Taken by the Himawari 8 satellite, this red-filter visible image of a volcanic eruption in Tonga was taken on 15 January 2022 at 04:50 (UTC) 5:50 PM (Tonga Local Time). This volcanic eruption produced a 3.9 foot (1.2 meter) tsunami which struck Nukuʻalofa, the capital of Tonga. The volcano also triggered tsunamis across the Pacific Ocean affecting countries and territories like Fiji, Samoa, Wallis and Futuna, Vanuatu, New Zealand, Australia, Japan, Russia, the United States, Canada, Mexico, Chile and Ecuador, and explosions and the shockwave from the eruption could be heard as far as Alaska and Canada. Also visible in this image is the remnants of Tropical Cyclone Cody to the southwest. Credit: Japan Meteorological Agency/NASA SPoRT. CC BY 4.0
The recent violent volcanic eruption on the Pacific island nation of Tonga is believed to be one of the strongest ever recorded, and future eruptions could be possible, according to a Texas A&M University geophysicist.
Andreas Kronenberg, professor and holder of the Michael T. Halbouty Chair in Geology at Texas A&M, said the eruption on Tonga likely ranks among the strongest in at least 30 years. The Polynesian country has about 170 islands, and is 500 miles east of Fiji.
The eruption caused a huge ash cloud to form on many of the islands, killed at least three people, and could be heard in New Zealand and seen from space.
“In general, the volcanoes around the Pacific Rim are much more powerful and explosive than Hawaiian-type volcanoes, mostly because of the volatile content and magma compositions in them,” Kronenberg said.
“This is why we are concerned about the volcanoes in the Oregon, Washington and Alaska regions,” Kronenberg said. “However, the Tonga subduction zone is a large one and the entire Southwest Pacific has what we call ‘stratovolcanoes.’ These are extremely powerful volcanoes and are also the kinds that include Mt. Vesuvius that covered Pompei in Italy and Mt. St. Helens, which exploded a few decades ago.”
Mt. St. Helens, which exploded in 1980, is considered the most powerful volcanic eruption in U.S. history and killed 57 people.
The largest eruption ever is believed to be the eruption of Krakatoa, which exploded near Indonesia in 1883 and killed more than 36,000 people.
Some have compared the Tonga eruption as similar to Krakatoa, and NASA has said the Tonga explosion was at least 500 times more powerful than the bomb dropped on Hiroshima in 1945.
“Krakatoa was truly epic, and Tonga was obviously devastating,” Kronenberg said. “And it appears that water entering into the volcano internally added to its explosiveness. The result can be tsunamis because they can be triggered by any disturbance of the seafloor that quickly moves large volumes of seawater, such as faults that suddenly change the shape of the seafloor.”
Could the Tonga explosion mean future eruptions in the area are possible?
“It is possible such an eruption could trigger nearby activity,” Kronenberg said. “But it is not necessarily guaranteed. This is a controversial topic when discussing earthquakes and subsequent eruptions, especially in areas over 10 to 15 miles from the original eruption.”
Researchers used thermochronometric data from four North American locations to determine the cause of the “Great Unconformity”—a massive loss of rock about 700 million years ago. Credit: Kalin McDannell
New research provides further evidence that rocks representing up to a billion years of geological time were carved away by ancient glaciers during the planet’s “Snowball Earth” period, according to a study published in Proceedings of the National Academy of Sciences.
The research presents the latest findings in a debate over what caused the Earth’s “Great Unconformity”—a time gap in the geological record associated with the erosion of rock up to 3 miles thick in areas across the globe.
“The fact that so many places are missing the sedimentary rocks from this time period has been one of the most puzzling features of the rock record,” said C. Brenhin Keller, an assistant professor of earth sciences and senior researcher on the study. “With these results, the pattern is starting to make a lot more sense.”
The massive amount of missing rock that has come to be known as the Great Unconformity was first named in the Grand Canyon in the late 1800s. The conspicuous geological feature is visible where rock layers from distant time periods are sandwiched together, and it is often identified where rocks with fossils sit directly above those that do not contain fossils.
“This was a fascinating time in Earth’s history,” said Kalin McDannell, a postdoctoral researcher at Dartmouth and the lead author of the paper. “The Great Unconformity sets the stage for the Cambrian explosion of life, which has always been puzzling since it is so abrupt in the fossil record—geological and evolutionary processes are usually gradual.”
For over a century, researchers have sought to explain the cause of the missing geological time.
In the last five years, two opposing theories have come into focus: One explains that the rock was carved away by ancient glaciers during the Snowball Earth period about 700 to 635 million years ago. The other focuses on a series of plate tectonic events over a much longer period during the assembly and breakup of the supercontinent Rodinia from about 1 billion to 550 million years ago.
Research led by Keller in 2019 first proposed that widespread erosion by continental ice sheets during the Cryogenian glacial interval caused the loss of rock. This was based on geochemical proxies that suggested that large amounts of mass erosion matched with the Snowball Earth period.
“The new research verifies and advances the findings in the earlier study,” said Keller. “Here we are providing independent evidence of rock cooling and miles of exhumation in the Cryogenian period across a large area of North America.”
The study relies on a detailed interpretation of thermochronology to make the assessment.
Thermochronology allows researchers to estimate the temperature that mineral crystals experience over time as well as their position in the continental crust given a particular thermal structure. Those histories can provide evidence of when missing rock was removed and when rocks currently exposed at the surface may have been exhumed.
The researchers used multiple measurements from previously published thermochronometric data taken across four North American locations. The areas, known as cratons, are parts of the continent that are chemically and physically stable, and where plate tectonic activity would not have been common during that time.
By running simulations that searched for the time-temperature path the rocks experienced, the research recorded a widespread signal of rapid, high magnitude cooling that is consistent with about 2-3 miles of erosion during Snowball Earth glaciations across the interior of North America.
“While other studies have used thermochronology to question the glacial origin, a global phenomenon like the Great Unconformity requires a global assessment,” said McDannell. “Glaciation is the simplest explanation for erosion across a vast area during the Snowball Earth period since ice sheets were believed to cover most of North America at that time and can be efficient excavators of rock.”
According to the research team, the competing theory that tectonic activity carved out the missing rock was put forth in 2020 when a separate research group questioned whether ancient glaciers were erosive enough to cause the massive loss of rock. While that research also used thermochronology, it applied an alternate technique at only a single tectonically active location and suggested that the erosion occurred prior to Snowball Earth.
“The underlying concept is pretty simple: Something removed a whole lot of rock, resulting in a whole lot of missing time,” said Keller. “Our research demonstrates that only glacial erosion could be responsible at this scale.”
According to the researchers, the new findings also help explain links between the erosion of rock and the emergence of complex organisms about 530 million years ago during the Cambrian explosion. It is believed that erosion during the Snowball Earth period deposited nutrient-rich sediment in the ocean that could have provided a fertile environment for the building blocks of complex life.
The study notes that the two hypotheses of how the rock eroded are not mutually exclusive—it is possible that both tectonics and glaciation contributed to global Earth system disruption during the formation of the Great Unconformity. It appears, however, that only glaciation can explain erosion in the center of the continent, far from the tectonic margins.
“Ultimately with respect to the Great Unconformity, it may be that the generally accepted reconstruction(s) of more concentrated equatorial packing of the Rodinian continents along with the unique environmental conditions of the Neoproterozoic, proved to be a time of geologic serendipity unlike most any other in Earth history,” the research paper says.
According to the team, this is the first research that uses their thermochronology modeling approach to study a period that extends well beyond a billion years. In the future, the team will repeat their work on other continents, where they hope to further test these hypotheses about how the Great Unconformity was created and preserved.
According to the team, resolving differences in the research is critical to understanding early Earth history and the interconnection of climatic, tectonic and biogeochemical processes.
“The fact that there may have been tectonic erosion along the craton margins does not rule out glaciation,” said McDannell. “Unconformities are composite features, and our work suggests Cryogenian erosion was a key contributor, but it is possible that both earlier and later erosion were involved in forming the unconformity surface in different places. A global examination will tell us more.”
William Guenthner, from the University of Illinois at Urbana-Champaign; Peter Zeitler from Lehigh University; and David Shuster from the University of California, Berkeley and the Berkeley Geochronology Center served as co-authors of the paper.
Paleontologist Dean Lomax with the fossilized ichthyosaur. (Matthew Power Photography/Anglian Water)
A gigantic prehistoric “sea dragon” discovered in the Midlands has been described as one of the greatest finds in the history of British palaeontology.
The fossil, identified as an ichthyosaur, an ancient marine reptile that swam in Earth’s prehistoric oceans when dinosaurs walked on land, was found poking out of the mud, and scientists say the ancient specimen is practically complete from tip to tail.
The ichthyosaur, which is about 180m years old with a skeleton measuring about 10 metres in length and a skull weighing about a tonne, is the largest and most complete fossil of its kind ever found in the UK. Joe Davis of the Leicestershire and Rutland Wildlife Trust discovered it during the routine draining of a lagoon island at the Rutland Water reservoir in February 2021.
The first ichthyosaurs, which are called sea dragons because they tend to have very large teeth and eyes, were discovered by the fossil hunter and palaeontologist Mary Anning in the early 19th century.
Ichthyosaurs, which were marine reptiles, first appeared about 250m years ago and went extinct 90m years ago. They varied in size from 1 to more than 25 metres in length and resembled dolphins in their general body shape.
The remains were dug out by a team of experts from around the UK in August and September.
“Our specimen, the Rutland Ichthyosaur or the Rutland Sea Dragon, is the biggest complete ichthyosaur ever found in Britain in over 200 years of collecting these things scientifically,” says paleontologist Dean Lomax who led the excavation.
Two incomplete and much smaller ichthyosaurs were found during the construction of Rutland Water in the 1970s, but the latest discovery is the first complete skeleton.
The spectacular specimen, only recently revealed to the public, is still wrapped in its plaster cast, stored in a secret location, and has not yet been studied in detail. The researchers plan to prepare academic papers describing the discovery once it has been cleaned up and conserved.
Natural History Museum of Los Angeles County (NHM) Dinosaur Institute volunteer Viji Shook lying next to the skull of Cymbospondylus youngorum for scale, during the preparation of the specimen. Photo by Martin Sander, courtesy of the Natural History Museum of Los Angeles County (NHM).
The two-meter skull of a newly discovered species of giant ichthyosaur, the earliest known, is shedding new light on the marine reptiles’ rapid growth into behemoths of the Dinosaurian oceans, and helping us better understand the journey of modern cetaceans (whales and dolphins) to becoming the largest animals to ever inhabit the Earth.
While dinosaurs ruled the land, ichthyosaurs and other aquatic reptiles (that were emphatically not dinosaurs) ruled the waves, reaching similarly gargantuan sizes and species diversity. Evolving fins and hydrodynamic body-shapes seen in both fish and whales, ichthyosaurs swam the ancient oceans for nearly the entirety of the Age of Dinosaurs.
“Ichthyosaurs derive from an as yet unknown group of land-living reptiles and were air-breathing themselves,” says lead author Dr. Martin Sander, paleontologist at the University of Bonn and Research Associate with the Dinosaur Institute at the Natural History Museum of Los Angeles County (NHM). “From the first skeleton discoveries in southern England and Germany over 250 years ago, these ‘fish-saurians’ were among the first large fossil reptiles known to science, long before the dinosaurs, and they have captured the popular imagination ever since.”
Excavated from a rock unit called the Fossil Hill Member in the Augusta Mountains of Nevada, the well-preserved skull, along with part of the backbone, shoulder, and forefin, date back to the Middle Triassic (247.2-237 million years ago), representing the earliest case of an ichthyosaur reaching epic proportions. As big as a large sperm whale at more than 17 meters (55.78 feet) long, the newly named Cymbospondylus youngorum is the largest animal yet discovered from that time period, on land or in the sea. In fact, it was the first giant creature to ever inhabit the Earth that we know of.
“The importance of the find was not immediately apparent,” notes Dr. Sander, “because only a few vertebrae were exposed on the side of the canyon. However, the anatomy of the vertebrae suggested that the front end of the animal might still be hidden in the rocks. Then, one cold September day in 2011, the crew needed a warm-up and tested this suggestion by excavation, finding the skull, forelimbs, and chest region.”
The new name for the species, C. youngorum, honors a happy coincidence, the sponsoring of the fieldwork by Great Basin Brewery of Reno, owned and operated by Tom and Bonda Young, the inventors of the locally famous Icky beer which features an ichthyosaur on its label.
In other mountain ranges of Nevada, paleontologists have been recovering fossils from the Fossil Hill Member’s limestone, shale, and siltstone since 1902, opening a window into the Triassic. The mountains connect our present to ancient oceans and have produced many species of ammonites, shelled ancestors of modern cephalopods like cuttlefish and octopuses, as well as marine reptiles. All these animal specimens are collectively known as the Fossil Hill Fauna, representing many of C. youngorum’s prey and competitors.
C. youngorum stalked the oceans some 246 million years ago, or only about three million years after the first ichthyosaurs got their fins wet, an amazingly short time to get this big. The elongated snout and conical teeth suggest that C. youngorum preyed on squid and fish, but its size meant that it could have hunted smaller and juvenile marine reptiles as well.
The giant predator probably had some hefty competition. Through sophisticated computational modeling, the authors examined the likely energy running through the Fossil Hill Fauna’s food web, recreating the ancient environment through data, finding that marine food webs were able to support a few more colossal meat-eating ichthyosaurs. Ichthyosaurs of different sizes and survival strategies proliferated, comparable to modern cetaceans’ — from relatively small dolphins to massive filter-feeding baleen whales, and giant squid-hunting sperm whales.
Co-author and ecological modeler Dr. Eva Maria Griebeler from the University of Mainz in Germany notes, “due to their large size and resulting energy demands, the densities of the largest ichthyosaurs from the Fossil Hill Fauna including C. youngourum must have been substantially lower than suggested by our field census. The ecological functioning of this food web from ecological modeling was very exciting as modern highly productive primary producers were absent in Mesozoic food webs and were an important driver in the size evolution of whales.”
Whales and ichthyosaurs share more than a size range. They have similar body plans, and both initially arose after mass extinctions. These similarities make them scientifically valuable for comparative study. The authors combined computer modeling and traditional paleontology to study how these marine animals reached record-setting sizes independently.
“One rather unique aspect of this project is the integrative nature of our approach. We first had to describe the anatomy of the giant skull in detail and determine how this animal is related to other ichthyosaurs,” says senior author Dr. Lars Schmitz, Associate Professor of Biology at Scripps College and Dinosaur Institute Research Associate. “We did not stop there, as we wanted to understand the significance of the new discovery in the context of the large-scale evolutionary pattern of ichthyosaur and whale body sizes, and how the fossil ecosystem of the Fossil Hill Fauna may have functioned. Both the evolutionary and ecological analyses required a substantial amount of computation, ultimately leading to a confluence of modeling with traditional paleontology.”
They found that while both cetaceans and ichthyosaurs evolved very large body sizes, their respective evolutionary trajectories toward gigantism were different. Ichthyosaurs had an initial boom in size, becoming giants early on in their evolutionary history, while whales took much longer to reach the outer limits of huge. They found a connection between large size and raptorial hunting — think of a sperm whale diving down to hunt giant squid — and a connection between large size and a loss of teeth — think of the giant filter-feeding whales that are the largest animals ever to live on Earth.
Ichthyosaurs’ initial foray into gigantism was likely thanks to the boom in ammonites and jawless eel-like conodonts filling the ecological void following the end-Permian mass extinction. While their evolutionary routes were different, both whales and ichthyosaurs relied on exploiting niches in the food chain to make it really big.
“As researchers, we often talk about similarities between ichthyosaurs and cetaceans, but rarely dive into the details. That’s one way this study stands out, as it allowed us to explore and gain some additional insight into body size evolution within these groups of marine tetrapods,” says NHM’s Associate Curator of Mammalogy (Marine Mammals), Dr. Jorge Velez-Juarbe. “Another interesting aspect is that Cymbospondylus youngorum and the rest of the Fossil Hill Fauna are a testament to the resilience of life in the oceans after the worst mass extinction in Earth’s history. You can say this is the first big splash for tetrapods in the oceans.”
C. youngorum will be permanently housed at the Natural History Museum of Los Angeles County, where it is currently on view.
Reference:
P. Martin Sander, Eva Maria Griebeler, Nicole Klein, Jorge Velez Juarbe, Tanja Wintrich, Liam J. Revell, Lars Schmitz. Early giant reveals faster evolution of large body size in ichthyosaurs than in cetaceans. Science, 2021; 374 (6575) DOI: 10.1126/science.abf5787
Turning one of the world’s finest gems—diamonds—into one of the worst greenhouse gasses—methane—does not seem a great idea. Yet this happened through the work of a group of researchers from the Universities of Bologna and Edimburgh (UK), the Centre National de la Recherche Scientifique (France) and HPSTAR (China). This outcome published in Nature Communications was not a clumsy lab mistake. In fact, this study might provide more insight on the deep carbon cycle and the formation of hydrocarbons through abiotic processes (i.e. unrelated to biological activities) in the deep Earth.
The deep earth’s carbon cycle accounts for about 90% of the whole carbon cycle. Despite this, to date the cycle happening beneath the earth’s surface is little known. This phenomenon is crucial to life on our planet as it allows carbon in the deep Earth to get back to the atmosphere.
“It is well known that the decomposition of methane may bring to diamond formation. What was less known until now is that the opposite process is also possible. Methane produced through the reaction between diamonds and hydrogen was the missing piece to a wider understanding of the deep carbon cycle”, explains Alberto Vitale Brovarone who is a professor a the Department of Biological, Geological and Environmental study at the University of Bologna and also one of the authors of the study.
The deep carbon cycle also includes the formation of hydrocarbons such as methane as the result of processes that do not involve biological activities. This theory has been under discussion for over a century. Wanting to test this theory, researchers started from diamonds that are essentially gems in the Earth’s mantle composed of solid carbon atoms in a crystal structure.
Scholars used a “diamond anvil cell” which is a high-pressure experimental apparatus used to press two diamond culets against each other and replicate the pressure conditions of the earth’s upper mantle, over 70 km deep. Then, by pushing one atmosphere of pure hydrogen at 300 °C, researchers observed methane rapidly forming with its molecules composed of one atom of carbon and four of hydrogen (CH4).
“We created an environment comparable to that of the outer layer of earth’s mantle in terms of temperature and pressure and observed that diamond and hydrogen reacted readily by producing methane within a few seconds”, states Vitale Bovarone. “This shows that hydrocarbons such as methane can form at abiotic depths. This phenomenon may play a key role in the deep Earth’s carbon cycle”.
Researchers replicated this experiment by adding graphite, which is composed of pure carbon too, and a glass-like carbon material. In both cases, they observed methane forming more rapidly and more copiously in comparison to when they used only diamonds. These results suggest that carbon-based graphitic materials may be very efficient reagents and can therefore act as sources of energy feeding methane reserves in the the earth’s upper mantle.
Reference:
Miriam Peña-Alvarez et al, In-situ abiogenic methane synthesis from diamond and graphite under geologically relevant conditions, Nature Communications (2021). DOI: 10.1038/s41467-021-26664-3
Igánâq, Greenland: view to the southwest from the Igánâq summit (~540m) towards Tunulliarfik and the snowy peaks of Ilímaussaq. Credit: University of St Andrews
A new understanding of how volcanic processes form deposits of rare earth metals, vital to everyday modern technology, is revealed in a new study from the University of St Andrews.
The research, led by a team from the School of Earth and Environmental Sciences at St Andrews and published in the journal Geology (Friday 3 December), provides new clues about how hot volcanic fluids concentrate rare earth metals and how these metals seep out from the magma body.
These rare metals, which include elements such as niobium and tantalum, are essential for the production of alloys, batteries, magnets and superconductors, and are vital for modern technologies ranging from mobile phones and laptops to MRI machines. These metals are also essential for green technologies and, crucially, the transition to a low-carbon economy must involve finding new sources of the rare earth metals.
Rare earth deposits are associated with extinct alkaline volcanoes. These volcanoes are unusual and only exposed in select regions around the world, such as south Greenland.
The team of researchers from the University of St Andrews wanted to understand why some volcanoes produce massive metals deposits, whilst others are devoid of mineralisation. By studying a metal-poor volcano in Greenland the researchers were able to show that fluids leaking from the magma body into the surrounding rocks can carry significant quantities of rare earth metals. Rather than concentrating metals, these fluids scatter them over a large area and significantly decrease the chances of forming an economically viable deposit.
Lead researcher Krzysztof Sokół from the School of Earth and Environmental Sciences said: “By measuring the chemical composition of the rocks around the chamber we showed that metals had been carried out of the magma chamber and into the surrounding rocks. This is the first time that the mass of material transported by this process was estimated. We also present a new way to visualize the distribution of metals in the surrounding rock.
“We show that during an episode of volcanic activity, the melts residing at shallow levels of the Earth’s crust can form a separate hot fluid enriched in critical metals, which subsequently leaks from the magma chamber into the surrounding rocks carrying a globally significant volume of the metals.”
The research team estimates that the total tonnage of the critical metals transported to the surrounding rocks by this processes is about 40 megatonnes, which is comparable to the mass of rare earth metals present in some of the world’s largest metal deposits.
Professor Adrian Finch and Dr. Will Hutchison, also from the School of Earth and Environmental Sciences at St Andrews, added: “We show that fluids can ‘leak’ from magma systems that would otherwise have crystallized to form large critical metal deposits within the chamber confines. Now that we understand this process more fully, we can predict more effectively how the deposits under these types of volcanoes formed. Armed with this information, we can guide far better exploration for the next generation of green technologies.”
Reference:
Krzysztof Sokół et al, Quantifying metasomatic high-field-strength and rare-earth element transport from alkaline magmas, Geology (2021). DOI: 10.1130/G49471.1
Vectiraptor greeni, a new fierce predatory dinosaur from the Isle of Wight. Image credit: Megan Jacobs
A new bird-like dinosaur that used brute strength to overcome its prey has been found by paleontologists combing through fossils found on the Isle of Wight, on the South Coast of Great Britain.
The new animal has been named Vectiraptor greeni after local collector Mick Green who discovered its bones after they became washed from the rocks on the island’s south coast. It was an older, more heavily built, relative of the predator Velociraptor. The fearsome animal was about the size of a wolf, about 3 metres (10 feet) long, from nose to tail, and would have used huge slashing talons on its feet to dispatch its prey. Its finely serrated teeth were then used to bite off pieces of the kill.
The dinosaur would have prowled through the forests that covered the land in the Early Cretaceous, 125 million years ago. It died and lay buried until 2004, when storms and waves eroded away the rocks that had kept its bones hidden. Yet another 20 years passed before scientists from the Universities of Bath and Portsmouth studied the fossils and made the surprising find that the bones represented a new species. Their discovery is described this week in the journal Cretaceous Research.
Vectiraptor belonged to a group of dinosaurs called dromaeosaurs, or raptors. These bird-like dinosaurs were specialist hunters and, like their modern-day avian relatives, were covered in long feathers. Their jaws were full of blade-like, serrated teeth and they had huge scythe-shaped claws on their feet, used to slash at their prey, causing it to rapidly bleed to death.
Well-known members of the raptors include Velociraptor from Mongolia, and Deinonychus, and the giant Utahraptor from the United States. A smaller raptor has previously been described from the Isle of Wight but Vectiraptor marks the first time a large raptor has been found in England. Although only fragments of the skeleton have survived- a pair of vertebrae from the back, and part of the hips — what is known suggests a large, powerfully built animal.
“This was a large, and very heavily constructed animal,” said Dr Nick Longrich, who led the study from the Milner Centre for Evolution at the University of Bath. “The bones are thick-walled and massive. It clearly didn’t hunt small prey, but animals as large or larger than itself.”
Although not the biggest predator in its environment — top predators included the allosaur Neovenator, spinosaurs like Baryonyx, and an early tyrannosaur called Eotyrannus — Vectiraptor would have been a threat both to smaller dinosaurs and juveniles of large dinosaurs. With strong arms and talons, it may have climbed trees like modern leopards. The heavy bones suggest an animal that relied less on speed and more on strength, and perhaps ambushes, to tackle its prey.
“It’s a tantalising hint at the diversity of dinosaurs in England at this time,” said Dr Longrich.
This is the first time a large raptor has been found in the UK. “There’s an extraordinary diversity of dinosaurs known in England in the Cretaceous, and even after more than a century of study, we continue to find new species,” said Dr Longrich. “Although palaeontologists have been studying these dinosaurs for a long time, it’s hard going. We have to wait for the sea cliffs to fall and expose bits of bone, or for the waves to wash them out of the rocks. We’ve spent two centuries on the Isle of Wight piecing together our picture of English dinosaurs.”
Co-author Professor Dave Martill of the University of Portsmouth notes that raptors closely related to Velociraptor have also been found in Mongolia, suggesting that England may have lain along an important dispersal route for dinosaurs. Professor Martill said, given the similarity between North American and Mongolian dinosaur faunas in the Early Cretaceous, it was only a matter of time before someone discovered a raptor dinosaur in England.
A remarkable number of dinosaur species originate from this small island off southern England. Ancient England was something of a crossroads for dinosaurs. At the time the continents were closer together, with some connected by land bridges. Dinosaurs likely wandered in from North America and Asia, or perhaps swam from Africa. Europe was a sort of crossroads linking the continents.
A chance encounter
Vectiraptor greeni was named after amateur paleontologist Mick Green, who discovered the remains in in 2004 but didn’t appreciate the importance of his find until he was forced by ill-health to stop collecting fossils in 2012. He then turned his attention to prising the dinosaur bones free from the hard ironstone surrounding them.
One day, chatting over a beer, he showed the fossils to Isle of Wight palaeontologist Megan Jacobs and Dr Longrich who puzzled over them, and at first struggled to make sense of them, until they noticed tell-tale similarities to other raptors. Mr Green allowed the bones to be studied, and they turned out to represent a new genus and species. The bones have now been donated to the Dinosaur Isle Museum at Sandown on the Isle of Wight.
“This dinosaur is incredibly exciting, adding to the huge diversity of dinosaurs here on the Isle of Wight, and helping to build a bigger picture of the Early Cretaceous world,” said Megan Jacobs, a collaborator on the project. “This little dinosaur also serves as an excellent example of the importance of amateur fossil collectors, and how working with them can produce important scientific research, which would otherwise not be possible.”
Without the dedication of Mick Green and others on the island, she noted, this dinosaur would have been lost to the sea.
Reference:
Nicholas R. Longrich, David M. Martill, Megan L. Jacobs. A new dromaeosaurid dinosaur from the Wessex Formation (Lower Cretaceous, Barremian) of the Isle of Wight, and implications for European palaeobiogeography. Cretaceous Research, 2021; 105123 DOI: 10.1016/j.cretres.2021.105123
Original artwork from scientific illustrator Emiliano Troco depicting a Brontosaurus (likely the most famous sauropod dinosaur) acting as an ecosystem engineer in a warm and vegetated landscape not dissimilar to modern-day savannah type biomes.
Giant, long-necked sauropods, thought to include the largest land animals ever to have existed, preferred to live in warmer, more tropical regions on Earth, suggesting they may have had a different physiology from other dinosaurs, according to a new study led by researchers at UCL and the University of Vigo.
The study, published in the journal Current Biology, investigated the enigma of why sauropod fossils are only found at lower latitudes, while fossils of other main dinosaur types seem ubiquitously present, with many located in the polar regions.
The researchers analysed the fossil record across the Mesozoic era (the time of the dinosaurs), lasting from around 230 to 66 million years ago, looking at occurrences of fossils of the three main dinosaur types: sauropods, which include the Brontosaurus and the Diplodocus, theropods (“lizard-hipped”), which include velociraptors and Tyrannosaurus rex, and ornithischians (“bird-hipped”) such as the Triceratops.
Combining this fossil data with data about climate throughout the period, along with information about how continents have moved across the globe, the researchers concluded that sauropods were restricted to warmer, drier habitats than other dinosaurs. These habitats were likely to be open, semi-arid landscapes, similar to today’s savannahs.
Co-author Dr Philip Mannion (UCL Earth Sciences) said: “Our research shows that some parts of the planet always seemed to be too cold for sauropods. They seem to have avoided any temperatures approaching freezing. Other dinosaur types, in contrast, could thrive in Earth’s polar regions, from innermost Antarctica to polar Alaska — which, due to the warmer climate, were ice-free, with lush vegetation.
“This suggests sauropods had different thermal requirements from other dinosaurs, relying more on their external environment to heat their bodies — slightly closer to being ‘cold-blooded’, like modern-day reptiles. Their grand size hints that this physiology may have been unique.”
First author Dr Alfio Alessandro Chiarenza, formerly of UCL who is now based at the University of Vigo, Spain, said: “It may be that sauropods were physiologically incapable of thriving in colder regions, or that they thrived less well in these areas than their dinosaurian cousins and were outcompeted.
“A mix of features may have helped sauropods shed heat more easily than mammals do today. Their long necks and tails would have given them a larger surface area, and they may have had a respiratory system more akin to birds, which is much more efficient.
“Some species of theropods and ornithischians are known to have had feathers or downy fur helping them retain body warmth. This suggests they may have generated their own body heat. For sauropods, however, there is no evidence of this kind of insulation.
“Sauropods’ strategies for keeping their eggs warm may also have differed from the other dinosaurs. Theropods probably warmed eggs by sitting on them, whereas ornithischians seem to have used heat generated by decaying plants. Sauropods, meanwhile, may have buried their eggs, relying on heat from the sun and the ground.”
In their paper, the researchers noted that the fossil record showed zero occurrences of sauropods above a latitude of 50 degrees north — an area encompassing most of Canada, Russia, northern Europe and the UK — or below 65 degrees south, encompassing Antarctica. In contrast, there are rich records for theropods and ornithischians living above 50 degrees north in later periods (from 145 million years ago).
To test if this was a true reflection of where sauropods lived, researchers used a statistical technique to adjust for gaps in the fossil record, and also analysed where the highest diversities of dinosaur types were in different periods throughout the Mesozoic era.
They combined fossil data with climate data, allowing an estimate of the temperature ranges of the dinosaur types’ habitats, finding that sauropods’ range across the latitudes was more restricted during colder periods.
They then used habitat modelling to infer which regions of the globe would likely be suitable for sauropods and the other dinosaur types to live.
While in the past it was believed that dinosaurs were ectothermic (“cold-blooded”), like reptiles today, relying on the external environment to heat their bodies, it is now thought they were closer to “warm-blooded” mammals, generating some of their own body heat (endothermic).
The study authors said sauropods may have had a unique in-between physiology, closer to being cold-blooded than other dinosaur types.
The study involved researchers from UCL, the University of Vigo, the University of Bristol, and the Natural Museum of Natural History, Smithsonian Institution, Washington, USA, and received funding from the European Research Council and the Royal Society.
Reference:
Alfio Alessandro Chiarenza, Philip D. Mannion, Alex Farnsworth, Matthew T. Carrano, Sara Varela. Climatic constraints on the biogeographic history of Mesozoic dinosaurs. Current Biology, 2021; DOI: 10.1016/j.cub.2021.11.061
The aftermath of a 2010 tsunami in Chile, which was analyzed in a new study in JGR Solid Earth. Earlier warnings made possible by the study of tsunami-generated magnetic fields could better prepare coastal areas for impending disasters. Credit: International Federation of Red Cross and Red Crescent Societies
A new study finds the magnetic field generated by a tsunami can be detected a few minutes earlier than changes in sea level and could improve warnings of these giant waves.
Tsunamis generate magnetic fields as they move conductive seawater through the Earth’s magnetic field. Researchers previously predicted that the tsunami’s magnetic field would arrive before a change in sea level, but they lacked simultaneous measurements of magnetics and sea level that are necessary to demonstrate the phenomenon.
The new study provides real-world evidence for using tsunamis’ magnetic fields to predict the height of tsunami waves using data from two real events — a 2009 tsunami in Samoa and a 2010 tsunami in Chile — that have both sets of necessary data. The new study was published in AGU’s Journal of Geophysical Research: Solid Earth, which focuses on the physics and chemistry of the solid Earth.
The study confirms the magnetic field generated by a tsunami arrives ahead of sea-level change and that its magnitude can be used to estimate the tsunami’s wave height. How much earlier the magnetic field arrives depends on water depth, but in their results, the study authors found the early arrival time to be about one minute prior to sea level change over a 4,800-meter deep sea.
This information could provide earlier disaster warning if incorporated into tsunami risk models, potentially saving lives.
“It is very exciting because in previous studies we didn’t have the observation [of] sea level change,” said Zhiheng Lin, senior study-author and a geophysicist at Kyoto University. “We have observations [of] sea level change, and we find that the observation agrees with our magnetic data as well as theoretical simulation.”
The research team looked at simultaneous measurements of sea level change from seafloor pressure data and magnetic fields during the two tsunamis. They found that the primary arrival of the magnetic field, similar to that of the beginning of a seismic wave, can be used for the purpose of early tsunami warning. The tsunami-generated magnetic field is so sensitive that even a wave height of a few centimeters can be detected.
“They did something that basically needed to be done,” said Neesha Schnepf, a researcher of geomagnetics at the University of Colorado, Boulder who was not involved in the study. “We’ve needed a study that compared the magnetic field data with the sea level change from the pressure data, and I’m pretty sure they’re the first to really compare how well the sea level from magnetic field matches the sea level from pressure, so that’s definitely very useful.”
When the researchers compared the horizontal and vertical components of the tsunami magnetic field with sea level change, they found that both components can precisely predict tsunami sea level change, if models include good estimates for ocean depth and the electrical structure below the seafloor.
This relationship between magnetic fields and wave height can be used to improve tsunami source models, which estimate the initial sea surface topography of a tsunami and then predict water wave arrival time and wave height — important data for informing disaster readiness and response.
The difficulty of maintaining already limited observational stations means these types of data from tsunamis are often not available. Furthermore, these findings only apply in deep-sea and not coastal environments, where deep water in the region filters out environmental noise to allow the tsunami signal to be detected.
However, providing warning for these severe events — which have the potential to cause intense damage to large areas — makes the predictions worthwhile, said Lin.
“I think the practical goal would be if your ability to model tsunamis is so improved, … you could come up with much better predictions of what areas might need to be warned [and] how badly it might hit certain places,” Schnepf said.
Reference:
Zhiheng Lin, Hiroaki Toh, Takuto Minami. Direct Comparison of the Tsunami‐Generated Magnetic Field With Sea Level Change for the 2009 Samoa and 2010 Chile Tsunamis. Journal of Geophysical Research: Solid Earth, 2021; 126 (11) DOI: 10.1029/2021JB022760
On September 29, 2009, a tsunami caused substantial damage and loss of life in American Samoa, Samoa, and Tonga. The tsunami was generated by a large earthquake in the Southern Pacific Ocean. Credit: NOAA
Earthquakes of similar magnitude can cause tsunamis of greatly varying sizes. This commonly observed, but not well-understood phenomenon has hindered reliable warnings of local tsunamis.
Research led by University of Hawai’i (UH) at Manoa scientists provides new insight that connects the characteristics of earthquakes — magnitude, depth where two tectonic plates slip past each other and the rigidity of the plates involved — with the potential size of a resulting tsunami.
Previous researchers identified a special class of events known as tsunami earthquakes, which produce disproportionately large tsunamis for their magnitude. Kwok Fai Cheung, professor of Ocean and Resources Engineering in the UH Manoa School of Ocean and Earth Science and Technology (SOEST), Thorne Lay from the University of California — Santa Cruz and co-authors discovered a straightforward explanation for this conundrum. Their findings were published recently in Nature Geoscience.
Using computer models, the team incorporated physical processes that produce earthquakes and tsunamis with a wide range of observations of real-world events, including those classified as tsunami earthquakes. The model results demonstrated that for a given earthquake magnitude, if the rupture extends to shallow depth in the less rigid part of the plate, the resulting tsunami is larger than if the rupture is deeper.
“In a subduction zone, the upper plate is thinner and less rigid than the underthrusting plate near the trench,” explained Cheung. “A concentrated near-trench or shallow rupture produces relatively weak ground shaking as recorded by seismometers, but the displaced water in the overlying deep ocean has enhanced energy and produces shorter tsunami waves that amplify at a high rate as they move toward the shore.”
“Earthquake and tsunamigenic processes are complex, involving many factors that vary from one event to another,” said Lay, professor of Earth and Planetary Sciences at UC Santa Cruz. “We utilized a simplified numerical model to isolate key earthquake parameters and evaluate their importance in defining tsunami size.”
Having verified that the presence of shallow earthquake rupture can be a more significant factor than the earthquake magnitude for the resulting tsunami size led the researchers to an important question: Can earthquake magnitude continue to be used as the primary indication of potential tsunami impacts?
“The practice of using earthquake magnitude to estimate potential tsunami threat has led to poor predictive capability for tsunami impacts, and more information about the source is required to do better,” said Cheung.
An important aspect of this interdisciplinary research is the synergy of expertise in seismology, with Lay, and tsunamis, with Cheung’s research group, applied to a large set of observations. This study motivates development of new seismological and seafloor geodesy research that can rapidly detect occurrence of shallow rupture in order to achieve more reliable tsunami warning.
While shorelines throughout the Pacific Ocean and along the “Ring of Fire” are vulnerable to tsunamis, the situation is most critical for coastal communities near the earthquake, where the tsunami arrives quickly — when detailed information about the earthquake is not yet available.
Cheung and Lay continue their collaboration to investigate prehistorical, historical, and future tsunami events to better understand the hazards posed to coastal communities and enable more accurate warning systems.
Reference:
Kwok Fai Cheung, Thorne Lay, Lin Sun, Yoshiki Yamazaki. Tsunami size variability with rupture depth. Nature Geoscience, 2021; DOI: 10.1038/s41561-021-00869-z
Stick-slip events in the earth cause damage like this, but limited data from these relatively rare earthquakes makes them difficult to model with machine learning. Transfer learning may provide a path to understanding when such deep faults slip. Credit: Dreamstime
A machine-learning approach developed for sparse data reliably predicts fault slip in laboratory earthquakes and could be key to predicting fault slip and potentially earthquakes in the field. The research by a Los Alamos National Laboratory team builds on their previous success using data-driven approaches that worked for slow-slip events in earth but came up short on large-scale stick-slip faults that generate relatively little data — but big quakes.
“The very long timescale between major earthquakes limits the data sets, since major faults may slip only once in 50 to 100 years or longer, meaning seismologists have had little opportunity to collect the vast amounts of observational data needed for machine learning,” said Paul Johnson, a geophysicist at Los Alamos and a co-author on a new paper, “Predicting Fault Slip via Transfer Learning,” in Nature Communications.
To compensate for limited data, Johnson said, the team trained a convolutional neural network on the output of numerical simulations of laboratory quakes as well as on a small set of data from lab experiments. Then they were able to predict fault slips in the remaining unseen lab data.
This research was the first application of transfer learning to numerical simulations for predicting fault slip in lab experiments, Johnson said, and no one has applied it to earth observations.
With transfer learning, researchers can generalize from one model to another as a way of overcoming data sparsity. The approach allowed the Laboratory team to build on their earlier data-driven machine learning experiments successfully predicting slip in laboratory quakes and apply it to sparse data from the simulations. Specifically, in this case, transfer learning refers to training the neural network on one type of data — simulation output — and applying it to another — experimental data — with the additional step of training on a small subset of experimental data, as well.
“Our aha moment came when I realized we can take this approach to earth,” Johnson said. “We can simulate a seismogenic fault in earth, then incorporate data from the actual fault during a portion of the slip cycle through the same kind of cross training.” The aim would be to predict fault movement in a seismogenic fault such as the San Andreas, where data is limited by infrequent earthquakes.
The team first ran numerical simulations of the lab quakes. These simulations involve building a mathematical grid and plugging in values to simulate fault behavior, which are sometimes just good guesses.
For this paper, the convolutional neural network comprised an encoder that boils down the output of the simulation to its key features, which are encoded in the model’s hidden, or latent space, between the encoder and decoder. Those features are the essence of the input data that can predict fault-slip behavior.
The neural network decoded the simplified features to estimate the friction on the fault at any given time. In a further refinement of this method, the model’s latent space was additionally trained on a small slice of experimental data. Armed with this “cross-training,” the neural network predicted fault-slip events accurately when fed unseen data from a different experiment.
Reference:
Kun Wang, Christopher W. Johnson, Kane C. Bennett, Paul A. Johnson. Predicting fault slip via transfer learning. Nature Communications, 2021; 12 (1) DOI: 10.1038/s41467-021-27553-5
The asteroid belt between Jupiter and Mars is the main source of extraterrestrial material that lands on Earth. (Illustration: ESA/ATG Medialab)
A new University of Liverpool study has found that the minerology of the rocks that a meteorite hits, rather than the size of the impact, determines how deadly an impact it will have.
The earth has been bombarded by meteorites throughout its long history. Meteorite impacts generate atmospheric dust and cover the Earth’s surface with debris and have long been considered as a trigger of mass extinctions through Earth’s history.
A multidisciplinary research team from the University of Liverpool and the Instituto Tecnológico y de Energías Renovables, Tenerife with expertise in palaeontology, asteroid stratigraphy, mineralogy, cloud microphysics and climate modelling, sought to explore why some meteorites have caused mass extinctions, for example the K/Pg Chixulclub impact that killed off dinosaurs, yet many which are larger in size have not.
They analysed 44 impacts over the past 600 million years using a new method: assessing the mineral content of the dust ejected into the atmosphere upon impact.
Their findings, published in the Journal of the Geological Society of London, reveal that meteorites that hit rocks rich in potassium feldspar (a common and rather benign mineral) always correspond with a mass extinction episode, irrespective of size.
Potassium feldspar is non-toxic. However, it is a powerful ice-nucleating mineral aerosol that strongly affects cloud dynamics, which makes them let through more solar radiation. This in turn warms up the planet and changes the climate. The atmosphere also becomes more sensitive to warming from greenhouse gas emissions, such as large volcanic eruptions.
Liverpool sedimentologist, Dr Chris Stevenson, from the University’s school of Earth, Ocean and Ecological Sciences co-authored the study.
He said: “For decades scientists have puzzled over why some meteorites cause mass extinctions, and others, even really big ones, don’t.
“It’s surprising when we put together the data: life carried on as normal during the 4th largest impact with a crater diameter of ~48 km, whereas an impact half the size was associated with a mass extinction only 5 million years ago.
“Many kill mechanisms have been proposed, such as large volcanic eruptions, but just like meteorites, these don’t always correlate with mass extinctions.
“Using this new method for assessing the mineral content of the meteorite ejecta blankets, we show that every time a meteorite, big or small, hits rocks rich in potassium feldspar it correlates with a mass extinction event.
This opens up a whole new avenue of research: what exactly kills off life during these episodes, and how long do the potassium feldspar effects last? Until now, only meteorites have changed the aerosol regime of the climate. However, present day human activities represent a similar mechanism with increasing emissions of mineral aerosols into the atmosphere.”
Reference:
M.J. Pankhurst, C.J. Stevenson, B.C. Coldwell. Meteorites that produce K-feldspar-rich ejecta blankets correspond to mass extinctions. Journal of the Geological Society, 2021; jgs2021-055 DOI: 10.1144/jgs2021-055
Dinosaur egg and embryo reconstruction (Julius Csotonyi)
A 72 to 66-million-year-old embryo found inside a fossilised dinosaur egg sheds new light on the link between the behaviour of modern birds and dinosaurs, according to a new study.
The embryo, dubbed ‘Baby Yingliang’, was discovered in the Late Cretaceous rocks of Ganzhou, southern China and belongs to a toothless theropod dinosaur, or oviraptorosaur. Among the most complete dinosaur embryos ever found, the fossil suggests that these dinosaurs developed bird-like postures close to hatching.
Scientists found the posture of ‘Baby Yingliang’ unique among known dinosaur embryos — its head lies below the body, with the feet on either side and the back curled along the blunt end of the egg. Previously unrecognised in dinosaurs, this posture is similar to that of modern bird embryos.
In modern birds, such postures are related to ‘tucking’ — a behaviour controlled by the central nervous system and critical for hatching success. After studying egg and embryo, researchers believe that such pre-hatching behaviour, previously considered unique to birds, may have originated among non-avian theropods.
Led by scientists from the University of Birmingham and China University of Geosciences (Beijing), the research team from institutions in China, UK and Canada today published its findings in iScience.
Life reconstruction of a close-to-hatching oviraptorosaur dinosaur embryo, based on the new specimen “Baby Yingliang.” Credit: Lida Xing
The embryo is articulated in its life position without much disruption from fossilisation. Estimated to be 27 cm long from head to tail, the creature lies inside a 17-cm-long elongatoolithid egg. The specimen is housed in Yingliang Stone Nature History Museum.
Fion Waisum Ma, joint first author and PhD researcher at the University of Birmingham, said: “Dinosaur embryos are some of the rarest fossils and most of them are incomplete with the bones dislocated. We are very excited about the discovery of ‘Baby Yingliang’ — it is preserved in a great condition and helps us answer a lot of questions about dinosaur growth and reproduction with it.
“It is interesting to see this dinosaur embryo and a chicken embryo pose in a similar way inside the egg, which possibly indicates similar prehatching behaviours.”
‘Baby Yingliang’ was identified as an oviraptorosaur based on its deep, toothless skull. Oviraptorosaurs are a group of feathered theropod dinosaurs, closely related to modern-day birds, known from the Cretaceous of Asia and North America. Their variable beak shapes and body sizes are likely to have allowed them to adopt a wide range of diets, including herbivory, omnivory and carnivory.
Birds are known to develop a series of tucking postures, in which they bend their body and bring their head under their wing, soon before hatching. Embryos that fail to attain such postures have a higher chance of death due to unsuccessful hatching.
By comparing ‘Baby Yingliang’ with the embryos of other theropods, long-necked sauropod dinosaurs and birds, the team proposed that tucking behaviour, which was considered unique to birds, first evolved in theropod dinosaurs many tens or hundreds of millions of years ago. Additional discoveries of embryo fossils would be invaluable to further test this hypothesis.
Professor Lida Xing from China University of Geosciences (Beijing), joint first author of the study, said: “This dinosaur embryo was acquired by the director of Yingliang Group, Mr Liang Liu, as suspected egg fossils around the 2000. During the construction of Yingliang Stone Nature History Museum in 2010s, museum staff sorted through the storage and discovered the specimens.
“These specimens were identified as dinosaur egg fossils. Fossil preparation was conducted and eventually unveiled the embryo hidden inside the egg. This is how ‘Baby Yingliang’ was brought to light.”
Professor Steve Brusatte from the University of Edinburgh, part of the research team, said: “This dinosaur embryo inside its egg is one of the most beautiful fossils I have ever seen. This little prenatal dinosaur looks just like a baby bird curled in its egg, which is yet more evidence that many features characteristic of today’s birds first evolved in their dinosaur ancestors.”
Reference:
Lida Xing, Kecheng Niu, Waisum Ma, Darla K. Zelenitsky, Tzu-Ruei Yang, Stephen L. Brusatte. An exquisitely preserved in-ovo theropod dinosaur embryo sheds light on avian-like prehatching postures. iScience, 2021; 103516 DOI: 10.1016/j.isci.2021.103516
Oregon State University research has uncovered the first fossil evidence of a rare botanical condition known as precocious germination in which seeds sprout before leaving the fruit.
In a paper published in Historical Biology, George Poinar Jr. of the Oregon State College of Science describes a pine cone, approximately 40 million years old, encased in Baltic amber from which several embryonic stems are emerging.
“Crucial to the development of all plants, seed germination typically occurs in the ground after a seed has fallen,” said Poinar, an international expert in using plant and animal life forms preserved in amber to learn about the biology and ecology of the distant past. “We tend to associate viviparity — embryonic development while still inside the parent — with animals and forget that it does sometimes occur in plants.”
Most typically, by far, those occurrences involve angiosperms, Poinar said. Angiosperms, which directly or indirectly provide most of the food people eat, have flowers and produce seeds enclosed in fruit.
“Seed germination in fruits is fairly common in plants that lack seed dormancy, like tomatoes, peppers and grapefruit, and it happens for a variety of reasons,” he said. “But it’s rare in gymnosperms.”
Gymnosperms such as conifers produce “naked,” or non-enclosed, seeds. Precocious germination in pine cones is so rare that only one naturally occurring example of this condition, from 1965, has been described in the scientific literature, Poinar said.
“That’s part of what makes this discovery so intriguing, even beyond that it’s the first fossil record of plant viviparity involving seed germination,” he said. “I find it fascinating that the seeds in this small pine cone could start to germinate inside the cone and the sprouts could grow out so far before they perished in the resin.”
At the sprouts’ tips are needle clusters, some in bundles of five, associating the fossil with the extinct pine species Pinus cembrifolia, which was previously described from Baltic amber, Poinar said.
Pine cones in Baltic amber are not commonly found, he added. The ones that do appear are prized by collectors and because the cones’ scales are hard, they’re usually very well preserved and appear lifelike.
Viviparity in plants typically shows up in one of two ways, Poinar said. Precocious germination is the more common of the two, the other being vegetative viviparity, such as when a bulbil emerges directly from the flower head of a parent plant.
“In the case of seed viviparity in this fossil, the seeds produced embryonic stems that are quite evident in the amber,” he said. “Whether those stems, known as hypocotyls, appeared before the cone became encased in amber is unclear. However, based on their position, it appears that some growth, if not most, occurred after the pine cone fell into the resin.
“Often some activity occurs after creatures are entombed in resin, such as entrapped insects depositing eggs,” Poinar said. “Also, insect parasites sometimes flee their hosts into the resin after the latter become trapped. In the case of the pine cone, the cuticle covering the exposed portions of the shoots could have protected them from rapid entrance of the resin’s natural fixatives.”
Research on viviparity in extant gymnosperms suggests the condition could be linked to winter frosts. Light frosts would have been possible if the Baltic amber forest had a humid, warm-temperate environment as has been posited, Poinar said.
“This is the first fossil record of seed viviparity in plants but this condition probably occurred quite a bit earlier than this Eocene record,” he said. “There’s no reason why vegetative viviparity couldn’t have occurred hundreds of millions of years ago in ancient spore-bearing plants like ferns and lycopods.”
Reference:
George Poinar. Precocious germination of a pine cone in Eocene Baltic amber. Historical Biology, 2021; 1 DOI: 10.1080/08912963.2021.2001808
“In the shallows near shore, Tetrapodophis amplectus glides through a tangle of branches from the conifer Duartenia araripensis that have fallen into the water, sharing this habitat with a water bug in the family Belostomatidae and small fish (Dastilbe sp.).” Image credit: Julius Csotonyi
Filling in the links of the evolutionary chain with a fossil record of a ”snake with four legs” connecting lizards and early snakes would be a dream come true for paleontologists. But a specimen formerly thought to fit the bill is not the missing piece of the puzzle, according to a new Journal of Systematic Palaeontology study led by University of Alberta paleontologist Michael Caldwell.
“It has long been understood that snakes are members of a lineage of four-legged vertebrates that, as a result of evolutionary specializations, lost their limbs,” said Caldwell, lead author of the study and professor in the departments of biological sciences and earth and atmospheric sciences.
“Somewhere in the fossil record of ancient snakes is an ancestral form that still had four legs. It has thus long been predicted that a snake with four legs would be found as a fossil.”
Missing link discovered?
In a paper published in the journal Sciencein 2015, a team of researchers reported the discovery of what was believed to be an example of the first known four-legged snake fossil, an animal they named Tetrapodophis amplectus.
“If correctly interpreted based on the preserved anatomy, this would be a very important discovery,” said Caldwell.
Caldwell explained that the new study of Tetrapodophis revealed a number of mischaracterizations of the anatomy and morphology of the specimen — traits that initially seemed to be shared most closely with snakes, suggesting this might be the long-sought-after snake with four legs.
“There are many evolutionary questions that could be answered by finding a four-legged snake fossil, but only if it is the real deal. The major conclusion of our team is that Tetrapodophis amplectus is not in fact a snake and was misclassified,” said Caldwell. “Rather, all aspects of its anatomy are consistent with the anatomy observed in a group of extinct marine lizards from the Cretaceous period known as dolichosaurs.”
The clues to this conclusion, Caldwell noted, were hiding in the rock the fossil was extracted from.
“When the rock containing the specimen was split and it was discovered, the skeleton and skull ended up on opposite sides of the slab, with a natural mould preserving the shape of each on the opposite side,” said Caldwell. “The original study only described the skull and overlooked the natural mould, which preserved several features that make it clear that Tetrapodophis did not have the skull of a snake — not even of a primitive one.”
A controversial specimen
Although Tetrapodophis may not be the snake with four legs that paleontologists prize, it still has much to teach us, said study coauthor Tiago Simões, a former U of A PhD student, Harvard post- doctoral fellow and Brazilian paleontologist, who pointed out some of the features that make it unique.
“One of the greatest challenges of studying Tetrapodophis is that it is one of the smallest fossil squamates ever found,” said Simões. “It is comparable to the smallest squamates alive today that also have reduced limbs.”
An additional challenge to studying the Tetrapodophis is access to the specimen itself.
“There were no appropriate permits for the specimen’s original removal from Brazil and, since its original publication, it has been housed in a private collection with limited access to researchers. The situation was met with a large backlash from the scientific community,” said Simões.
“In our redescription of Tetrapodophis, we lay out the important legal status of the specimen and emphasize the necessity of its repatriation to Brazil, in accordance not only with Brazilian legislation but also international treaties and the increasing international effort to reduce the impact of colonialist practices in science.”
Reference:
Michael W. Caldwell, Tiago R. Simões, Alessandro Palci, Fernando F. Garberoglio, Robert R. Reisz, Michael S. Y. Lee, Randall L. Nydam. Tetrapodophis amplectus is not a snake: re-assessment of the osteology, phylogeny and functional morphology of an Early Cretaceous dolichosaurid lizard. Journal of Systematic Palaeontology, 2021; 1 DOI: 10.1080/14772019.2021.1983044
Map showing the Great Basin drainage basin as defined hydrologically. (Image credit: Kmusser/Wikimedia Commons)
When geologist Elizabeth Miller started mapping a fault system in Death Valley, she questioned the origin of some sedimentary rocks previously assumed to be locally derived. Now, analysis has revealed where they really came from: central Nevada, indicating that part of today’s Great Basin was the highest land in North America some 40 million to 20 million years ago.
The journey of these sediments southward in river systems draining into the ancient Pacific Ocean tells a story about the history of the Earth and the much-debated formation of the Sierra Nevada mountain range, the awe-inspiring backbone of eastern California that encompasses three national parks: Sequoia, Kings Canyon and Yosemite.
The ancestral Sierra Nevada began as a volcanic chain more than 100 million years ago, a time when dinosaurs still roamed the Earth. New work published Nov. 15 as chapters in a Geological Society of America Special Paper on the paleogeography and topography of the western U.S. suggests that the mountains later “died” — meaning they were dwarfed by a vast plateau — during a region-wide volcanic flare-up about 40 million to 20 million years ago. Then, they were “reborn” about 10 million years ago, lifting to the scenic heights we know today.
“The highest points 40 to 20 million years ago were in central Nevada. Then, basin and range faulting came along and broke it all up, and now the Sierra Nevada is the westernmost or last of those major fault blocks,” Miller said. “As a mountain range, it’s had three completely different histories.”
The findings from Miller and Jens-Erik Lund Snee, who conducted the research while a PhD student at Stanford, propose that the Continental Divide — which is typically considered to be static — went through a progressive shift eastward. The divide, which separates the watersheds that drain into the Pacific Ocean from those draining eastward, remained in the ancestral Sierra Nevada in eastern California for tens of millions of years before moving into central Nevada when the volcanism that started 40 million years ago lifted the Earth’s surface in a south-migrating wave.
The papers describe how the region-wide flare-up of volcanic activity in southern Idaho, Nevada and Utah caused the inland plateau to rise above the ancestral Sierra. That upheaval in the Earth’s mantle and crust created whole new systems of rivers, some of which carried sediment southward, forming the layers that Miller studied near Death Valley with co-author Mark Raftrey, a former graduate student.
“The material from those volcanoes made it all the way out to the Pacific side of the Sierra Nevada — that’s how we know the region in central Nevada where the eruptions occurred was higher than everything else,” said Miller, noting that previous papers charted the ancient rivers that carried the volcanic material. “Our work adds to this previous work in that we argue that the volcanism itself actually caused a big increase in the topography because there was so much hot material coming up from below the continent.”
For tens of million years after the plateau rose, the ancestral Sierra range was “merely the ramp from the high country in Nevada down to the paleo-ocean in what’s now the Central Valley,” Lund Snee said. That was also when much of the famous California gold was deposited in ancient rivers that flowed west from central Nevada out to the Central Valley. Then, beginning around 10 million years ago, the new Sierra Nevada emerged when the western U.S. was chiseled apart by basin and range faulting, which involved uplift and extension — a process that had very little to do with its earlier history, according to Miller.
“There’s been a lot of recent debate about when the Sierra Nevada came up as a mountain range, and our work is suggesting that both prevailing views are right — it’s old and also young for completely different tectonic reasons,” said Lund Snee, who is now a Mendenhall Research Fellow at the U.S. Geological Survey.
When the ancestral Sierra Nevada first arose over 100 million years ago, the mountains marked the edge of the North American continent, bordered by the Pacific Ocean to the west. East of that area, geologists have long thought the Earth’s crust thickened and became unstable, eventually causing the continent to spread apart and form today’s basin and range topography.
But Miller and Lund Snee found that the region east of the ancestral Sierra was relatively low, supported by thinner, more stable crust until the wave of volcanic eruptions 40 million to 20 million years ago lifted the plateau higher than the ancestral range. The eruptions came from dozens of Yellowstone-like supervolcano calderas in addition to hundreds of smaller volcanoes — an event that blanketed some areas with thousands of feet of lava.
The research paints a picture of the topographic evolution of the western U.S., which has been debated since the area was first explored by geologists in the 1800s and flooded by gold miners seeking fortunes in the Sierra Nevada’s western foothills. It also impacts our understanding of how plants and animals evolved and dispersed across the West; in order to understand migration, biologists need a clear grasp of landscape evolution.
The authors refined geologic maps and used radiometric dating of the minerals zircon and feldspar to gauge the timing of eruptions and changes in topography. They also revised the ages of previous estimates of elevation and climate from stable isotope analyses of calcite in sediments deposited before and after the volcanic rock.
“You need to know when things happened and how long it took things to happen to truly understand them in the geologic context,” Miller said. “It’s an evolving story, and as we pick up more pieces, the story begins to get tighter and tighter.”
The research was supported by the National Science Foundation and a Gerald J. Lieberman Fellowship.
Note: The above post is reprinted from materials provided by Stanford University. Original written by Danielle Torrent Tucker.
A ruptured fault in Searles Valley, California, after the 2019 Ridgecrest earthquakes. A study of earthquakes led by The University of Texas at Austin found that seismic shockwaves are shaped by jagged faults and the debris wedged between them. Credit: Ben Brooks/USGS
New research from The University of Texas at Austin could change the way scientists think about potential damage from earthquakes.
The study examined data from one of the densest seismic arrays ever deployed and found that earthquakes emit their strongest seismic shockwaves in four opposing directions. The effect, which leaves a pattern resembling a four-leaf clover, has been known for decades but never measured in such vivid detail.
Daniel Trugman, an earthquake geophysicist at the Department for Geological Sciences in the UT Jackson School of Geosciences, said that the study looked at only one type of seismic shaking caused by very small earthquakes in northern Oklahoma.
“What’s important in these results is that close to the source we’re seeing a variation in ground motion, and that’s not accounted for in any sort of hazard model,” Trugman said. He added that efforts were already underway to see how the phenomena plays out in California’s big fault systems.
The analysis was published in the September issue of Geophysical Research Letters and is based on measurements of two-dozen small earthquakes recorded by the LArge-n Seismic Survey in Oklahoma (LASSO), an array of 1,829 seismic sensors deployed for 28 days in 2016 to monitor a remote corner of the state measuring 15 by 20 miles.
When earthquakes strike, they release a thunderclap of seismic energy at many frequencies, but the actual ground shaking people feel ranges from about 1 hertz to 20 hertz. The study found that low frequency energy — about 1 to 10 hertz — shot from the fault in four directions, but barely registered outside of the four-leaf clover pattern. This is important because buildings are more vulnerable to low frequency waves. The four-leaf clover pattern wasn’t found for higher frequency waves, which travelled at equal strength in all directions, like ripples in a pond.
Co-author Victor Tsai, a geophysicist at Brown University, said that the reason the Earth shook unevenly at different frequencies might have something to do with the complex geometry of earthquake faults and the broken-up material packed between them.
“What happens when you have an earthquake is that pieces of broken rock inside the fault zone start to move around like pinballs,” he said. The jostling pieces redirect the energy randomly but at lower frequencies, seismic waves simply bypass the rough geologic mess near the fault, travelling in a nice four-leaf clover pattern just as physics predicts.
This means that on the surface, a person might feel the same shaking regardless of where they stood, but buildings — which are sensitive to low frequency waves — would feel the earthquake much more intensely within the lines of the four-leaf clover pattern.
Geophysicists have long known about this pattern; it’s taught in seismology 101. But, until now, evidence of its effect has been sparse. That’s because over large distances seismic waves are refracted regardless of frequency, smoothing out their differences and making earthquakes seem the same in all directions.
Near an earthquake’s source, however, the pattern should be distinct. That’s where the LASSO array came in. Its closely packed sensors recorded earthquakes while they were unfolding, gathering measurements from hundreds of locations in northern Oklahoma that the U.S. Geological Survey, which funded and deployed the array, made freely available online.
To test their idea about uneven shaking near faults, Trugman developed algorithms to filter the LASSO data. At low frequencies, each earthquake showed a four-leaf clover pattern of shaking; at higher frequencies there was no clear pattern, just as Tsai had predicted.
Although the tremors recorded by the LASSO array were barely perceptible, the physics that drive them should be the same for stronger quakes. The scientists have already begun examining larger faults to see whether their age or shape can change the intensity of ground motion. Their goal is to build a catalogue of earthquake zones, showing which faults can generate the strongest and most dangerous types of seismic waves.
The research was funded by the U.S. Geological Survey and the National Science Foundation. Trugman is also a researcher at the University of Texas Institute for Geophysics, a unit of the Jackson School of Geosciences.
Reference:
Daniel T. Trugman, Shanna X. Chu, Victor C. Tsai. Earthquake Source Complexity Controls the Frequency Dependence of Near‐Source Radiation Patterns. Geophysical Research Letters, 2021; 48 (17) DOI: 10.1029/2021GL095022
A lab-grown crystal of a synthetic form of the rare earth mineral, monazite, shows extensive damage to one face after exposure to bio-leaching compound generated by Gluconobacter oxydans. Credit: Credit: Brian Balta/Provided
Rare earth elements from ore are vital for modern life but refining them after mining is costly, harms the environment and mostly occurs abroad.
A new study describes a proof of principle for engineering a bacterium, Gluconobacter oxydans, that takes a big first step towards meeting skyrocketing rare earth element demand in a way that matches the cost and efficiency of traditional thermochemical extraction and refinement methods and is clean enough to meet U.S. environmental standards.
“We’re trying to come up with an environmentally friendly, low-temperature, low-pressure method for getting rare earth elements out of a rock,” said Buz Barstow, the paper’s senior author and an assistant professor of biological and environmental engineering at Cornell University.
The elements — of which there are 15 in the periodic table — are necessary for everything from computers, cell phones, screens, microphones, wind turbines, electric vehicles and conductors to radars, sonars, LED lights and rechargeable batteries.
While the U.S. once refined its own rare earth elements, that production stopped more than five decades ago. Now, refinement of these elements takes place almost entirely in other countries, particularly China.
“The majority of rare earth element production and extraction is in the hands of foreign nations,” said co-author Esteban Gazel, associate professor of earth and atmospheric sciences at Cornell. “So for the security of our country and way of life, we need to get back on track to controlling that resource.”
To meet U.S. annual needs for rare earth elements, roughly 71.5 million tonnes (~78.8 million tons) of raw ore would be required to extract 10,000 kilograms (~22,000 pounds) of elements.
Current methods rely on dissolving rock with hot sulphuric acid, followed by using organic solvents to separate very similar individual elements from each other in a solution.
“We want to figure out a way to make a bug that does that job better,” Barstow said.
G. oxydans is known for making an acid called biolixiviant that dissolves rock; the bacteria uses the acid to pull phosphates from rare earth elements. The researchers have begun to manipulate G. oxydans’ genes so it extracts the elements more efficiently.
To do so, the researchers used a technology that Barstow helped develop, called Knockout Sudoku, that allowed them to disable the 2,733 genes in G. oxydans’ genome one by one. The team curated mutants, each with a specific gene knocked out, so they could identify which genes play roles in getting elements out of rock.
“I am incredibly optimistic,” Gazel said. “We have a process here that is going to be more efficient than anything that was done before.”
Alexa Schmitz, a postdoctoral researcher in Barstow’s lab, is first author of the study, “Gluconobacter oxydans Knockout Collection Finds Improved Rare Earth Element Extraction,” published in Nature Communications.
The study was funded by the Cornell Atkinson Center for Sustainability, the Cornell Energy Systems Institute, the Burroughs Welcome Fund and the Advanced Research Projects Agency-Energy.
Reference:
Alexa M. Schmitz, Brooke Pian, Sean Medin, Matthew C. Reid, Mingming Wu, Esteban Gazel, Buz Barstow. Generation of a Gluconobacter oxydans knockout collection for improved extraction of rare earth elements. Nature Communications, 2021; 12 (1) DOI: 10.1038/s41467-021-27047-4
Note: The above post is reprinted from materials provided by Cornell University. Original written by Krishna Ramanujan, courtesy of the Cornell Chronicle.
Photo courtesy Gunther Kletetschka Geologists inspect an outcrop near the sample collection site in New Mexico.
A University of Alaska Fairbanks scientist has discovered a method for detecting and better defining meteorite impact sites that have long lost their tell-tale craters. The discovery could further the study of not only Earth’s geology but also that of other bodies in our solar system.
The key, according to work by associate research professor Gunther Kletetschka at the UAF Geophysical Institute, is in the greatly reduced level of natural remanent magnetization of rock that has been subjected to the intense forces from a meteor as it nears and then strikes the surface.
Rocks unaltered by humanmade or non-Earth forces have 2% to 3% natural remanent magnetization, meaning they consist of that quantity of magnetic mineral grains — usually magnetite or hematite or both. Kletetschka found that samples collected at the Santa Fe Impact Structure in New Mexico contained less than 0.1% magnetism.
Kletetschka determined that plasma created at the moment of impact and a change in the behavior of electrons in the rocks’ atoms are the reasons for the minimal magnetism.
Kletetschka reported his findings in a paper published Wednesday in the journal Scientific Reports.
The Santa Fe Impact Structure was discovered in 2005 and is estimated to be about 1.2 billion years old. The site consists of easily recognized shatter cones, which are rocks with fantail features and radiating fracture lines. Shatter cones are believed to only form when a rock is subjected to a high-pressure, high-velocity shock wave such as from a meteor or nuclear explosion.
Kletetschka’s work will now allow researchers to determine an impact site before shatter cones are discovered and to better define the extent of known impact sites that have lost their craters due to erosion.
“When you have an impact, it’s at a tremendous velocity,” Kletetschka said. “And as soon as there is a contact with that velocity, there is a change of the kinetic energy into heat and vapor and plasma. A lot of people understand that there is heat, maybe some melting and evaporation, but people don’t think about plasma.”
Plasma is a gas in which atoms have been broken into free-floating negative electrons and positive ions.
“We were able to detect in the rocks that a plasma was created during the impact,” he said.
Earth’s magnetic field lines penetrate everything on the planet. Magnetic stability in rocks can be knocked out temporarily by a shock wave, as they are when hitting an object with a hammer, for example. The magnetic stability in rocks returns immediately after the shock wave passes.
At Santa Fe, the meteorite’s impact sent a massive shock wave through the rocks, as expected. Kletetschka found that the shock wave altered the characteristics of atoms in the rocks by modifying the orbits of certain electrons, leading to their loss of magnetism.
The modification of the atoms would allow for a quick remagnetization of the rocks, but Kletetschka also found that the meteorite impact had weakened the magnetic field in the area. There was no way for the rocks to regain their 2% to 3% magnetism even though they had the capability to do so.
That’s because of the presence of plasma in the rocks at the impact surface and below. Presence of the plasma increased the rocks’ electrical conductivity as they converted to vapor and molten rock at the leading edge of the shock wave, temporarily weakening the ambient magnetic field.
“This plasma will shield the magnetic field away, and therefore the rock finds only a very small field, a residue,” Kletetschka said.
Kletetschka is also affiliated with Charles University in Prague, Czech Republic. Charles University students Radana Kavkova and Hakan Ucar assisted in the research.
Reference:
Gunther Kletetschka, Radana Kavkova, Hakan Ucar. Plasma shielding removes prior magnetization record from impacted rocks near Santa Fe, New Mexico. Scientific Reports, 2021; 11 (1) DOI: 10.1038/s41598-021-01451-8
Copper-rich minerals indicating widespread volcanic activity at the end-Permian mass extinction in different regions in southern China (A: Taoshujing locality; B: Lubei locality; C: Guanbachong; D: Taoshujing locality; E: Longmendong locality). The minerals are all copper sulfides, mostly Malachite–the minerals’ green patches. Photo credit: H. Zhang, Nanjing Institute of Geology and Palaeontology.
A team of scientists has identified an additional force that likely contributed to a mass extinction event 250 million years ago. Its analysis of minerals in southern China indicate that volcano eruptions produced a “volcanic winter” that drastically lowered earth’s temperatures — a change that added to the environmental effects resulting from other phenomena at the time.
The research, which appears in the journal Science Advances, examined the end-Permian mass extinction (EPME), which was the most severe extinction event in the past 500 million years, wiping out 80 to 90 percent of species on land and in the sea.
“As we look closer at the geologic record at the time of the great extinction, we are finding that the end-Permian global environmental disaster may have had multiple causes among marine and non-marine species,” says Michael Rampino, a professor in New York University’s Department of Biology and one of the authors of the paper.
For decades, scientists have investigated what could have caused this global ecological catastrophe, with many pointing to the spread of vast floods of lava across what is known as the Siberian Traps — a large region of volcanic rock in the Russian province of Siberia. These eruptions caused environmental stresses, including severe global warming from volcanic releases of carbon dioxide and related reduction in oxygenation of ocean waters — the latter causing the suffocation of marine life.
The team for the Science Advances work, composed of more than two dozen researchers, including scientists from China’s Nanjing University and Guangzhou Institute of Geochemistry as well as Smithsonian Institution’s National Museum of Natural History and Montclair State University, considered other factors that may have contributed to the end of the Permian Period, which stretched from 300 million to 250 million years ago.
Specifically, they found mineral and related deposits on land in the south China region — notably copper and mercury — whose age coincided with the end-Permian mass extinction in non-marine localities. Specifically, these deposits were marked by anomalies in their composition likely due to sulfur-rich emissions from nearby volcanic eruptions — they were covered by layers of volcanic ash.
“Sulfuric acid atmospheric aerosols produced by the eruptions may have been the cause of rapid global cooling of several degrees, prior to the severe warming seen across the end-Permian mass-extinction interval,” explains Rampino.
The team’s findings suggested that the Siberian Traps eruptions were not the sole cause of the end-Permian mass extinction, and that the environmental effects of the eruptions in South China, and elsewhere, may have played a vital role in the disappearance of dozens of species.
Reference:
Hua Zhang, Feifei Zhang, Jiu-bin Chen, Douglas H. Erwin, Drew D. Syverson, Pei Ni, Michael Rampino, Zhe Chi, Yao-feng Cai, Lei Xiang, Wei-qiang Li, Sheng-Ao Liu, Ru-cheng Wang, Xiang-dong Wang, Zhuo Feng, Hou-min Li, Ting Zhang, Hong-ming Cai, Wang Zheng, Ying Cui, Xiang-kun Zhu, Zeng-qian Hou, Fu-yuan Wu, Yi-gang Xu, Noah Planavsky, Shu-zhong Shen. Felsic volcanism as a factor driving the end-Permian mass extinction. Science Advances, 2021; 7 (47) DOI: 10.1126/sciadv.abh1390
