Prehistoric Worm Built Tube-like 'Houses' on Sea Floor
Earth History, Fossils 6:24 PM
The worm shaped animal would have lived inside of a porous tube, and used its "U" shaped structure to attach itself in place within the tube. Photo: Jean-Bernard Caron
The fossilised remnants of tube-like "dwellings" which housed a primitive type of prehistoric sea worm on the ocean floor have been identified in a new study.
According to researchers, the long, perforated tubes may have looked like narrow chimneys reaching up from the sea bed, and were made by a creature called Oesia, which lived a solitary existence inside them about 500 million years ago.
The findings emerge from a study undertaken by academics from Canada and the UK, in which they reassess fossils originally believed to have come from a type of seaweed called Margaretia. Instead, they found that these were the vestiges of tubular structures which protected these ancient worms.
The research, which is published in the journal BMC Biology, was carried out by academics from the Universities of Cambridge, Toronto and Montréal, and at the Royal Ontario Museum in Toronto.
Part of its importance is that it confirms Oesia was a primitive specimen from a group of creatures called hemichordates. These belong to a bigger group called deuterostomes, of which vertebrates (including humans) form a separate branch. By finding out more about these early creatures, researchers hope eventually to be able to identify and characterise a distant ancestor common to all deuterostomes, from sea worms to humans.
In particular, the research supports the increasingly common view that this ancestor was probably a "filter feeder," which ate by sucking in water and straining out nutrients. Oesia was one such filter feeder, with gills down most of its body to expel water afterwards, and holes in the walls of its tubular home to let the water in and out.
Karma Nanglu, from the University of Toronto and the study's lead author, said: "Hemichordates are central to our understanding of how deuterostomes evolved. Through them, we can get clues about the anatomy and lifestyle of the last common ancestor that we all share, and this adds further evidence to the hypothesis that the ancestor was a filter-feeder like Oesia."
Professor Simon Conway Morris, from St John's College, University of Cambridge and a co-author, said: "Oesia fossils are pretty enigmatic -- they are very rare and until now we could not prove which group they belonged to. Now we know that they were primitive hemichordates -- perhaps the most primitive of all."
The study was possible thanks to the discovery of a rich source of fossilised remains near Marble Canyon, in the Canadian Rockies (Kootenay National Park, B.C.), which is run by Parks Canada.
"Marble Canyon is one of the most recently discovered fossil localities in the Burgess Shale, a geological formation known for its exceptional quality of fossil preservation," said co-author Dr. Jean-Bernard Caron, Senior Curator of Invertebrate Palaeontology at the Royal Ontario Museum and Associate Professor at the University of Toronto. "Oesia has been known from an older Burgess Shale site for over 100 years, but the specimens from Marble Canyon are far more abundant and better preserved, giving us unprecedented details of the animal's internal anatomy."
The research establishes that Oesia was a rather phallic-shaped creature, similar to modern acorn worms with a proboscis, a collar, and a long trunk. Co-author Christopher B. Cameron, Associate Professor at the Université de Montréal said: "Acorn worms are notoriously sparse in the fossil record. Only a handful of fossil species have been described, making the recognition of such an ancient representative of the group particularly noteworthy."
The average Oesia was about 53mm long, and rarely more than 10mm wide. Unusually, these worms had U-shaped gills running down most the length of their bodies to enable filter feeding. Gill slits seem to be a characteristic common to all deuterostomes; even humans have slits in their necks at an early stage in their embryonic development, and this is seen as evidence that all deuterostomes are related to a distant, common ancestor.
The researchers realised that Oesia must have lived in tubes because among the Marble Canyon finds there are dozens of examples where the fossil remains of the worm are found within those of Margaretia.
Since the 1920s, Margaretia has been classified as a type of algae, albeit one unlike any other known species from this period in prehistory. The direct association with Oesia explains why Margaretia looks so exotic: This was no seaweed, but rather a perforated tube-like structure that the worm inhabited.
The study suggests that in some cases these structures exceeded 50cm in height and that they were typically at least twice the width of the worm, giving it plenty of room. The ends were sealed off, making life inside a rather lonely experience. "Only single worms are found within tubes, suggesting a solitary mode of life," Nanglu added.
At some point, the fossil record suggests that acorn worms underwent a transition, leaving their tubes and instead opting for a life under the sea bed. The study argues that as evolution gathered pace and more predators appeared on the scene, digging into the sea floor may simply have been a safer option. Certainly, modern-day acorn worms have adopted this lifestyle; rather than filter feeding they live in the sediment and eat nutrients within it.
"In its own depressing way this is a story of Darwinian competition," Conway Morris explained. "The levels of competition and predation increased, life sped up and got harder, and animals had to protect themselves more. One way of doing this was to abandon life filter feeding in a tube, and instead to dig into the sediment and eat mud. Once there, they found a new niche and were able to make a perfectly good life for themselves."
The above story is based on Materials provided by St John's College, University of Cambridge.
The worm shaped animal would have lived inside of a porous tube, and used its "U" shaped structure to attach itself in place within the t...
Unraveling Secrets of Diamond Formation
Diamonds, Tectonic 6:34 PM
Understanding the global carbon cycle provides scientists with vital clues about the planet's habitability.
It's the reason why the Earth has a clement stable climate and a low carbon dioxide atmosphere compared to that of Venus, for instance, which is in a runaway greenhouse state with high surface temperatures and a thick carbon dioxide atmosphere.
One major difference between Earth and Venus is the existence of active plate tectonics on Earth, which make our environment unique within our solar system.
But the atmosphere, oceans, and Earth's crust are only part of the story. The mantle, which represents 75% of Earth's volume, potentially holds more carbon than all other reservoirs combined.
Carbon – one of the essential building blocks of organic life – is taken into Earth's interior by subduction, where it drastically lowers the melting point of the solid mantle, forming carbonated melts (carbon-rich molten rocks) in the shallow mantle, fuelling surface volcanoes. Carbonate minerals may also be transported much deeper into the Earth, reaching the lower mantle, but what happens next is uncertain.
Answering that question is beset with challenges – conditions deep within the Earth are extreme and samples from the mantle are rare. The solution is to recreate those conditions in the lab using sophisticated technology.
Now a team of experimental geoscientists from the University of Bristol have done just that. Their results, published open access in Earth and Planetary Science letters, uncover new clues about what happens to carbonate minerals when they are transported into the mantle via subduction of the oceanic crust (where one of Earth's tectonic plates slides below another).
Their findings have uncovered a barrier to subduction of carbonate beyond depths of around 1,000km, where it reacts with silica in the oceanic crust to form diamonds that are stored in the deep Earth over geological timescales.
Dr. James Drewitt from the School of Earth Sciences explains: "Do carbonate minerals remain stable through the Earth's lower mantle, and if not, what pressure/temperature changes does it take to spark reactions between the minerals and what do they look like? These are the questions we wanted to find the answers to – and the only way to get those answers was to reproduce the conditions of the Earth's interior."
Dr. Drewitt and his team subjected synthetic carbonate rocks to very high pressures and temperatures comparable to deep Earth conditions of up to 90 GPa (about 900,000 atmospheres) and 2000 degrees C using a laser-heated diamond anvil cell. They found that carbonate remains stable up to depths of 1,000-1,300km, almost halfway to the core.
Under these conditions carbonate then reacts with surrounding silica to form a mineral known as bridgmanite, which forms most of the Earth's mantle. The carbon released by this reaction is in the form of solid carbon dioxide. As the hot surrounding mantle eventually heats up the subducted slab, this solid carbon dioxide breaks down to form superdeep diamonds.
Dr. Drewitt adds: "Eventually the superdeep diamonds could be returned to the surface in upwelling mantle plumes, and this process could represent one of the sources of superdeep diamonds that we find at the surface and which provide the only direct evidence we have of the composition of the deep earth.
"This is exciting because the deepest humans have ever been able to drill is about 12 km, less than half the depth of Earth's crust. This pales in comparison to the massive scale of Earth's mantle, which extends to nearly 3,000 km depth."
The team used a diamond anvil cell to generate pressures equivalent to those found at these depths, loading samples under a microscope into a pressure chamber drilled out of a metal gasket which is then compressed between the gem quality, brilliant cut diamond anvils. The crystal structure of those samples was then analysed using X-ray diffraction at the UK synchrotron facility in Oxfordshire.
Dr. Drewitt now plans to apply these high pressure and high-temperature experiments along with advanced computer simulation techniques to other minerals and materials, adding: "As well as carbon, there is potentially several ocean's worth of water transported deep into the mantle, and when released this will induce melting of Earth's upper and lower mantle.
"However, we cannot adequately test or understand current models of the dynamic behaviour of this water rich molten rock because we do not know their composition or their physical properties. The experiments at extreme conditions and advanced computer simulations that we are currently working on will help to resolve these problems."
The above story is based on Materials provided by University of Bristol.
Understanding the global carbon cycle provides scientists with vital clues about the planet's habitability. It's the reason...
Fossilized Insect Discovered Not in Amber, But in Opal
famous, Fossils, gemstones 5:28 PM
Photo: (Brian Berger/Instagram/@velvetboxsociety)
In a find unlike anything seen before, a piece of opal from the island of java in indonesia holds some remarkable cargo: a stunningly preserved insect that may be at least four to seven million years old.
Previously, plenty of ancient insects have been found in amber, a gemstone made of fossilized tree resin. When animals became encased in the fresh resin, it entombs them rapidly enough to preserve the remains, often with exquisite detail.
On a trip to Indonesia, gemologist Brian Berger purchased an opal that appeared to have an insect entombed inside. Insects trapped in amber are a common-enough sight, but in a slow-forming gemstone like opal?
"Some researchers weren't sure it was possible," Berger told Gizmodo. "Now we know it's possible. Is it likely? Extremely unlikely."
Berger had the stone analyzed by the Gemological Institute of America, which confirmed its authenticity. He published a blog in Entomology about his finding and is looking for entomologists to further analyze it.
Plants produce a sticky substance called resin mostly as a means to protect themselves. Under the right circumstances, the chemical structures of these resins can change over time, fossilizing into amber—occasionally trapping and preserving an insect inside.
This specimen probably started as a typical insect trapped in amber—but then it appears to have gone through a second process called opalization, where some of the amber turned into opal. Opals are essentially spheres of silicon dioxide with water combined into their chemistry. Organic specimens can turn into opal similar to the way fossilization turns bone into stone; paleontologists in Australia have recently found an opalized dinosaur fossil.
At least, this is what Berger speculates happened. How the specimen formed remains unclear.
One entomologist, Ryan McKellar, curator of invertebrate palaeontology at the Royal Saskatchewan Museum in Canada, told Gizmodo "it is a pretty neat find, and a bit puzzling." Though commenting only on Berger's blog post in Entomology Today, McKellar said it "definitely looks like an insect inclusion." He noted that he'd seen a comparable specimen in Canada, where a piece of wood was partially embedded in resin and partially exposed to the surrounding environment. The amber preserved the wood, but silica replaced the organic matter outside the amber and turned it into petrified wood.
McKellar thought that perhaps this specimen was formed by a similar process, and said he'd be interested in the age of the deposit where it was found.
Meanwhile, well-known American entomologist George Poinar Jr. from Oregon State University remained cautious. He found the specimen "interesting," but wanted to wait for an entomologist's opinion before offering any further comment without examining the object himself.
Photo: (Brian Berger/Instagram/@velvetboxsociety) In a find unlike anything seen before, a piece of opal from the island of java in i...
New Dinosaur Species With Spiky Backbone Discovered in Argentina
dinosaur, Earth History, Fossils 5:58 PM
A replica of the skull and neck of the "Bajadasaurus pronuspinax," a new species of sauropod discovered in Patagonia
Paleontologists in Argentina have uncovered a dinosaur unlike anything ever seen before. Alive some 140 million years ago, these majestic herbivores featured long, forward-pointing spikes running along their necks and backs. These spikes may have served a defensive role, but their exact purpose now presents a fascinating new mystery.
A herbivorous dinosaur that fended off predators with a row of spines running along its back and lived 140 million years ago has been found in Argentine Patagonia.
The discovery of the new species of dicraeosauridae, christened Bajadasaurus pronuspinax, was revealed in Scientific Reports.
A reproduction of its spiny neck was exhibited in the Cultural Science Center in Buenos Aires.
"We believe that the long and sharp spines—very long and thin—on the neck and back of Bajadasaurus and Amargasaurus cazaui (another dicraeosauridae) must have been to deter possible predators," said Pablo Gallina, an assistant researcher at the state council of scientific and technical investigations (CONICET) and Maimonides University.
"We think that had they been just bare bone structures or covered only by skin, they could have been easily broken or fractured with a blow or when being attacked by other animals," he added.
"These spines must have been covered by a keratin sheath similar to what happens in the horns of many mammals."
Bajadasaurus was a quadruped and part of the wider Sauropod family that lived from the late Triassic period (around 230 million years ago) until the end of the late Cretaceous (70 million years ago).
Amargasaurus cazaui lived in the South American continent around 15 million years after Bajadasaurus and both species were found in the Neuquen province around 1,120 miles (1,800 kilometers) south of Buenos Aires.
It's the same zone in which Giganotosaurus carolinii, considered the biggest carnivorous dinosaur of all time, was discovered in 1993.
It lived during the late Cretaceous period and could have fed on Bajadasaurus.
CONICET said in a statement the spines could have been used to regulate the dinosaur's temperature or even to render it more sexually attractive to a potential mate.
It said Bajadasaurus could have had a fleshy hump between the spines that served a similar role to that of a camel.
The Bajadasaurus skull is the best preserved example of a dicraeosauridae ever found.
"Studies suggest this animal spent much of its time feeding on ground plants while its eye sockets, close to the top of its skull, allowed it to key an eye on what was happening around it," said CONICET.
The research has been published in Scientific Reports.
A replica of the skull and neck of the "Bajadasaurus pronuspinax," a new species of sauropod discovered in Patagonia Pale...
Massive Bolivian Earthquake Reveals Mountains 660 Kilometers Below Earth's Surface
earth, Geology, Tectonic 11:02 AM
Scientists aren't sure how high the underground mountains are, but said they could be bigger than anything above Earth's surface
Credit: THE SUN
Mountains buried 400 miles underground 'could be BIGGER than Everest' – and were only found after massive Bolivian Earthquake
Most schoolchildren learn that the Earth has three (or four) layers: a crust, mantle and core, which is sometimes subdivided into an inner and outer core. That's not wrong, but it does leave out several other layers that scientists have identified within the Earth.
In a study published this week in Science, Princeton geophysicists Jessica Irving and Wenbo Wu, in collaboration with Sidao Ni from the Institute of Geodesy and Geophysics in China, used data from an enormous earthquake in Bolivia to find mountains and other topography on a layer located 660 kilometers (410 miles) straight down, which separates the upper and lower mantle. (Lacking a formal name for this layer, the researchers simply call it "the 660-km boundary.")
To peer deep into the Earth, scientists use the most powerful waves on the planet, which are generated by massive earthquakes. "You want a big, deep earthquake to get the whole planet to shake," said Irving, an assistant professor of geosciences.
Big earthquakes are vastly more powerful than small ones -- energy increases 30-fold with every step up the Richter scale -- and deep earthquakes, "instead of frittering away their energy in the crust, can get the whole mantle going," Irving said. She gets her best data from earthquakes that are magnitude 7.0 or higher, she said, as the shockwaves they send out in all directions can travel through the core to the other side of the planet -- and back again. For this study, the key data came from waves picked up after a magnitude 8.2 earthquake -- the second-largest deep earthquake ever recorded -- that shook Bolivia in 1994.
"Earthquakes this big don't come along very often," she said. "We're lucky now that we have so many more seismometers than we did even 20 years ago. Seismology is a different field than it was 20 years ago, between instruments and computational resources."
Seismologists and data scientists use powerful computers, including Princeton's Tiger supercomputer cluster, to simulate the complicated behavior of scattering waves in the deep Earth.
The technology depends on a fundamental property of waves: their ability to bend and bounce. Just as light waves can bounce (reflect) off a mirror or bend (refract) when passing through a prism, earthquake waves travel straight through homogenous rocks but reflect or refract when they encounter any boundary or roughness.
"We know that almost all objects have surface roughness and therefore scatter light," said Wu, the lead author on the new paper, who just completed his geosciences Ph.D. and is now a postdoctoral researcher at the California Institute of Technology. "That's why we can see these objects -- the scattering waves carry the information about the surface's roughness. In this study, we investigated scattered seismic waves traveling inside the Earth to constrain the roughness of the Earth's 660-km boundary."
The researchers were surprised by just how rough that boundary is -- rougher than the surface layer that we all live on. "In other words, stronger topography than the Rocky Mountains or the Appalachians is present at the 660-km boundary," said Wu. Their statistical model didn't allow for precise height determinations, but there's a chance that these mountains are bigger than anything on the surface of the Earth. The roughness wasn't equally distributed, either; just as the crust's surface has smooth ocean floors and massive mountains, the 660-km boundary has rough areas and smooth patches. The researchers also examined a layer 410 kilometers (255 miles) down, at the top of the mid-mantle "transition zone," and they did not find similar roughness.
"They find that Earth's deep layers are just as complicated as what we observe at the surface," said seismologist Christine Houser, an assistant professor at the Tokyo Institute of Technology who was not involved in this research. "To find 2-mile (1-3 km) elevation changes on a boundary that is over 400 miles (660 km) deep using waves that travel through the entire Earth and back is an inspiring feat. ... Their findings suggest that as earthquakes occur and seismic instruments become more sophisticated and expand into new areas, we will continue to detect new small-scale signals which reveal new properties of Earth's layers."
The presence of roughness on the 660-km boundary has significant implications for understanding how our planet formed and continues to function. That layer divides the mantle, which makes up about 84 percent of the Earth's volume, into its upper and lower sections. For years, geoscientists have debated just how important that boundary is. In particular, they have investigated how heat travels through the mantle -- whether hot rocks are carried smoothly from the core-mantle boundary (almost 2,000 miles down) all the way up to the top of the mantle, or whether that transfer is interrupted at this layer. Some geochemical and mineralogical evidence suggests that the upper and lower mantle are chemically different, which supports the idea that the two sections don't mix thermally or physically. Other observations suggest no chemical difference between the upper and lower mantle, leading some to argue for what's called a "well-mixed mantle," with both the upper and lower mantle participating in the same heat-transfer cycle.
"Our findings provide insight into this question," said Wu. Their data suggests that both groups might be partially right. The smoother areas of the 660-km boundary could result from more thorough vertical mixing, while the rougher, mountainous areas may have formed where the upper and lower mantle don't mix as well.
In addition, the roughness the researchers found, which existed at large, moderate and small scales, could theoretically be caused by heat anomalies or chemical heterogeneities. But because of how heat in transported within the mantle, Wu explained, any small-scale thermal anomaly would be smoothed out within a million years. That leaves only chemical differences to explain the small-scale roughness they found.
What could cause significant chemical differences? The introduction of rocks that used to belong to the crust, now resting quietly in the mantle. Scientists have long debated the fate of the slabs of sea floor that get pushed into the mantle at subduction zones, the collisions happening found all around the Pacific Ocean and elsewhere around the world. Wu and Irving suggest that remnants of these slabs may now be just above or just below the 660-km boundary.
"It's easy to assume, given we can only detect seismic waves traveling through the Earth in its current state, that seismologists can't help understand how Earth's interior has changed over the past 4.5 billion years," said Irving. "What's exciting about these results is that they give us new information to understand the fate of ancient tectonic plates which have descended into the mantle, and where ancient mantle material might still reside."
She added: "Seismology is most exciting when it lets us better understand our planet's interior in both space and time."
The above story is based on Materials provided by Princeton University. Original written by Liz Fuller-Wright.
Scientists aren't sure how high the underground mountains are, but said they could be bigger than anything above Earth's surface ...
Mantle Plumes Can Destroy Diamonds
Diamonds, Earth History 7:37 PM
Examples of rough diamonds from the Letseng mine, Lesotho
Kimberlites (pipe-like bodies) are the host rocks for the majority of diamonds, and kimberlites are dominantly located in regions of ancient continental crust.
However, only a small proportion of kimberlites are diamond-bearing. It has been long realized that diamonds are not inherently part of kimberlite melts but are "stowaways." They reside in the mantle roots of ancient crustal blocks and are grabbed by ascending kimberlite magmas (see Figure). The potential for diamonds in kimberlites depends on their abundance and distribution in the deep lithospheric mantle roots beneath continental crust.
We recently published a paper that provides an explanation for why kimberlites in certain regions of the Earth would lack diamonds. In this paper, we modeled the effect of a hot mantle plume arising underneath a region of ancient crust.
Mantle plumes are thermally buoyant upwellings from the deep mantle, and upon reaching areas of thin lithosphere (<100 km thick), they can partially melt and produce huge volumes of liquid rock of mainly basaltic composition termed Large Igneous Provinces (LIPs, for short) and they can also cause formation of kimberlite magmas under adjacent areas of thicker lithosphere (see Figure).
Credit: Richard Ernst
[By the way, LIP events are of such a scale that they would cover the entirety of Canada (or the US) with liquid rock to a depth of at least 10 m up to nearly 8 km. LIPs are also associated with the breakup of supercontinents such as Pangea, and also older examples, with some types of major ore deposits (notably Ni-Cu-PGE), and with catastrophic climate change including mass extinction events where up to 90% of life on Earth was wiped out.
However, don't worry, LIP events are rare; they only happen every 20-30 million years. LIPs are also present on other terrestrial bodies, notably Venus and Mars]. Where portions of the rising mantle plume are stopped beneath thick lithosphere (>100 km thick) the plume transmits heat into the deep lithospheric mantle and the resulting increase in temperature can cause deep lithospheric diamonds to be turned into graphite.
A slightly younger pulse of kimberlite magmas rising through the lithosphere would therefore only see graphite and not diamonds and would reach the paleosurface as barren kimberlites (lacking diamonds). However, once the thermal pulse from the plume had faded (over about 100 million years), then the lower lithospheric mantle "root" would again be cool enough for diamonds to reform from the graphite. Subsequent rising kimberlite magmas would, therefore, encounter diamonds and bring them to the paleosurface, where they could be mined (and make romantic couples happy).
We have identified examples of both situations (loss of diamonds and regrowth of diamonds). For instance, in Siberia, 250-225 million-year-old kimberlites lack diamonds because of a prior (370 million-year-old) mantle plume event (that destroyed the diamond potential). In northern Canada, 1100 million old kimberlites are barren because of an 1140 million-year-old plume/LIP event. However, in the same area much younger 180-150 million-year-old kimberlites are again diamond-rich, because of the long period of cooling (between 1100 and 180 million years ago) allowed diamonds to reform.
The study was published in the journal Earth and Planetary Science Letters.
Examples of rough diamonds from the Letseng mine, Lesotho Kimberlites (pipe-like bodies) are the host rocks for the majority of dia...
Giant Dinosaur Trackway Discovered in Queensland
dinosaur, Earth History 6:09 PM
The three dinosaur footprint types found at the site: the left footprints of a sauropod (outlined in blue). Credit: Swinburne University of Technology
Gigantic dinosaur footprints preserved in an outback creek bed have been saved from the floods that have ravaged western Queensland.
A well-preserved dinosaur trackway, travelled by three different types of dinosaurs, has been discovered in Winton in central west Queensland.
The discovery was announced today by the Queensland Tourism Industry Development Minister Kate Jones.
Swinburne palaeontologist, Dr Stephen Poropat, is leading the research team for the Australian Age of Dinosaurs Museum in Winton, where the footprints are being taken for display.
He says that having three major dinosaur groups – sauropods, ornithopods and theropods – represented on the same trackway surface is incredibly rare.
"The small ornithopod and theropod footprints were clearly made by very similar (if not identical) trackmakers to those preserved at Dinosaur Stampede National Monument, which is located about 100km south of this site," he says.
According to Dr Poropat, the longest sequence of sauropod footprints can be followed continuously for over 40 metres and would have comprised nearly two dozen fore and hind footprint sets when complete.
Best dinosaur footprints in Australia
"These footprints are the best of their kind in Australia and their shape can be distinguished from all known sauropod footprints worldwide."
Dr Poropat says that many of the footprints are surrounded by concentric mud cracks that were spread through the once-moist sediment by the weight of the sauropod's footfalls.
"That these fine details are so well preserved after 95 million years is remarkable," he says.
Dr Poropat says the sauropod footprints cannot be assigned to any particular sauropod species despite the fact that there are three different sauropods known from the Winton Formation – a rock formation that covers large areas of central-western Queensland – and that at least one had a thumb claw.
"All we can say with confidence at this point is that these footprints were made by titanosauriform sauropods," he says.
Executive Chairman of the Australian Age of Dinosaurs Museum, David Elliott, who led the excavation in April 2018, says that the newly exposed trackway was extremely fragile and its removal from the creek bed was a very high priority for the Museum.
Relocation of trackway continuing
Relocation of the trackway began in September 2018 and 25 per cent of the total area, including all of the fragile footprints that were in danger of being destroyed, has now been removed.
"This is a very slow and painstaking process. The total weight of the trackway is in the vicinity of 500 tonnes and we are transporting it back to the Museum, one two-tonne trailer load at a time," Mr Elliott says.
A scientific analysis of the trackway has been submitted for peer review by Dr Poropat and his colleagues and Mr Elliott is hoping that the attraction, named March of the Titanosaurs, will be open to the public from May 2020.
"Very few museums in the world can boast a multi-sequence sauropod trackway as one of their in-house exhibitions, much less one 55m long with the footprints of all three major groups of Dinosauria represented," Mr Elliott says.
The above story is based on materials provided by Swinburne University.
The three dinosaur footprint types found at the site: the left footprints of a sauropod (outlined in blue). Credit: Swinburne University ...
Rare Spider Fossil Preserves 100-Million-Year-Old Glowing Eyes
Flint rock preserved characteristics of the spider fossils differently than the more common amber-preserved spiders. Glowing Spider Eyes, Revealed by Fossil Preserved in Rock
Usually, soft-bodied species like spiders aren't fossilized in rock like animals with bones and teeth. More often, ancient spiders and insects are more likely to be discovered preserved in amber.
Yet a new paper in the Journal of Systematic Palaeontology, co-written by a University of Kansas researcher, describes fossil spiders found in an area of Korean shale called the Lower Cretaceous Jinju Formation.
What's most remarkable: Two of the fossils from the extinct spider family Lagonomegopidae feature reflective eyes that enabled their nighttime hunting.
"Because these spiders were preserved in strange slivery flecks on dark rock, what was immediately obvious was their rather large eyes brightly marked with crescentic features," said Paul Selden, Gulf-Hedberg Distinguished Professor of Geology and director of the Paleontological Institute at KU's Biodiversity Institute and Natural History Museum. "I realized this must have been the tapetum -- that's a reflective structure in an inverted eye where light comes in and is reverted back into retina cells. This is unlike a straightforward eye where light goes through and doesn't have a reflective characteristic."
Selden said that some contemporary spiders feature eyes with a tapetum, but the new paper is the first to describe the anatomical feature in a fossilized spider. The research team said the discovery provides evidence for lagonomegopid enlarged eyes being posterior medians.
"ln spiders, the ones you see with really big eyes are jumping spiders, but their eyes are regular eyes -- whereas wolf spiders at nighttime, you see their eyes reflected in light like cats," he said. "So, night-hunting predators tend to use this different kind of eye. This was the first time a tapetum had been in found in fossil. This tapetum was canoe-shaped -- it looks a bit like a Canadian canoe. That will help us place this group of spiders among other families."
Selden's collaborators were Tae-Yoon Park of the Korea Polar Research Institute and amateur fossil hunter Kye-Soo Nam of the Daejeon Science High School for the Gifted, who found the fossils preserved in the shale.
The description of the fossils boosts the number of known spiders from the Jinju Formation from one to 11. The KU researcher said the spiders, who lived between 110 and 113 million years ago, must somehow have been protected from deterioration to have become so well-preserved in the shale formation.
"This is so rare because they're very soft -- they don't have hard shells so they very easily decay," Selden said. "It has to be a very special situation where they were washed into a body of water. Normally, they'd float. But here, they sunk, and that kept them away from decaying bacteria -- it may have been a low-oxygen condition.
These rocks also are covered in little crustaceans and fish, so there maybe was some catastrophic event like an algal bloom that trapped them in a mucus mat and sunk them -- but that's conjecture. We don't really know what caused this, but something killed off a lot of animals around the lake at one time or on an annual basis."
The discovery was made possible because of the unique geography of South Korea, where the shale containing the fossils was exposed during a construction project.
"It's all black shale, and in that area it's very hilly," Selden said. "South Korea doesn't have much flat land to build anything. So, they carve away the hillsides to make a flat area, and there are temporary excavations while they're cutting away and building a factory or whatever -- that's where they found these fossils."
According to Selden, the shale preserved the spider fossils in a manner that highlighted the reflectivity of the tapetum, a feature that may have been missed had the spiders been preserved in amber instead, as is more typical.
"Amber fossils are beautiful, they look wonderful, but they preserve things in a different way," he said. "Now, we want to go back and look at the amber fossils and see if we can find the tapetum, which stares out at you from rock fossils but isn't so obvious in amber ones because the mode of preservation is so different."
Beyond the novelty of discovering the first fossilized-spider tapetum, Selden said the spiders informed the scientific understanding of Cretaceous biodiversity.
"This is an extinct family of spiders that were clearly very common in the Cretaceous and were occupying niches now occupied by jumping spiders that didn't evolve until later," he said. "But these spiders were doing things differently.
Their eye structure is different from jumping spiders. It's nice to have exceptionally well-preserved features of internal anatomy like eye structure. It's really not often you get something like that preserved in a fossil."
The above story is based on materials provided by The University of Kansas.
Flint rock preserved characteristics of the spider fossils differently than the more common amber-preserved spiders. Glowing Spider Eyes,...
Extratropical Volcanoes Influence Climate More Than Assumed
climate, volcano 4:59 PM
The eruption of Sarychev Peak in 2009 seen from the ISS. The eruption transported sulphur gases into the stratosphere.
Eruptions well north and south of the tropics strongly influence climate, contrary to conventional thinking.
In recent decades, extratropical eruptions including Kasatochi (Alaska, USA, 2008) and Sarychev Peak (Russia, 2009) have injected sulfur into the lower stratosphere. The climatic forcing of these eruptions has however been weak and short-lived.
So far, scientists have largely assumed this to be a reflection of a general rule; that extratropical eruptions lead to weaker forcing than their tropical counterparts. Researchers from the GEOMAR Helmholtz Centre for Ocean Research Kiel, the University of Oslo, the Max Planck Institute for Meteorology in Hamburg together with colleagues from Switzerland, the UK and the USA now contradict this assumption in the international journal Nature Geoscience.
"Our investigations show that many extratropical volcanic eruptions in the past 1250 years have caused pronounced surface cooling over the Northern Hemisphere, and in fact, extratropical eruptions are actually more efficient than tropical eruptions in terms of the amount of hemispheric cooling in relation to the amount of sulfur emitted by the eruptions," says Dr. Matthew Toohey from GEOMAR, first author of the current study.
Large-scale cooling after volcanic eruptions occurs when volcanoes inject large quantities of sulfur gases into the stratosphere, a layer of the atmosphere which starts at about 10-15 kilometers height. There the sulfur gases produce a sulfuric aerosol haze that persists for months or years. The aerosols reflect a portion of incoming solar radiation, which can no longer reach the lower layers of the atmosphere and the Earth's surface.
Until now, the assumption was that aerosols from volcanic eruptions in the tropics have a longer stratospheric lifetime because they have to migrate to mid or high latitudes before they can be removed. As a result they would have a greater effect on the climate. Aerosols from eruptions at higher latitudes would be removed from the atmosphere more quickly.
The recent extratropical eruptions, which had minimal but measurable effects on the climate, fit this picture. However, these eruptions were much weaker than that of Pinatubo. To quantify the climate impact of extratropical vs. tropical eruptions, Dr. Toohey and his team compared new long-term reconstructions of volcanic stratospheric sulfur injection from ice cores with three reconstructions of Northern Hemisphere summer temperature from tree rings extending back to 750 CE. Surprisingly, the authors found that extratropical explosive eruptions produced much stronger hemispheric cooling in proportion to their estimated sulfur release than tropical eruptions.
To help understand these results, Dr. Toohey and his team performed simulations of volcanic eruptions in the mid to high latitudes with sulfur amounts and injection heights equal to that of Pinatubo. They found that the lifetime of the aerosol from these extratropical explosive eruptions was only marginally smaller than for tropical eruptions. Furthermore, the aerosol was mostly contained within the hemisphere of eruption rather than globally, which enhanced the climate impact within the hemisphere of eruption.
The study goes on to show the importance of injection height within the stratosphere on the climate impact of extratropical eruptions. "Injections into the lowermost extratropical stratosphere lead to short-lived aerosol, while those with stratospheric heights similar to Pinatubo and the other large tropical eruptions can lead to aerosol lifetimes roughly similar to the tropical eruptions," says co-author Prof. Dr. Kirstin Krüger from the University of Oslo.
The results of this study will help researchers better quantify the degree to which volcanic eruptions have impacted past climate variability. It also suggests that future climate will be affected by explosive extratropical eruptions.
"There have been relatively few large explosive eruptions recorded in the extratropics compared to the tropics over the last centuries, but they definitely do happen" says Dr. Toohey. The strongest Northern Hemisphere cooling episode of the past 2500 years was initiated by an extratropical eruption in 536 CE. This new study helps explain how the 536 CE eruption could have produced such strong cooling.
The above story is based on Materials provided by Helmholtz Centre for Ocean Research Kiel (GEOMAR).
The eruption of Sarychev Peak in 2009 seen from the ISS. The eruption transported sulphur gases into the stratosphere. Eruption...
Earth's Largest Extinction Event Likely Took Plants First
Earth History, extinction, Fossils 9:03 PM
Chaleuria cirrosa fossil land plant (Lower Devonian; New Brunswick, southeastern Canada
Little life could endure the Earth-spanning cataclysm known as the Great Dying, but plants may have suffered its wrath long before many animal counterparts, says new research led by the University of Nebraska-Lincoln.
About 252 million years ago, with the planet's continental crust mashed into the supercontinent called Pangaea, volcanoes in modern-day Siberia began erupting. Spewing carbon and methane into the atmosphere for roughly 2 million years, the eruption helped extinguish about 96 percent of oceanic life and 70 percent of land-based vertebrates -- the largest extinction event in Earth's history.
Yet the new study suggests that a byproduct of the eruption -- nickel -- may have driven some Australian plant life to extinction nearly 400,000 years before most marine species perished.
"That's big news," said lead author Christopher Fielding, professor of Earth and atmospheric sciences. "People have hinted at that, but nobody's previously pinned it down. Now we have a timeline."
The researchers reached the conclusion by studying fossilized pollen, the chemical composition and age of rock, and the layering of sediment on the southeastern cliffsides of Australia. There they discovered surprisingly high concentrations of nickel in the Sydney Basin's mud-rock -- surprising because there are no local sources of the element.
Tracy Frank, professor and chair of Earth and atmospheric sciences, said the finding points to the eruption of lava through nickel deposits in Siberia. That volcanism could have converted the nickel into an aerosol that drifted thousands of miles southward before descending on, and poisoning, much of the plant life there. Similar spikes in nickel have been recorded in other parts of the world, she said.
"So it was a combination of circumstances," Fielding said. "And that's a recurring theme through all five of the major mass extinctions in Earth's history."
If true, the phenomenon may have triggered a series of others: herbivores dying from the lack of plants, carnivores dying from a lack of herbivores, and toxic sediment eventually flushing into seas already reeling from rising carbon dioxide, acidification and temperatures.
'It Lets Us See What's Possible'
One of three married couples on the research team, Fielding and Frank also found evidence for another surprise. Much of the previous research into the Great Dying -- often conducted at sites now near the equator -- has unearthed abrupt coloration changes in sediment deposited during that span.
Shifts from grey to red sediment generally indicate that the volcanism's ejection of ash and greenhouse gases altered the world's climate in major ways, the researchers said. Yet that grey-red gradient is much more gradual at the Sydney Basin, Fielding said, suggesting that its distance from the eruption initially helped buffer it against the intense rises in temperature and aridity found elsewhere.
Though the time scale and magnitude of the Great Dying exceeded the planet's current ecological crises, Frank said the emerging similarities -- especially the spikes in greenhouse gases and continuous disappearance of species -- make it a lesson worth studying.
"Looking back at these events in Earth's history is useful because it lets us see what's possible," she said. "How has the Earth's system been perturbed in the past? What happened where? How fast were the changes? It gives us a foundation to work from -- a context for what's happening now."
The above story is based on Materials provided by University of Nebraska-Lincoln. Original written by Scott Schrage.
Chaleuria cirrosa fossil land plant (Lower Devonian; New Brunswick, southeastern Canada Little life could endure the Earth-spanni...