PRESS-NEWS.org - Press Release Distribution
PRESS RELEASES DISTRIBUTION

Did the world's best-preserved dinosaurs really die in 'Pompeii-type' events?

China's famous fossils may have a more ordinary explanation

Did the world's best-preserved dinosaurs really die in 'Pompeii-type' events?
2024-11-04
(Press-News.org) Between about 120 million and 130 million years ago, during the age of dinosaurs, temperate forests and lakes hosted a lively ecosystem in what is now northeast China. Diverse fossils from that time remained pretty much undisturbed until the 1980s, when villagers started finding exceptionally preserved creatures, which fetched high prices from collectors and museums. This started a fossil gold rush. Both locals and scientists have now dug so much, their work can be seen from space―perhaps the most extensive paleontological excavations anywhere.

By the 1990s, it was clear that the so-called Yixian Formation contained uniquely well preserved remains of dinosaurs, birds, mammals, insects, frogs, turtles and other creatures. Unlike the skeletal and often fragmentary fossils unearthed in most other places, many animals came complete with internal organs, feathers, scales, fur and stomach contents. It suggested some kind of sudden, unusual preservation process at work. The finds even included a cat-size mammal and a small dinosaur locked in mortal combat, stopped in mid-action when they died. The world’s first known non-avian feathered dinosaurs showed up—some so intact that scientists worked out the feathers’ colors. The discoveries revolutionized paleontology, clarifying the evolution of feathered dinosaurs, and proving without a doubt that modern birds are descended from them.

How did these fossils come to be so perfect? The leading hypothesis up to now has been sudden burial by volcanism, perhaps like the waves of hot ash from Mt. Vesuvius that entombed many citizens of Pompeii in A.D. 79. The Yixian deposits have been popularly dubbed the “Chinese Pompeii.”

A new study says the Pompeii idea is highly appealing―and totally wrong. Instead, the creatures were preserved by more mundane events including collapses of burrows and rainy periods that built up sediments that buried the dead in oxygen-free pockets. Earlier studies have suggested that multiple Pompeii-type events took place in pulses over about a million years. The current study uses newly sophisticated technology to date the fossils to a compact period of less than 93,000 years when nothing particular happened.

The study was just published in the journal Proceedings of the National Academy of Sciences.

“These are probably the most important dinosaur discoveries of the last 120 years,” said study coauthor Paul Olsen, a paleontologist at the Columbia Climate School’s Lamont-Doherty Earth Observatory. “But what was said about their method of preservation highlights an important human bias. That is, to ascribe extraordinary causes, i.e. miracles, to ordinary events when we don’t understand their origins. These [fossils] are just a snapshot of everyday deaths in normal conditions over a relatively brief time.”

The Yixian Formation fossils come in two basic varieties: intact, perfectly articulated 3D skeletons from deposits formed mainly on land, and flattened but highly detailed carcasses found in lake sediments, some containing soft tissues.

To come up with fossil ages, the study’s lead author, Scott MacLennan of South Africa’s University of the Witwatersrand, analyzed tiny grains of the mineral zircon, taken from both surrounding rocks and the fossils themselves. Within these, he measured ratios of radioactive uranium against lead, using a new, extremely precise method called chemical abrasion isotope dilution thermal ionization mass spectroscopy, or CA-ID-TIMS. The fossils and surrounding material consistently dated to 125.8 million years ago, centered around a period of less than 93,000 years, though the exact number is not clear.

Further calculations showed that this timeframe contained three periods controlled by variations in the Earth’s orbit when the weather was relatively wet. This caused sediments to build up in lakes and on land far more rapidly than previously had been thought. Many deceased creatures were quickly buried, and oxygen that normally would fuel decomposition was sealed out. The sealing effect was fastest in lakes, resulting in the preservation of soft tissues.

The researchers rule out volcanism on multiple counts. Some previous studies have suggested that creatures were encased by lahars, fast-moving concrete-like slurries of mud that flow off volcanoes following eruptions. But lahars are extremely violent, said Olsen, and apt to rip apart any living or dead thing they encounter, so this explanation does not work.

Others have said pyroclastic flows―fast-moving waves of searing ash and poisonous gases á la Mt. Vesuvius―were responsible. These struck down residents of Pompeii, then wrapped the bodies in protective layers of material that preserved them as they were at the moment of death. Even when remains decayed, voids in the ashes remained, from which investigators have made lifelike plaster casts. The remains characteristically are curled in so-called pugilistic positions, torturously doubled over and with limbs severely drawn up, as blood boiled and bodies crumpled in the explosive heat. Victims of modern fires exhibit similar poses.

While there are in fact layers of volcanic ash, lava and intrusions of magma in the Yixian Formation, the remains there don’t match those of the unfortunate Pompeiians. For one thing, feathers, fur and everything else would almost certainly have been burned in a pyroclastic flow. For another, the dinosaurs and other animals are not in pugilistic positions; rather, many are found with arms and tails tucked cozily around their bodies, as if they were sleeping, perhaps dreaming dinosaur dreams, when death found them.

The evidence points instead to sudden burrow collapses, say the researchers. Cores of rock surrounding the skeletonized fossils generally consist of coarse grains, but grains immediately around and within the skeletons tend to be much finer. The researchers interpret this to mean that there was enough oxygen around for a while for bacteria or insects to degrade at least the animals’ skin and organs, and as this happened, whatever fine grains were in the surrounding material preferentially seeped in and filled the voids; the more decay-resistant bones remained intact. Even today, burrow collapses are a common cause of death for birds such as penguins, said Olsen. The frozen-in-time mammal-dinosaur battle may well have happened as the mammal invaded the dinosaur’s burrow to try and eat it or its babies, he said.

As to what caused the burrow collapses, this is speculation, he said. One thought: bigger dinosaurs (whose remains don’t appear here but who were almost certainly around) could have squished burrows simply by tromping around. Exceptionally rainy times could have helped destabilize the ground.

Olsen believes the Yixian Formation is not unique. “It’s just that there is no place else where such intense collecting has been done in this kind of environment,” he said. China has tried to limit for-profit fossil sales, but the market is still thriving, and huge government resources are going into development of tourism around the fossil sites.

Olsen’s personal Holy Grail is feathered dinosaurs, but these are exceedingly rare even in the richest deposits, he pointed out. “You have to dig out, say, 100,000 fish to find one feathered dinosaur, and no one is digging on the Yixian scale,” he said. Just in the eastern United States, several places that once had environments similar to the Yixian could yield such fossils, Olsen said. These include a rock quarry straddling the North Carolina-Virginia border where he has found thousands of perfectly preserved insects; sites in Connecticut where small excavations have shown promise; and a former quarry in North Bergen, N.J., now sandwiched between a highway and a strip mall that in the past yielded fabulously preserved fish and reptiles. Systematic excavations of such spots are more or less the size of a bathroom, he said.

“It takes enormous effort, which is expensive. And land is valuable in these areas,” he said. “So no one is doing it. At least not yet.”

The study was coauthored by Sean Kinney and Clara Chang of Lamont-Doherty Earth Observatory, and researchers from the Nanjing Institute of Geology and Paleontology, the Institute of Paleontology and Paleoanthropology at the Chinese Academy of Sciences, and Princeton University.

# # #

 Scientist contacts:
Paul Olsen  polsen@ldeo.columbia.edu
Scott MacLennan scott.maclennan@wits.ac.za

More information: Kevin Krajick, Senior editor, science news, Columbia Climate School/Lamont-Doherty Earth Observatory kkrajick@climate.columbia.edu 917-361-7766

END


[Attachments] See images for this press release:
Did the world's best-preserved dinosaurs really die in 'Pompeii-type' events? Did the world's best-preserved dinosaurs really die in 'Pompeii-type' events? 2 Did the world's best-preserved dinosaurs really die in 'Pompeii-type' events? 3

ELSE PRESS RELEASES FROM THIS DATE:

Not the usual suspects: Novel genetic basis of pest resistance to biotech crops

2024-11-04
If left unchecked, insect pests can devastate crops. To minimize damage and reduce the need for insecticide sprays, crops have been genetically engineered to produce bacterial proteins that kill key pests but are not harmful to people or wildlife. However, widespread planting of such transgenic crops has led to rapid adaptation by some pests. A new study in the Proceedings of the National Academy of Sciences reveals a novel genetic basis of resistance to transgenic crops in one of the most important crop pests in the United States. Researchers from the University of Arizona Department of Entomology in the College of Agriculture, Life and Environmental Sciences used genomics to investigate the ...

Jill Tarter to receive Inaugural Tarter Award for Innovation in the search for life beyond earth

Jill Tarter to receive Inaugural Tarter Award for Innovation in the search for life beyond earth
2024-11-04
Jill Tarter to Receive Inaugural Tarter Award for Innovation in the Search for Life Beyond Earth November 4, 2024, Mountain View, CA – Renowned astronomer, Dr. Jill Tarter, SETI Institute co-founder and pioneering SETI researcher, will be honored with the inaugural Tarter Award for Innovation in the Search for Life Beyond Earth at the SETI Institute’s 40th Anniversary celebration on November 20, 2024, in Menlo Park, CA. This new award recognizes individuals whose projects or ideas significantly advance humanity’s search for extraterrestrial life and intelligence. The Tarter Award honors contributions ...

Survey finds continued declines in HIV clinician workforce

2024-11-04
November 4, 2024 — The supply of healthcare professionals available to provide HIV care continues to decline, even as the need for HIV care and prevention is expected to increase, reports a survey study in the November/December issue of The Journal of the Association of Nurses in AIDS Care (JANAC). The official journal of the Association of Nurses in AIDS Care, JANAC is published in the Lippincott portfolio by Wolters Kluwer. "Our study provides new insights into the numbers and characteristics of clinicians who will be available to provide HIV care in the coming years. This information ...

Researchers home in on tumor vulnerabilities to improve odds of treating glioblastoma

Researchers home in on tumor vulnerabilities to improve odds of treating glioblastoma
2024-11-04
A team led by researchers at the University of Toronto has uncovered new targets that could be the key to effectively treating glioblastoma, a lethal type of brain cancer. These targets were identified through a screen for genetic vulnerabilities in patient-derived cancer stem cells that represent the variability found in tumours. Glioblastoma is the most common type of brain cancer in adults. It is also the most challenging to treat due to the resistance of glioblastoma cancer stem cells, from which tumours grow, to therapy. Cancer stem cells that survive after a tumour is treated go on to form new tumours that do not respond to further treatment. “Glioblastoma tumors have ...

Awareness of lung cancer screening remains low

2024-11-04
There is a lung cancer screening test that is saving lives – and yet most people who could be getting the test have never heard of it or never talked about it with a doctor. “We’ve got a screening test that works. It works as well, if not better, than breast and colorectal cancer screening in terms of mortality reduction. It's one of the most life-saving things we have for a cancer that kills more people than either of those two combined,” said lung cancer pulmonologist Gerard Silvestri, M.D. And yet, he said, “Eighty percent of those eligible for this screening, regardless of race, education, ethnicity, health or income, hadn’t heard of or ...

Hospital COVID-19 burden and adverse event rates

2024-11-04
About The Study: In this cohort study of hospital admissions among Medicare patients during the COVID-19 pandemic, greater hospital COVID-19 burden was associated with an increased risk of in-hospital adverse effects among both patients with and without COVID-19. These results illustrate the need for greater hospital resilience and surge capacity to prevent declines in patient safety during surges in demand.  Corresponding Author: To contact the corresponding author, Mark L. Metersky, MD, email metersky@uchc.edu. To access the embargoed study: Visit our For The Media website at this link https://media.jamanetwork.com/ (doi:10.1001/jamanetworkopen.2024.42936) Editor’s ...

NSF NOIRLab astronomers discover the fastest-feeding black hole in the early universe

NSF NOIRLab astronomers discover the fastest-feeding black hole in the early universe
2024-11-04
Supermassive black holes exist at the center of most galaxies, and modern telescopes continue to observe them at surprisingly early times in the Universe’s evolution. It’s difficult to understand how these black holes were able to grow so big so rapidly. But with the discovery of a low-mass supermassive black hole feasting on material at an extreme rate, seen just 1.5 billion years after the Big Bang, astronomers now have valuable new insights into the mechanisms of rapidly growing black holes in the early Universe. LID-568 was discovered ...

Translational science reviews—a new JAMA review

2024-11-04
About The Article: To help clinicians keep up with ongoing basic and translational science discoveries that affect the diagnosis and treatment of human disease, JAMA has launched a new series, “Translational Science Reviews.” These new article types are succinct and informative summaries of important basic science advances that are transforming diagnosis and treatment of human disease.  Corresponding Author: To contact the corresponding author, Mary M. McDermott, MD, email mdm608@northwestern.edu. To access the embargoed study: Visit our For The Media website at this link https://media.jamanetwork.com/ (doi:10.1001/jama.2024.21146) Editor’s Note: Please ...

How the keto diet could one day treat autoimmune disorders

2024-11-04
Scientists have long suspected the keto diet might be able to calm an overactive immune system and help some people with diseases like multiple sclerosis. Now, they have reason to believe it could be true. Scientists at UC San Francisco have discovered that the diet makes the gut and its microbes produce two factors that attenuated symptoms of MS in mice. If the study translates to humans, it points toward a new way of treating MS and other autoimmune disorders with supplements. The keto diet severely restricts carbohydrate-rich ...

Influence of tool corner radius on chip geometrical characteristics of machining Zr-based bulk metallic glass

Influence of tool corner radius on chip geometrical characteristics of machining Zr-based bulk metallic glass
2024-11-04
Different from traditional alloys, BMGs exhibit a unique atomic arrangement characterized by short-range order and long-range disorder at the atomic level. Such atomic structure leads to the absence of defects such as grain boundaries and dislocations, resulting in exceptional mechanical properties. The promising properties of BMGs have rapidly positioned them as a new class of structural and functional materials, showing great application potential in various fields including structural, energy and chemical engineering. In order to facilitate their engineering applications, research has reported their cutting characteristics from various aspects, ...

LAST 30 PRESS RELEASES:

Bacteria breakthrough could accelerate mosquito control schemes

Argonne to help drive AI revolution in astronomy with new institute led by Northwestern University

Medicaid funding for addiction treatment hasn’t curbed overdose deaths

UVA co-leads $2.9 million NIH investigation into where systems may fail people with disabilities

With the help of AI, UC Berkeley researchers confirm Hollywood is getting more diverse

Weight loss interventions associated with improvements in several symptoms of PCOS

Federal government may be overpaying for veterans’ health care in Medicare Advantage plans

Researchers awarded $2.5 million grant to increase lung cancer screenings in underserved communities

New trigger proposed for record-smashing 2022 Tonga eruption

Lupus Research Alliance announces Lupus Research Highlights at ACR Convergence 2024

Satellite imagery may help protect coastal forests from climate change

The secrets of baseball's magic mud

Toddlers understand concept of possibility

Small reductions to meat production in wealthier countries may help fight climate change, new analysis concludes

Scientists determine why some patients don’t respond well to wet macular degeneration treatment, show how new experimental drug can bridge gap

Did the world's best-preserved dinosaurs really die in 'Pompeii-type' events?

Not the usual suspects: Novel genetic basis of pest resistance to biotech crops

Jill Tarter to receive Inaugural Tarter Award for Innovation in the search for life beyond earth

Survey finds continued declines in HIV clinician workforce

Researchers home in on tumor vulnerabilities to improve odds of treating glioblastoma

Awareness of lung cancer screening remains low

Hospital COVID-19 burden and adverse event rates

NSF NOIRLab astronomers discover the fastest-feeding black hole in the early universe

Translational science reviews—a new JAMA review

How the keto diet could one day treat autoimmune disorders

Influence of tool corner radius on chip geometrical characteristics of machining Zr-based bulk metallic glass

Megan Huisingh-Scheetz, MD, MPH, of the University of Chicago recognized with AFAR’s Terrie Fox Wetle Rising Star Award in Health Services and Aging Research

Steven N. Austad, PhD, to receive inaugural George M. Martin Lifetime Achievement in Mentoring Award

Jeremy D. Walston, MD, of Johns Hopkins University to receive AFAR 2024 Irving S. Wright Award of Distinction

SwRI receives $23 million in U.S. Air Force contracts to sustain aging aircraft

[Press-News.org] Did the world's best-preserved dinosaurs really die in 'Pompeii-type' events?
China's famous fossils may have a more ordinary explanation