wjfox wrote: ↑Tue Oct 04, 2022 6:50 pmAsteroid that wiped out the dinosaurs also triggered a global tsunami
Published 1:59 PM EDT, Tue October 4, 2022
When a city-size asteroid slammed into Earth 66 million years ago, it wiped out the dinosaurs – and sent a monster tsunami rippling around the planet, according to new research.
[...]
It’s the first global simulation of the tsunami caused by the Chicxulub impact to be published in a peer-reviewed scientific journal, according to the authors.
The tsunami was powerful enough to create towering waves more than a mile high and scour the ocean floor thousands of miles away from where the asteroid hit, according to the study. It effectively wiped away the sediment record of what happened before the event, as well as during it.
“This tsunami was strong enough to disturb and erode sediments in ocean basins halfway around the globe, leaving either a gap in the sedimentary records or a jumble of older sediments,” said lead author Molly Range, who began working on the study as an undergraduate student and completed it for her master’s thesis at the University of Michigan.
Researchers estimate that the tsunami was up to 30,000 times more energetic than the December 26, 2004 Indian Ocean tsunami, one of the largest on record, that killed more than 230,000 people. The energy of the asteroid impact was at least 100,000 times larger than the Tonga volcanic eruption earlier this year.
I'd bet the wave would look kind of like the one in 2012. It was probably still 500+ even entering the indian ocean. Imagine such a tsunami happening now. 5 billion people dead?
weatheriscool wrote: ↑Wed Oct 05, 2022 5:43 am
Imagine such a tsunami happening now. 5 billion people dead?
Difficult to calculate, but around 40% of the world's population lives within 100 km of the coast.
I think casualties from the immediate impact wouldn't actually be that high (relatively speaking). Most deaths would probably come later, from the plunging temperatures and collapse of agriculture.
It seems unlikely that the human race could survive an impact on the scale of Chicxulub. It would be a thoroughly miserable end. Only a few mammals smaller than, say, a cat, would survive – in underground burrows, etc.
The Big Bang theory explains where all the hydrogen and helium in the universe came from.
In the 1940s, Ralph Alpher and George Gamow calculated that the early universe was hot and dense enough to make virtually all the helium, lithium and deuterium (hydrogen with a neutron attached) present in the cosmos today; later research showed where the primordial hydrogen came from. This is known as “Big Bang nucleosynthesis,” and it stands as one of the most successful predictions of the theory. The heavier elements (such as oxygen, iron and uranium) were formed in stars and supernova explosions.
The best evidence for the Big Bang is in the form of microwaves. Early on, the whole universe was dense enough to be completely opaque. But at a time roughly 380,000 years after the Big Bang, expansion spread everything out enough to make the universe transparent.
The light released from this transition, known as the cosmic microwave background (CMB), still exists. It was first observed in the 1960s by Arno Penzias and Robert Wilson. That discovery cemented the Big Bang theory as the best description of the universe; since then, observatories such WMAP and Planck have used the CMB to tell us a lot about the total structure and content of the cosmos.
Some 66 million years ago, a 10-kilometer asteroid hit Earth, triggering the extinction of the dinosaurs. New evidence suggests that the Chicxulub impact also triggered an earthquake so massive that it shook the planet for weeks to months after the collision. The amount of energy released in this "mega-earthquake" is estimated at 1023 joules, which is about 50,000 times more energy than was released in the magnitude 9.1 Sumatra earthquake in 2004.
Hermann Bermúdez will present evidence of this "mega-earthquake" at the upcoming GSA Connects meeting in Denver this Sunday, October 9. Earlier this year, Bermúdez visited outcrops of the infamous Cretaceous-Paleogene (K-Pg) mass extinction event boundary in Texas, Alabama, and Mississippi to collect data, supplementing his previous work in Colombia and Mexico documenting evidence of the catastrophic impact.
Research Finds Unprecedented Levels of Insects Damaging Plants October 10, 2022
Introduction:
(EurekAlert) Insects today are causing unprecedented levels of damage to plants, even as insect numbers decline, according to new research led by University of Wyoming scientists.
The first-of-its-kind study compares insect herbivore damage of modern-era plants with that of fossilized leaves from as far back as the Late Cretaceous period, nearly 67 million years ago. The findings appear in the prestigious journal Proceedings of the National Academy of Sciences.
“Our work bridges the gap between those who use fossils to study plant-insect interactions over deep time and those who study such interactions in a modern context with fresh leaf material,” says the lead researcher, UW Ph.D. graduate Lauren Azevedo-Schmidt, now a postdoctoral research associate at the University of Maine. “The difference in insect damage between the modern era and the fossilized record is striking.”
Azevedo-Schmidt conducted the research along with UW Department of Botany and Department of Geology and Geophysics Professor Ellen Currano, and Assistant Professor Emily Meineke of the University of California-Davis.
The study examined fossilized leaves with insect feeding damage from the Late Cretaceous through the Pleistocene era, a little over 2 million years ago, and compared them with leaves collected by Azevedo-Schmidt from three modern forests. The detailed research looked at different types of damage caused by insects, finding marked increases in all recent damage compared to the fossil record.
caltrek’s comment: The article goes on to explain how human activities may account for the differences. The way things are going, this means the results of such studies will be restricted to a postgraduate audience.
Why?
Because presenting these results to younger people might make them “feel bad” about themselves. Better to condemn the future of our biosphere to continued degradation than present anything that might make children “feel bad” about themselves. Of course, in such circumstances, one suspects that it is the tender feelings of parents which is really at center stage.
Ostrich-like dinosaurs found in Mississippi are among the world's largest ornithomimosaurs at more than 800 kg https://phys.org/news/2022-10-ostrich-l ... rgest.html
by Public Library of Science
Ostrich-like dinosaurs called ornithomimosaurs grew to enormous sizes in ancient eastern North America, according to a study published October 19, 2022, in the open-access journal PLOS ONE by Chinzorig Tsogtbaatar of the North Carolina Museum of Natural Sciences and colleagues.
During the Late Cretaceous Period, North America was split by a seaway into two landmasses: Laramidia to the west and Appalachia to the east. But fossils from Appalachia are rare, and therefore ancient ecosystems from this region are poorly understood. In this study, Chinzorig and colleagues describe new fossils of ornithomimosaur dinosaurs from the Late Cretaceous Eutaw Formation of Mississippi.
Ornithomimosaurs, the so-called "bird-mimic" dinosaurs, were superficially ostrich-shaped with small heads, long arms, and strong legs. The new fossils, including foot bones, are around 85 million years old, making them a rare glimpse into a poorly known interval of North American dinosaur evolution
By comparing the proportions of these fossils and the patterns of growth within the bones, the authors determined that the fossils likely represent two different species of ornithomimosaurs, one relatively small and one very large. They estimate the larger species to have weighed over 800 kg, and the individual examined was likely still growing when it died. This makes it among the largest ornithomimosaurs known.
How Magnetism Could Help Explain Earth’s Formation November 2, 2022
Introduction:
(EurekAlert) There are several theories about how the Earth and the Moon were formed, most involving a giant impact. They vary from a model where the impacting object strikes the newly formed Earth a glancing blow and then escapes, through to one where the collision is so energetic that both the impactor and the Earth are vaporized.
Now scientists at the University of Leeds and the University of Chicago have analysed the dynamics of fluids and electrically conducting fluids and concluded that the Earth must have been magnetized either before the impact or as a result of it.
They claim this could help to narrow down the theories of the Earth-Moon formation and inform future research into what really happened.
Professor David Hughes, an applied mathematician in the School of Mathematics at the University of Leeds, said: “Our new idea is to point out that our theoretical understanding of the Earth’s magnetic field today can actually tell us something about the very formation of the Earth-Moon system.
“At first glance, this seems somewhat surprising, and previous theories had not recognized this potentially important connection.”
With wings spanning nearly 16 feet, a new species of pterosaurs has been identified from the Atlantic coast of Angola.
An international team, including two vertebrate paleontologists from Southern Methodist University (SMU), named the new genus and species Epapatelo otyikokolo. This flying reptile of the dinosaur age was found in the same region of Angola as fossils from large marine animals currently on display at the Smithsonian's National Museum of Natural History.
Pterosaur fossils that date back to the Late Cretaceous are extremely rare in sub-Saharan Africa, said team member Michael J. Polcyn, research associate in the Huffington Department of Earth Sciences and senior research fellow, ISEM at SMU (Southern Methodist University).
"This new discovery gives us a much better understanding of the ecological role of the creatures that were flying above the waves of Bentiaba, on the west coast of Africa, approximately 71.5 million years ago," Polcyn said.
Paleontologist Louis L. Jacobs, SMU professor emeritus of earth sciences and president of ISEM, an interdisciplinary institute at the university, also collaborated on the research. The team's findings were published in the journal Diversity.
Hundred-year-old Riddle in Botany Reveals Key Plant Adaptation to Dry Land November 10, 2022
Introduction:
(EurekAlert) Průhonice, Czech Republic - The green world that we live in would not have been possible without hidden changes to the plant body over the last 400 million years. To grow beyond just centimetres tall outside of the wettest places on land, plants had to re-arrange their water-conducting tissues to keep them safe from drought. A new study by Martin Bouda of the Institute of Botany of the Czech Academy of Science and co-authors, published in the journal Science, shows how the solution to a hundred-year-old debate in botany reveals a key adaptation that allowed plants to colonise dry land.
Background: All but the tiniest plants need vascular tissues to supply water throughout their body and avoid drying out as they capture carbon from the surrounding air. If a plant is subjected to drought, the chain of water molecules being pulled up the stem can break, forming an embolism: a bubble of gas that blocks water transport in one entire vascular conduit. If embolism spreads from this conduit throughout the tissue, the plant’s water-supplying vasculature becomes effectively blocked, the plant dries out and dies.
The new discovery shows that the original arrangement of vascular tissues—a cylinder at the centre of the stem—becomes increasingly vulnerable to embolism spread with size. "If conduits are all bundled up together the plant may face exponential spread of embolism on the resulting vascular network. If they are strung out in a long narrow shape, embolism has to overcome many successive cell walls to go very far, which can save the plant’s life in a drought,” says Dr. Bouda, the lead author of the study.
The first vascular plants were just centimetres tall and constrained to live where water was readily available. To grow taller and begin exploring the landscape, they first had to find alternatives to their ancestral vascular arrangement. “We were struck by the fact that only very few living plants have kept the original layout of the stem, which puts the vascular tissue in a cylinder right at the centre. That seeming detail actually held the key to deciphering this whole evolutionary episode,” adds Bouda.
A pair of researchers from the Federal University of Santa Maria working with a colleague from the Federal University of Juiz de Fora, have identified a new species of Triassic-era reptile that was unearthed recently at a dig site in Brazil.
In their paper published in Journal of Systematic Palaeontology, Rodrigo Temp Müller, Mauricio Silva Garcia and André de Oliveira Fonseca, describe the fossil they found and where the new species fits in the historical record.
Paleontologists have been working for some time at the Rio Grande do Sul dig site in Brazil, and in so doing have found a large number of dinosaur bones. During that time, few reptile remains have been found, however.
Thus, the researchers were surprised when they found a complete leg fossil from an unknown ancient reptile, along with configurations of the foot that was once attached to it. The researchers knew the fossils were ancient; the rock around them has been dated to 230 million years ago—during a time when the dinosaurs were still roaming the earth.
Subsequent analysis of the fossil showed that it belonged to an ancient class of reptiles called proterochampsids—a group that had only ever been found in Argentina and Brazil. Prior research has shown that despite having physical characteristics similar to modern crocodiles and alligators, no strong degree of kinship has been found.
The researchers also found that the fossil represented a species that had not been seen before, which meant that they got to name it. They chose Tenoscelida aurantiacus, a nod to the slenderness of the leg and the orange color of the rocky bed in which it was found.
Based on the size of the fossil, the researchers estimated the creature would have been approximately 1.40 meters long, and would have walked on all-fours. They also suspect, based on similar species of the time, that the reptile was a meat eater. They opine that its build lent itself to a life near the water, similar to modern alligators.
wjfox wrote: ↑Tue Oct 04, 2022 6:50 pmAsteroid that wiped out the dinosaurs also triggered a global tsunami
Published 1:59 PM EDT, Tue October 4, 2022
When a city-size asteroid slammed into Earth 66 million years ago, it wiped out the dinosaurs – and sent a monster tsunami rippling around the planet, according to new research.
[...]
It’s the first global simulation of the tsunami caused by the Chicxulub impact to be published in a peer-reviewed scientific journal, according to the authors.
The tsunami was powerful enough to create towering waves more than a mile high and scour the ocean floor thousands of miles away from where the asteroid hit, according to the study. It effectively wiped away the sediment record of what happened before the event, as well as during it.
“This tsunami was strong enough to disturb and erode sediments in ocean basins halfway around the globe, leaving either a gap in the sedimentary records or a jumble of older sediments,” said lead author Molly Range, who began working on the study as an undergraduate student and completed it for her master’s thesis at the University of Michigan.
Researchers estimate that the tsunami was up to 30,000 times more energetic than the December 26, 2004 Indian Ocean tsunami, one of the largest on record, that killed more than 230,000 people. The energy of the asteroid impact was at least 100,000 times larger than the Tonga volcanic eruption earlier this year.
Artificial Intelligence Indicates Dinosaur Footprints Belonged to a Predator by Jens N. Lallensack, Anthony Romilio and Peter L. Falkingham
November 9, 2022
Introduction:
(The Royal Society) Fossil tracks are important palaeobiological data sources. The quantitative analysis of their shape, however, has been hampered by their high variability and lack of discrete margins and landmarks. We here present the first approach using deep convolutional neural networks (DCNNs) to study fossil tracks, overcoming the limitations of previous statistical approaches. We employ a DCNN to discriminate between theropod and ornithischian dinosaur tracks based on a total of 1372 outline silhouettes. The DCNN consistently outperformed human experts on an independent test set. We also used the DCNN to classify tracks of a large tridactyl trackmaker from Lark Quarry, Australia, the identity of which has been subject to intense debate. The presented approach can only be considered a first step towards the wider application of machine learning in fossil track research, which is not limited to classification problems. Current limitations, such as the subjectivity and information loss inherent in interpretive outlines, may be overcome in the future by training neural networks on three-dimensional models directly, though this will require an increased uptake in digitization among workers in the field.
Earth Might Be Experiencing 7th Mass Extinction, Not 6th – “A True Decrease in the Abundance of Organisms”
NOVEMBER 25, 2022
550-million-year-old creatures’ message to the present.
Earth is currently in the midst of a mass extinction, losing thousands of species each year. New research suggests environmental changes caused the first such event in history, which occurred millions of years earlier than scientists previously realized.
“We’ve shown a true decrease in the abundance of organisms.” — Chenyi Tu
Most dinosaurs famously disappeared 66 million years ago at the end of the Cretaceous period. Prior to that, a majority of Earth’s creatures were snuffed out between the Permian and Triassic periods, roughly 252 million years ago.
Patagotitan: Colossal dinosaur heading for UK display
10 hours ago
A replica of what could have been the largest animal ever to walk on land is coming to London in the New Year.
A cast of the sauropod dinosaur known as Patagotitan will go on show at the Natural History Museum - assuming it fits within the gallery space.
Measuring some 35m (115ft) from nose to tail, the beast could have weighed up to 60 or 70 tonnes in life.
"We should be able to get it in but there won't be much wriggle room," said exhibition developer Sinéad Marron.
The replica skeleton is being loaned from Argentina's Museo Paleontológico Egidio Feruglio (MEF), whose staff excavated the animal's giant bones in 2014.
Three researchers, one with the University of Michigan, the other two with the University of Casablanca, have found a skull and partial skeleton in Morocco that they suggest link together several species of ancient whales. In their paper published in the open access journal PLOS ONE, Philip Gingerich, Ayoub Amane and Samir Zouhri describe the fossils and how they tie together the evolution of land-based creatures that evolved into modern whales.
The fossils found by the researchers were dated to approximately 40 million years ago (during the Eocene) and were identified as a member of Basilosaurid, a family of ancient whales that were land-based but had developed multiple aquatic adaptions, such as flippers. Prior research has shown they lived around what is now Africa, North America and Europe.
Eventually (over the ensuing 5 million years) they evolved to become modern whales. But the researchers noted differences in the fossils that connect several types of whales that belonged to the species Antaecetus, such as Pachycetus paulsonii and Pachycetus wardii. The differences were great enough to earn the fossil its own genus, Antaecetus aithai. The main trait that differentiated it from the others was its comparatively small skull.
The researchers note that members of the species were known to have thick, dense bones that hint at musculature, but they also suggest that they were relatively slow swimmers and not agile in the water. It has been theorized that because they were still evolving from land animals to sea creatures, it is likely they had a large lung capacity.
Fossils of a tiny sea creature that died more than half a billion years ago may compel a science textbook rewrite of how brains evolved.
A study published in Science—led by Nicholas Strausfeld, a Regents Professor in the University of Arizona Department of Neuroscience, and Frank Hirth, a reader of evolutionary neuroscience at King's College London—provides the first detailed description of Cardiodictyon catenulum, a wormlike animal preserved in rocks in China's southern Yunnan province. Measuring barely half an inch (less than 1.5 centimeters) long and initially discovered in 1984, the fossil had hidden a crucial secret until now: a delicately preserved nervous system, including a brain.
67-million-year-old Fossil Upends Bird Evolutionary Tree by Dyani Lewis
November 30, 2022
Introduction:
(Nature) A prehistoric toothed bird that lived 67 million years ago is turning the bird tree of life on its head. The bird — named Janavis finalidens — shares crucial features with its modern cousins such as chickens and ducks, which is forcing a rethink about bird evolution*.
A stone-encased fossil was plucked from a Belgian quarry two decades ago2. It was found in a geological layer that dates back to the Late Cretaceous period (100.5 million to 66 million years ago), just before the mass extinction event that wiped out all non-avian dinosaurs. At the time of the fossil’s discovery, it seemed to comprise just a handful of bones from the spine, wings, shoulders and legs.
Daniel Field, a palaeontologist at the University of Cambridge, UK, and his colleagues re-examined the bones using micro-computed tomography to better investigate the creature’s anatomy. From those scans, they were able to describe the specimen as a new species of ancient bird that shared a common ancestor with modern birds. When it lived, Janavis finalidens would have been similar in size to a grey heron. The study is published in Nature today.
The team also discovered that one of the bones, previously thought to be a shoulder bone, was actually from the skull — a bone called the pterygoid. “It is from a very interesting part of the skull, from the bony palate of the bird,” says Field. The bony palate has crucial features that researchers use to group birds, both living and extinct.
A team of researchers from Seoul National University, the University of Alberta and the Mongolian Academy of Sciences has identified the first known example of a streamlined, non-avian theropod dinosaur to walk on two legs. In their paper published in Communications Biology, the group describes where the fossil was found, its condition, and its features that were used to help identify it as a new dinosaur species.
The dinosaur was excavated at the Hermiin Tsav fossil formation in Mongolia back in 2008 as part of the Korean-Mongolian International Dinosaur Expedition. Since that time, it has been in storage with hundreds of other fossils awaiting study by experts.
In their study of the fossil, the researchers found it to be well-preserved and nearly complete—it had most of its two hindlimbs, one of its forelimbs, most of its skull and most of its spinal column. It also had a mouthful of teeth. The researchers noted that the skeleton was similar in shape to many modern water birds, sleek and trim, suggesting it lived on or near the water and survived by fishing offshore.
The researchers also noted that its ribs pointed toward its tail, another common feature of waterbirds. But it was not avian—there was no sign of wings. The researchers also noted that the overall shape of the skeleton suggested very strongly that it did not use its forelimbs for walking, likely giving it a penguin-like gait.
It was probably still 500+ even entering the indian ocean. Imagine such a tsunami happening now. 5 billion people dead?
