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Research into deadly 2016 Italian earthquakes could improve future seismic forecasts

Location of survey site at rupture across a road near Castelluccio, Italy. The rupture occurred during the third earthquake in the seismic sequence and gives researchers a record of the deformation.
Location of survey site at rupture across a road near Castelluccio, Italy. The rupture occurred during the third earthquake in the seismic sequence and gives researchers a record of the deformation. Credit: Laura Gregory, University of Leeds

The timing and size of three deadly earthquakes that struck Italy in 2016 may have been pre-determined, according to new research that could improve future earthquake forecasts.

A joint British-Italian team of geologists and seismologists have shown that the clustering of the three quakes might have been caused by the arrangement of a cross-cutting network of underground faults.

The findings show that although all three earthquakes occurred on the same major fault, several smaller faults prevented a single massive earthquake from occurring instead and also acted as pathways for naturally occurring fluids that triggered later earthquakes.

The cluster of three earthquakes, termed a “seismic sequence” by seismologists, each had magnitudes greater than six and killed more than 300 people in Italy’s Apennine mountains between 24 August and 30 October 2016.

The research, led by Durham University, UK, comes ahead of the second anniversary of the start of the earthquake sequence.

The study is published in the journal Earth and Planetary Science Letters.

The researchers say the findings could have wider implications for the study of seismic hazards, enabling scientists to better understand potential earthquake sequences following a quake.

Dr Richard Walters, Assistant Professor in the Department of Earth Sciences, Durham University, said: “These results address a long-standing mystery in earthquake science — why a major fault system sometimes fails in a single large earthquake that ruptures its entire length, versus failing in multiple smaller earthquakes drawn-out over months or years.

“Our results imply that even though we couldn’t have predicted when the earthquake sequence would start, once it got going, both the size and timing of the major earthquakes may have been pre-determined by the arrangement of faults at depth.

“This is all information we could hypothetically know before the event, and therefore, this could be a hugely important avenue for improving future earthquake forecasts.”

Dr Walters and the team used satellite data to estimate which part of the fault failed in each earthquake, and compared this pattern with the location and timing of thousands of tiny aftershocks throughout the seismic sequence.

They found that intersections of small faults with the main fault system separated each of the three largest earthquakes, strongly suggesting these intersections stop the growth of each earthquake and prevent the faults failing in a single large event.

But in addition, the scientists also found that after the first earthquake, thousands of aftershocks crept northwards along these same fault intersections at a rate of around 100 metres per day, in a manner consistent with naturally occurring water and gas being pumped along the faults by the first earthquake on 24 August, 2016.

The second earthquake, on the 26 October, occurred exactly when these fluids reached its location, therefore controlling the relative timing of failure.

Dr Walters added: “It was a big surprise that these relatively small faults were having such a huge influence over the whole sequence.

“They stop the first earthquake in its tracks, and then they channel the fluids that start the sequence up again months later. No-one’s ever seen this before.”

Co-author Dr Laura Gregory, in the School of Earth and Environment, at the University of Leeds, UK, said it was important to understand whether or not a fault fails in a seismic sequence, and that the team’s results were only made possible by combining a varied array of different datasets.

Dr Gregory said: “A seismic sequence has vastly different implications for seismic hazard compared to a single large earthquake. If the faults in Italy in 2016 had failed together in one big event, the impact on the local population would have been much worse.

“This is the first time we’ve ever had this quality of modern data over one of these earthquake sequences, and bringing together a range of specialists was key for unpicking how the earthquakes related to one another.

“I was scrambling over the mountainside immediately after each earthquake with British and Italian colleagues, measuring the metre-high cliffs that had suddenly formed. Meanwhile, other members of our team were analysing data from seismometers stationed around the world, or were mapping the tiny bending of the ground around the faults using satellites orbiting the planet at 500 miles altitude.”

The research was partly supported by the UK’s Natural Environment Research Council, via an Urgency Grant, and through the Centre for the Observation and Modelling of Earthquakes, Volcanoes and Tectonics (COMET).

Reference:
R.J. Walters, L.C. Gregory, L.N.J. Wedmore, T.J. Craig, K. McCaffrey, M. Wilkinson, J. Chen, Z. Li, J.R. Elliott, H. Goodall, F. Iezzi, F. Livio, A.M. Michetti, G. Roberts, E. Vittori. Dual control of fault intersections on stop-start rupture in the 2016 Central Italy seismic sequence. Earth and Planetary Science Letters, 2018; 500: 1 DOI: 10.1016/j.epsl.2018.07.043

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

Two new Chinese dinosaurs discovered

From left to right: Haplocheirus, Xiyunykus, Bannykus, and Shuvuuia. Note the lengthening of the jaws, reduction of the teeth, and changes in the hand and arm.
From left to right: Haplocheirus, Xiyunykus, Bannykus, and Shuvuuia. Note the lengthening of the jaws, reduction of the teeth, and changes in the hand and arm. Credit: Viktor Radermacher

Professor Jonah Choiniere from the University of the Witwatersrand, Johannesburg, South Africa was a leading member of the team and is a co-author on the research.

The dinosaurs are both alvarezsaurs, an enigmatic group of theropod [meat-eating] dinosaurs, which have many similarities with birds and which show adaptations thought to be related to eating insects that live in colonies.

“Alvarezsaurs are weird animals,” said Choiniere. “With their strong, clawed hands and weak jaws, they appear to be the dinosaurian analogue to today’s aardvarks and anteaters.”

But alvarezsaurs did not originally eat insects. The earliest members of the group had more typically meat-eating teeth and hands, useful for catching small prey. Only later-evolving members reduced their teeth and evolved a hand with a huge, single claw capable – perhaps – of tearing open rotting logs and anthills.

“The new fossils have long arms, and so show that alvarezsaurs evolved short arms only later in their evolutionary history, in species with small body sizes. This is quite different to what happens in the classic example of tyrannosaurs, which have short arms and giant size,” said co-author Professor Roger Benson of Oxford University.

Bannykus and Xiyunykus are important because they show transitional steps in the process of alvarezsaurs adapting to new diets.

“The fossil record is the best source of information about how anatomical features evolve,” said James Clark, co-author and an Honorary Professor at Wits University. “And like other classic examples of evolution such as the ‘horse series’, these dinosaurs show us how a lineage can make a major shift in its ecology over time.”

The specimens were discovered during collaborative international fieldwork in China. Xiyunykus was discovered in 2005 in Xinjiang, north-western China. Bannykus was discovered a few years later, in 2009, in Inner Mongolia, north-central China.

Both research trips were joint expeditions co-led by Professors Xu Xing (Institute for Vertebrate Palaeontology and Palaeoanthropology, Beijing) and James Clark (George Washington University, Washington DC).

“Our international field teams have been tremendously productive over the years,” said Xing. “And this research showcases just some of our incredible discoveries.”

Once the fossils were discovered, their further study was made possible by a joint South Africa/China collaborative grant through South Africa’s National Research Foundation, held by Choiniere and Xu.

“The joint research programme has helped in so many ways,” said Choiniere. “China and South Africa have a great deal of overlap in palaeontology, and it has been a privilege to cross-train students over the last two years.”

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

Landslides triggered by human activity on the rise

Photograph panorama looking over the devastation of the Kedarnath landslide, June 2013, Uttarakhand state, India.
Photograph panorama looking over the devastation of the Kedarnath landslide, June 2013, Uttarakhand state, India. Credit: Vaibhav Kaul, University of Sheffield

More than 50,000 people were killed by landslides around the world between 2004 and 2016, according to a new study by researchers at UK’s Sheffield University. The team, who compiled data on over 4800 fatal landslides during the 13-year period, also revealed for the first time that landslides resulting from human activity have increased over time. The research is published today in the European Geosciences Union journal Natural Hazards and Earth System Sciences.

The team found that over 700 fatal landslides that occurred between 2004 and 2016 had a human fingerprint. Construction works, legal and illegal mining, as well as the unregulated cutting of hills (carving out land on a slope) caused most of the human-induced landslides.

“We were aware that humans are placing increasing pressure on their local environment, but it was surprising to find clear trends within the database that fatal landslides triggered by construction, illegal hillcutting and illegal mining were increasing globally during the period of 2004 and 2016,” says Melanie Froude, a postdoctoral researcher at Sheffield’s Department of Geography and lead author of the study.

While the trend is global, Asia is the most affected continent: “All countries in the top 10 for fatal landslide triggered by human activity are located in Asia,” says Froude. The number 1 country is India, which accounts for 20% of these events. It is also the country where human-triggered fatal landslides are increasing at the highest rate, followed by Pakistan, Myanmar and the Philippines.

Dave Petley, a professor and Vice-President for Research and Innovation at the University of Sheffield, started collecting data on fatal landslides after realising that many databases on natural disasters were “significantly underestimating the extent of landslide impact.” While earthquakes and storms are deadlier, landslides do cause a significant number of fatalities.

The researchers identified a total of 4800 fatal landslides, excluding those triggered by earthquakes, that occurred around the world between 2004 and 2016 and caused a total of about 56,000 deaths. The most tragic event identified by the researchers was the Kedarnath landslide in June 2013 in India, which resulted in over 5000 deaths. It was due to extreme weather conditions that caused flash floods and massive mudflows, which affected thousands of religious pilgrims trapped in a mountain area.

Since 2004, Petley has painstakingly collected data on fatal landslides from online English-language media reports. To confirm the news were accurate, Petley — and more recently Froude, who reviewed all landslide accounts — checked each report whenever possible against government and aid agency articles, academic studies or through personal communication. Details about the landslides, such as location, impacts or cause, were added to their Global Fatal Landslide Database.

“Collecting these reports and organising them into a database shows us where landslides are frequently harming people, what causes these landslides and whether there are patterns in fatal landslide occurrence over time. The database provides us with an overview of the impact of landslides on society,” explains Petley.

Aside from Asia, where 75% of landslides in the database occurred, the areas most affected are in Central and South America, the Caribbean islands, and East Africa. In Europe, the Alps are the region with more fatal landslides.

In support of past studies, the researchers also found that 79% of landslides in their database were triggered by rainfall. Most events happen during the northern hemisphere summer, when cyclones, hurricanes and typhoons are more frequent and the monsoon season brings heavy rains to parts of Asia.

The Natural Hazards and Earth System Sciences study highlights that fatal landslides are more common in settlements, along roads, and at sites rich in precious resources. They occur more frequently in poor countries and affect poor people disproportionately, the researchers say.

In the Himalayan mountain region, especially in Nepal and India, many of the fatal landslides triggered by construction occurred on road construction sites in rural areas, while in China many happened in urban building sites. “The prevalence of landslides in these settings suggests that regulations to protect workers and the public are insufficient or are not being sufficiently enforced. In the case of roads, maintaining safety during construction is difficult when it is economically unviable to completely shut roads because alternative routes involve substantial 100 mile + detours,” says Froude.

Landslides triggered by hillcutting are mostly a problem in rural areas, where many people illegally collect material from hillslopes to build their houses. “We found several incidents of children being caught-up in slides triggered as they collected coloured clay from hillslopes, for decoration of houses during religious festivals in Nepal. Educating communities who undertake this practise on how to do it safely, will save lives,” Froude says.

“With appropriate regulation to guide engineering design, education and enforcement of regulation by specialist inspectors, landslides triggered by construction, mining and hillcutting are entirely preventable,” Froude emphasises. “The study highlights that we need to refocus our efforts globally on preventable slope accidents,” concludes Petley.

Reference:
Melanie J. Froude, David N. Petley. Global fatal landslide occurrence from 2004 to 2016. Natural Hazards and Earth System Sciences, 2018; 18 (8): 2161 DOI: 10.5194/nhess-18-2161-2018

Note: The above post is reprinted from materials provided by European Geosciences Union.

228 million year old fossil sheds light on how turtles evolved

Eorhynchochelys
Illustration showing what Eorhynchochelys would have looked like in life. Credit: Adrienne Stroup, Field Museum

There are a couple of key features that make a turtle a turtle: its shell, for one, but also its toothless beak. A newly-discovered fossil turtle that lived 228 million years ago is shedding light on how modern turtles developed these traits. It had a beak, but while its body was Frisbee-shaped, its wide ribs hadn’t grown to form a shell like we see in turtles today.

“This creature was over six feet long, it had a strange disc-like body and a long tail, and the anterior part of its jaws developed into this strange beak,” says Olivier Rieppel, a paleontologist at Chicago’s Field Museum and one of the authors of a new paper in Nature. “It probably lived in shallow water and dug in the mud for food.”

The new species has been christened Eorhynchochelys sinensis — a mouthful, but with a straightforward meaning. Eorhynchochelys (“Ay-oh-rink-oh-keel-is”) means “dawn beak turtle” — essentially, first turtle with a beak — while sinensis, meaning “from China,” refers to the place where it was found by the study’s lead author, Li Chun of China’s Institute of Vertebrate Paleontology and Paleoanthropology.

Eorhynchochelys isn’t the only kind of early turtle that scientists have discovered — there is another early turtle with a partial shell but no beak. Until now, it’s been unclear how they all fit into the reptile family tree. “The origin of turtles has been an unsolved problem in paleontology for many decades,” says Rieppel. “Now with Eorhynchochelys, how turtles evolved has become a lot clearer.”

The fact that Eorhynchochelys developed a beak before other early turtles but didn’t have a shell is evidence of mosaic evolution — the idea that traits can evolve independently from each other and at a different rate, and that not every ancestral species has the same combination of these traits. Modern turtles have both shells and beaks, but the path evolution took to get there wasn’t a straight line. Instead, some turtle relatives got partial shells while others got beaks, and eventually, the genetic mutations that create these traits occurred in the same animal.

“This impressively large fossil is a very exciting discovery giving us another piece in the puzzle of turtle evolution,” says Nick Fraser, an author of the study from National Museums Scotland. “It shows that early turtle evolution was not a straightforward, step-by-step accumulation of unique traits but was a much more complex series of events that we are only just beginning to unravel.”

Fine details in the skull of Eorhynchochelys solved another turtle evolution mystery. For years, scientists weren’t sure if turtle ancestors were part of the same reptile group as modern lizards and snakes — diapsids, which early in their evolution had two holes on the sides of their skulls — or if they were anapsids that lack these openings. Eorhynchochelys’s skull shows signs that it was a diapsid. “With Eorhynchochelys’s diapsid skull, we know that turtles are not related to the early anapsid reptiles, but are instead related to evolutionarily more advanced diapsid reptiles. This is cemented, the debate is over,” says Rieppel.

The study’s authors say that their findings, both about how and when turtles developed shells and their status as diapsids, will change how scientists think about this branch of animals. “I was surprised myself,” says Rieppel. “Eorhynchochelys makes the turtle family tree make sense. Until I saw this fossil, I didn’t buy some of its relatives as turtles. Now, I do.”

This study was contributed to by Institute of Vertebrate Paleontology and Paleoanthropology, the CAS Center for Excellence in Life and Paleoenvironment, National Museums Scotland, the Field Museum, and the Canadian Museum of Nature.

Reference:
Chun Li, Nicholas C. Fraser, Olivier Rieppel, Xiao-Chun Wu. A Triassic stem turtle with an edentulous beak. Nature, 2018; 560 (7719): 476 DOI: 10.1038/s41586-018-0419-1

Note: The above post is reprinted from materials provided by Field Museum.

Amber unveils evolution of ancient antlions

lacewing larvae
Reconstruction of two lacewing larvae. Credit: YANG Dinghua

Myrmeleontiformia, consisting of antlions and their relatives, are an ancient group of lacewing insects characterized by predatory larvae with unusual morphologies and behaviors. An international team led by Prof. WANG Bo from the Chinese Academy of Sciences (NIGPAS) and two Italian researchers found fossil Myrmeleontiformia fauna from the mid-Cretaceous (approximately 100 million years ago) preserved in Burmese amber. The study was published in Nature Communications on August 22, 2018.

Their findings show that Myrmeleontiformia did not gain considerable morphological novelty during the subsequent 100 million years, and their diversity seemed to result from different combinations of a limited set of character traits in a complex trade-off. This morphological stasis helped in reconstructing behaviors not preserved by a trace in the fossil record. Inference of these behaviors sheds light on the ecological niche and lifestyle of extinct Myrmeleontiformia.

Statistical correlation analysis strongly supports a correlation between a selection of morphological traits and two hunting strategies of these ambush predators—camouflaging and fossoriality—allowing the researchers to reconstruct habits of the extinct species.

The findings suggested that fossorial specializations evolved more than once across Myrmeleontiformia from arboreal ancestors. The fossorial lifestyle of antlions was certainly one of the factors leading to their success, allowing these insects to colonize and diversify in arid habitats where they survived considerable changes in terrestrial environments during the Cretaceous lineages.

The Burmese fossils showed that debris carrying characterized this lineage for at least 100 million years. All of these camouflaging lacewings were equipped with elongate protuberances. The strong statistical correlation between the presence of these protuberances and camouflaging behavior demonstrated that this trait is an indicator of such behavior, even when the debris covering is not directly preserved in the amber piece together with the larvae.

This research also implies that camouflaging behavior arose at least three times within Myrmeleontiformia. Camouflaging and fossoriality appear widespread across the lineage, and both behaviors allowed the predatory larvae to hide from their unsuspecting prey.

Reference:
Davide Badano et al, Diverse Cretaceous larvae reveal the evolutionary and behavioural history of antlions and lacewings, Nature Communications (2018). DOI: 10.1038/s41467-018-05484-y

Note: The above post is reprinted from materials provided by Chinese Academy of Sciences.

A timescale for the origin and evolution of all of life on Earth

Earth from near space.
Credit: © dell / Fotolia

A new study led by scientists from the University of Bristol has used a combination of genomic and fossil data to explain the history of life on Earth, from its origin to the present day.

Palaeontologists have long sought to understand ancient life and the shared evolutionary history of life as a whole.

However, the fossil record of early life is extremely fragmented, and its quality significantly deteriorates further back in time towards the Archaean period, more than 2.5 billion years ago, when the Earth’s crust had cooled enough to allow the formation of continents and the only life forms were microbes.

Holly Betts, lead author of the study, from the University of Bristol’s School of Earth Sciences, said: “There are few fossils from the Archaean and they generally cannot be unambiguously assigned to the lineages we are familiar with, like the blue-green algae or the salt-loving archaebacteria that colours salt-marshes pink all around the world.

“The problem with the early fossil record of life is that it is so limited and difficult to interpret — careful reanalysis of the some of the very oldest fossils has shown them to be crystals, not fossils at all.”

Fossil evidence for the early history of life is so fragmented and difficult to evaluate that new discoveries and reinterpretations of known fossils have led to a proliferation of conflicting ideas about the timescale of the early history of life.

Co-author Professor Philip Donoghue, also from Bristol’s School of Earth Sciences, added: “Fossils do not represent the only line of evidence to understand the past. A second record of life exists, preserved in the genomes of all living creatures.”

Co-author Dr Tom Williams, from Bristol’s School of Biological Sciences, said: “Combining fossil and genomic information, we can use an approach called the ‘molecular clock’ which is loosely based on the idea that the number of differences in the genomes of two living species (say a human and a bacterium) are proportional to the time since they shared a common ancestor.”

By making use of this method the team at Bristol and Mark Puttick from the University of Bath were able to derive a timescale for the history of life on Earth that did not rely on the ever-changing age of the oldest accepted fossil evidence of life.

Co-author Professor Davide Pisani said: “Using this approach we were able to show that the Last Universal Common Ancestor all cellular life forms, ‘LUCA’, existed very early in Earth’s history, almost 4.5 Billion years ago — not long after Earth was impacted by the planet Theia, the event which sterilised Earth and led to the formation of the Moon.

“This is significantly earlier than the currently accepted oldest fossil evidence would suggest.

“Our results indicate that two “primary” lineages of life emerged from LUCA (the Eubacteria and the Archaebacteria), approximately one Billion years after LUCA.

“This result is testament to the power of genomic information, as it is impossible, based on the available fossil information, to discriminate between the oldest eubacterial and archaebacterial fossil remains.”

The study confirms modern views that the eukaryotes, the lineage to which human life belongs (together with the plants and the fungi, for example), is not a primary lineage of life. Professor Pisani added: “It is rather humbling to think we belong to a lineage that is billions of years younger than life itself.”

Reference:
Holly C. Betts, Mark N. Puttick, James W. Clark, Tom A. Williams, Philip C. J. Donoghue, Davide Pisani. Integrated genomic and fossil evidence illuminates life’s early evolution and eukaryote origin. Nature Ecology & Evolution, 2018; DOI: 10.1038/s41559-018-0644-x

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

New Antarctic rift data has implications for volcanic evolution

Representative Image : Volcanic Eruption

New data revealing two tectonic plates fused to form a single Antarctic Plate 15 million years later than originally predicted and this extra motion has major implications for understanding of the tectono-volcanic activity surrounding the Pacific Ocean, from the Alpine mountains in New Zealand to the California geological setting, according to research from Ben-Gurion University of the Negev (BGU).

In a study published in Nature Communications, Dr. Roi Granot of BGU’s Department of Geological and Environmental Sciences, and Dr. Jérôme Dyment from the Institut de Physique du Globe de Paris, France, present marine magnetic data collected near the northern edge of the West Antarctic rift system that shows motion between East and West Antarctica, which was assumed to have ended abruptly 26 million years ago, actually continued for another 15 million years.

“Since Antarctica tectonically connects the Pacific Plate to the rest of the world, these results have important ramifications for understanding the tectonic evolution around the Pacific Ocean — the rise of New Zealand’s Alpine Mountains, motions along the San Andreas Fault in California, and more,” says Dr. Granot.

Over 200 million years ago, a rift bisected Antarctica. The motion between East Antarctic and West Antarctic Plates accommodated along the length of this rift created one of the longest mountain ranges in the world (the Transantarctic Mountains). It also caused the eruption of hundreds of volcanoes, mostly under the ice sheets, and shaped the sub-ice topography. These motions dictated, and still dictate, the heat flow rate that the crust releases under the ice and is one of the factors controlling the rate by which the glaciers are advancing toward the surrounding southern ocean.

GPS data and a lack of seismic activity suggest that the rift in Antarctica is no longer tectonically active. According to the researchers, one of the key unanswered question was: How did the plates drift relative to each other over the last 26 million years and when did the rift stop being active?

New marine geophysical data recorded during two excursions on a French icebreaker enabled Drs. Roi Granot and Jérôme Dyment to date the ocean floor and calculate the relative motion between the Antarctic Plates and the Australian Plate.

“Antarctica forms an important link in the global plate tectonic circuits which enable to calculate the motion along different plate boundaries. Understanding past plate motions between East and West Antarctica therefore affects our ability to accurately predict the kinematic evolutions of other plate boundaries,” says Dr. Granot.

Reference:
Roi Granot, Jérôme Dyment. Late Cenozoic unification of East and West Antarctica. Nature Communications, 2018; 9 (1) DOI: 10.1038/s41467-018-05270-w

Note: The above post is reprinted from materials provided by American Associates, Ben-Gurion University of the Negev.

Enigmatic African fossils rewrite story of when lemurs got to Madagascar

Fossilized fragments of primate jaws and teeth from Africa are changing what researchers thought they knew about when lemurs made it to Madagascar.
Fossilized fragments of primate jaws and teeth from Africa are changing what researchers thought they knew about when lemurs made it to Madagascar. Shown here is Propotto leakeyi, which lived roughly 20 million years ago in Kenya. Original housed in the National Museums of Kenya. Credit: 3-D microCT scans and animation generated at Duke SMIF

Discovered more than half a century ago in Kenya and sitting in museum storage ever since, the roughly 20-million-year-old fossil Propotto leakeyi was long classified as a fruit bat.

Now, it’s helping researchers rethink the early evolution of lemurs, distant primate cousins of humans that today are only found on the island of Madagascar, some 250 miles off the eastern coast of Africa. The findings could rewrite the story of just when and how they got to the island.

In a study to be published August 21 in the journal Nature Communications, researchers have re-examined Propotto’s fossilized remains and suggest that the strange creature wasn’t a bat, but an ancient relative of the aye-aye, the bucktoothed nocturnal primate that represents one of the earliest branches of the lemur family tree.

The reassessment challenges a long-held view that today’s 100-some lemur species descended from ancestors that made their way to Madagascar in a single wave more than 60 million years ago, becoming some of the first mammals to colonize the island.

Instead, the study lends support to the idea that two lineages of lemurs split in Africa before coming to Madagascar. One lineage eventually led to the aye-aye, and the other to all other lemurs. There are no lemurs left on mainland Africa. These ancestors then colonized Madagascar independently, and millions of years later than once believed.

“One implication is that lemurs have had a much less extensive evolutionary history on Madagascar than was previously thought,” said study co-author Erik Seiffert, professor of anatomy at the University of Southern California.

When Propotto was first described in the 1960s, experts didn’t agree about what they were looking at. They didn’t have a lot to go on: just three lower jaw bones, each barely an inch long, and a handful of teeth less than three millimeters across.

In 1967, paleontologist George Gaylord Simpson inspected the fragments and classified the specimen as a previously unknown member of the loris family, nocturnal primates with enormous eyes. But a colleague named Alan Walker took a look and thought otherwise, eventually convincing Simpson that the bones belonged to a bat.

For nearly half a century the creature’s identity appeared to have been settled, until 2016, when another paleontologist, the late Gregg Gunnell of Duke University, began taking a fresh look at the fossil. To Gunnell’s eye, the creature’s hind teeth were more reminiscent of a primate than a bat. He also noted the stump of a broken front tooth, just visible in cross section, which would have jutted out from its mouth like a dagger — a trait only known in aye-ayes, the only living primates with rodent-like teeth.

“Gregg wrote to us and said, ‘Tell me I’m crazy,'” Seiffert said.

To verify Propotto’s place in the primate family tree, Seiffert and Steven Heritage of Duke’s Division of Fossil Primates analyzed more than 395 anatomical features and 79 genes for 125 mammal species, living and extinct.

With help from Doug Boyer, associate professor of evolutionary anthropology at Duke, the team also compiled microCT scans of the lower molars of 42 living and extinct mammal groups, including bats, treeshrews and primates. They then used a computer program to compare the bumps, pits and ridges on the scans of Propotto’s teeth to those of other animals.

The researchers found that Propotto shared a number of features with a similarly buck-toothed primate that lived 34 million years ago in Egypt called Plesiopithecus, and that both were ancient relatives of the aye-aye.

In the new study, Seiffert, Gunnell and colleagues propose that the ancestors of aye-ayes split from the rest of the lemur family tree roughly 40 million years ago, while still on the African continent, and the resulting two lineages didn’t make their separate ways to Madagascar until later.

The findings suggest they arrived around the same time as other mammals, such as rodents, Malagasy mongooses and hedgehog- and shrew-like animals called tenrecs. Frogs, snakes and lizards may have made the trip around the same time.

Lemurs can’t swim, so some scientists hypothesize that the small-bodied creatures crossed the 250-mile-wide channel that lies between Africa and Madagascar after being swept out to sea in a storm, by holding on to tree limbs or floating mats of vegetation before finally washing ashore.

But if the arrival were more recent, they might have had a shorter distance to travel, thanks to lower sea levels when the Antarctic ice sheet was much larger.

“It’s possible that lemurs weren’t in Madagascar at all until maybe the Miocene,” as recently as 23 million years ago, Boyer said.

“Some of the lowest sea levels were also during this time,” Heritage said.

Either way, “the fossils tell us something we never could have guessed from the DNA evidence about the history of lemurs on Madagascar,” Boyer said.

Reference:
Gregg F. Gunnell, Doug M. Boyer, Anthony R. Friscia, Steven Heritage, Fredrick Kyalo Manthi, Ellen R. Miller, Hesham M. Sallam, Nancy B. Simmons, Nancy J. Stevens, Erik R. Seiffert. Fossil lemurs from Egypt and Kenya suggest an African origin for Madagascar’s aye-aye. Nature Communications, 2018; 9 (1) DOI: 10.1038/s41467-018-05648-w

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

Study uses seismic noise to track water levels in underground aquifers

Earth
Earth. Credit: CC0 Public Domain

Seismic noise—the low-level vibrations caused by everything from subway trains to waves crashing on the beach—is most often something seismologists work to avoid. They factor it out of models and create algorithms aimed at eliminating it so they can identify the signals of earthquakes.

But Tim Clements thinks it might be tool to monitor one of the most precious resources in the world—water.

A graduate student working in the lab of Assistant Professor of Earth and Planetary Sciences Marine Denolle, Clements is the lead author of a recent study that used seismic noise to measure the size and the water levels in underground aquifers in California. The technique could even be used to track whether and how aquifers rebound following precipitation, and understand geological changes that might occur as water is pumped out. The study is described in a recently-published paper in Geophysical Research Letters.

“The way this would commonly be done today would be to take a measurement at a groundwater well,” Clements said. “And if you have a network of those wells, you can develop a model where you assume a number of hydrological parameters…and that allows you to measure the health of the aquifer.

“But what we showed is we can just directly measure these waves that are travelling through the entire aquifer,” he continued. “So we don’t have to make those assumptions, because we can directly measure the waves.”

Using those measurements, researchers were able to measure the water depth of the San Gabriel Valley aquifer, located just outside Los Angeles, to within a centimeter. Efforts to measure the size of the aquifer were limited by the existing seismic network, Clements said, and so were accurate only to about a kilometer.

“That gives us a way to begin thinking about volume,” Denolle said. “What we found is that using this method the volume we calculated as having been pumped out of the aquifer equaled the volume that was published.”

“We estimated it at about half a cubic kilometer,” Clements said. “And that’s exactly what the San Gabriel water master said they pumped out during the drought to meet demand.”

That drought, Clements said, was one reason researchers chose to focus on the San Gabriel Valley.

“They had experienced a massive drought over the last five years, and there are over 1 million people who live in this relatively small area outside Los Angeles who depend on the groundwater for all their water-use needs,” he said. “Over the past five years, they had lost a large amount of ground water, and there’s a large financial cost to that, so our goal was to understand if we can use seismic waves to understand what’s happening with the aquifer.”

The region is also already equipped with a network of seismographs, he said, making it relatively easy to obtain seismic noise data and use it to examine the aquifer.

While the study wasn’t the first to hit upon the idea of using seismic noise to study groundwater, Denolle said earlier efforts were hampered because they relied on a signal that was relatively weak in comparison to environmental factors like temperature and pressure.

“This was a large signal we looked at,” she said. “The aquifer oscillated with 20 meters of water-height changes in a couple years, so it’s a bigger signal than any environmental influence.”

The system could also be a useful tool for anyone involved in water resource management, Clements said, because it can give them a moment-to-moment view of precisely what is happening in an underground aquifer.

“This could be used for water management,” Clements said. “In this study, we looked at about 17 years of data, from 2000 to 2017, but going forward this could be used in a water management application, so you could get a picture of what’s happening with the aquifer on a daily basis.”

Aside from providing groundwater measurements, the technique can also be used to monitor the health of an aquifer over time.

“If we had the data, we may be able to use this technology to look back at what aquifers looked like the past and study the long-term evolution of an aquifer,” Denolle said. “One of the challenges for people who manage water resources is whether aquifers still respond elastically, meaning can we recharge it with the same storagage capacity or is it losing capacity over time as we pump water out? Using seismic waves, we can potentially find out whether these aquifers are elastic or not.”

Going forward, Clements said, he plans to pursue ways to improve the resolution of the system at both the micro and macro levels.

Working in collaboration with faculty at Tufts University, he installed wells and seismometers on campus to track changes as groundwater is pumped to the surface to irrigate sports fields. Other efforts are focused on using the existing seismometer network in California to improve ways to measure the overall size of aquifers.

Reference:
Timothy Clements et al, Tracking Groundwater Levels Using the Ambient Seismic Field, Geophysical Research Letters (2018). DOI: 10.1029/2018GL077706

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

Laughing Gas May Have Helped Warm Early Earth and Given Breath to Life

Ancient tiger eye BIF (banded iron formation)
Ancient tiger eye BIF (banded iron formation) rock with varying layers that include iron that fell out of ancient oceans. An eon ago, oceans appear to have been full of ferrous iron, which would have facilitated production of N2O (laughing gas). Credit: Georgia Tech / Allison Carter

More than an eon ago, the sun shone dimmer than it does today, but the Earth stayed warm due to a strong greenhouse gas effect, geoscience theory holds. Astronomer Carl Sagan coined this “the Faint Young Sun Paradox,” and for decades, researchers have searched for the right balance of atmospheric gases that could have kept early Earth cozy.

A new study led by the Georgia Institute of Technology suggests that nitrous oxide, known for its use as the dental sedative laughing gas, may have played a significant role.

The research team carried out experiments and atmospheric computer modeling that in detail substantiated an existing hypothesis about the presence of nitrous oxide (N2O), a powerful greenhouse gas, in the ancient atmosphere. Established research has already pointed to high levels of carbon dioxide and methane, but they may not have been plentiful enough to sufficiently keep the globe warm without the help of N2O.

Jennifer Glass, an assistant professor at Georgia Tech, and Chloe Stanton, formerly an undergraduate research assistant in the Glass lab at Georgia Tech, published the study in the journal Geobiology on Wednesday, August 22, 2018. Their work was funded by the NASA Astrobiology Institute. Stanton is now a graduate research assistant at the Pennsylvania State University.

No ‘boring billion’

The study focused on the middle of the Proterozoic Eon, over a billion years ago. The proliferation of complex life was still a few hundred million years out, and the pace of our planet’s evolution probably appeared deceptively slow.

“People in our field often refer to this middle chapter in Earth’s history roughly 1.8 to 0.8 billion years ago as the ‘boring billion’ because we classically think of it as a very stable period,” said Stanton, the study’s first author. “But there were many important processes affecting ocean and atmospheric chemistry during this time.”

Chemistry in mid-Proterozoic ocean was heavily influenced by abundant soluble ferrous iron (Fe2+) in oxygen-free deep waters.

Ancient iron key

“The ocean chemistry was completely different back then,” said Glass, the study’s principal investigator. “Today’s oceans are well-oxygenated, so iron rapidly rusts and drops out of solution. Oxygen was low in Proterozoic oceans, so they were filled with ferrous iron, which is highly reactive.”

In lab experiments, Stanton found that Fe2+ in seawater reacts rapidly with nitrogen molecules, especially nitric oxide, to yield nitrous oxide in a process called chemodenitrification. This nitrous oxide (N2O) can then bubble up into the atmosphere.

When Stanton plugged the higher fluxes of nitrous oxide into the atmospheric model, the results showed that nitrous oxide could have reached ten times today’s levels if mid-Proterozoic oxygen concentrations were 10 percent of those today. This higher nitrous oxide would have provided an extra boost of global warming under the Faint Young Sun.

Breathing laughing gas

Nitrous oxide could have also been what some ancient life breathed.

Even today, some microbes can breathe nitrous oxide when oxygen is low. There are many similarities between the enzymes that microbes use to breathe nitric and nitrous oxides and enzymes used to breathe oxygen. Previous studies have suggested that the latter evolved from the former two.

The Georgia Tech model provides a plentiful source of nitrous oxide in ancient iron-rich seas for this evolutionary scenario. And prior to the Proterozoic, when oxygen was extremely low, early aquatic microbes could have already been breathing nitrous oxide.

“It’s quite possible that life was breathing laughing gas long before it began breathing oxygen,” Glass said. “Chemodenitrification might have supplied microbes with a steady source of it.”

Note: The above post is reprinted from materials provided by Georgia Institute of Technology.

99-million-year-old beetle trapped in amber served as pollinator to evergreen cycads

mid-Cretaceous beetle Cretoparacucujus cycadophilus
This image shows a dorsal view of the mid-Cretaceous beetle Cretoparacucujus cycadophilus, including the mandibular cavities it likely used for pollination. Credit: Chenyang Cai

Flowering plants are well known for their special relationship to the insects and other animals that serve as their pollinators. But, before the rise of angiosperms, another group of unusual evergreen gymnosperms, known as cycads, may have been the first insect-pollinated plants. Now, researchers reporting in the journal Current Biology on August 16 have uncovered the earliest definitive fossil evidence of that intimate relationship between cycads and insects.

The discovery came in the form of an ancient boganiid beetle preserved in Burmese amber for an estimated 99 million years along with grains of cycad pollen. The beetle also shows special adaptations, including mandibular patches, for the transport of cycad pollen.

“Boganiid beetles have been ancient pollinators for cycads since the Age of Cycads and Dinosaurs,” says Chenyang Cai, now a research fellow at the University of Bristol. “Our find indicates a probable ancient origin of beetle pollination of cycads at least in the Early Jurassic, long before angiosperm dominance and the radiation of flowering-plant pollinators, such as bees, later in the Cretaceous.”

When Cai’s supervisor Diying Huang at the Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, first showed him the beetle trapped in amber, he was immediately intrigued. He recognized that its large mandibles with bristly cavities might suggest the beetle was a pollinator of cycads.

After cutting, trimming, and polishing the specimen to get a better look under a microscope, Cai’s excitement only grew. The beetle carried several clumps of tiny pollen grains. Cai consulted Liqin Li, an expert in ancient pollen at the Chinese Academy of Sciences, who confirmed that the pollen grains belonged to a cycad.

The researchers also conducted an extensive phylogenetic analysis to explore the beetle’s family tree. Their analysis indicates the fossilized beetle belonged to a sister group to the extant Australian Paracucujus, which pollinate the relic cycad Macrozamia riedlei. The finding, along with the current disjunct distribution of related beetle-herbivore and cycad-host pairs in South Africa and Australia, support an ancient origin of beetle pollination of cycads, the researchers say.

Cai notes that the findings together with the distribution of modern boganiid beetles lead him to suspect that similar beetle pollinators of cycads are yet to be found. He’s been looking for them for the last five years. The challenge, he says, is that older Jurassic beetles are generally found as compression fossils not trapped in amber.

Reference:
Chenyang Cai, Hermes E. Escalona, Liqin Li, Ziwei Yin, Diying Huang, Michael S. Engel. Beetle Pollination of Cycads in the Mesozoic. Current Biology, 2018; DOI: 10.1016/j.cub.2018.06.036

Note: The above post is reprinted from materials provided by Cell Press.

Meteorite bombardment likely to have created the Earth’s oldest rocks

Oldest rock on Earth
Oldest rock on Earth: Acasta River gneiss (stock image). Credit: © Xenomanes / Fotolia

Scientists have found that 4.02-billion-year-old silica-rich felsic rocks from the Acasta River, Canada — the oldest rock formation known on Earth — probably formed at high temperatures and at a surprisingly shallow depth of the planet’s nascent crust. The high temperatures needed to melt the shallow crust were likely caused by a meteorite bombardment around half a billion years after the planet formed. This melted the iron-rich crust and formed the granites we see today. These results are presented for the first time at the Goldschmidt conference in Boston (14 August), following publication in the peer-reviewed journal Nature Geoscience.

The felsic rocks (rocks rich in silica/quartz) found at the Acasta River in Canada, are the Earth’s oldest rocks, although there are older mineral crystals*. Scientists have long known that the Acasta rocks are different to the majority of felsic rocks we see today, such as the granites widely used as a building or decorative material. Now a group of scientists from Australia and China have modelled the formation of the oldest Acasta felsic rocks and found that they could only have been formed at low pressures and very high temperatures.

Scientists believe that the primitive crust largely comprised dark, silica-poor mafic rocks, so there has been a question over how the Acasta River felsic rocks could have formed.

“Our modelling shows that the Acasta River rocks derived from the melting of pre-existing iron-rich basaltic rock, which formed the uppermost layers of crust on the primitive Earth,” said team leader Tim Johnson, from Curtin University, Perth.

“We used phase equilibria and trace element modelling to show that the Acasta River rocks were produced by partial melting of the original mafic rocks at very low pressures. It would have needed something special to produce the 900°C temperatures needed to generate these early felsic rocks at such low pressures, and that probably means a drastic event, most likely the intense heating caused by meteorite bombardment.

We estimate that rocks within the uppermost 3km of mafic crust would have been melted in producing the rocks we see today. We think that these ancient felsic rocks would have been very common, but the passage of 4 billion years, and the development of plate tectonics, means that almost nothing remains.

We believe that these rocks may be the only surviving remnants of a barrage of extraterrestial impacts which characterized the first 600 million years of Earth History.”

The Acasta River is part of the Slave Craton formation in Northern Canada, north of Yellowknife and the Great Slave Lake. The area is the homeland of the Tlicho people, which led to the geologists who discovered the rocks giving them the name “Idiwhaa,” derived from the Tlicho word for ancient.

Commenting, Dr Balz Kamber (Trinity College Dublin) said: “The idea of making felsic melts by large or giant impacts seems plausible considering the high-energy nature of these events and the pockmarked ancient surfaces of other inner Solar System planets and moons. However, the implied pressure-temperature regime might also permit melting of shallow crust below a super-heated impact melt sea. In other words, an indirect consequence of the impact itself.”

* Rocks from Jack Hills in Australia contain zircon crystals from up to 4.4 billion years ago, embedded in younger rocks.

Reference:
Tim E. Johnson, Nicholas J. Gardiner, Katarina Miljković, Christopher J. Spencer, Christopher L. Kirkland, Phil A. Bland, Hugh Smithies. An impact melt origin for Earth’s oldest known evolved rocks. Nature Geoscience, 2018; DOI: 10.1038/s41561-018-0206-5

Note: The above post is reprinted from materials provided by Goldschmidt Conference.

Rare teeth from ancient mega-shark found on Australia beach

shark tooth
Fossil enthusiast Philip Mullaly was strolling along an area known as a fossil hotspot at Jan Juc, on the country’s famous Great Ocean Road, when he spotted a giant shark tooth

A rare set of teeth from a giant prehistoric mega-shark twice the size of the great white have been found on an Australian beach by a keen-eyed amateur enthusiast, scientists said Thursday.

Philip Mullaly was strolling along an area known as a fossil hotspot at Jan Juc, on the country’s famous Great Ocean Road some 100 kilometres (60 miles) from Melbourne, when he made the find.

“I was walking along the beach looking for fossils, turned and saw this shining glint in a boulder and saw a quarter of the tooth exposed,” he said.

“I was immediately excited, it was just perfect and I knew it was an important find that needed to be shared with people.”

He told Museums Victoria, and Erich Fitzgerald, senior curator of vertebrate palaeontology, confirmed the seven centimetre-long (2.7 inch) teeth were from an extinct species of predator known as the great jagged narrow-toothed shark (Carcharocles angustidens).

The shark, which stalked Australia’s oceans around 25 million years ago, feasting on small whales and penguins, could grow more than nine metres long, almost twice the length of today’s great white shark.

“These teeth are of international significance, as they represent one of just three associated groupings of Carcharocles angustidens teeth in the world, and the very first set to ever be discovered in Australia,” Fitzgerald said.

He explained that almost all fossils of sharks worldwide were just single teeth, and it was extremely rare to find multiple associated teeth from the same shark.

This is because sharks, who have the ability to regrow teeth, lose up to a tooth a day and cartilage, the material a shark skeleton is made of, does not readily fossilise.

Fitzgerald suspected they came from one individual shark and there might be more entombed in the rock.

So he led a team of palaeontologists, volunteers, and Mullaly on two expeditions earlier this year to excavate the site, collecting more than 40 teeth in total.

Most came from the mega-shark, but several smaller teeth were also found from the sixgill shark (Hexanchus), which still exists today.

Museums Victoria palaeontologist Tim Ziegler said the sixgill teeth were from several different individuals and would have become dislodged as they scavenged on the carcass of the Carcharocles angustidens after it died.

“The stench of blood and decaying flesh would have drawn scavengers from far around,” he said.

“Sixgill sharks still exist off the Victorian coast today, where they live off the remains of whales and other animals. This find suggests they have performed that lifestyle here for tens of millions of years.”

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

Faster way to make mineral to remove carbon dioxide from atmosphere

Natural magnesite crystal (4 microns wide).
Natural magnesite crystal (4 microns wide). Credit: Ian Power

Scientists have found a rapid way of producing magnesite, a mineral which stores carbon dioxide. If this can be developed to an industrial scale, it opens the door to removing CO2 from the atmosphere for long-term storage, thus countering the global warming effect of atmospheric CO2. This work is presented at the Goldschmidt conference in Boston.

Scientists are already working to slow global warming by removing carbon dioxide from the atmosphere, but there are serious practical and economic limits on developing the technology. Now, for the first time, researchers have explained how magnesite forms at low temperature, and offered a route to dramatically accelerating its crystallization. A tonne of naturally-occurring magnesite can remove around half a tonne of CO2 from the atmosphere, but the rate of formation is very slow.

Project leader, Professor Ian Power (Trent University, Ontario, Canada) said: “Our work shows two things. Firstly, we have explained how and how fast magnesite forms naturally. This is a process which takes hundreds to thousands of years in nature at Earth’s surface. The second thing we have done is to demonstrate a pathway which speeds this process up dramatically.”

The researchers were able to show that by using polystyrene microspheres as a catalyst, magnesite would form within 72 days. The microspheres themselves are unchanged by the production process, so they can ideally be reused.

“Using microspheres means that we were able to speed up magnesite formation by orders of magnitude. This process takes place at room temperature, meaning that magnesite production is extremely energy efficient.”

“For now, we recognise that this is an experimental process, and will need to be scaled up before we can be sure that magnesite can be used in carbon sequestration (taking CO2 from the atmosphere and permanently storing it as magnesite). This depends on several variables, including the price of carbon and the refinement of the sequestration technology, but we now know that the science makes it do-able.”

Commenting, Professor Peter Kelemen at Columbia University’s Lamont Doherty Earth Observatory (New York) said: “It is really exciting that this group has worked out the mechanism of natural magnesite crystallization at low temperatures, as has been previously observed — but not explained — in weathering of ultramafic* rocks. The potential for accelerating the process is also important, potentially offering a benign and relatively inexpensive route to carbon storage, and perhaps even direct CO2 removal from air.”

Notes:

Professor Keleman was not involved in this work, this is an independent comment.

*Ultramafic rocks are rich in magnesium, with low silica content. Commercially, magnesite (MgCO3, magnesium carbonate) is used in the production of magnesium oxide mainly for the steel industry. It is also used as an inexpensive gemstone.

This research was funded by the Natural Sciences and Engineering Research Council of Canada (NSERC).

Reference:
I.M. Power, A.L. Harrison, P.A. Kenward, G.M. Dipple, S.A. Wilson. Magnesite formation at Earth’s surface. Goldschmidt Abstracts, 2018. https://goldschmidtabstracts.info/abstracts/abstractView?id=2018001242

Note: The above post is reprinted from materials provided by Goldschmidt Conference.

Mantle xenon has a story to tell

Etna eruption
Etna eruption, Catania, Sicily. Credit: Wead / Fotolia

The Earth has been through a lot of changes in its 4.5 billion year history, including a shift to start incorporating and retaining volatile compounds from the atmosphere in the mantle before spewing them out again through volcanic eruptions.

This transport could not have begun much before 2.5 billion years ago, according to new research by Washington University in St. Louis, published in the August 9 issue of the journal Nature.

“Life on Earth cares about changes in the volatile budget of the surface,” said Rita Parai, assistant professor of geochemistry in Earth and Planetary Sciences in Arts & Sciences and first author of the study. “And there’s an interplay between what the deep Earth was doing and how the surface environment changed over billion-year timescales.”

Volatiles — such as water, carbon dioxide and the noble gases — come out of the mantle through volcanism and may be injected into the Earth’s interior from the atmosphere, a pair of processes called mantle degassing and regassing. The exchange controls the habitability of the planet, as it determines the surface availability of compounds that are critical to life — such as carbon, nitrogen and water.

The new model presented by Parai and collaborator Sujoy Mukhopadhyay, of the University of California, Davis, also establishes a range of dates during which the Earth shifted from a net degassing regime — again, think about those oozy volcanoes — to one that tilted the balance to net regassing potentially enabled by subduction, the conveyor-belt action of tectonic plates.

Mechanical properties change as water is added or removed from the mantle, so the onset of regassing had an important effect on the internal churning of the mantle, known as convection, which controls plate motions at the surface, Parai said.

Parai uses noble gases to address questions about how planetary bodies form and evolve over time. In this new research, she modeled the fate and transport of volatile compounds into the Earth’s mantle using xenon isotopes as tracers.

“Xenon is an excellent volatile tracer, because all minerals that carry water also carry xenon,” Parai said. “So if xenon regassing was negligible, water regassing must also have been negligible during the Archean (4 billion-2.5 billion years ago).”

Substantial regassing began sometime between a few hundred million to 2.5 billion years ago, the researchers found.

If plate tectonics and subduction began earlier than 2.5 billion years ago, then perhaps by then the Earth’s interior had cooled sufficiently for volatiles to remain in subducting plates, rather than getting released and percolating back to the surface through magmatism, Parai suggests.

“Most people rarely have an occasion to think about volatiles trapped in the Earth’s interior,” Parai said. “They’re present at low concentrations, but the mantle is huge in terms of mass. So for the Earth’s total volatile budget, the mantle is an important reservoir.”

She plans to focus her future research on pushing the limits of precision in xenon isotopic measurements in a variety of geological samples.

“The more observational constraints we have, the better,” she said.

Reference:
Rita Parai, Sujoy Mukhopadhyay. Xenon isotopic constraints on the history of volatile recycling into the mantle. Nature, 2018; 560 (7717): 223 DOI: 10.1038/s41586-018-0388-4

Note: The above post is reprinted from materials provided by Washington University in St. Louis. Original written by Talia Ogliore.

Study of material surrounding distant stars shows Earth’s ingredients ‘pretty normal’

Artists impression of white dwarf star (on right) showing dust disc, and surrounding planetary bodies.
Artists impression of white dwarf star (on right) showing dust disc, and surrounding planetary bodies. Credit: NASA/JPL-Caltech

The Earth’s building blocks seem to be built from ‘pretty normal’ ingredients, according to researchers working with the world’s most powerful telescopes. Scientists have measured the compositions of 18 different planetary systems from up to 456 light years away and compared them to ours, and found that many elements are present in similar proportions to those found on Earth.

This is amongst the largest examinations to measure the general composition of materials in other planetary systems, and begins to allow scientists to draw more general conclusions on how they are forged, and what this might mean for finding Earth-like bodies elsewhere.

“Most of the building blocks we have looked at in other planetary systems have a composition broadly similar to that of the Earth,” said researcher Dr Siyi Xu of the Gemini Observatory in Hawaii, who was presenting the work at the Goldschmidt conference in Boston.

The first planets orbiting other stars were only found in 1992 (this was orbiting a pulsar), since then scientists have been trying to understand whether some of these stars and planets are similar to our own solar system.

“It is difficult to examine these remote bodies directly. Because of the huge distances involved, their nearby star tends to drown out any electromagnetic signal, such as light or radio waves” said Siyi Xu. “So we needed to look at other methods.”

Because of this, the team decided to look at how the planetary building blocks affect signals from white dwarf stars. These are stars which have burnt off most of their hydrogen and helium, and shrunk to be very small and dense — it is anticipated that our Sun will become a white dwarf in around 5 billion years.

Dr Xu continued, “White dwarfs’ atmospheres are composed of either hydrogen or helium, which give out a pretty clear and clean spectroscopic signal. However, as the star cools, it begins to pull in material from the planets, asteroids, comets and so on which had been orbiting it, with some forming a dust disk, a little like the rings of Saturn. As this material approaches the star, it changes how we see the star. This change is measurable because it influences the star’s spectroscopic signal, and allows us to identify the type and even the quantity of material surrounding the white dwarf. These measurements can be extremely sensitive, allowing bodies as small as an asteroid to be detected.”

The team took measurements using spectrographs on the Keck telescope in Hawaii, the world’s largest optical and infrared telescope, and on the Hubble Space Telescope.

Siyi Xu continued, “In this study, we have focused on the sample of white dwarfs with dust disks. We have been able to measure calcium, magnesium, and silicon content in most of these stars, and a few more elements in some stars. We may also have found water in one of the systems, but we have not yet quantified it: it’s likely that there will be a lot of water in some of these worlds. For example, we’ve previously identified one star system, 170 light years away in the constellation Boötes, which was rich in carbon, nitrogen and water, giving a composition similar to that of Halley’s Comet. In general though, their composition looks very similar to bulk Earth.

This would mean that the chemical elements, the building blocks of earth are common in other planetary systems. From what we can see, in terms of the presence and proportion of these elements, we’re normal, pretty normal. And that means that we can probably expect to find Earth-like planets elsewhere in our Galaxy.”

Dr Xu continued “This work is still on-going and the recent data release from the Gaia satellite, which so far has characterized 1.7 billion stars, has revolutionized the field. This means we will understand the white dwarfs a lot better. We hope to determine the chemical compositions of extrasolar planetary material to a much higher precision”

Professor Sara Seager, Professor of Planetary Science at Massachusetts Institute of Technology, is also the deputy science director of the recently-launched TESS (Transiting Exoplanet Survey Satellite) mission, which will search for exoplanets. She said:

“It’s astonishing to me that the best way to study exoplanet interiors is by planets ripped apart and absorbed by their white dwarf host star. It is great to see progress in this research area and to have solid evidence that planets with Earth-like compositions are common — fueling our confidence that an Earth-like planet around a very nearby normal star is out there waiting to be found.”

Note: The above post is reprinted from materials provided by Goldschmidt Conference.

New research predicts landslide boundaries two weeks before they happen

Credit: CC0 Public Domain

University of Melbourne researchers have developed a software tool that uses applied mathematics and big data analytics to predict the boundary of where a landslide will occur, two weeks in advance.

Professor Antoinette Tordesillas from the School of Mathematics and Statistics said there are always warning signs in the lead up to a collapse or ‘failure’, the tricky part is identifying what they are.

“These warnings can be subtle. Identifying them requires fundamental knowledge of failure at the microstructure level—the movement of individual grains of earth,” Professor Tordesillas said.

“Of course, we cannot possibly see the movement of individual grains in a landslide or earthquake that stretches for kilometres, but if we can identify the properties that characterise failure in the small-scale, we can shed light on how failure evolves in time, no matter the size of the area we are observing.”

These early clues include patterns of motion that change over time and become synchronised.

“In the beginning, the movement is highly disordered,” said Professor Tordesillas. “But as we get closer to the point of failure—the collapse of a sand castle, crack in the pavement or slip in an open pit mine—motion becomes ordered as different locations suddenly move in similar ways.

“Our model decodes this data on movement and turns it into a network, allowing us to extract the hidden patterns on motion and how they are changing in space and time. The trick is to detect the ordered motions in the network as early as possible, when movements are very subtle.”

Professor Robin Batterham from the Department of Chemical and Biomolecular Engineering said the new software focuses on turning algorithms and big data into risk assessment and management actions that can save lives.

“People have gone somewhat overboard on so-called data analytics, machine learning and so on,” said Professor Batterham.

“While we’ve been doing this sort of stuff for 40 years, this software harnesses the computer power and memory available to look not just at the surface movement, but extract the relevant data patterns. We’re able to do things that were just unimaginable in a mathematical sense 30 years ago.

“We can now predict when a rubbish landfill might break in a developing country, when a building will crack or the foundation will move, when a dam could break or a mudslide occur. This software could really make a difference.”

Reference:
Antoinette Tordesillas et al, A data-driven complex systems approach to early prediction of landslides, Mechanics Research Communications (2018). DOI: 10.1016/j.mechrescom.2018.08.008

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

Maya rituals unearthed

The Valley of Peace Archaeology project team explore an ancient Maya site in central Belize.
The Valley of Peace Archaeology project team explore an ancient Maya site in central Belize. Credit: Jeannie Larmon

Deep in the untamed lowlands, we search for artifacts buried under hundreds of years of sediment. We are excavating two ancient Maya sites nestled in the sacred landscape of Cara Blanca in central Belize. Both date to A.D. 800-900, when prolonged and severe droughts struck this region, disrupting the daily life of the Maya.

These two structures – a platform teetering on the edge of a 60-meter-deep pool and a sweatbath compound – were part of a ritual pilgrimage circuit traversed by the ancient Maya to pay tribute to the rain god Chahk during the extended droughts.

Openings in the earth like this pool were thought to be portals to the underworld, places where deities and ancestors resided. In previous years studying this poolside platform, we discovered a massive burning event and thousands of ceramic sherds purposely placed on the plaster floor.

Burnings and offerings of this nature were a common practice with the ancient Maya. These were part of termination rituals, meant to “deanimate” objects or spaces and remove them from the life cycle. Everything was believed to contain a life force, making deanimation a critical process for the Maya.

Our aim this year is to garner a deeper understanding of this ritual space. We scrape away at the soil, trowel by trowel, filling buckets and sifting each one to avoid missing any bit of data. The deeper we go, the harder it becomes to hoist the dirt out of this trench.

It isn’t long before we unexpectedly uncover another platform. The ceramics at this layer seem to be from a much earlier time period – about A.D. 600! This suggests the Maya were ritually engaging with the Cara Blanca landscape before the drought period began – much earlier than we anticipated.

This older, deeper platform has thin floors and few walls. No human remains are buried here. This might reflect a wetter, less socially trying time.

As we walk from the trench to a sweatbath compound 10 minutes away, tiny pink petals fallen from flowering trees paint the walkways. The sweatbath appears heavily looted; our goal is to salvage whatever information remains. But when we start to excavate, we find no looters’ debris. We also find no large stones, which are usually present in a building collapse. This suggests the Maya dismantled this structure themselves during a termination ritual prior to their total abandonment of the area.

As we leave the site, driving off-road for 20 minutes down a rocky ravine, we ponder the importance of Cara Blanca to the ancient Maya. The intense effort they made to build and terminate these structures may reflect just how dire their circumstances were in the time of the droughts.

Note: The above post is reprinted from materials provided by University of Illinois at Urbana-Champaign.

200-million year old Pterosaur ‘built for flying’

Caelestiventus hanseni
Factfile on Caelestiventus hanseni a new species of flying reptiles, known as Pterosaurs, discovered in US state of Utah.

Scientists on Monday unveiled a previously unknown species of giant pterosaur, the first creatures with a backbone to fly under their own power.

Neither dino nor bird, pterosaurs—more commonly known as pterodactyls—emerged during the late Triassic period more than 200 million years ago and lorded over primeval skies until a massive space rock slammed into Earth, wiping out the dinosaurs and most other forms of life some 65 million years ago.

The newly discovered member of the family, identified through remains found in northeastern Utah, had a wing-span of 1.5 metres (five feet) and 112 teeth, including fang-like spikes sticking out near the snout.

A jutting lower jaw suggests a pelican-like pouch, perhaps to scoop up fish and unsuspecting small reptiles.

“They are delicately framed animals that are built for flying,” said Brooks Britt, a paleontologist at Brigham Young University in Utah and lead author of a study in Nature Ecology & Evolution.

Caelestiventus hanseni—roughly, “heavenly wind”—is probably the most complete skeletal remains of a pterosaur ever found.

“Most pterosaurs bones look like road-kill,” Britt told AFP, noting that there are only 30-odd specimens worldwide from the Triassic period which lasted some 51 million years.

By contrast, the new specimen comprises dozens of intact bones and teeth, along with an entire brain casing.

The wings are in fact skin membranes largely held up by the fourth “finger”, or digit, of their forelimbs. Huge sockets suggest C. hanseni had “fantastic eyesight”, said Britt.

Saints & Sinners

When not soaring in search of a meal, it walked on all fours with its wings folded vertically.

The fossil remains are still encased in sandstone, but scientists generated accurate 3-D images and models of each bone using CAT-scan technology.

The site where C. hanseni was unearthed, known to fossil hunters as Saints & Sinners, reveals a dramatic story of survival and local extinction in the face of climate change, the researchers said.

The rocks it was found in were part of an oasis in a two-million square kilometre (775,000 square mile) desert covered with giant sand dunes.

“During droughts, large numbers of animals—including pterosaurs, predatory dinosaurs and crocodylomorphs—were drawn to the pond in the middle of the oasis, where they died as water dried up,” said Britt.

The result was a treasure trove of more than 18,000 bones and fragments from dozens of water-starved animals.

C. hanseni is not the biggest pterosaur ever found, but was likely the largest of its era, especially for a desert environment.

It also predates other desert-dwelling specimens by about 65 million years. Pterosaurs from the same period found so far came from ancient coastal areas in what is now Europe and Greenland.

That the high-flying creatures were spread across much of the globe may have helped them survive the end-of-Triassic mass extinction, which wiped out half of the species on land and in the sea.

Reference:
Brooks B. Britt et al. Caelestiventus hanseni gen. et sp. nov. extends the desert-dwelling pterosaur record back 65 million years, Nature Ecology & Evolution (2018). DOI: 10.1038/s41559-018-0627-y

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

Those fragrances you enjoy? Dinosaurs liked them first

Glandular laurel in amber.
Glandular laurel in amber. Credit: Image courtesy of Oregon State University

The compounds behind the perfumes and colognes you enjoy have been eliciting olfactory excitement since dinosaurs walked the Earth amid the first appearance of flowering plants, new research reveals.

Oregon State University entomologist George Poinar Jr. and his son Greg, a fragrance collector, found evidence that floral scents originated in primitive flowers as far back as 100 million years ago as pollinator attractants — a role they still play even though today’s flowers also have colorful petals for luring pollinators.

“I bet some of the dinosaurs could have detected the scents of these early flowers,” George Poinar said. “In fact, floral essences from these early flowers could even have attracted these giant reptiles.”

The Poinars examined amber flowers from Burma, including the now extinct glandular laurel flower (Cascolaurus burmensis) and veined star flower (Tropidogyne pentaptera).

The research revealed that the flower-based chemical compounds that are the basis for the perfumes and colognes we use today have been providing olfactory excitement to pollinating insects and other animals since the mid-Cretaceous Period.

Without colorful petals, flowers from that period had to rely solely on scents to attract pollinators.

“You can’t detect scents or analyze the chemical components of fossil flowers, but you can find the tissues responsible for the scents,” said George Poinar, professor emeritus in the OSU College of Science.

The floral secretory tissues producing these scents include nectaries, glandular trichomes, eliaphores and osmophores.

Nectaries are glands that produce fragrances and sweet deposits that insects love. Glandular trichomes are hairs with cells that make and send out scented secretory products. Eliaphores are stalked aromatic oil glands. oOsmophores, also known as floral fragrance glands, are cell clusters specializing in scent emission.

The study also found that secretory tissues of these Cretaceous flowers are similar in structure to those of their modern descendants. That suggests modern and ancient flowers of the same lineages produced similar essences.

Some of flowers studied were even in the process of emitting compounds at the time they were engulfed by the tree resin that later became amber.

The study also included a milkweed flower (Discoflorus neotropicus) and an acacia flower (Senegalia eocaribbeansis) in 20- to 30-million-year-old Dominican Republic amber.

The anther glands on the fossil acacia flower were especially attractive to bees, one of which was fossilized while visiting the stamens. Today, honeybees are still visiting acacia flowers that have the same type of flora glands that existed in the ancient past.

“It’s obvious flowers were producing scents to make themselves more attractive to pollinators long before humans began using perfumes to make themselves more appealing to other humans,” George Poinar said.

Reference:
George Poinar, Greg Poinar. The antiquity of floral secretory tissues that provide today’s fragrances. Historical Biology, 2018; 1 DOI: 10.1080/08912963.2018.1502288

Note: The above post is reprinted from materials provided by Oregon State University. Original written by Steve Lundeberg.

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