around 1,100 after-shocks, including 19 quakes registering between four and five magnitude and 240 of between three and four magnitude, the National Institute of Geophysics and Volcanology said.
The strongest was 4.8, occurring on Tuesday shortly before 0800 GMT.
Note: The above post is reprinted from materials provided by AFP.
A destroyed house in the village of Pretare, near Arquata del Tronto, Italy, Tuesday, Nov. 1, 2016. Earthquake aftershocks gave central Italy no respite on Tuesday, haunting a region where thousands of people were left homeless and frightened by a massive weekend tremor that razed centuries-old towns. Credit: AP Photo/Sandro Perozzi
A wave of earthquakes has rocked central Italy in recent months, shattering medieval towns and destroying ancient homes, churches and landmarks. The latest—a magnitude 6.6—over the weekend struck a cluster of historic mountain towns, the most powerful temblor to hit Italy in more than three decades. The new shaking comes as the region reeled from a deadly magnitude 6.2 quake in August that killed 300 people and a pair of strong quakes last week.
How are the quakes related? Do they foreshadow an even bigger temblor? Scientists are studying the relationship of the quakes, which occurred on several faults in the Apennines mountain range.
A look at earthquake terminology:
Q: How are earthquakes defined?
A: An earthquake is generally characterized as a foreshock, main shock or aftershock.
The largest quake in a series is the main shock. Foreshocks are quakes that strike before the main shock along the same fault. Aftershocks are smaller quakes that rattle the same general area following the main event. Aftershocks generally become less powerful and less frequent over time.
Not all quakes have foreshocks, but moderate and strong quakes are followed by a series of aftershocks.
Scientists don’t know beforehand what type of quake it’ll be until the shaking has played out.
Q: What about the Italy quakes?
A: The Italy quakes are under investigation, but it appears the previous quakes including the deadly August temblor were foreshocks to Sunday’s quake, said U.S. Geological Survey seismologist Paul Earle.
While the latest quake was the largest in the sequence, no deaths were reported because thousands of people had evacuated to shelters and hotels after the earlier quakes.
Earle said the chances of an even larger quake striking the same area are low.
Q: Can a main shock become a foreshock?
A: Days before the 2011 Fukushima nuclear disaster in Japan, several strong quakes including a magnitude 7.3 rattled the region. That quake had been considered the main shock until a magnitude 9 struck off the coast of Japan, generating a tsunami that swamped the Fukushima Daiichi nuclear power plant.
Q: How long can aftershocks last?
A: Aftershocks can last for days, weeks or even years depending on the strength of the main quake.
Recent disasters—such as Fukushima and the 2004 magnitude 9.1 quake in Indonesia that triggered an Indian Ocean tsunami that killed 230,000 people in a dozen countries—have been followed by tens of thousands of aftershocks.
Note: The above post is reprinted from materials provided by The Associated Press.
Securing the mammoth skull and tusks with straps before hoisting it out of the pit. Pictured from left to right (all from U-M): former archaeology graduate student Ashley Lemke, Earth and Environmental Sciences undergraduate Jessica Hicks, former paleontology graduate student John Fronimos (Ph.D. 2016), paleontologist Daniel Fisher, and paleontology graduate student Joe El-Adli. Image credit: Daryl Marshke, Michigan Photography
On the fourth floor of the University of Michigan’s Museum of Natural History, in a large gallery set aside for temporary exhibits, a room has been built to display the remains of an ice age mammoth pulled from a farmer’s field near Chelsea on Oct. 1, 2015.
The Bristle Mammoth exhibit opens to the public Nov. 5. And unlike most other museum exhibits, the designers left empty space to accommodate additional research findings and mammoth remains that could be added in the future.
That’s because the Bristle Mammoth investigation is a scientific work in progress. And if tantalizing preliminary results are confirmed through additional studies—including a planned return to the Bristle farm next month for a second excavation—the museum curators will likely need every square foot of that extra display space.
A multi-pronged analysis of Bristle Mammoth bones, tusks and teeth over the past year suggests the specimen could help rewrite the story of Michigan prehistory, specifically the timing of the arrival of the first humans and their earliest interactions with mammoths, whose meat was a prized food source.
The oldest well-documented, published evidence for humans in Michigan is about 13,000 years ago, the age of the spear-wielding Clovis hunters. But several lines of evidence from the Bristle Mammoth, including a single, noteworthy radiocarbon date, imply that humans processed its carcass more than 1,000 years before the Clovis hunters arrived.
If the preliminary findings can be bolstered and then published in a peer-reviewed scientific journal, James Bristle’s farm near Chelsea could join a handful of well-documented pre-Clovis archaeological sites in the Americas, including locations in Texas, Washington, Oregon, Pennsylvania, Wisconsin, Florida and South America.
“What’s so interesting about the Bristle site is that there’s a mammoth with evidence of human association at a very early date—well before Clovis times,” said U-M paleontologist Daniel Fisher, who led the Bristle dig and who is overseeing the analysis of the remains.
The first radiocarbon date is considered preliminary and will be reported when the team submits its findings for publication.
“That makes it all the more important to do a complete documentation of this site, and that’s why we intend to return to the Bristle farm and open a second excavation adjacent to where we dug before,” said Fisher, director of the U-M Museum of Paleontology and a professor in the Department of Earth and Environmental Science and in the Department of Ecology and Evolutionary Biology.
The first mammoth bones were discovered last year while Bristle was installing drainage pipe at a low spot in one of his fields. Bristle gave U-M researchers one day to recover whatever remains they could find; after that, the drainage project needed to resume.
As soon as the U-M team opened the excavation on the morning of Oct. 1, 2015, they exposed the skull with both tusks still attached, and a number of other bones. The team spent most of the day uncovering the skull and tusks, using a backhoe to hoist them from the muddy pit as daylight faded.
Several days after the dig, the Bristles donated the mammoth remains to U-M.
“The striking thing about this project is how incredibly excited people are about it. The community has shown more excitement about the Bristle Mammoth than any other project I can remember,” said Amy Harris, director of the U-M Museum of Natural History.
A direct mail and crowdfunding campaign raised about $48,000 to pay for the exhibit and to help defray Fisher’s ongoing research expenses.
“This exhibit is really about viewing research as an unfolding process of discovery,” Harris said. “We don’t find all the answers right away. It takes time to pursue lines of investigation.”
The Bristle exhibit will remain on display until January 2018 and will then move to the Museum of Natural History’s new home in the U-M Biological Science Building, which is under construction now.
“I didn’t realize how big this was going to be, how important it would be to a lot of people. It’s still overwhelming to me,” Bristle said. “Any inconvenience to us is a small price to pay for what we may learn. Who am I, in the whole scheme of things, to stand in the way of learning more about our past?”
Late in 2015, once the mud was washed from the bones, Fisher’s crew began documenting three main lines of evidence for human involvement with the Bristle Mammoth. The animal was a male in its mid-40s and would have weighed about 9 tons.
First, they found what Fisher describes as “intentional breakage” of multiple skull bones “targeted toward removal of nutritious tissues that humans might wish to harvest,” including the brain, the trunk and the tusk pulp cavities. Wooden, stone or bone tools were apparently used to break bones around the base of both tusks, the base of the trunk, and along the back rear portion of the skull, Fisher said.
For the upcoming exhibit, the researchers modeled the broken skull fragments digitally and used a 3-D printer to make plastic replacements for them. Exhibit visitors will see the real skull on display, fitted with a mosaic of white plastic segments so the scientists can continue to study the real broken bones.
The exhibit will also include a fiberglass cast of the Bristle Mammoth’s left tusk, which is 11 feet long and curved like a banana with a slight spiral twist.
The second line of evidence for human involvement with the Bristle Mammoth consists of three boulders recovered alongside the skull during the dig. One is the size of a medicine ball, one is about as big as a basketball, and the third is roughly the size and shape of a football.
The mammoth bones were found embedded in fine-grained pond sediments, with no signs of a stream or other natural geologic feature that could have carried the boulders to their final resting place next to the mammoth skull. Fisher suspects early humans butchered the carcass and placed selected portions at the bottom of the pond for storage, then used the boulders to anchor their meat stash.
The third line of evidence for human involvement fits into the meat-storage scenario. Some of the recovered bones were fully articulated when found, meaning they remained in the same positions, relative to each other, as when the animal was alive.
But some of these fully articulated sections were separated from other parts of the carcass, as if placed in separate piles. Such a pattern is unlikely to occur naturally but could happen if humans placed chunks of the carcass in the pond for storage, Fisher said.
During the Bristle dig, 55 to 60 nearly complete mammoth bones were found. In addition to the skull with teeth and tusks, most of the vertebrae and ribs were found, along with parts of the shoulder blades and the pelvis.
Altogether, 30 to 40 percent of the animal’s skeletal mass was recovered, Fisher said. Notably missing are the limb and foot bones and the tail vertebrae. One goal of the second excavation is to find more bones.
But a much higher priority during the second dig will be to reconstruct the geological context of the mammoth remains, something that simply wasn’t possible during last year’s get-what-you-can-in-a-day dig. The Bristle bones were found about 10 feet below the current land surface, in fine-grained clays and marls from a pond that no longer exists.
A prime goal of the next dig is to sample each of the sediment layers above the bones, as well as the clays up to 2 feet below the bone layer. Whenever possible, organic material from each layer—whether it’s twigs or spruce cones or just the remains of phytoplankton that grew in the ancient pond—will be radiocarbon-dated. Pollen grains and fungal spores will also be analyzed in this effort to reconstruct ancient environments and provide proper context for the mammoth find.
“If we went down to a depth of 12 feet, that would be back 16,000 years or so, shortly after the ice sheets melted back, revealing the landscape of Michigan’s Lower Peninsula,” Fisher said.
“And if we could get a series of dates from the sequence of sediments in the various layers, then the expectation would be that the lower ones would be older than the higher ones. And those radiocarbon dates had better come back from the lab in the expected order, or you’re going to know that something is seriously wrong.”
Other tests completed or under way include a season-of-death study and a mitochondrial DNA analysis.
In the season-of-death study, growth layers in the base of the mammoth’s tusk are analyzed using microCT scans to determine the time of year the animal died. Autumn is typically the time when early hunters pursued mammoths and mastodons, because that’s when it was critical to cache food for the winter, Fisher said. Also, these extinct relatives of elephants gained weight throughout the summer and were in prime condition by fall.
On the other hand, late spring or early summer deaths have been associated with animals that died in mating-season battles. Death from starvation, in contrast, would have been more likely at the end of winter.
Mitochondrial DNA is genetic material passed from mother to offspring. The Bristle Mammoth’s skeleton shows physical signs that it may have been a hybrid between a woolly mammoth and a Columbian mammoth, Fisher said. Such hybrids are not unusual among the mammoths found in the Great Lakes region.
The mitochondrial DNA test will examine the animal’s matrilineal ancestry to see if its genetic inheritance supports hybridization between a woolly and Columbian mammoth.
Over the decades, pieces from about 300 mastodons and 30 mammoths have been recovered in Michigan. The U-M Museum of Natural History currently displays two mounted mastodon skeletons but has not previously exhibited mammoth bones, according to Harris.
In addition to the skull and tusk, the Bristle exhibit will include a sequence of neck vertebrae, part of the pelvis, part of the mandible, and a rib that visitors can touch. Those specimens are real mammoth bones, not casts.
Visitors will also be able to closely examine some of the mammoth bones by manipulating 3-D digital models on a touch-screen monitor. Dramatic videos from the October 2015 dig will also be available, along with a life-size mammoth silhouette suitable for selfies.
The exhibit’s opening weekend events begin with a public lecture by Fisher on Friday night, Nov. 4.
Nepal is home to some 3,000 glacial lakes. Credit: AFP/Subel Bhandari
Nepal has successfully drained part of a giant glacial lake near Mount Everest, averting risk of a disastrous flood that could have threatened thousands of lives, officials said Monday.
Scientists say climate change is causing Himalayan glaciers to melt at an alarming rate, creating huge glacial lakes which could burst their banks and devastate mountain communities.
Imja Tsho, located at an altitude of 5,010 metres (16,437 feet), just 10 kilometres (6.2 miles) south of the world’s highest peak, is the fastest-growing glacial lake in Nepal.
The Himalayan nation was devastated by a 7.8-magnitude earthquake last year, raising alarm about the risks of flash flooding from glacial lakes.
“Draining the lake was on the priority of the government because of its high risk. We have successfully mitigated a disaster right now,” Top Bahadur Khatri, the project manager of the Community Based Flood and Glacial Lake Outburst Risk Reduction Project, told AFP.
Khatri said that the lake, nearly 150 metres deep, had its water lowered by 3.5 metres after six months of rigorous work—draining more than five million cubic metres of water.
The Nepal government worked together with United Nations Development Programme (UNDP) to drain the lake.
A team of 40 Nepal army personnel and more than 100 local high altitude workers worked in shifts since April to complete the project, airlifting or using yaks to transport the equipment.
“A 45-metres long tunnel was constructed to aid outflow of the lake downstream. We have also installed a mechanical gate to control the discharge,” said Lieutenant Colonel Bharat Lal Shrestha, who led the army team.
“Because of the wind, snow and thin air, we could work only two or three hours a day. It was a challenging task,” he told AFP.
The surface area covered by the lake expanded from 0.4 to 1.01 square kilometres between 1984 and 2009, triggering concerns that it may breach its banks and flood villages downstream.
Experts say that a flood would have a catastrophic impact on the lives of more than 50,000 people living in nearby villages and even in southern districts of the country.
As part of the project, early warning systems have also been installed in villages downstream.
“Our plan is to now replicate the work in other high-risk glacial lakes,” Khatri said.
Nepal is home to some 3,000 glacial lakes.
In 2014 a major international study warned that glaciers in the Everest region could shrink by 70 percent or disappear entirely by the end of the century, owing to climate change.
A study published by the Kathmandu-based International Centre for Integrated Mountain Development used satellite imagery to show how Nepal’s glaciers had already shrunk by nearly a quarter between 1977 and 2010.
Note: The above post is reprinted from materials provided by AFP.
Oil field at Signal Hill in the Los Angeles Basin in 1923. Credit: The Aerograph Co./ US Library of Congress
Historical sleuthing has turned up evidence for a possible link between oil production and a handful of damaging earthquakes that took place in the Los Angeles Basin during its oil boom in the early 20th century, according to a new study published 1 November in the Bulletin of the Seismological Society of America (BSSA).
In particular, the 1920 Inglewood quake, the 1929 Whittier quake, the 1930 Santa Monica quake and the 1933 Long Beach earthquake may have been induced by oil production activities that took place prior to the time of the seismic events, say Susan Hough and Morgan Page of the U.S. Geological Survey.
Their study is one of the first to look at evidence for earthquakes caused by industry activity in the Los Angeles region before 1935. Oil and gas production practices then were significantly different from today’s retrieval methods, the researchers note, so their findings “do not necessarily imply a high likelihood of induced earthquakes at the present time” in the L.A. Basin.
Other studies have concluded that there was no significant evidence for induced earthquakes in the area after 1935.
“With the advent of water flooding and other changes in industry practices, you may not find these kinds of induced earthquakes after 1935,” says Hough. “It’s possible it was just an early 20th century phenomenon.”
If researchers can confirm that some of these larger earthquakes such as the magnitude 6.4 Long Beach quake were human-caused, however, the findings could re-shape how seismologists calculate the rate of natural earthquake activity in the basin.
“If you take our four—the 1920, 1929, 1930 and 1933 earthquakes—out of the calculations as induced or potentially induced, it does call into question what the rate of natural earthquakes in the L.A. Basin really is,” Hough suggests. “Maybe the L.A. Basin as a geological unit is more seismically stable than we’ve estimated.”
Los Angeles’ oil boom began in 1892 when oil was discovered near present-day Dodger Stadium, and L.A. Basin oil fields accounted for nearly 20 percent of the world’s total production of crude oil by 1923. Despite this massive scale of production, it does not appear that induced earthquakes were common in the basin during the early 20th century.
Compiling the data to study this question, however, was a complicated task for Hough and Page. The researchers had to put together a list of all “felt” earthquake events in the L.A. Basin during the time period, using reports of shaking and property damage to calculate quake epicenters and magnitudes for earthquakes recorded by few if any seismometers.
For Hough, this meant a few interesting trips through the Cal Tech archives, where she found historical gems such as renowned seismologist Charles Richter’s unpublished notes on the 1929 Whittier earthquake. “I was literally following in his footsteps, for example where he had gone down San Gabriel Boulevard, starting in Pasadena, and stopping at every place where there was a dwelling and making observations of earthquake effects,” she says.
Hough’s earlier studies of historic induced earthquakes in Oklahoma gave her the idea to look for oil permits and other industry records online, and she eventually found a site containing state reports that summarized the operations of California oil fields in the early 20th century.
By comparing the earthquake lists with the industry data, the researchers found several links between earthquakes and significant oil production activities that took place nearby and close to the same time as the quakes. The precise location of the wells—whether they were close to a existing fault, for instance—along with well depth, appear to be important factors in whether an earthquake was induced.
Drilling deeper “gets you closer to the basement rock, and that is where the tectonically active faults are, the ones that are storing up tectonic stress,” Hough explains.
The recent increase in human-caused earthquakes in the central United States and Canada make it important to understand the “full context” of how, where and why earthquakes are induced, Hough notes. “We want to look at all the data we can, because the last decade is a just a tiny snapshot of the record that we have for induced seismicity.”
Reference:
“Potentially Induced Earthquakes in the Los Angeles Basin during the Early 20th Century,” Bulletin of the Seismological Society of America, DOI: 10.1785/0120160157
A paper published in the Nature journal Scientific Reports shows how higher latitude ecosystems recovered after the World’s most cataclysmic extinction event 252 million years ago. New fossils discovered by Uppsala University palaeontologists record an empty alien world from immediately after the extinction.
“Life on the sea floor had totally collapsed, with up 90% of all species becoming extinct,” says Dr Michal Zaton from the University of Silesia in Poland, and lead author on the international study.
“The seas were oxygen depleted and acidic, with a very low diversity bottom-living fauna comprising bivalves and vast colonies of filter-feeding microconchid tube worms. These would have encrusted shells and algal mats, which provided both suitable substrates and a potential source of oxygen,” says Dr Zaton.
Microconchid fossils have never previously been reported from ancient higher latitudes. “At the very beginning of the Age of Dinosaurs 252 million years ago, East Greenland was on the edge of a Boreal seaway stretching to the North Pole”, says Dr Benjamin Kear from the Museum of Evolution at Uppsala University and leader of the project funded by the Swedish Polar Research Secretariat. “Our discovery is significant because it shows for the first time that sea floor life at higher latitudes suffered the same global extinction process, and subsequent ecosystem recovery,” says Dr Kear.
Palaeontologists from Uppsala University spent more than two months collecting fossils in East Greenland. They are investigating the interplay between extinction events and major milestones in aquatic animal evolution. “Our project, First Steps From and To the Water, focuses upon geological timeframes at which back-boned animals first emerged from water onto land 360 million years ago, and then transitioned back to the seas 252 million years ago, what is formally known as the Permian-Triassic boundary. East Greenland is the only landmass where rocks of these ages occur together in the same place,” says Dr Henning Blom of the Evolutionary Biology Centre at Uppsala University, and co-investigator on the Swedish Polar Research Secretariat project.
“Our recent findings not only demonstrate global extinction recovery, but also that Triassic bottom-living communities rapidly adapted over time,” says co-author Dr Grzegorz Niedzwiedzki also from the Evolutionary Biology Centre at Uppsala University. “We found completely new microconchid species that invaded brackish lagoons as the seas retreated. This environmental opportunism was probably key to their survival and ecological success in the wake of massive ecosystem collapse.”
Note: The above post is reprinted from materials provided by Uppsala University.
