WFS News: Scientists determine source of world’s largest mud eruption

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On May 29, 2006, mud started erupting from several sites on the Indonesian island of Java. Boiling mud, water, rocks and gas poured from newly-created vents in the ground, burying entire towns and compelling many Indonesians to flee. By September 2006, the largest eruption site reached a peak, and enough mud gushed on the surface to fill 72 Olympic-sized swimming pools daily.

Indonesians frantically built levees to contain the mud and save the surrounding settlements and rice fields from being covered. The eruption, known as Lusi, is still ongoing and has become the most destructive ongoing mud eruption in history. The relentless sea of mud has buried some villages 40 meters (130 feet) deep and forced nearly 60,000 people from their homes. The volcano still periodically spurts jets of rocks and gas into the air like a geyser. It is now oozing around 80,000 cubic meters (3 million cubic feet) of mud each day — enough to fill 32 Olympic-sized pools. Watch a video of the Lusi eruption here: https://www.youtube.com/watch?v=1PXS1OIAD4o&feature=youtu.be

Now, more than 11 years after it first erupted, researchers may have figured out why the mudflows haven’t stopped: deep underground, Lusi is connected to a nearby volcanic system.

On May 29, 2006, mud started erupting from several sites on the Indonesian island of Java and hasn’t stopped since. The eruption became known as Lusi and is the most destructive ongoing mud eruption in history. Credit: Adriano Mazzini/The Lusi Lab Project

On May 29, 2006, mud started erupting from several sites on the Indonesian island of Java and hasn’t stopped since. The eruption became known as Lusi and is the most destructive ongoing mud eruption in history.Credit: Adriano Mazzini/The Lusi Lab Project

In a new study, researchers applied a technique geophysicists use to map Earth’s interior to image the area beneath Lusi. The images show the conduit supplying mud to Lusi is connected to the magma chambers of the nearby Arjuno-Welirang volcanic complex through a system of faults 6 kilometers (4 miles) below the surface.

Volcanoes can be connected to each other deep underground and scientists suspected Lusi and the Arjuno-Welirang volcanic complex were somehow linked, because previous research showed some of the gas Lusi expels is typically found in magma. But no one had yet shown that Lusi is physically connected to Arjuno-Welirang.

The researchers discovered that the scorching magma from the Arjuno-Welirang volcano has essentially been “baking” the organic-rich sediments underneath Lusi. This process builds pressure by generating gas that becomes trapped below the surface. In Lusi’s case, the pressure grew until an earthquake triggered it to erupt.

Studying the connection of these two systems could help scientists to better understand how volcanic systems evolve, whether they erupt magma, mud or hydrothermal fluids.

“We clearly show the evidence that the two systems are connected at depth,” said Adriano Mazzini, a geoscientist at CEED — University of Oslo and lead author of the new study in the Journal of Geophysical Research: Solid Earth, a journal of the American Geophysical Union. “What our new study shows is that the whole system was already existing there — everything was charged and ready to be triggered.”

Finding a connection

Java is part of a volcanic island arc, formed when one tectonic plate subducts below another. As the island rose upward out of the sea, volcanoes formed along its spine, with basins of shallow water between them. Lusi’s mud comes from sediments laid down in those basins while the island was still partially submerged underwater.

Mazzini has been studying Lusi since soon after the eruption began. Two years ago, the study’s authors installed a network of 31 seismometers around Lusi and the neighboring volcanic complex. Researchers typically use seismometers to measure ground shaking during earthquakes, but scientists can also use them to create three-dimensional images of the areas underneath volcanoes.

Using 10 months of data recorded by the seismometers, Mazzini and his colleagues imaged the area below Lusi and the surrounding volcanoes. The images showed a tunnel protruding from the northernmost of Arjuno-Welirang’s magma chambers into the sedimentary basin where Lusi is located. This allows magma and hydrothermal fluids originating in the mantle to intrude into Lusi’s sediments, which triggers massive reactions and creates gas that generates high pressure below Earth’s surface. Any perturbation — like an earthquake — can then trigger this system to erupt.

“It’s just a matter of reactivating or opening these faults and whatever overpressure you have gathered in the subsurface will inevitably want to escape and come to the surface, and you have a manifestation on the surface, and that is Lusi,” Mazzini said.

Triggering an eruption

Mazzini and other researchers suspect a magnitude 6.3 earthquake that struck Java two days before the mud started flowing was what triggered the Lusi eruption, by reactivating the fault system that connects it to Arjuno-Welirang.

By allowing magma to flow into Lusi’s sedimentary basin, the fault system could be an avenue for moving the entire volcanic system northward, said Stephen Miller, a professor of geodynamics at the University of Neuchâtel in Neuchâtel, Switzerland who was not connected to the study.

“It looks like this might be the initial stages of this march forward of this volcanic arc,” Miller said. “Ultimately, it’s bringing all this heat over toward Lusi, which is driving that continuous system.”

Mazzini and other scientists are unsure how much longer Lusi will continue to erupt. While mud volcanoes are fairly common on Java, Lusi is a hybrid between a mud volcano and a hydrothermal vent, and its connection to the nearby volcano will keep sediments cooking for years to come.

“So what it means to me is that Lusi’s not going to stop anytime soon,” Miller said.

  1. Mohammad Javad Fallahi, Anne Obermann, Matteo Lupi, Karyono Karyono, Adriano Mazzini. The plumbing system feeding the Lusi eruption revealed by ambient noise tomography. Journal of Geophysical Research: Solid Earth, 2017; DOI: 10.1002/2017JB014592
American Geophysical Union. “Scientists determine source of world’s largest mud eruption.” ScienceDaily. ScienceDaily, 17 October 2017. <www.sciencedaily.com/releases/2017/10/171017114344.htm>.
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WFS News: Bryozoans: Fossil fills missing evolutionary link

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Lurking in oceans, rivers and lakes around the world are tiny, ancient animals known to few people. Bryozoans, tiny marine creatures that live in colonies, are “living fossils” — their lineage goes back to the time when multi-celled life was a newfangled concept. But until now, scientists were missing evidence of one important breakthrough that helped the bryozoans survive 500 million years as the world changed around them.

Today, the diverse group of bryozoans that dominate modern seas build a great range of structures, from fans to sheets to weird, brain-like blobs. But for the first 50 or 60 million years of their existence, they could only grow like blankets over whatever surface they happened upon.

Scientists recently announced the discovery of that missing evolutionary link — the first known member of the modern bryozoans to grow up into a structure. Called Jablonskipora kidwellae, it is named after UChicago geophysical scientists David Jablonski and Susan Kidwell.

Jablonskipora kidwellae, the first known member of the modern bryozoans to grow up into a structure. Credit: Paul Taylor/London's Natural History Museum

Jablonskipora kidwellae, the first known member of the modern bryozoans to grow up into a structure.
Credit: Paul Taylor/London’s Natural History Museum

Both are prominent scholars in their fields: Jablonski in origins, extinctions and other forces shaping biodiversity across time and space in marine invertebrates; Kidwell in the study of how fossils are preserved and the reliability of paleobiologic data, especially for detecting recent, human-driven changes to ecosystems. They also happen to be married.

“We were absolutely thrilled. What a treat and an honor, to have this little guy named after us,” said Jablonski, the William R. Kenan Jr. Distinguished Service Professor of Geophysical Sciences.

“I never expected to have a fossil named after me,” said Kidwell, the William Rainey Harper Professor in Geophysical Sciences, “and here it’s one that is an evolutionary breakthrough. We’re still smiling about it.”

Jablonskipora kidwellae lived about 105 million years ago, latching on to rocks and other hard surfaces in shallow seas — a bit like corals, though they’re not related. The fossils came from southwest England, along cliffs near Devon, originally collected in 1903 and analyzed by co-discoverers Paul Taylor and Silviu Martha from London’s Natural History Museum.

Bryozoans never figured out a symbiotic partnership with photosynthetic bacteria, as coral did, so their evolution took a different turn. Each one in a colony is genetically identical, but they have specialized roles, like ants or bees. Their shelly apartment complexes house thousands of the creatures, which have soft bodies with tiny tentacles to catch nutrients.

Growing upright was an evolutionary hack for Jablonskipora kidwellae, the two professors said: building bigger colonies extending upward from just a tiny attachment site was a good evolutionary move, allowing it to tap the water flowing above the sea floor — both for food and to scatter its offspring further. “This is a huge competitive advantage for them,” Jablonski said, “but it required some evolutionary organization to create a vertical structure.” Kidwell added: “This is the next level of cooperation among these individuals within the colony.”

They expressed a fondness for the creature, which they said was, like other bryozoans, “small and slow, but fierce.” Bryozoan fossils are sometimes found having bulldozed right over neighboring colonies in an intense battle for growing space. In a manner of speaking: this all would have taken place in extremely slow motion.

“They’re pretty fabulous little animals,” Kidwell said.

Jablonski and Kidwell have been friends with Taylor, one of the discoverers, since they spent summers on various research at the London Natural History Museum in the 1980s, but they said his news took them both completely by surprise. Jablonski had previously co-authored one paper with Taylor; Kidwell is currently collaborating with him on a study of bryozoan skeletal debris in modern sediments from the Channel Islands off Los Angeles.

It is the second honor of the year for both Kidwell and Jablonski: In April she received the Moore Medal from the Society for Sedimentary Geology, and in October he received the Paleontological Society Medal, that society’s highest honor.

Jablonski had one previous species named after him — a tiny clam — but Jablonskiporawill now be a genus in addition to a species.

Ref: Silviu O. Martha, Paul D. Taylor. The oldest erect cheilostome bryozoan: Jablonskipora gen. nov. from the upper Albian of south-west England. Papers in Palaeontology, 2017; DOI: 10.1002/spp2.1097

University of Chicago. “Bryozoans: Fossil fills missing evolutionary link.” ScienceDaily. ScienceDaily, 16 November 2017. <www.sciencedaily.com/releases/2017/11/171116172456.htm>.
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WFS News: 280-Million-Year-Old Fossil Forest Discovered in Antarctica

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Antarctica wasn’t always a land of ice. Millions of years ago, when the continent was still part of a huge Southern Hemisphere landmass called Gondwana, trees flourished near the South Pole.

Now, newfound, intricate fossils of some of these trees are revealing how the plants thrived — and what forests might look like as they march northward in today’s warming world.

“Antarctica preserves an ecologic history of polar biomes that ranges for about 400 million years, which is basically the entirety of plant evolution,” said Erik Gulbranson, a paleoecologist at the University of Wisconsin-Milwaukee. [See Images of a Fossil Forest Unearthed in the Arctic]

It’s hard to look at Antarctica’s frigid landscape today and imagine lush forests. To find their fossil specimens, Gulbranson and his colleagues have to disembark from planes landed on snowfields, then traverse glaciers and brave bone-chilling winds. But from about 400 million to 14 million years ago, the southern continent was a very different, and much greener place. The climate was warmer, though the plants that survived at the low southern latitudes had to cope with winters of 24-hour-per-day darkness and summers during which the sun never set, just as today.

 A 280-million-year-old tree stump still attached to its roots in Antarctica. Plants grew on what is today the iciest continent from 400 million to 14 million years ago. Understanding ancient polar forests might help researchers develop predictions about how trees will react as man-made climate change warms the globe. Credit: Erik Gulbranson

A 280-million-year-old tree stump still attached to its roots in Antarctica. Plants grew on what is today the iciest continent from 400 million to 14 million years ago. Understanding ancient polar forests might help researchers develop predictions about how trees will react as man-made climate change warms the globe.
Credit: Erik Gulbranson

Gulbranson and his team are focused on an era centered around 252 million years ago, during the Permian-Triassic mass extinction. During this event, as many of 95 percent of Earth’s species died out. The extinction was probably driven by massive greenhouse gas emissions from volcanoes, which raised the planet’s temperatures to extreme levels and caused the oceans to acidify, scientists have found. There are obvious parallels to contemporary climate change, Gulbranson said, which is less extreme but similarly driven by greenhouse gases.

Prior to the end-Permian mass extinction, the southern polar forests were dominated by one type of tree, those in the Glossopteris genus, Gulbranson told Live Science. These were behemoths that grew from 65 to 131 feet (20 to 40 meters) tall, with broad, flat leaves longer than a person’s forearm, Gulbranson said. Before the Permian extinction, Glossopteris dominated the landscape below the 35th parallel south to the South Pole. (The 35th parallel south is a circle of latitude that crosses through two landmasses: the southern tip of South American and the southern tip of Australia.)

Last year, while fossil-hunting in Antarctica, Gulbranson and his team found the oldest polar forest on record from the southern polar region. They haven’t dated that forest precisely yet, but it probably flourished about 280 million years ago before being rapidly buried in volcanic ash, which preserved it down to the cellular level, the researchers said.

On Thanksgiving Day, Gulbranson will return to Antarctica for more excavations at two sites. Those sites contain fossils from a period spanning from before to after the Permian extinction. After the extinction, Gulbranson said, the forests didn’t disappear, but they changed. Glossopteris was out, but a new mix of evergreen and deciduous trees, including relatives of today’s gingkoes, moved in.

“What we’re trying to research is what exactly caused those transitions to occur, and that’s what we don’t know very well,” Gulbranson said.

The plants are so well-preserved in rock that some of the amino acid building blocks that made up the trees’ proteins can still be extracted, said Gulbranson, who specializes in geochemistry techniques. Studying these chemical building blocks may help clarify how the trees handled the southern latitudes’ weird sunlight conditions, as well as the factors that allowed those plants to thrive but drove Glossopteris to its death, he said.

This season, the field team will have access to helicopters, which can land closer to the rugged outcrops in the Transantarctic Mountains where the fossil forests are found. The team (members hail from the United States, Germany, Argentina, Italy and France) will camp out for months at a time, hitching helicopter rides to the outcrops as the fickle Antarctic weather allows. The 24-hour sun allows for long days, even middle-of-the-night expeditions that combine mountaineering with fieldwork, Gulbranson said.

“It’s definitely a treat as a geologist,” he said.

Original article on Live Science

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WFS news: World’s longest sauropod dinosaur track way brought to light

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In 2009, the world’s largest dinosaur tracks were discovered in the French village of Plagne, in the Jura Mountains. Since then, a series of excavations at the site has uncovered other tracks, sprawling over more than 150 meters. They form the longest sauropod trackway ever to be found. Having compiled and analyzed the collected data, which is published in Geobios, scientists from the Laboratoire de Géologie de Lyon (CNRS / ENS de Lyon / Claude Bernard Lyon 1 University), the Laboratoire Magmas et Volcans (CNRS / Université Clermont Auvergne / Université Jean Monnet / IRD), and the Pterosaur Beach Museum conclude these tracks were left 150 million years ago by a dinosaur at least 35 m long and weighing no less than 35 t.

Dinosaur tracks in Plagne, France (stock image). Credit: © nmnac01 / Fotolia

    Dinosaur tracks in Plagne, France (stock image).Credit: © nmnac01 / Fotolia

In 2009, when sauropod tracks were discovered in the French village of Plagne — near Lyon — the news went round the world. After two members of the Oyonnax Naturalists’ Society spotted them, scientists from the Paléoenvironnements et Paléobiosphère research unit (CNRS / Claude Bernard Lyon 1 University) confirmed these tracks were the longest in the world. Between 2010 and 2012, researchers from the Laboratoire de Géologie de Lyon supervised digs at the site, a meadow covering three hectares. Their work unearthed many more dinosaur footprints and trackways. It turns out the prints found in 2009 are part of a 110-step trackway that extends over 155 m — a world record for sauropods, which were the largest of the dinosaurs.

Dating of the limestone layers reveals that the trackway was formed 150 million years ago, during the Early Tithonian Age of the Jurassic Period. At that time, the Plagne site lay on a vast carbonate platform bathed in a warm, shallow sea. The presence of large dinosaurs indicates the region must have been studded with many islands that offered enough vegetation to sustain the animals. Land bridges emerged when the sea level lowered, connecting the islands and allowing the giant vertebrates to migrate from dry land in the Rhenish Massif.

Additional excavations conducted as late as 2015 enabled closer study of the tracks. Those left by the sauropod’s feet span 94 to 103 cm and the total length can reach up to 3 meters when including the mud ring displaced by each step. The footprints reveal five elliptical toe marks, while the handprints are characterized by five circular finger marks arranged in an arc. Biometric analyses suggest the dinosaur was at least 35 m long, weighted between 35 and 40 t, had an average stride of 2.80 m, and traveled at a speed of 4 km/h. It has been assigned to a new ichnospecies1: Brontopodus plagnensis. Other dinosaur trackways can be found at the Plagne site, including a series of 18 tracks extending over 38 m, left by a carnivore of the ichnogenus Megalosauripus. The researchers have since covered these tracks to protect them from the elements. But many more remain to be found and studied in Plagne.

1 The prefix ichno- indicates that a taxon (e.g., a genus or species) has been defined on the basis of tracks or other marks left behind, rather than anatomical remains like bones.

  1. Jean-Michel Mazin, Pierre Hantzpergue, Nicolas Olivier. The dinosaur tracksite of Plagne (early Tithonian, Late Jurassic; Jura Mountains, France): The longest known sauropod trackway. Geobios, 2017; 50 (4): 279 DOI: 10.1016/j.geobios.2017.06.004
      2. CNRS. “World’s longest sauropod dinosaur trackway brought to light.” ScienceDaily. ScienceDaily, 13 November 2017. <www.sciencedaily.com/releases/2017/11/171113195133.htm>.
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WFS News: Site of asteroid impact changed the history of life

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An asteroid, also known as the Chicxulub Impactor, hit Earth some 66 million years ago, causing a crater 180 km wide. The impact of the asteroid heated organic matter in rocks and ejected it into the atmosphere, forming soot in the stratosphere.

Soot is a strong, light-absorbing aerosol that caused global climate changes that triggered the mass extinction of dinosaurs, ammonites, and other animals, and led to the macroevolution of mammals and the appearance of humans.

Based on results of a new study, the researchers say that the probability of the mass-extinction occurring was only 13 percent. This is because the catastrophic chain of events could only have occurred if the asteroid had hit the hydrocarbon-rich areas occupying approximately 13 percent of Earth’s surface.

Mass extinction only occurred when the asteroid having 9-km diameter hit the orange areas. Credit: Kunio Kaiho

Mass extinction only occurred when the asteroid having 9-km diameter hit the orange areas.
                                                                      Credit: Kunio Kaiho

Led by Tohoku University Professor Kunio Kaiho, the researchers came by their hypothesis by calculating the amount of soot in the stratosphere and estimating climate changes caused by soot using a global climate model developed at the Meteorological Research Institute. The results are significant because they explain the pattern of extinction and survival.

During the study, Kaiho thought that the amount of soot and temperature anomaly might have been affected by the amount of sedimentary organic-matter. So, he analyzed the amount of sedimentary organic-matter in Earth to obtain readings of temperature anomaly caused by soot in the stratosphere.

Naga Oshima of the Meteorological Research Institute conducted the global climate model calculations to obtain temperature anomalies caused by various amounts of soot injected into the stratosphere.

Kaiho clarified the relationship between the findings and concluded that the significant cooling and mass-extinction event could have only have occurred if the asteroid had hit hydrocarbon-rich areas occupying approximately 13 percent of Earth’s surface.

If the asteroid had hit a low-medium hydrocarbon area on Earth (occupying approximately 87 percent of Earth’s surface), mass extinction could not have occurred and the Mesozoic biota could have persisted beyond the Cretaceous/Paleogene boundary.

The site of the asteroid impact, therefore, changed the history of life on Earth.

According to the study, soot from hydrocarbon-rich areas caused global cooling of 8-11°C and cooling on land of 13-17°C. It also caused a decrease in precipitation by approximately 70-85 percent on land and a decrease of approximately 5-7°C in seawater temperature at a 50-m water depth, leading to mass extinction of life forms including dinosaurs and ammonites.

At the time, these hydrocarbon-rich areas were marine coastal margins, where the productivity of marine algae was generally high and sedimentary rocks were thickly deposited. Therefore, these areas contained a high amount of organic matter, part of which became soot from the heat of the asteroid’s impact.

Thus, the researchers concluded that the Chicxulub impact occurred in a hydrocarbon-rich area and is a rare case of mass extinction being caused at such an impact site.

Kaiho and Oshima are doing further studies to clarify the frequency of all the cooling events by impacts. Kaiho’s team is analyzing climate change caused by large volcanic eruptions that may have contributed to other mass extinctions. It is hoped that the results will lead to further understanding of the processes behind those mass extinctions.

  1. Kunio Kaiho, Naga Oshima. Site of asteroid impact changed the history of life on Earth: the low probability of mass extinction. Scientific Reports, November 2017 DOI: 10.1038/s41598-017-141990-x 
      2. Tohoku University. “Site of asteroid impact changed the history of life.” ScienceDaily. ScienceDaily, 10 November 2017. <www.sciencedaily.com/releases/2017/11/171110113950.htm>
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WFS News:Fossil of beaver the size of a bear found in Manitoba

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Part of the skull of a prehistoric giant beaver — which rivalled the modern bear in size — has been found in a gravel pit in southeastern Manitoba.

The jaw bone, including a long front incisor and the back teeth in near-perfect condition, was discovered in a quarry south of Steinbach.

(Randy Mooi / Manitoba Museum photo) Giant beaver jaw (Castoroides) compared to a modern beaver (Castor canadensis). Part of the skull of a giant beaver has turned up in southeastern Manitoba.

Dr. Randy Mooi / Manitoba Museum
giant beaver jaw (Castoroides) compared to a modern beaver (Castor canadensis).Part of the skull of a giant beaver has turned up in southeastern Manitoba. The beaver, which was as large as our bears today, is estimated by Manitoba Museum paleontologist Graham Young to be from 50,000 years ago during a thawing period of the Ice Age. It’s the first such fossil found in Manitoba and only the fourth occurrence of a giant beaver fossil in Canada.

The giant beaver fossil is the first of its kind found in Manitoba — and only the fourth in Canada — even though it has long been believed to have existed in the province. There is a replica giant beaver skull on display at Oak Hammock Marsh.

The giant beaver species became extinct more than 10,000 years ago.

Graham Young, the curator of paleontology at the Manitoba Museum, said people often telephone the Winnipeg institution with what they think is an important find, but when a staff take a look, it usually turns out to not be the case.

“This fellow just walked in around lunch time and said, I’ve got these things, are you interested in seeing them? He thought maybe it was a pig’s jaw because the front tooth is like a tusk,” said Young.

Instead, it’s one of the best paleontological finds in Manitoba in recent years. The jaw bone has not yet been radiocarbon dated — it’s in a lengthy line behind numerous other fossils found in the province — but wood in the vicinity has been dated to 44,000 years ago.

“This is an amazing piece, it really is,” said Young. “With so many bones, you can’t tell what it is right away. With this giant beaver jaw, there was no question what it was immediately.”

Not only is the jaw intact, but a dentist would give its teeth a gold star: the front tooth is almost 12 centimetres long.

“There’s nothing more diagnostic than finding the jaw. The big front tooth is like a chisel on these giant beavers,” Young said.

The man who brought in the fossil also donated an ancient bison vertebrae and a long, curved length of bone believed to be a rib from either a mammoth or mastodon.

(It could be a mastodon because a tree radiocarbon dated in the area was black spruce, Young said, and mastodon used to feast on black spruce sprigs. A mastodon tooth has also been found in southern Manitoba, near Blumenort.)

The donor has requested anonymity, and not to reveal the exact location the beaver fossil was found.

“One thing to emphasize is there’s a heck of a lot of gravel out there and it’s rare to find anything at all. To find bone, it’s a real needle in a haystack,” said Young.

The period of the giant beaver was during the Ice Age, but the fossil’s time would have likely been during an interval when the ice sheet retreated to the north somewhat before advancing again south.

The tail of a giant beaver was skinny, not flat like the modern beaver, and grew to up to 2 1/2 metres long. It’s been debated whether the giants were lodge-builders or made their homes by burrowing into the ground. Its front teeth are strong and long but shaped differently than today’s rodent, so they didn’t eat bark, Young said.

It’s believed the giant beaver wasn’t as prevalent as its family members are now in Canada.

The donated fossil jaw is in such good shape, the animal likely died near where it was found, Young said. Fossils are sometimes transported long distances by various natural forces.

Previous giant beaver fossils in Canada have been found near Old Crow in the Yukon, in New Brunswick and in the Don Valley area of Toronto.

The fossil at the Manitoba Museum is now undergoing a long, slow drying process in controlled-climate conditions that will take months, in order to reduce the chances of cracking.

“The pieces we got have probably been sitting below the water table for probably over 40,000 years and are incredibly saturated,” Young said.

Young believes the giant beaver went extinct around 11,000 years ago, along with about 25 other large animals due to the arrival of people in North America and the animals being stressed by climate change.

He hopes to eventually put the jaw on display in an exhibit of fossils found in southeast Manitoba.

Source: Article by Bill Redekop, winnipeg free press

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WFS News: Finger and toe fossils belonged to tiny primates 45 million years ago

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At Northern Illinois University, Dan Gebo opens a cabinet and pulls out a drawer full of thin plastic cases filled with clear gelatin capsules. Inside each numbered capsule is a tiny fossil — some are so small they rival the diminutive size of a mustard seed.

It’s hard to imagine that anyone would be able to recognize these flecks as fossils, much less link them to an ancient world that was very different from our own, yet has quite a bit to do with us — or the evolution of us.

The nearly 500 finger and toe bones belonged to tiny early primates — some half the size of a mouse. During the mid-Eocene period, about 45 million years ago, they lived in tree canopies and fed on fruit and insects in a tropical rainforest in what is now China.

The fossilized phalanges are described in detail in a new study by Gebo and colleagues, published online this fall ahead of print in the Journal of Human Evolution.

The fossils provide further evidence that early anthropoids were minuscule creatures. Credit: Northern Illinois University

          The fossils provide further evidence that early anthropoids were minuscule creatures.
                                                        Credit: Northern Illinois University

Representing nine different taxonomic families of primates and as many as 25 species, the specimens include numerous fossils attributed to Eosimias, the very first anthropoid known to date, and three fossils attributed to a new and much more advanced anthropoid. The anthropoid lineage would later include monkeys, apes and humans.

“The fossils are extraordinarily small, but in terms of quantity this is the largest single assemblage of fossil primate finger and toe specimens ever recorded,” said Gebo, an NIU professor of anthropology and biology who specializes in the study of primate anatomy.

All of the finger and toe fossils imply tree-dwelling primates with grasping digits in both hands and feet. Many of the smaller fossils are between 1 and 2 millimeters in length, and the animals would have ranged in full body size from 10 to 1,000 grams (0.35 to 35.3 ounces).

“The new study provides further evidence that early anthropoids were minuscule creatures, the size of a mouse or smaller,” Gebo said. “It also adds to the evidence pointing toward Asia as the initial continent for primate evolution. While apes and fossil humans do come from Africa, their ancestors came from Asia.”

The newly described fossils were originally recovered from a commercial quarry near the village of Shanghuang in the southern Jiangsu Province of China, about 100 miles west of Shanghai. In recent decades, Shanghuang has become well-known among paleontologists.

“Shanghuang is truly an amazingly diverse fossil primate locality, unequaled across the Eocene,” Gebo said. “Because no existing primate communities show this type of body-size distribution, the Shanghuang primate fauna emphasizes that past ecosystems were often radically different from those we are familiar with today.”

Co-author Christopher Beard, a paleontologist at the University of Kansas in Lawrence who has been working on Shanghuang fossils for 25 years, said the limestone in the quarry is of Triassic age — from the very beginning of the Age of Dinosaurs some 220 million years ago. Owing to a subsequent phase of erosion, the limestone developed large fissures containing fossil-rich sediments dating to the middle Eocene, after dinosaurs went extinct.

In the early 1990s, more than 10 tons of fossil-bearing matrix were collected from the fissures and shipped to the Institute of Vertebrate Paleontology and Paleoanthropology in Beijing and the Carnegie Museum of Natural History in Pittsburgh. There, the matrix was washed and screened, yielding fossil bones and teeth from ancient mammals, many of which remain to be identified.

“Because of commercial exploitation of the quarry site, the fossil-bearing fissure-fillings at Shanghuang are now exhausted,” Beard said. “So, the fossils that we currently have are all that will ever be found from this site.”

Gebo was initially recruited during the late 1990s to spearhead research on primate limb and ankle bones from Shanghuang. That led to two publications in 2000, when he and colleagues first announced the discovery of 45 million-year-old, thumb-length primates, the smallest ever recovered, from this same site. The work identifying body parts also helped cement the status of Eosimias, first identified by Beard on the basis of jaw fragments discovered at the site, as an extremely primitive anthropoid lying at the very beginning of our lineage’s evolutionary past.

In more recent years, Gebo found additional specimens, sifting through miscellaneous elements from Shanghuang both at the Carnegie Museum and the University of Kansas. He brought the delicate and minuscule finger and toe fossils to NIU for study using traditional and electron-scanning microscopes.

The fossils that endured the millennia may be small but still have a story to tell. “We can actually identify different types of primates from the shapes of their fingers and toes,” Gebo said.

Primates are mammals, characterized by having bigger brains, grasping hands and feet, nails instead of claws and eyes located in the front of the skull. Living prosimians, or living lower primates, include lemurs and tarsiers, and have broader fingertips. In contrast, most living anthropoids, also known as higher primates, have narrow fingertips.

Fossils from the unnamed advanced anthropoid are narrow, Gebo said.

“These are the earliest known examples of those narrow fingers and toes that are key to anthropoid evolution,” he added. “We can see evolution occurring at this site, from the broader finger or toe tips to more narrow.”

Unlike other prehistoric forests across the globe that have a mixture of large and small primates, Shanghuang’s fossil record is unique in being nearly absent of larger creatures.

The unusual size distribution is likely the result of a sampling bias, Gebo said. Researchers might be missing the larger primate fauna because of processes affecting fossil preservation, and for similar reasons scientists at other Eocene localities could be missing the small-sized fauna.

“Many of the fossil specimens from Shanghuang show evidence of partial digestion by predatory birds, which may have specialized on preying upon the small primates and other mammals that are so common at Shanghuang, thus explaining the apparent bias toward small fossil species there,” Beard added.

Some of the primate fossils found in Shanghuang are found in other countries. Eosimias fossils have been recovered in Myanmar, for example. But Shanghuang stands out because of the presence of more advanced anthropoids and the sheer diversity of primates.

“You don’t find all of these fossil primates in one place except at Shanghuang,” Gebo said.

  1. Daniel L. Gebo, Marian Dagosto, Xijun Ni, K. Christopher Beard. Phalangeal morphology of Shanghuang fossil primates. Journal of Human Evolution, 2017; 113: 38 DOI: 10.1016/j.jhevol.2017.08.001
  2. Northern Illinois University. “Finger and toe fossils belonged to tiny primates 45 million years ago.” ScienceDaily. ScienceDaily, 9 November 2017. <www.sciencedaily.com/releases/2017/11/171109131215.htm>

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WFS News: Mammals were nocturnal until dinosaur extinction…

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With enormous predators like Tyrannosaurus Rex skulking around in the daytime it is not surprising that the first mammals chose to live under the cover of darkness.

In fact, a new study, from University College London has found that our ancestors did not emerge from the shadows until after the dinosaurs became extinct, around 66 million years ago.

Before then, all mammals were nocturnal, sleeping in the daytime and hunting or foraging at night, new data suggests.

After dinosaurs became extinct 66 million years ago, mammals became diurnal CREDIT: STOCKTREK IMAGES, INC. / ALAMY

After dinosaurs became extinct 66 million years ago, mammals became diurnal                                                                        CREDIT: STOCKTREK IMAGES, INC. / ALAMY

Researchers used computer algorithms to analyse details from 2415 species of living mammals to reconstruct the activity patterns of their ancestors.

They found that following the comet strike which killed off the dinosaurs, mammals shifted to an intermediate stage of mixed day and night living, before primarily venturing into the daylight.

“We were very surprised to find such close correlation between the disappearance of dinosaurs and the beginning of daytime activity in mammals, but we found the same result unanimously using several alternative analyses,” said lead author, doctoral student student Roi Maor of UCL.

The team found that the ancestors of gorillas and gibbons were the first to give up their nocturnal activity, a discovery which fits in with the fact that their descendants – which include humans – are the only mammals that see well in daylight.

Their vision and colour perception is comparable to those of diurnal reptiles and birds – groups which never left the daytime.

“It’s very difficult to relate behaviour changes in mammals that lived so long ago to ecological conditions at the time, so we can’t say that the dinosaurs dying out caused mammals to start being active in the daytime,” added co-author Professor Kate Jones.

“However, we see a clear correlation in our findings.”

Ancestral reconstruction is the extrapolation back in time from measured characteristics of individuals, or species, to their common ancestors.

For example, if  a mammal had long fingers and its sibling also has long fingers  it is likely that a parent had long fingers.

The research was published in the journal Nature Ecology and Evolution.

Source: Article by 

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WFS News: komatiites may offer new insights into earth’s evolution

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The first 1.5 billion years of Earth’s evolution is subject to considerable uncertainty due to the lack of any significant rock record prior to four billion years ago and a very limited record until about three billion years ago. Rocks of this age are usually extensively altered making comparisons to modern rock quite difficult. In new research conducted at LSU, scientists have found evidence showing that komatiites, three-billion-year old volcanic rock found within the Earth’s mantle, had a different composition than modern ones. Their discovery may offer new information about the first one billion years of Earth’s development and early origins of life. Results of the team’s work has been published in the October 2017 edition of NATURE Geoscience.

The basic research came from more than three decades of LSU scientists studying and mapping the Barberton Mountains of South Africa. The research team, including LSU geology professors Gary Byerly and Huiming Bao, geology PhD graduate Keena Kareem, and LSU researcher Benjamin Byerly, conducted chemical analyses of hundreds of komatiite rocks sampled from about 10 lava flows.

“Early workers had mapped large areas incorrectly by assuming they were correlatives to the much more famous Komati Formation in the southern part of the mountains. We recognized this error and began a detailed study of the rocks to prove our mapping-based interpretations,” said Gary Byerly.

Photomicrographs of fresh olivine (large green, blue and pink crystals) and glass inclusion (lower left inset). Komatiite volcanic rocks from the 3.3 billion-year-old Weltevreden Formation are the freshest yet discovered in from Earth's early Archean. Trace elements, radiogenic and stable isotopes from these rocks and olivine separates provide key evidence for evolution of Earth's mantle. Credit: Keena Kareem, LSU

Photomicrographs of fresh olivine (large green, blue and pink crystals) and glass inclusion (lower left inset). Komatiite volcanic rocks from the 3.3 billion-year-old Weltevreden Formation are the freshest yet discovered in from Earth’s early Archean. Trace elements, radiogenic and stable isotopes from these rocks and olivine separates provide key evidence for evolution of Earth’s mantle.Credit: Keena Kareem, LSU

Within the rocks, they discovered original minerals called fresh olivine, which had been preserved in remarkable detail. Though the mineral is rarely found in rocks subjected to metamorphism and surface weathering, olivine is the major constituent of Earth’s upper mantle and controls the nature of volcanism and tectonism of the planet. Using compositions of these fresh minerals, the researchers had previously concluded that these were the hottest lavas to ever erupt on Earth’s surface with temperatures near 1600 degrees centigrade, which is roughly 400 degrees hotter than modern eruptions in Hawaii.

“Discovering fresh unaltered olivine in these ancient lavas was a remarkable find. The field work was wonderfully productive and we were eager to return to the lab to use the chemistry of these preserved olivine crystals to reveal clues of the Archean Mantle,” said Kareem

The researchers suggest that maybe a chunk of early-Earth magma ocean is preserved in the approximately 3.2 billion year-old minerals.

“The modern Earth shows little or no evidence of this early magma ocean because convection of the mantle has largely homogenized the layering produced in the magma ocean. Oxygen isotopes in these fresh olivines support the existence of ancient chunks of the frozen magma ocean. Rocks like this are very rare and scientifically valuable. An obvious next step was to do oxygen isotopes,” said Byerly.

This study grew out of work taking place in LSU’s laboratory for the study of oxygen isotopes, a world-class facility that attracts scientists from the U.S. and international institutions for collaborative work. The results of the study were so unusual that it required extra care to be certain of the results. Huiming Bao, who is also the head of LSU’s oxygen isotopes lab, said that the team triple and quadruple checked the data by running with different reference minerals and by calibrating with other independent labs.

“We attempted to reconcile the findings with some of the conventional explanations for lavas with oxygen isotope compositions like these, but nothing could fully explain all of the observations. It became apparent that these rocks preserve signatures of processes that occurred over four billion years ago and that are still not completely understood,” said Benjamin Byerly.

Oxygen isotopes are measured by the conversion of rock or minerals into a gas and measuring the ratios of oxygen with the different masses of 16, 17, and 18. A variety of processes fractionate oxygen on Earth and in the Solar System, including atmospheric, hydrospheric, biological, and high temperature and pressure.

“Different planets in our solar system have different oxygen isotope ratios. On Earth this is modified by surface atmosphere and hydrosphere, so variations could be due either to heterogeneous mantle (original accumulation of planetary debris or remnants of magma ocean) or surface processes,” said Byerly. “Either might be interesting to study. The latter because it would also provide information about the early surface temperature of Earth and early origins of life.”

This work was supported by a National Science Foundation grant awarded to Byerly, a NASA grant awarded to Bao, and general support from LSU.

  1. Benjamin L. Byerly, Keena Kareem, Huiming Bao, Gary R. Byerly. Early Earth mantle heterogeneity revealed by light oxygen isotopes of Archaean komatiites. Nature Geoscience, 2017; 10 (11): 871 DOI: 10.1038/ngeo3054

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WFS News: Chicxulub asteroid impact cooled Earth’s climate more than previously thought

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The Chicxulub asteroid impact that wiped out the dinosaurs likely released far more climate-altering sulfur gas into the atmosphere than originally thought, according to new research.

A new study makes a more refined estimate of how much sulfur and carbon dioxide gas were ejected into Earth’s atmosphere from vaporized rocks immediately after the Chicxulub event. The study’s authors estimate more than three times as much sulfur may have entered the air compared to what previous models assumed, implying the ensuing period of cool weather may have been colder than previously thought.

The new study lends support to the hypothesis that the impact played a significant role in the Cretaceous-Paleogene extinction event that eradicated nearly three-quarters of Earth’s plant and animal species, according to Joanna Morgan, a geophysicist at Imperial College London in the United Kingdom and co-author of the new study published in Geophysical Research Letters, a journal of the American Geophysical Union.

“Many climate models can’t currently capture all of the consequences of the Chicxulub impact due to uncertainty in how much gas was initially released,” Morgan said. “We wanted to revisit this significant event and refine our collision model to better capture its immediate effects on the atmosphere.”

The Chicxulub Crater was created by an asteroid that struck the Earth about 66 million years ago

The Chicxulub Crater was created by an asteroid that struck the Earth about 66 million years ago

The new findings could ultimately help scientists better understand how Earth’s climate radically changed in the aftermath of the asteroid collision, according to Georg Feulner, a climate scientist at the Potsdam Institute for Climate Impact Research in Potsdam, Germany who was not involved with the new research. The research could help give new insights into how Earth’s climate and ecosystem can significantly change due to impact events, he said.

“The key finding of the study is that they get a larger amount of sulfur and a smaller amount of carbon dioxide ejected than in other studies,” he said. “These improved estimates have big implications for the climactic consequences of the impact, which could have been even more dramatic than what previous studies have found.”

A titanic collision

The Chicxulub impact occurred 66 million years ago when an asteroid approximately 12 kilometers (7 miles) wide slammed into Earth. The collision took place near what is now the Yucatán peninsula in the Gulf of Mexico. The asteroid is often cited as a potential cause of the Cretaceous-Paleogene extinction event, a mass extinction that erased up to 75 percent of all plant and animal species, including the dinosaurs.

The asteroid collision had global consequences because it threw massive amounts of dust, sulfur and carbon dioxide into the atmosphere. The dust and sulfur formed a cloud that reflected sunlight and dramatically reduced Earth’s temperature. Based on earlier estimates of the amount of sulfur and carbon dioxide released by the impact, a recent study published in Geophysical Research Letters showed Earth’s average surface air temperature may have dropped by as much as 26 degrees Celsius (47 degrees Fahrenheit) and that sub-freezing temperatures persisted for at least three years after the impact.

In the new research, the authors used a computer code that simulates the pressure of the shock waves created by the impact to estimate the amounts of gases released in different impact scenarios. They changed variables such as the angle of the impact and the composition of the vaporized rocks to reduce the uncertainty of their calculations.

The new results show the impact likely released approximately 325 gigatons of sulfur and 425 gigatons of carbon dioxide into the atmosphere, more than 10 times global human emissions of carbon dioxide in 2014. In contrast, the previous study in Geophysical Research Letters that modeled Earth’s climate after the collision had assumed 100 gigatons of sulfur and 1,400 gigatons of carbon dioxide were ejected as a result of the impact.

Improving the impact model

The new study’s methods stand out because they ensured only gases that were ejected upwards with a minimum velocity of 1 kilometer per second (2,200 miles per hour) were included in the calculations. Gases ejected at slower speeds didn’t reach a high enough altitude to stay in the atmosphere and influence the climate, according to Natalia Artemieva, a senior scientist at the Planetary Science Institute in Tucson, Arizona and co-author of the new study.

Older models of the impact didn’t have as much computing power and were forced to assume all the ejected gas entered the atmosphere, limiting their accuracy, Artemieva said.

The study authors also based their model on updated estimates of the impact’s angle. An older study assumed the asteroid hit the surface at an angle of 90 degrees, but newer research shows the asteroid hit at an angle of approximately 60 degrees. Using this revised angle of impact led to a larger amount of sulfur being ejected into the atmosphere, Morgan said.

The study’s authors did not model how much cooler Earth would have been as a result of their revised estimates of how much gas was ejected. Judging from the cooling seen in the previous study, which assumed a smaller amount of sulfur was released by the impact, the release of so much sulfur gas likely played a key role in the extinction event. The sulfur gas would have blocked out a significant amount of sunlight, likely leading to years of extremely cold weather potentially colder than the previous study found. The lack of sunlight and changes in ocean circulation would have devastated Earth’s plant life and marine biosphere, according to Feulner.

The release of carbon dioxide likely led to some long-term climate warming, but its influence was minor compared to the cooling effect of the sulfur cloud, Feulner said.

Along with gaining a better understand of the Chicxulub impact, researchers can also use the new study’s methods to estimate the amount of gas released during other large impacts in Earth’s history. For example, the authors calculated the Ries crater located in Bavaria, Germany was formed by an impact that ejected 1.3 gigatons of carbon dioxide into the atmosphere. This amount of gas likely had little effect on Earth’s climate, but the idea could be applied to help understand the climactic effects of larger impacts.

Natalia Artemieva, Joanna Morgan. Quantifying the Release of Climate-Active Gases by Large Meteorite Impacts With a Case Study of Chicxulub. Geophysical Research Letters, 2017; DOI: 10.1002/2017GL074879 

American Geophysical Union. “Dinosaur-killing asteroid impact cooled Earth’s climate more than previously thought.” ScienceDaily. ScienceDaily, 31 October 2017. <www.sciencedaily.com/releases/2017/10/171031111446.htm>.

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