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The formation of gold deposits in South Africa

The left picture shows uraninite (uranium ore) that surrounds gold. In the right picture, a computer programme was used the remove the uraninite to illustrate the large volume hidden in the uranium ore. Credit: S. Fuchs, GEOMAR.

At a first glance, the Witwatersrand basin, the largest known gold resource on our planet, is not automatically related to ocean research. However, in its 3 billion years old geological history, the Witwatersrand basin in South Africa has been covered by seawater, but experienced also episodes of drying out, flooding and erosion by rivers and the repeated coverage by seawater. In 1852, the English prospector J.H. Davis discovered the first gold in the Witwatersrand, leading to the South African gold rush and the discovery of much more gold deposits within the basin. Although the Witwatersrand has been subject for decades of research, the genesis of gold and uranium ore is still unclear.

A group of scientists from Canada and the GEOMAR Helmholtz Centre of Ocean Research Kiel, successfully unravelled some mechanisms of the ore-forming process using complex analytical techniques. The results were recently published in the scientific journal Precambrian Research.

In this study, the scientists analysed samples from the Witwatersrand ore deposits with high-resolution scanning- and transmission-electron microscopes, and the processed their data using novel 2D and 3D software. “We were able to find out that fossil oil, that has been formed by organic matter derived from the first living organisms on Earth, mobilized uranium in the basin. Uraninite nanoparticles flocculated in the oil and formed uranium ore”, explains Dr. Sebastian Fuchs from the GEOMAR, the first author of the study. “Hot hydrothermal fluids, similar to those fluids that we find today in modern seafloor Black Smoker systems, transported dissolved gold and formed oil-in-water emulsions at the site of the deposits. The oil droplets in the hydrothermal fluids initiated the efficient chemical precipitation of native gold and the formation of very complex-structured gold and uranium ore.”

Using high-resolution imaging techniques, the researchers were able to visualize a to date unknown ore-forming process, in which migrating oil plays the dominant role in the distribution and concentration of metals. “With our method we have been able to show remnants of fossil oil entrapped in gold for the very first time” says Dr. Sebastian Fuchs.

“We are surprised to see such an intimate spatial relationship between the oil products and the metals”, reports Dr. Fuchs. “We hope that our study gives new impulses to industry and science to explore new mineral deposits. Perhaps it is possible at some day to extract gold and other metals from mined crude oil”.

With the methods used, it is now possible to study not only ore particles on the ocean floor in the range of millimetre to nanometre, but also the smallest fossils and living organisms, such as micro-organisms. “We are curious about what else we might discover on the ocean floor in the future”, Fuchs concludes.

Reference:
Sebastian H.J. Fuchs et al, Gold and uranium concentration by interaction of immiscible fluids (hydrothermal and hydrocarbon) in the Carbon Leader Reef, Witwatersrand Supergroup, South Africa, Precambrian Research (2017). DOI: 10.1016/j.precamres.2017.03.007

Note: The above post is reprinted from materials provided by Helmholtz Association of German Research Centres.

Geologist studies South Pacific volcano that’s been erupting continuously for hundreds of years

University of Iowa volcanologist Ingrid Ukstins spent two weeks collecting samples from Yasur, a continuously erupting volcano on Tanna, an island in the remote South Pacific archipelago of Vanuatu, to study its chemical composition and determine how the gasses it produces may be affecting people who live nearby. Credit: Ingrid Ukstins

For two weeks last fall, Ingrid Ukstins lived life on the wild and dangerous side. The University of Iowa volcanologist spent her days collecting samples from a volcano on Tanna, an island in the remote South Pacific archipelago of Vanuatu. The volcano, called Yasur, spews out flaming masses or “bombs”—some the size of a small car.

So, Ukstins trained her eyes on Yasur’s craters, about a quarter mile above sea level, to wait for molten rocks to be ejected—and “try not to get hit on the head by any,” she adds.

“I would just wait for a big explosion and watch for one of the chunks of rock to fall somewhere,” says Ukstins, associate professor in the UI Department of Earth and Environmental Sciences. “When you find the hole where the rock hit, you know it just came out of the volcano.”

Ukstins traveled to Yasur because it’s a living laboratory: The volcano has been erupting continuously since at least 1774 when it was first observed by the British explorer Captain James Cook. New research has shown it has been ejecting material without major pause for more than 1,400 years—and possibly as long as 20,000 years.

“It’s about as close to a continuous record as you can get,” Ukstins says.

What Ukstins aims to learn is whether the concentration of toxic gases, such as sulfur dioxide and fluorine, differ between the liquid inside the volcano and the ejected material. She also wants to study activity in the magma chamber, the frothing stew of lava just inside the volcanic cone, to learn more about how eruptions change over hours or days.

“If we can understand how Yasur works, we can understand better how other volcanoes work,” she says.

Ukstins has studied volcanoes in Chile, China, Greenland, Hawaii, and Iceland, among others. Though she can gain valuable insights from each, she was especially interested in studying an active volcano.

She learned about a research team from the University of Auckland (New Zealand), led by professor and volcano expert Shane Cronin, that since 1999 has been studying the effects of Yasur’s gases on people living nearby. Ukstins obtained grant money from UI International Programs and the Department of Earth and Environmental Sciences to join the Auckland team. She arrived on Tanna in late November.

“I was just very lucky to tag along, scientifically speaking,” Ukstins says.

She slept in a bungalow with netting tucked around her bed.

“This was jungle,” she says. “There were spiders as big as tennis balls.”

In the field, Ukstins watched for eruptions and located the fallen debris. The material came in all shapes, sizes, and states: Some chunks were huge and crispy black on the outside, a result of the red-hot exterior solidifying during the material’s brief flight. Other pieces were partly liquid, like fiery water balloons that landed on the ground with a splat. Ukstins carried a hammer and chipped off samples from the larger, solid chunks, taking care not to burn her hands as she amassed her inventory.

The samples she collected are now at the UI. Beginning in the summer, Ukstins’ team will analyze the specimens to determine their chemical, elemental, and mineral compositions using two high-powered instruments—an electron microprobe and an inductively coupled mass spectrometer.

“We have a time record of three months of volcanic activity from both monitoring and sampling new bombs as they were erupted,” she says, “so we have a unique opportunity to link observations of explosive activity and gas flux with any changes we see in the erupted lava bombs.”

Ukstins was especially struck by Yasur’s effects on the villagers who live near it, many of whom display physical symptoms, from pock marks in their teeth to brittle bones. The Auckland researchers suspect the physical ailments are the result of overexposure to fluorine, which the villagers breathe in the air and ingest in plants that absorb and store the gas. Ukstins helped her Auckland colleagues obtain plant and soil samples around the volcano that will be measured for their concentration of fluorine and other potentially harmful volcanic byproducts.

“This has real health implications,” Ukstins says. “It means more than simply studying volcanoes.”

Note: The above post is reprinted from materials provided by University of Iowa.

Grand challenges to better prepare for volcanic eruptions

Annotated aerial photo of Bogoslof volcano on January 10, 2017, showing morphological changes associated with the 2016–2017 eruption. Credit: USGS/AVO

Despite broad understanding of volcanoes, our ability to predict the timing, duration, type, size, and consequences of volcanic eruptions is limited, says a new report by the National Academies of Sciences, Engineering, and Medicine. To improve eruption forecasting and warnings to save lives, the report identifies research priorities for better monitoring of volcanic eruptions and three grand challenges facing the volcano science community.

Volcano monitoring is critical for forecasting eruptions and mitigating risks of their hazards. However, few volcanoes are adequately observed, and many are not monitored at all. For example, fewer than half of the 169 potentially active volcanoes in the U.S. have any seismometers — an instrument to detect small earthquakes that signal underground magma movement. And only three have continuous gas measurements, which are crucial because the composition and quantity of dissolved gases in magma drive eruptions. Enhanced monitoring combined with advances in experimental and mathematical models of volcanic processes can improve the understanding and forecasting of eruptions, the report says.

The committee that conducted the study and wrote the report also highlighted the need for satellite measurements of ground deformation and gas emissions, drone observations, advanced seismic monitoring, and real-time high-speed acquisition of data during eruptions. New approaches in analytical capabilities to decipher magma history, and conceptual and experimental models of magmatic and volcanic phenomena, will provide new insights on the processes that explain how magma is generated and erupts.

“There have been great improvements in conceptual models of volcanic phenomena, compared with those used a few decades ago, but the volcano science community is not yet adequately prepared for the next large eruption,” said Michael Manga, professor in the department of earth and planetary science at the University of California, Berkeley, and chair of the committee. “There are fundamental challenges that need to be addressed and require a sustained effort from across disciplines. By working toward these grand challenges, the volcano science community can help quantify the global effect of eruptions and mitigate hazards, ultimately benefiting millions of people living in volcanically active areas.”

The committee outlined several key questions and research priorities in areas such as the processes that move and store magma beneath volcanoes; how eruptions begin, evolve, and end; how a volcano erupts; forecasting eruptions; the response of landscapes, oceans, and the atmosphere to volcanic eruptions; and the response of volcanoes to changes on Earth’s surface.

Based on these research priorities, the committee identified three overarching grand challenges for advancing volcano science and monitoring:

Forecasting the size, duration, and hazard of eruptions by integrating observations with models

Current forecasts are based on recognizing patterns in monitoring data. These approaches have had mixed success because monitoring data do not capture the diversity of volcanoes or their evolution over time. An approach based on models of physical and chemical processes, informed by monitoring data, as is done in weather forecasting, could improve the accuracy of eruption forecasts. Such an approach requires integrating data and methodologies from multiple disciplines, the report says.

Quantifying the life cycles of volcanoes and overcoming our current biased understanding

Current understanding of a volcano’s life cycle is skewed because only a small number of volcanoes are studied. Extended monitoring from the ground, sea, and space can overcome some of these observational biases, the report says. Expanding and maintaining monitoring capabilities and supporting the infrastructure to make historical and monitoring data available are critical for advancing understanding of volcanic processes and assessing volcanic hazards. The committee noted that emerging technologies such as inexpensive sensors, drones, and new micro-analytical geochemical methods are promising tools to provide new insights into volcanic activity.

Building a coordinated volcano science community

Close to 100 volcanoes erupt somewhere on Earth each year. Strengthening multidisciplinary research, domestic and international research and monitoring partnerships, and training networks can help the research community maximize scientific advances that result from the study of eruptions around the world, the committee said.

The report cites the ongoing eruption at Bogoslof volcano in Alaska as an example that highlights these three challenges. A remote, initially submarine volcano in the Aleutian Island arc, the eruption started in late December 2016 and the activity has been continuing as of February 2017. In just one month, the volcano produced numerous explosions with plumes rising 20,000-35,000 feet, posing a significant hazard to North Pacific aviation. The U.S. Geological Survey Alaska Volcano Observatory (AVO) has been relying on distant seismometers, satellite data, infrasound, and lightning detection to monitor the activity because there are no ground-based instruments on the volcano. The committee said AVO has been able to provide early warning for only some of these hazardous events. This eruption also underscores the limited understanding of magma eruption. In more than 20 discrete events, the emerging volcano has reshaped its coastlines repeatedly, providing snapshots of volcano-landscape interactions.

Note: The above post is reprinted from materials provided by National Academies of Sciences, Engineering, and Medicine.

Ancient reptile tracks in the Pyrenees may include evidence of a new type of footprint

A large set of tracks made by archosauromorphs in the Pyrenees mountain range may include a new type of footprint made by reptiles that lived 247 million years ago, according to a study published April 19, 2017 in the open-access journal PLOS ONE by Eudald Mujal from Universitat Autònoma de Barcelona, Spain, and colleagues. Credit: All figures and photographic images will be published under a Creative Commons Attribution License (CCAL), which allows them to be freely used, distributed, and built upon as long as proper attribution is given.

A large set of tracks made by archosauromorphs in the Pyrenees mountain range may include a new type of footprint made by reptiles that lived 247 million years ago, according to a study published April 19, 2017 in the open-access journal PLOS ONE by Eudald Mujal from Universitat Autònoma de Barcelona, Spain, and colleagues.

The Permian mass extinction resulted in the loss of 90 percent of species. The environmental and climactic conditions hindered the recovery of vertebrate species following this devastating event.

To investigate which vertebrates lived during beginning of the Mesozoic Era, which followed the Permian extinction, Mujal and colleagues examined trace fossils of vertebrates in the Pyrenees mountains in Catalonia from approximately 247 to 248 million years ago. The researchers made 3D models and created silicone molds of these ephemeral fossils, enabling them to preserve the fossils in scientific collections.

The researchers identified that most tracks were made by archosauromorphs, the ancestors of crocodiles and dinosaurs. The majority were small, about half a meter in length, although a few specimens were longer than three meters. The researchers also identified a new footprint, Prorotodactylus mesaxonichnus, and the new fossil evidence from the Pyrenean tracks suggests that at least the Pyrenean Prorotodactylus genus is related to archosauromorphs, rather than being a dinosauromorph as previously thought from other records.

The authors suggest that the abundance of archosauromorph fossils in the Pyrenees provides evidence that archosauromorphs may have played a large role in vertebrate recovery following the Permian mass extinction. Further research could explore how the archosauromorph lineage may have evolved and spread following this time period.

“Trace fossils are evidence that archosauromorphs dominated the fluvial environments of the Catalan Pyrenees during the Triassic vertebrate recovery, early after the end-Permian mass extinction,” says Mujal.

Reference:
Mujal E, Fortuny J, Bolet A, Oms O, López JÁ (2017) An archosauromorph dominated ichnoassemblage in fluvial settings from the late Early Triassic of the Catalan Pyrenees (NE Iberian Peninsula). PLoS ONE 12(4): e0174693. DOI: 10.1371/journal.pone.0174693

Note: The above post is reprinted from materials provided by Public Library of Science.

Newly discovered Egyptian carnivore named after Anubis, ancient Egyptian god of underworld

Hyaenodont skull. Credit: Matthew Borths

Analysis of Egyptian fossils has identified a new species of extinct carnivorous mammals called hyaenodonts, according to a study published April 19, 2017 in the open-access journal PLOS ONE by Matthew Borths from Ohio University, United States of America, and Erik Seiffert from University of Southern California, United States of America.

Hyaenodonts preceded modern terrestrial carnivores in Africa and also lived in Europe, Asia, and North America. Some were tree-dwelling; others were terrestrial. The Afro-Arabian hyaenodont records are the oldest, making them key to understanding the evolution of these extinct meat-eaters. The authors of the present study characterized 34 million-year-old Egyptian fossils of a new skunk-sized species of hyaenodont. They named it Masrasector nananubis, the species name referring to Anubis, the canine-headed Egyptian god associated with the afterlife. This hyaenodont was a teratodontine, a carnivorous clade that has been difficult to align with other lineages due to poorly known cranial anatomy. The fossils of the new hyaenodont are the most complete known remains of a teratodontine from the Paleogene Period, and include largely complete skulls, jaws and limb bones.

Based on the morphology of the new hyaenodont’s bones, the researchers concluded that teratodontines are a close sister group of Hyainailourinae, one of two major hyaenodont clades that were hypercarnivorous, eating mostly meat. Comparison of the limb bones with those of other meat-eating mammals suggests that the new species was terrestrial and moved fast. The researchers state that the fossils of this new species will inform all future explorations of hyaenodont evolution and ecological diversity.

“Hyaenodonts were the the top predators in Africa after the extinction of the dinosaurs,” says Borths. “This new species is associated with a dozen specimens, including skulls and arm bones, which means we can explore what it ate, how it moved, and consider why these carnivorous mammals died off as the relatives of dogs, cats, and hyenas moved into Africa.”

Reference:
Borths MR, Seiffert ER (2017) Craniodental and humeral morphology of a new species of Masrasector (Teratodontinae, Hyaenodonta, Placentalia) from the late Eocene of Egypt and locomotor diversity in hyaenodonts. PLoS ONE 12(4): e0173527. DOI: 10.1371/journal.pone.0173527

Note: The above post is reprinted from materials provided by Public Library of Science.

New study ranks hazardous asteroid effects from least to most destructive

The trace left in the sky by the meteor that broke up over Chelyabinsk, Russia, in 2013. A new study explored seven effects associated with asteroid impacts — heat, pressure shock waves, flying debris, tsunamis, wind blasts, seismic shaking and cratering — and estimated their lethality for varying sizes. Credit: Alex Alishevskikh

If an asteroid struck Earth, which of its effects — scorching heat, flying debris, towering tsunamis — would claim the most lives? A new study has the answer: violent winds and shock waves are the most dangerous effects produced by Earth-impacting asteroids.

The study explored seven effects associated with asteroid impacts — heat, pressure shock waves, flying debris, tsunamis, wind blasts, seismic shaking and cratering — and estimated their lethality for varying sizes. The researchers then ranked the effects from most to least deadly, or how many lives were lost to each effect.

Overall, wind blasts and shock waves were likely to claim the most casualties, according to the study. In experimental scenarios, these two effects accounted for more than 60 percent of lives lost. Shock waves arise from a spike in atmospheric pressure and can rupture internal organs, while wind blasts carry enough power to hurl human bodies and flatten forests.

“This is the first study that looks at all seven impact effects generated by hazardous asteroids and estimates which are, in terms of human loss, most severe,” said Clemens Rumpf, a senior research assistant at the University of Southampton in the United Kingdom, and lead author of the new study published in Geophysical Research Letters, a journal of the American Geophysical Union.

Rumpf said his findings, which he plans to present at the 2017 International Academy of Astronautics Planetary Defense Conference in Tokyo, Japan, could help hazard mitigation groups better prepare for asteroid threats because it details which impact effects are most dominant, which are less severe and where resources should be allocated.

Though studies like his are necessary to reduce harm, deadly asteroid impacts are still rare, Rumpf said. Earth is struck by an asteroid 60 meters (more than 190 feet) wide approximately once every 1500 years, whereas an asteroid 400 meters (more than 1,300 feet) across is likely to strike the planet every 100,000 years, according to Rumpf.

“The likelihood of an asteroid impact is really low,” said Rumpf. “But the consequences can be unimaginable.”

Modeling asteroid effects

Rumpf and his colleagues used models to pepper the globe with 50,000 artificial asteroids ranging from 15 to 400 meters (49 to 1312 feet) across — the diameter range of asteroids that most frequently strike Earth. The researchers then estimated how many lives would be lost to each of the seven effects.

Land-based impacts were, on average, an order of magnitude more dangerous than asteroids that landed in oceans.

Large, ocean-impacting asteroids could generate enough power to trigger a tsunami, but the wave’s energy would likely dissipate as it traveled and eventually break when it met a continental shelf. Even if a tsunami were to reach coastal communities, far fewer people would die than if the same asteroid struck land, Rumpf said. Overall, tsunamis accounted for 20 percent of lives lost, according to the study.

The heat generated by an asteroid accounted for nearly 30 percent of lives lost, according to the study. Affected populations could likely avoid harm by hiding in basements and other underground structures, Rumpf said.

Seismic shaking was of least concern, as it accounted for only 0.17 percent of casualties, according to the study. Cratering and airborne debris were similarly less concerning, both garnering fewer than 1 percent of deaths.

Only asteroids that spanned at least 18 meters (nearly 60 feet) in diameter were lethal. Many asteroids on the lower end of this spectrum disintegrate in Earth’s atmosphere before reaching the planet’s surface, but they strike more frequently than larger asteroids and generate enough heat and explosive energy to deal damage. For example, the meteor involved in the 2013 impact in Chelyabinsk, Russia, was 17 to 20 meters (roughly 55 to 65 feet) across and caused more than 1,000 injuries, inflicting burns and temporary blindness on people nearby.

Understanding risk

“This report is a reasonable step forward in trying to understand and come to grips with the hazards posed by asteroids and comet impactors,” said geophysicist Jay Melosh, a distinguished professor in the Department of Earth, Atmospheric and Planetary Sciences at Purdue University in Lafayette, Indiana.

Melosh, who wasn’t involved in the study, added that the findings “lead one to appreciate the role of air blasts in asteroid impacts as we saw in Chelyabinsk.” The majority of the injuries in the Chelyabinsk impact were caused by broken glass sent flying into the faces of unknowing locals peering through their windows after the meteor’s bright flash, he noted.

The study’s findings could help mitigate loss of human life, according to Rumpf. Small towns facing the impact of an asteroid 30 meters across (about 98 feet) may fare best by evacuating. However, an asteroid 200 meters wide (more than 650 feet) headed for a densely-populated city poses a greater risk and could warrant a more involved response, he said.

“If only 10 people are affected, then maybe it’s better to evacuate the area,” Rumpf said. “But if 1,000,000 people are affected, it may be worthwhile to mount a deflection mission and push the asteroid out of the way.”

Reference:
Clemens M. Rumpf, Hugh G. Lewis, Peter M. Atkinson. Asteroid impact effects and their immediate hazards for human populations. Geophysical Research Letters, 2017; DOI: 10.1002/2017GL073191

Note: The above post is reprinted from materials provided by American Geophysical Union.

Morning Glory Pool

Morning Glory Pool is a hot spring in the Upper Geyser Basin of Yellowstone National Park in the United States.

History

The pool was named by Mrs E. N. McGowan, wife of Assistant Park Superintendent, Charles McGowan in 1883. She called it “Convolutus”, the Latin name for the morning glory flower, which the spring resembles. By 1889, the name Morning Glory Pool had become common usage in the park. Many early guidebooks called this feature Morning Glory Spring.

Sea scorpions: The original sea monster

This illustration shows a sea scorpion attacking an early vertebrate. Credit: Nathan Rogers

Four hundred and thirty million years ago, long before the evolution of barracudas or sharks, a different kind of predator stalked the primordial seas. The original sea monsters were eurypterids—better known as sea scorpions.

Related to both modern scorpions and horseshow crabs, sea scorpions had thin, flexible bodies. Some species also had pinching claws and could grow up to three metres in length. New research by University of Alberta scientists Scott Persons and John Acorn hypothesise that the sea scorpions had another weapon at their disposal: a serrated, slashing tail spine.

Armed and dangerous

“Our study suggests that sea scorpions used their tails, weaponized by their serrated spiny tips, to dispatch their prey,” says Scott Persons, paleontologist and lead author on the study.

Sparked by the discovery of a new fossil specimen of the eurypterid Slimonia acuminata, Persons and Acorn make the biomechanical case that these sea scorpions attacked and killed their prey with sidelong strikes of their serrated tail.

The fossil, collected from the Patrick Burn Formation near Lesmahagow, Scotland, shows a eurypterid Slimonia acuminate, with a serrated-spine-tipped tail curved strongly to one side.

Powerful weapons

Unlike lobsters and shrimps, which can flip their broad tails up and down to help them swim, eurypterid tails were vertically inflexible but horizontally highly mobile.

“This means that these sea scorpions could slash their tails from side to side, meeting little hydraulic resistance and without propelling themselves away from an intended target,” explains Persons. “Perhaps clutching their prey with their sharp front limbs eurypterids could kill pretty using a horizontal slashing motion.”

Among the likely prey of Slimonia acuminata and other eurypterids were ancient early vertebrates.

The paper, “A sea scorpion’s strike: New evidence of extreme lateral flexibility in the opisthoma of eurypterids,” was published in The American Naturalist in April 2017.

Reference:
W. Scott Persons, John Acorn. A Sea Scorpion’s Strike: New Evidence of Extreme Lateral Flexibility in the Opisthosoma of Eurypterids. The American Naturalist, 2017; 000 DOI: 10.1086/691967

Note: The above post is reprinted from materials provided by University of Alberta. Original written by Katie Willis.

Megafaunal extinctions driven by too much moisture

Representative Image: A Glacier cave on Perito Moreno Glacier, in Los Glaciares National Park, southern Argentina. Credit: Martin St-Amant/Wikipedia

Studies of bones from Ice Age megafaunal animals across Eurasia and the Americas have revealed that major increases in environmental moisture occurred just before many species suddenly became extinct around 11-15,000 years ago. The persistent moisture resulting from melting permafrost and glaciers caused widespread glacial-age grasslands to be rapidly replaced by peatlands and bogs, fragmenting populations of large herbivore grazers.

Research led by the Australian Centre for Ancient DNA (ACAD) at the University of Adelaide, published today in Nature Ecology and Evolution, has revealed that the ancient bones preserve direct biochemical evidence of the environmental upheavals, which can be traced through time.

Using 511 radiocarbon dated bones from animals such as bison, horse, and llamas the team was able to investigate the role of environmental change in the mysterious megafaunal extinctions, which claimed the vast majority of existing large land animals such as giant sloths and sabre-toothed cats.

“We didn’t expect to find such clear signals of moisture increases occurring so widely across all of Europe, Siberia and the Americas,” says study leader Professor Alan Cooper, ACAD Director. “The timing varied between regions, but matches the collapse of glaciers and permafrost and occurs just before most species go extinct.

The international team of researchers, including the University of Alaska Fairbanks, University of Oslo, the Yukon Government, and palaeontologists across Russia and Canada, measured nitrogen isotopes preserved in dated ancient animal bones and teeth recovered from permafrost areas and caves across Europe, Siberia, North and South America. They found distinctive biochemical signals reflecting massive increases of moisture on the landscape.

“Grassland megafauna were critical to the food chains. They acted like giant pumps that shifted nutrients around the landscape,” says lead author Dr Tim Rabanus-Wallace, from the University of Adelaide. “When the moisture influx pushed forests and tundras to replace the grasslands, the ecosystem collapsed and took many of the megafauna with it.”

“The idea of moisture-driven extinctions is really exciting because it can also explain why Africa is so different, with a much lower rate of megafaunal extinctions and many species surviving to this day,, says Professor Cooper. “Africa’s position across the equator means that grassland zones have always surrounded the central monsoon region. The stable grasslands are what has allowed large herbivores to persist — rather than any special wariness of hunters learned from humans evolving there.”

Professor Matthew Wooller, of the University of Alaska Fairbanks, says: “We find that on different continents the climate changes happened at different times, but they all showed that moisture increased massively just prior to extinction. The really elegant feature of this study is that it produces direct evidence from the fossils themselves — these extinct creatures are informing us about the climate they experienced leading up to their own extinctions.”

Reference:
M. Timothy Rabanus-Wallace, Matthew J. Wooller, Grant D. Zazula, Elen Shute, A. Hope Jahren, Pavel Kosintsev, James A. Burns, James Breen, Bastien Llamas, Alan Cooper. Megafaunal isotopes reveal role of increased moisture on rangeland during late Pleistocene extinctions. Nature Ecology & Evolution, 2017; 1 (5): 0125 DOI: 10.1038/s41559-017-0125

Note: The above post is reprinted from materials provided by University of Adelaide.

The giant sloth megatherium was a vegetarian

It lived 10,000 years ago and subsisted on a strictly vegetarian diet: the Giant Sloth Megatherium. Credit: Drawing by Joseph Smit, from “Extinct Monsters; a Popular Account of Some of the Larger Forms of Ancient Animal Life”

Together with an international team, Senckenberg scientists examined the diet of the extinct Giant Sloth Megatherium. Based on analyses of the collagen in the fossil bones, the researchers concluded in their study, which was recently published in the scientific journal “ScienceDirect,” that Megatherium subsisted on an exclusively vegetarian diet. Until recently, there had been much speculation about the food habits of these elephant-sized, ground-dwelling animals.

Sloths may well rank among the world’s most peculiar animals: With their backs pointing downward, they hang in trees and move in slow motion from branch to branch with the aid of their sickle-shaped claws. “Sloths already occurred 10,000 years ago, for example the species Megatherium,” explains Professor Dr. Hervé Bocherens of the Senckenberg Center for Human Evolution and Palaeoenvironment at the University of Tübingen.

The extinct relatives of the sloths could reach the size of an elephant and were much too heavy to spend a significant amount of time in the trees. Instead, they lived on the ground, where they excavated large burrows. For many years, their dietary habits were an enigma; the long claws on their hands and feet, in particular, gave rise to various speculations. Did the sloths use their claws to dig up subterranean insect colonies? Did the long claws serve as hunting tools, and were the giant animals carnivores? Or did the fossil representatives live on a strictly vegetarian diet, like the recent sloths? “These questions were at the center of our new study,” adds Bocherens.

Normally it is possible to deduce the feeding habits of fossil animals on the basis of the shape and wear of their teeth – however, the teeth of the Giant Sloth are not comparable to those of modern animals. “We therefore had to use a different method, so we measured the composition of carbon isotopes – the ratio of protein and mineral content – in the fossilized sloth bones,” explains Bocherens, and he continues, “Our measurements show that Megatherium lived on an exclusively vegetarian diet.”

In carnivores, the proportion of proteins is significantly higher than in herbivores, which primarily eat food high in carbohydrates. These differences can be documented in the isotopes. In order to reinforce their results, the scientists compared their data with more than 200 bones from modern mammals, whose diet is known, as well as with fossil specimens from both carnivores and herbivores. “Our results show that by using this method, it is possible to reconstruct the feeding habits of animals even several thousand years after their death,” adds the biogeologist from Tübingen.

Knowledge of the sloths’ feeding habits is important in order to understand their role in past ecosystems. “Moreover, the results can help us understand the interactions between Megatherium and the first human inhabitants of America – their habitats overlapped for several thousand years, before the Giant Sloth became extinct,” offers Bocherens as a preview.

Reference:
Hervé Bocherens et al. Isotopic insight on paleodiet of extinct Pleistocene megafaunal Xenarthrans from Argentina, Gondwana Research (2017). DOI: 10.1016/j.gr.2017.04.003

Note: The above post is reprinted from materials provided by Senckenberg Research Institute and Natural History Museum.

Japan Tsunami 2011

The March 11 earthquake and tsunami left more than 28,000 dead or missing. See incredible footage of the tsunami swamping cities and turning buildings into rubble.

The 2011 earthquake off the Pacific coast of Tōhoku was a magnitude 9.0 (Mw) undersea megathrust earthquake off the coast of Japan that occurred at 14:46 JST (05:46 UTC) on Friday 11 March 2011, with the epicentre approximately 70 kilometres (43 mi) east of the Oshika Peninsula of Tōhoku and the hypocenter at an underwater depth of approximately 30 km (19 mi).

The earthquake triggered powerful tsunami waves that reached heights of up to 40.5 metres (133 ft) in Miyako in Tōhoku’s Iwate Prefecture, and which, in the Sendai area, travelled up to 10 km (6 mi) inland. The earthquake moved Honshu (the main island of Japan) 2.4 m (8 ft) east, shifted the Earth on its axis by estimates of between 10 cm (4 in) and 25 cm (10 in), and generated sound waves detected by the low-orbiting GOCE satellite.

Lessons from Parkfield help predict continued fault movements after earthquakes

These two photos showing evidence of afterslip were taken where the West Napa fault crosses Highway 12 at Cuttings Wharf Road. The first offset measurement was taken the day of the earthquake — about 6 cm (2 in) of right-lateral offset. The following day (almost 24 hrs later), the same feature had 11 cm (4 in) of offset. Credit: USGS/ Photos courtesy of Tim Dawson, California Geological Survey

A new study shows that the San Andreas Fault continued to slip gradually for six to twelve years after the 2004 magnitude 6.0 Parkfield, California earthquake, raising the issue of continued damage to structures built across fault zones after damaging earthquakes. This long period of “afterslip” compares to just a year of afterslip for a similar magnitude quake in Napa, California in 2014, demonstrating large variation in fault behavior after earthquakes.

The findings, reported April 18 in the Bulletin of the Seismological Society of America (BSSA), suggest that there can be a range of afterslip durations along faults, making it more challenging to predict how post-earthquake movements might damage nearby infrastructure for years after a major earthquake.

Afterslip refers to the aseismic movement or “creeping” that takes place along a fault, including the trace of its surface rupture, after an earthquake. Some faults have long been known to creep aseismically between earthquakes, such as the part of the San Andreas Fault involved in the Parkfield quake, and these faults are thought to be more prone to afterslip. The fault involved in the Napa earthquake, although not known to be creeping between quakes, exhibited less afterslip.

James Lienkaemper, an emeritus research geophysicist with the U.S. Geological Survey, said the urban Hayward Fault near San Francisco also experiences interseismic creep, and is located in a similar geological setting to the Parkfield fault. He and his colleague Forrest McFarland of San Francisco State University suggest in the BSSA paper that there could be significant afterslip for possibly up to a decade along the Hayward Fault after an expected magnitude 6.8 earthquake there.

Prolonged afterslip could delay post-earthquake recovery by continuing to cause damage to critical infrastructure built across the fault such as rapid transit and utilities, said Lienkaemper, who noted that better forecasts of afterslip “can be used to plan temporary and final repairs to rapid transit tracks, water, gas and data lines.”

“Other major faults of the San Francisco Bay Areas, including Rodgers Creek, Northern Calaveras and Concord-Green Valley, also expect large earthquakes, and should expect significant afterslip, especially in locations where interseismic creep rates are high, and where faults cross deep sedimentary basins,” Lienkaemper added.

Lienkaemper and McFarland found that only about 74 percent of the predicted amount of afterslip for the Parkfield earthquake—a maximum expected value of about 35 centimeters—was complete a year after the earthquake. Their analysis of slip at the six-year mark indicated that afterslip would be completed everywhere on the ruptured fault between six and twelve years after the 2004 earthquake.

The ends of the Parkfield fault were the most likely areas to experience prolonged slipping after the earthquake, Lienkaemper noted, suggesting that slip in these parts of the fault gradually increased as stress transferred from movement of the central section of the rupture.

By contrast, nearly all of the predicted afterslip for the Napa quake was completed a year after the mainshock. After comparing the Parkfield and Napa afterslip with historical afterslip data from around the world, the researchers suggest that there may be a considerable range in the duration of afterslip events. Understanding the susceptibility of a fault to creep, however, could refine estimates of the amount and duration of fault movement during recovery after large earthquakes.

Reference:
“Long-term Afterslip of The M6.0, 2004 Parkfield, California, Earthquake—Implications for Forecasting Amount and Duration of Afterslip on Other Major Creeping Faults,” Bulletin of the Seismological Society of America (2017). DOI: 10.1785/0120160321

Note: The above post is reprinted from materials provided by Seismological Society of America.

Retreating Yukon glacier caused a river to disappear

Images captured by the European Space Agency’s Sentinel2 satellite in 2015 and 2016 show a dramatic drop in the Slims River’s flow. The receding toe of Kaskawulsh Glacier is seen at the bottom. Kluane Lake can be seen at the top of the 2016 image. Water now flows east and then south via the Kaskawulsh River. Credit: European Space Agency

The massive Kaskawulsh Glacier in northern Canada has retreated about a mile up its valley over the past century.

Last spring, its retreat triggered a geologic event at relatively breakneck speed. The toe of ice that was sending meltwater toward the Slims River and then north to the Bering Sea retreated so far that the water changed course, joining the Kaskawulsh River and flowing south toward the Gulf of Alaska.

This capture of one river’s flow by another, documented in a study led by the University of Washington Tacoma and published April 17 in Nature Geoscience, is the first known case of “river piracy” in modern times. “Geologists have seen river piracy, but nobody to our knowledge has documented it happening in our lifetimes,” said lead author Dan Shugar, a geoscientist at the University of Washington Tacoma. “People had looked at the geological record — thousands or millions of years ago — not the 21st century, where it’s happening under our noses.”

River piracy, also known as stream capture, can happen due to tectonic motion of Earth’s crust, landslides, erosion or, in this case, changes in a glacial dam. The new study documents one of the less-anticipated shifts that can occur in a changing climate.

Shugar and co-authors Jim Best at the University of Illinois and John Clague at Canada’s Simon Fraser University had planned fieldwork last summer on the Slims River, a geologically active system that feeds Kluane Lake in the Yukon. When they arrived in August, the river was not flowing. River gauges show an abrupt drop over four days from May 26 to 29, 2016.

By late summer, “there was barely any flow whatsoever. It was essentially a long, skinny lake,” Shugar said. “The water was somewhat treacherous to approach, because you’re walking on these old river sediments that were really goopy and would suck you in. And day by day we could see the water level dropping.”

The research team puzzled about what to do next. They got permission to use their mapping drone to create a detailed elevation model of the glacier tongue and headwater region. The resulting paper is a geological postmortem of the river’s disappearance.

“For the last 300 years, Slims River flowed out to the Bering Sea, and the smaller Kaskawulsh River flowed to the Gulf of Alaska. What we found was the glacial lake that fed Slims River had actually changed its outlet,” Shugar said. “A 30-meter (100-foot) canyon had been carved through the terminus of the glacier. Meltwater was flowing through that canyon from one lake into another glacial lake, almost like when you see champagne poured into glasses that are stacked in a pyramid.”

That second lake drains via the Kaskawulsh River in a different direction than the first. The situation is fairly unique, Shugar said, since the glacier’s toe was sitting on a geologic divide.

Clague began studying this glacier years ago for the Geological Survey of Canada. He observed that Kluane Lake, which is Yukon’s largest lake, had changed its water level by about 40 feet (12 meters) a few centuries ago. He concluded that the Slims River that feeds it had appeared as the glacier advanced, and a decade ago predicted the river would disappear again as the glacier retreated.

“The event is a bit idiosyncratic, given the peculiar geographic situation in which it happened, but in a broader sense it highlights the huge changes that glaciers are undergoing around the world due to climate change,” Clague said.

The geologic event has redrawn the local landscape. Slims River crosses the Alaska Highway, and its banks were a popular hiking route. Now that the riverbed is exposed, Dall sheep from Kluane National Park are making their way down to eat the fresh vegetation, venturing into territory where they can legally be hunted. With less water flowing in, Kluane Lake did not refill last spring, and by summer 2016 was about 3 feet (1 meter) lower than ever recorded for that time of year. Waterfront land, which includes the small communities of Burwash Landing and Destruction Bay, is now farther from shore. As the lake level continues to drop researchers expect this will become an isolated lake cut off from any outflow.

On the other hand, the Alsek River, a popular whitewater rafting river that is a UNESCO world heritage site, was running higher last summer due to the addition of the Slims River’s water.

Shifts in sediment transport, lake chemistry, fish populations, wildlife behavior and other factors will continue to occur as the ecosystem adjusts to the new reality, Shugar said.

“So far, a lot of the scientific work surrounding glaciers and climate change has been focused on sea-level rise,” Shugar said. “Our study shows there may be other underappreciated, unanticipated effects of glacial retreat.”

The Kaskawulsh Glacier is retreating up the valley because of both readjustment after a cold period centuries ago, known as the Little Ice Age, and warming due to greenhouse gases. A technique published in 2016 by UW co-author Gerard Roe shows a 99.5 percent probability that this glacier’s retreat is showing the effects of modern climate change.

“I always point out to climate-change skeptics that Earth’s glaciers are becoming markedly smaller, and that can only happen in a warming climate,” Clague said.

Reference:
Daniel H. Shugar, John J. Clague, James L. Best, Christian Schoof, Michael J. Willis, Luke Copland, Gerard H. Roe. River piracy and drainage basin reorganization led by climate-driven glacier retreat. Nature Geoscience, 2017; DOI: 10.1038/ngeo2932

Note: The above post is reprinted from materials provided by University of Washington.

Radioactive Minerals

Radioactivity in minerals are caused by the inclusion of naturally-occurring radioactive elements in the mineral’s composition. The degree of radioactivity is dependent on the concentration and isotope present in the mineral. For the most part, minerals that contain potassium (K), uranium (U), and thorium (Th) are radioactive.

Radioactivity is an attribute of minerals that contain radioactive elements. Radioactive elements are elements that contain disintegrating nuclei, emitting alpha rays, beta rays, and gamma rays. Uranium and thorium are the best known radioactive elements. Minerals that contain these elements in their chemical structure will be radioactive.

Radioactive minerals are unstable, meaning the elements in their structure continually break down. This destroys the mineral’s crystal lattice, causing it lose its crystal shape. When this happens, its crystal edges become rounded, and the mineral eventually becomes amorphous.

Radioactive minerals can be identified with special instruments that detect radiation. The device used to measure this is the Geiger counter. Electric charges develop in a Geiger counter when it is placed near radioactive material; this can measure the presence and intensity of radiation. Geiger counters are normally used by scientists and specialists, but collectors may also obtain inexpensive Geiger counters.

Table of Naturally Occurring Radioactive Isotopes

Element

Isotope
Symbol

Natural
Abundance


Half-life (Years)

Primary
Decay Mode
Tellurium

130Te

33.97%


2,400,000,000,000,000,000,000.00
Vanadium

50V

0.25%


390,000,000,000,000,000.00

EC
Zirconium

96Zr

2.80%


360,000,000,000,000,000.00
Samarium

149Sm

13.80%


10,000,000,000,000,000.00

alpha
Samarium

148Sm

11.30%


7,000,000,000,000,000.00

alpha
Osmium

186Os

1.58%


2,000,000,000,000,000.00

alpha
Neodymium

145Nd

8.30%


1,100,000,000,000,000.00

alpha
Platinum

192Pt

0.79%


1,000,000,000,000,000.00

alpha
Indium

115In

95.70%


600,000,000,000,000.00

beta –
Gadolinium

152Gd

0.20%


110,000,000,000,000.00

alpha
Tellurium

123Te

0.89%


13,000,000,000,000.00

EC
Platinum

190Pt

0.01%


690,000,000,000.00

alpha

Samarium

147Sm

15.00%


108,000,000,000.00

alpha

Rubidium

87Rb

27.83%


49,000,000,000.00

beta –

Rhenium

187Re

62.60%


45,000,000,000.00

beta –

Lutetium

176Lu

2.59%


22,000,000,000.00

beta –

Thorium

232Th

100.00%


14,000,000,000.00

alpha

Uranium

238U

99.28%


4,460,000,000.00

alpha

Potassium

40K

0.01%


1,250,000,000.00

beta –

Uranium

235U

0.72%


704,000,000.00

alpha

Amazing view for the Great Blue Hole from Helicopter

The Great Blue Hole is a giant submarine sinkhole off the coast of Belize. It lies near the center of Lighthouse Reef, a small atoll 70 km (43 mi) from the mainland and Belize City. The hole is circular in shape, over 300 m (984 ft) across and 124 m (407 ft) deep. It was formed during several episodes of quaternary glaciation when sea levels were much lower. Analysis of stalactites found in the Great Blue Hole shows that formation took place 153,000; 66,000; 60,000; and 15,000 years ago.

Drones collect measurements from a volcanic plume at Volcán de Fuego, Guatemala

Volcán de Fuego (near with plume), neighbouring Volcán de Acatenango, and Volcán de Agua (far). Picture taken on a BVLOS long-range flight. Credit: Universities of Bristol, Cambridge and INSIVUMEH

A team of volcanologists and engineers from the Universities of Bristol and Cambridge have collected measurements from directly within volcanic clouds, together with visual and thermal images of inaccessible volcano peaks.

During a ten-day research trip the team carried out many proof-of-concept flights at the summits of both Volcán de Fuego and Volcán de Pacaya in Guatemala. Using lightweight modern sensors they measured temperature, humidity and thermal data within the volcanic clouds and took images of multiple eruptions in real-time.

This is one of the first times that bespoke fixed-wing unmanned aerial vehicles (UAVs) have been used at a volcano such as Fuego, where the lack of close access to the summit vent has prevented robust gas measurements. Funding from the Cabot Institute has helped the team to develop technologies to enable this capability. The UAVs were successfully flown beyond-visual-line-of-sight (BVLOS) at distances of up to 8 kilometres away, and 10,000 feet above the launch site.

The group plan to return to Guatemala later in the year with a wider range of sensors including a multiGAS gas analyser (CO2, SO2, H2S); a four-stage filter pack; carbon stubs for ash sampling; thermal and visual cameras, and atmospheric sensors.

Dr Emma Liu, Volcanologist from the Department of Earth Sciences at Cambridge, said: “Volcanoes are prodigious sources of volatiles and trace metals and have a key role in the geochemical cycling of these elements through the Earth system. Drones offer an invaluable solution to the challenges of in-situ sampling and routine monitoring of volcanic emissions, particularly those where the near-vent region is prohibitively hazardous or inaccessible. These sensors not only help to understand emissions from volcanoes, they could also be used in the future to help alert local communities of impending eruptions — particularly if the flights can be automated.”

Dr Tom Richardson, Senior Lecturer in Flight Dynamics in the Department of Aerospace Engineering at Bristol, explained: “Building on our award winning work on Ascension Island, the team carried out multiple beyond-visual-line-of-sight (BVLOS) flights from the observatory flying up to 10,000 feet above the launch site to reach the summit of Volcán de Fuego. Our success has resulted in direct invitations from the Dirección General de Aeronáutica Civil and Instituto Nacional de Sismología, Vulcanología, Meteorología e Hidrología to return and continue this ground-breaking work.”

Dr Kieran Wood, Senior Research Associate in the Department of Aerospace Engineering at Bristol, added: “Even during this initial campaign we were able to meet significant science and engineering targets. For example, multiple imaging flights over several days captured the rapidly changing topography of Fuego’s summit. These showed that the volcano was erupting from not just one, but two active summit vents.”

Ben Schellenberg, a first year Aerospace Engineering PhD student at Bristol, expressed: “Being involved in a field trip of this type so early on in my PhD has been incredibly exciting. Initial analysis of the sensor and flight data tell us that we will be able to automatically identify when we are in volcanic emissions. I can’t wait to return to test out this hypothesis.”

Taking time out from their sample flights, the research group also used their aircraft to map the topology of a barranca and the volcanic deposits within it. These deposits were formed by a recent pyroclastic flow, a fast-moving cloud of superheated ash and gas, which travelled down the barranca from Fuego. The data captured will assist in modelling flow pathways and the potential impact of future volcanic eruptions on nearby settlements.

Dr Matt Watson, Reader in Natural Hazards in the School of Earth Sciences at Bristol, said: “This is exciting initial research for future investigations, and would not be possible without a very close collaboration between volcanology and engineering.”

The team of engineers and volcanologists involved in the research trip were: Dr Colin Greatwood, Dr Tom Richardson, Ben Schellenberg, Dr Helen Thomas, Dr Matt Watson, Dr Kieran Wood from the University of Bristol and Dr Emma Liu from the University of Cambridge.

Note: The above post is reprinted from materials provided by University of Bristol.

How Do Opalised Fossils Form?

It is extremely rare for conditions to be right for formation of fossils; and even more rare for opalised fossils to form. Usually, only the hard parts of living things fossilise – for example seed pods, wood, teeth, bones and shells. This often happens after the plant or animal (or a part of it) is buried in sand or other sediments that slowly turn to stone.

Opal forms in cavities within rocks. If a cavity has formed because a bone, shell or pinecone was buried in the sand or clay that later became the rock, and conditions are right for opal formation, then the opal forms a fossil replica of the original object that was buried. We get opalised fossils of two kinds:

  1. Internal details not preserved: Opal starts as a solution of silica in water. If the silica solution fills an empty space left by a shell, bone etc that has rotted away – like jelly poured into a mould – it may harden to form an opalised cast of the original object. Most opalised shell fossils are ‘jelly mould’ fossils – the outside shape is beautifully preserved, but the opal inside doesn’t record any of the creature’s internal structure.
  2. Internal details preserved: If the buried organic material hasn’t rotted away and a silica solution soaks into it, when the silica hardens it may form an opal replica of the internal structure of the object. This happens sometimes with wood or bone.

 

Moabosaurus discovered in Utah’s ‘gold mine’

BYU researcher Brooks Britt is with the newly discovered Moabosaurus, on display at BYU’s Museum of Paleontology. Credit: Jaren Wilkey, BYU

Move over, honeybee and seagull: it’s time to meet Moabosaurus utahensis, Utah’s newly discovered dinosaur, whose past reveals even more about the state’s long-term history.

The Moabosaurus discovery was published this week by the University of Michigan’s Contributions from the Museum of Paleontology. The paper, authored by three Brigham Young University researchers and a BYU graduate at Auburn University, profiles Moabosaurus, a 125-million-year-old dinosaur whose skeleton was assembled using bones extracted from the Dalton Wells Quarry, near Arches National Park.

BYU geology professor and lead author Brooks Britt explained that in analyzing dinosaur bones, he and colleagues rely on constant comparisons with other related specimens. If there are enough distinguishing features to make it unique, it’s new.

“It’s like looking at a piece of a car,” Britt said. “You can look at it and say it belongs to a Ford sedan, but it’s not exactly a Focus or a Fusion or a Fiesta. We do the same with dinosaurs.”

Moabosaurus belongs to a group of herbivorous dinosaurs known as sauropods, which includes giants such as Brontosaurus and Brachiosaurus, who had long necks and pillar-like legs. Moabosaurus is most closely related to species found in Spain and Tanzania, which tells researchers that during its time, there were still intermittent physical connections between Europe, Africa and North America.

Moabosaurus lived in Utah before it resembled the desert we know — when it was filled with large trees, plentiful streams, lakes and dinosaurs. “We always think of Moab in terms of tourism and outdoor activities, but a paleontologist thinks of Moab as a gold mine for dinosaur bones,” Britt said.

In naming the species, Britt and his team, which included BYU Museum of Paleontology curator Rod Scheetz and biology professor Michael Whiting, decided to pay tribute to that gold mine. “We’re honoring the city of Moab and the State of Utah because they were so supportive of our excavation efforts over the decades it’s taken us to pull the animal out of the ground,” Britt said, referencing the digs that began when he was a BYU geology student in the late ’70s.

A previous study indicates that a large number of Moabosaurus and other dinosaurs died in a severe drought. Survivors trampled their fallen companions’ bodies, crushing their bones. After the drought ended, streams eroded the land, and transported the bones a short distance, where they were again trampled. Meanwhile, insects in the soils fed on the bones, leaving behind tell-tale burrow marks.

“We’re lucky to get anything out of this site,” Britt said. “Most bones we find are fragmentary, so only a small percentage of them are usable. And that’s why it took so long to get this animal put together: we had to collect huge numbers of bones in order to get enough that were complete.”

BYU has a legacy of collecting dinosaurs that started in the early 1960s, and Britt and colleagues are continuing their excavation efforts in eastern Utah. Moabosaurus now joins a range of other findings currently on display at BYU’s Museum of Paleontology — though, until its placard is updated, it’s identified as “Not yet named” (pronunciation: NOT-yet-NAIM-ed).

“Sure, we could find bones at other places in the world, but we find so many right here in Utah,” Britt said. “You don’t have to travel the world to discover new animals.”

Reference:
Britt, Brooks B.; Scheets, Rodney D.; Whiting, Michael F.; Wilhite, D. Ray. MOABOSAURUS UTAHENSIS, N. Gen., N. SP., A New Sauropod From The Early Cretaceous (Aptian) of North America. Contributions from the Museum of Paleontology, 2017 https://deepblue.lib.umich.edu/handle/2027.42/136227

Note: The above post is reprinted from materials provided by Brigham Young University. Original written by Andrea Christensen.

Geophysicist Helps Develop High-Res Map of Earth’s Magnetic Field

Lithospheric magnetic field. Credit: European Space Agency (ESA)

A University of Kentucky geophysicist is helping an international team of scientists reveal dramatic new information about the Earth’s magnetic field.

Two years ago, Dhananjay Ravat, who is a professor in the UK Departments of Earth and Environmental Sciences and Physics and Astronomy, was asked by the leader of the Swarm Satellite Constellation Application and Research Facility of the European Space Agency (ESA) to collaborate with their team to create a map of the magnetic features of the Earth’s lithosphere. Ravat, who has worked on geophysical data from several space missions around the Earth, Mars and the moon, was intrigued by the Swarm project, and his involvement ultimately led to the development of the highest resolution map of the planet’s magnetic field from space to date.

ESA launched three spacecrafts, known as the Swarm satellites, into Earth’s orbit in 2013 to track and study the planet’s lithospheric magnetic field. The field is responsible for deflecting dangerous solar winds, and impacts the planet’s climate and rotation. Up until now, scientists have not been able to fully map the magnetic field, but thanks to the Swarm mission, they now have a more complete understanding.

“Magnetic fields have been measured in space by satellites for the last 50 years, but it is the measurement of magnetic ‘gradients’ from the three Swarm satellites and data from a previous German CHAMP satellite that make this the highest resolution possible,” Ravat said. “Gradients change over shorter distances than the fields themselves and they also have the capability of eliminating background magnetic effects from the Earth’s core, ionosphere and magnetosphere—some of which were problematic from previous studies. It is also the first time anyone has put together a magnetic variation map from just the gradients of the field.”

The map also reveals the Earth’s “polarity flips” in great detail. Every 700,000 years or so, Earth’s poles reverse. This means the pointer on a compass will face south again one day, and that reversal could happen on human time-scale since the last reversal took place about 720,000 years ago. This new map shows striking patterns of these flipped polarities over time—solidified minerals have formed “stripes” on the sea floor and provide a record of Earth’s magnetic history.

“These stripes are symmetric about the mid-oceanic ridge,” Ravat said. “They tell us about how the Earth’s magnetic field behaved in the past. That is why this map is so important, it’s a continuous record of the last 200 million years of Earth’s history.”

The new map can define magnetic field features down to about 250 kilometers and will help scientists investigate geology and temperatures in Earth’s lithosphere, especially in parts of the African continent that do not have detailed magnetic field variation maps.

“We are just beginning to understand how this map will change the understanding of the Earth’s crust and its mineral resources,” Ravat said. “So far we have looked at a few well-known magnetic features. One of the strong features observed includes the Bangui region of central Africa and there are a number of different hypotheses regarding its origin, one that includes a giant meteorite impact. The high resolution of the new map will be able to discriminate between various competing hypotheses about its origin. But one thing is for sure, the map will bring attention to this forgotten continent.”

Note: The above post is reprinted from materials provided by University of Kentucky.

A new mineral from the oldest solar system solids in meteorites

Researchers have identified a new mineral in the oldest solar system solids from primitive meteorites. They’ve named it “rubinite” after Dr. Alan E. Rubin, a pioneering cosmochemist at University of California, Los Angeles. Rubinite was officially approved in March 2017 by the International Mineralogical Association. Credit: Tohoku University

Researchers have identified a new mineral in the oldest solar system solids from primitive meteorites. They’ve named it “rubinite” after Dr. Alan E. Rubin, a pioneering cosmochemist at University of California, Los Angeles. Rubinite was officially approved in March 2017 by the International Mineralogical Association.

Calcium-aluminum-rich inclusions (CAIs) are the first solar system solids that formed at high temperatures in a region close to the protosun about 4.568 billion years ago. They occur as submillimeter- to centimeter-sized rocks in carbonaceous chondrites – meteorites derived from primitive asteroids. Because CAIs retain the properties of physico-chemical conditions of the early solar system, they are very valuable to the study of planetary science.

CAIs from two different carbonaceous chondrites were studied independently by Takashi Yoshizaki from Tohoku University and Chi Ma of the California Institute of Technology. They found tiny (< 10 µm in diameter) grains of a new garnet mineral rubinite (chemical formula: Ca3Ti3+2Si3O12). In both cases, the new minerals show high Ti3+ contents, indicating that they formed under highly reducing conditions. Further cosmochemical studies of rubinite will uncover new insights into nebular processes and evolution of the early solar system.

Reference:
Authors: Ma, C., Yoshizaki, T., Nakamura, T. and Muto, J., Title: Rubinite, IMA 2016-110. CNMNC Newsletter No. 36, April 2017, Journal: Mineralogical Magazine, 81. DOI: 10.1180/minmag.2017.081.022

Note: The above post is reprinted from materials provided by Tohoku University.

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