Prehistoric Flora & Fauna

Ash From Dinosaur-Era Volcanoes Linked With Shale Oil, Gas

Thursday, March 15, 2018

Nutrient-rich ash from an enormous flare-up of volcanic eruptions toward the end of the dinosaurs' reign kicked off a chain of events that led to the formation of shale gas and oil fields from Texas to Montana.

That's the conclusion of a new study by Rice University geologists that appears this week in Nature Publishing's online journal Scientific Reports.

"One of the things about these shale deposits is they occur in certain periods in Earth's history, and one of those is the Cretaceous time, which is around the time of the dinosaurs," said study lead author Cin-Ty Lee, professor and chair of Rice's Department of Earth, Environmental and Planetary Sciences. "This was about 90 million to 100 million years ago, which is about the same time as a massive flare-up of arc volcanoes along what is today the Pacific rim of the Western United States."

Advances in horizontal drilling and hydraulic fracturing over the past 20 years led to a U.S. energy boom in "unconventionals," a category that includes the shale gas and "tight" oil found in shale fields like the Cretaceous Eagle Ford and Mowry and older ones like the Barnett and Bakken.

An enormous volcanic flare-up at the end of the dinosaurs’ reign kicked off a chain of events that led to the formation of the U.S. shale oil and gas fields from Texas to Montana. Rice University geologists said older shale gas fields, like the Marcellus in Pennsylvania and Ohio, may have formed from similar volcanic flare-ups hundreds of millions of years earlier. Credit: Wikimedia Commons

"These types of natural gas and oil are in tiny, tiny pores that range from a few millionths of a meter in diameter to a few thousandths of a meter," Lee said. "The deposits are in narrow bands that can only be accessed with horizontal drilling, and the oil and gas are locked in these little pockets and are only available with techniques like hydraulic fracturing."

Lee said that there have always been hints of a connection between ancient volcanic eruptions and unconventional shale hydrocarbons. During field trips out to West Texas, he and Rice students noticed hundreds of ash layers in exposed rock that dated to the Cretaceous period when much of western North America lay beneath a shallow ocean.

One of these trips happened in 2014 while Lee and Rice colleagues also were studying how a flare-up of Cretaceous-era arc volcanoes along the U.S. Pacific rim had impacted Earth's climate through enhanced volcanic production of carbon dioxide.

"We had seen ash layers before, but at this site we could see there were a lot of them, and that got us thinking," Lee said. Lee, graduate student Hehe Jiang and Rice undergraduates Elli Ronay, Jackson Stiles and Matthew Neal decided to investigate the ash beds in collaboration with Daniel Minisini, a colleague at Shell Oil who had been doing extensive work on quantifying the exact number of ash beds.

"It's almost continuous," Lee said. "There's an ash layer at least every 10,000 years."

The eruption of Alaska’s Pavlof Volcano as seen from the International Space Station May 18, 2013. The volcano’s ash cloud rose to 20,000 feet and extended over hundreds of miles of the northern Pacific Ocean. Credit: NASA/ISS Crew Earth Observations experiment and Image Science and Analysis Laboratory, Johnson Space Center

Lee said the team determined that ash had come from hundreds of eruptions that spanned some 10 million years. The layers had been transported several hundred miles east of their volcanic source in California. The ash was deposited on the seafloor after being blown through plumes that rose miles into the atmosphere and drifted over the ocean. Lee and students analyzed samples of the ash beds in the geochemical facilities at Rice.

"Their chemical composition didn't look anything like it would have when they left the volcano," he said. "Most of the original phosphorus, iron and silica were missing."

That brought to mind the oceanic "dead zones" that often form today near the mouths of rivers. Overfertilization of farms pumps large volumes of phosphorus down these rivers. When that hits the ocean, phytoplankton gobble up the nutrients and multiply so quickly they draw all the available oxygen from the water, leaving a "dead" region void of fish and other organisms.

Lee suspected the Cretaceous ash plumes might have caused a similar effect. To nail down whether the ash could have supplied enough nutrients, Lee and his team used trace elements like zirconium and titanium to match ash layers to their volcanic sources. By comparing rock samples from those sources with the depleted ash, the team was able to calculate how much phosphorus, iron and silica were missing.

"Normally, you don't get any deposition of organic matter at the bottom of the water column because other living things will eat it before it sinks to the bottom," Lee said. "We found the amount of phosphorus entering the ocean from this volcanic ash was about 10 times more than all the phosphorus entering all the world's oceans today. That would have been enough to feed an oxygen-depleted dead zone where carbon could be exported all the way down to the sediment."

The combination of the ashfall and oceanic dead zone concentrated enough carbon to form hydrocarbons.

Oxygen-depleted “dead zones” often form in the northern Gulf of Mexico due to nutrient-rich runoff from the Mississippi and Atchafalaya rivers, which are seen here as tan and greenish-brown plumes visible from the International Space Station in 2012. Nutrient-rich volcanic ash may have fed similar dead zones that produced shale oil and gas fields from Texas to Montana. Credit: NASA/GSFC/Aqua MODIS

"To generate a hydrocarbon deposit of economic value, you have to concentrate it," Lee said. "In this case, it got concentrated because the ashes drove that biological productivity, and that's where the organic carbon got funneled in."

Lee said shale gas and tight oil deposits are not found in the ash layers but appear to be associated with them. Because the layers are so thin, they don't show up on seismic scans that energy companies use to look for unconventionals. The discovery that hundreds of closely spaced ash layers could be a tell-tale sign of unconventionals might allow industry geologists to look for bulk properties of ash layers that would show up on scans, Lee said.

"There also are implications for the nature of marine environments," he said. "Today, phosphorus is also a limiting nutrient for the oceans, but the input of the phosphorus and iron into the ocean from these volcanoes has major paleoenvironmental and ecological consequences."

While the published study looked specifically at the Cretaceous and North America, Lee said arc volcano flare-ups at other times and locations on Earth may also be responsible for other hydrocarbon-rich shale deposits.

"I suspect they could," he said. "The Vaca Muerta field in Argentina is the same age and was behind the same arc as what we were studying. The rock record gets more incomplete as you go further back in time, but in terms of other U.S. shales, the Marcellus in Pennsylvania was laid down more than 400 million years ago in the Ordovician, and it's also associated with ashes."

More information: Cin-Ty A. Lee et al. Volcanic ash as a driver of enhanced organic carbon burial in the Cretaceous, Scientific Reports (2018). DOI: 10.1038/s41598-018-22576-3

Journal reference: Scientific Reports

Provided by: Rice University


Paleontologists Find ‘Bubbles of Oxygen’ in 1.6-Billion-Year-Old Stromatolites

Thursday, March 8, 2018

Fossilized bubbles and cyanobacterial fabric from 1.6 billion-year-old phosphatized microbial mats of the Chitrakoot Formation in central India. Image credit: Stefan Bengtson.

An international research team led by Swedish Museum of Natural History scientists has found that stromatolites (solid, laminar structures of biological origin) from the 1.6-billion-year-old Chitrakoot Formation in India contain abundant fossilized oxygen bubbles.

“Microbes were the first life forms on Earth,” said lead author Dr. Therese Sallstedt, from the Department of Paleobiology at the Swedish Museum of Natural History, and colleagues.

“They turned our planet into a tolerable environment for plants and animals and thus their activity paved the way for life as we know it today.”

“Some of these early microbes were cyanobacteria that thrived in early shallow waters. They produced oxygen by photosynthesis, and sometimes the oxygen got trapped as bubbles within sticky microbial mats.”

Dr. Sallstedt’s team studied fossilized sediments from central India and found round spheres in the microbial mats.

Fossilized bubbles and cyanobacterial fabric from 1.6 billion-year-old phosphatized microbial mats of the Chitrakoot Formation. Image credit: Stefan Bengtson.

Dr. Sallstedt’s team studied fossilized sediments from central India and found round spheres in the microbial mats.

These ‘bubbles’ were created by tiny microbes in what was once a shallow sea somewhere on the young Earth, according to the researchers.

“We interpret them as oxygen bubbles created in cyanobacterial biomats in shallow waters 1.6 billion years ago,” Dr. Sallstedt said.

SEM micrograph of the fossilized bubbles. Image credit: Stefan Bengtson.

“Cyanobacteria changed the face of the Earth irreversibly since they were responsible for oxygenating the atmosphere. Simultaneously they constructed stromatolites, which still exist on Earth today,” the paleontologists said.

“We now think that cyanobacteria played a larger role than previously believed in creating phosphorites in shallow waters, thereby allowing today’s scientists a unique window into ancient ecosystems.”

The team’s findings were published in the March 2018 issue of the journal Geobiology.


T. Sallstedt et al. 2018. Evidence of oxygenic phototrophy in ancient phosphatic stromatolites from the Paleoproterozoic Vindhyan and Aravalli Supergroups, India. Geobiology 16 (2): 139-159; doi: 10.1111/gbi.12274


New Research Sheds Light on Dinosaurs of ‘Lost Landmass’ of Appalachia

Thursday, February 22, 2018

Paleogeography of North America during the late Campanian Stage of the Late Cretaceous (~75 Ma). Modified after Blakey.

Around 90 million years ago, eastern and western North America were isolated from each other by a salty sea, creating two landmasses: Appalachia and Laramidia. The ancestors of Triceratops and Tyrannosaurus strutted about on the latter in what would one day become Utah and Alberta, leaving plentiful bones behind. A lack of fossils from eastern North America, however, has obscured Appalachia, leading to it being called a ‘lost landmass.’ Now, new research is broadening our knowledge of the dinosaurs that lived and died near the major metropolises of the eastern United States and Canada.

Dinosaurs from eastern North America have always been regarded as rather strange by scientists.

One relative of Tyrannosaurus rex from New Jersey has gigantic hands tipped with giant claws, a far cry from the notoriously puny arms of its western cousin. Giant duck-billed dinosaurs, more than 35 feet long from beak to tail, left their remains in the sediments of North Carolina.

All named eastern North American dinosaurs are known only from incomplete or fragmentary skeletons. Unlike the world-class fossil deposits of the American West, eastern North American sediments usually produce only the stray bone shard or tooth.

Unfortunately, this lack of fossils from eastern North America has hindered attempts at better understanding the distribution and evolution of dinosaurs during a period known as the Cretaceous, which lasted from about 140-65 million years ago.

For the past few years, Chase Brownstein, a research associate of paleontology at the Stamford Museum & Nature Center in Stamford, Connecticut, has been investigating this issue.

The paleontologist tallied up reports of dinosaurs from across the eastern part of the continent as presented in publications spanning over 150 years of scientific inquiry.

“This is, to my knowledge, the most complete review of eastern North American dinosaurs out there,” he said.

Additionally, Brownstein compared the compiled Appalachian dinosaur faunas to each other and to those from the American West to understand how the former changed from the latter during the 30 million year period of their separation.

The results suggest that eastern North American dinosaur faunas were not only distinct from those of the west, but also that the former were by-and-large composed of species rather more ‘primitive’ than their relatives from western North America and Asia, a hypothesis that has been gaining ground in recent years.

Additionally, the new research may show that the dinosaur wildlife from different parts of Appalachia differed from that of other areas of the landmass.

“A phenomenon known as faunal provincialism, in which different regions of a larger area have distinct assortments of species, may have occurred on Laramidia, and only recently has it been proposed for Appalachian dinosaurs,” Brownstein said.

“The new data does seem to indicate limited provincialism may have occurred among Appalachian dinosaur faunas, but future research will be needed to better substantiate this hypothesis.”

This research was published in the journal Palaeontologia Electronica.


Chase D. Brownstein. 2018. The biogeography and ecology of the Cretaceous non-avian dinosaurs of Appalachia. Palaeontologia Electronica 21.1.5A: 1-56; doi: 10.26879/801


Flowering Plants Originated Between 149 and 256 Million Years Ago, Researchers Say

Sunday, February 11, 2018

Flowering plants likely originated between 149 million years ago (Jurassic period) and 256 million years ago (Permian period). Image credit: Ilona Ilyés.

Angiosperms (flowering plants) are neither as old as suggested by previous molecular studies, nor as young as a literal interpretation of their fossil record, according to new research.

“The discrepancy between estimates of angiosperm evolution from molecular data and fossil records has caused much debate,” said co-author Dr. Jose Barba-Montoya, of University College London.

“Even Darwin described the origin of this group as an ‘abominable mystery’.”

“To uncover the key to solving the mystery of when flowers originated, we carefully analyzed the genetic make-up of flowering plants, and the rate at which mutations accumulate in their genomes.”

Through the lens of the fossil record, angiosperms appear to have diversified suddenly, precipitating a Cretaceous Terrestrial Revolution in which pollinators, herbivores and predators underwent explosive co-evolution.

Molecular-clock dating studies, however, have suggested a much older origin for angiosperms, implying a cryptic evolution of flowers that is not documented in the fossil record.

“In large part, the discrepancy between these two approaches is an artifact of false precision on both paleontological and molecular evolutionary timescales,” said co-lead author Professor Philip Donoghue, from the University of Bristol.

Paleontological timescales calibrate the family tree of plants to geological time based on the oldest fossil evidence for its component branches.

Molecular timescales build on this approach, using additional evidence from genomes for the genetic distances between species, aiming to overcome gaps in the fossil record.

“Previous studies into molecular timescales failed to explore the implications of experimental variables and so they inaccurately estimate the probable age of flowering plants with undue precision,” said co-lead author Professor Ziheng Yang, of University College London.

“Similarly, interpretations of the fossil record have not fully recognized its shortcomings as an archive of evolutionary history, that is, that the oldest fossil evidence of angiosperms comes from very advanced, not primitive flowering plant lineages,” Professor Donoghue said.

The team compiled a large collection of genetic data for many angiosperm groups including a dataset of 83 genes from 644 taxa, together with a comprehensive set of fossil evidence to address the timescale of angiosperm diversification.

“By using Bayesian statistical methods that borrow tools from physics and mathematics to model how the evolutionary rate changes with time, we showed that there are broad uncertainties in the estimates of flowering plant age, all compatible with early to mid-Cretaceous origin for the group,” said co-author Dr. Mario dos Reis, from Queen Mary University of London.

This research was presented in a paper published in the journal New Phytologist on February 5, 2018.


Jose Barba-Montoya et al. Constraining uncertainty in the timescale of angiosperm evolution and the veracity of a Cretaceous Terrestrial Revolution. New Phytologist, published online February 5, 2018; doi: 10.1111/nph.15011



A Method for Studying Dinosaurs Can Also Help Fight the Spread of the Flu

Sunday, February 11, 2018

Mark Garlick/Science Photo Library via Getty Images

Dinosaurs and influenza would seem to have nothing in common, but a powerful new method of analyzing biogeographical data can be applied to both — helping to solve mysteries about long-extinct animals, while also preventing flu's spread.

Non-avian dinosaurs and flu viruses would appear to share few, if any, characteristics. After all, one group consisted of large animals that went extinct millions of years ago, while the other includes pathogenic particles that are unfortunately still very much with us.

The evolutionary histories of dinosaurs and viruses have more in common than one might expect. And a new method for studying the animals is already being recruited in the fight against influenza and additional viruses that can infect humans and other species. The groundbreaking technique is described in the journal Nature Ecology & Evolution.

The breakthrough involves projecting shifting rates of evolutionary change onto the surface of a sphere, instead of on a flat plane. This allows biogeographical data to be analyzed within an Earth-resembling model that captures speed, direction, and distance moved over short to long periods of time.

"As long as a group of organisms can be placed in a phylogenetic tree, which describes how species are related to each other, or a single species of interest can be placed in the context of its close relationships within a phylogenetic tree, and has geographical data — longitudes and latitudes of where the organisms have occurred on the Earth — the method we develop can reconstruct where the organisms’ ancestors existed on the globe," co-author Andrew Meade of the University of Reading told Seeker.

On the dinosaur side of the research, the technique has already revealed new insights concerning the origin and dispersal of dinosaurs.

Meade, lead author Ciara O'Donovan, and senior author Chris Venditti plugged extensive information on dinosaurs and their fossil record into their model. The data came from the Paleobiology Database, an online resource curated by numerous scientists around the world.

The information shows that dinosaurs first evolved in what is now South America at close to the beginning of the Mesozoic Era, which lasted in its entirety from about 252–66 million years ago.

"Prior to the dinosaurs’ origination there was an extreme extinction event," O'Donovan told Seeker. "This happened 252 million years ago, at the Permian-Triassic boundary and is the largest extinction event to have occurred in Earth’s history."

"This decimated the majority of life on Earth and therefore may well have provided the dinosaurs with a blank canvas to colonize," she added. "This fairly ‘empty Earth’ would have been totally open and up for grabs, and the dinosaurs were able to spread across the globe quickly, taking every ecological opportunity in their path."

Pangea — the single, giant landmass that later broke up to form the continents — was additionally whole when the dinosaurs originated about 231 million years ago. This meant that there were few, if any, geographical barriers preventing the dinosaurs' movement.

O'Donovan and her team suspect that the dinosaurs must have had some beneficial biological predisposition, enabling them to take advantage of the "blank canvas" they found themselves on. This aided their moving, dispersing, and colonizing new habitats. The remains of dinosaurs have remarkably been found on every continent, from what are now the polar regions to nearly every place in between.

The researchers tracked the movements through evolutionary time of the four major groups of dinosaurs — Ornithischians, Sauropods, Theropods, and birds — as well as certain individual species, like Tyrannosaurus rex.

Six reconstructed evolutionary paths for the dinosaur species a) Rhoetosaurus brownei, b) Archaeopteryx lithographica, c) Stegosaurus stenops, d) Andesaurus delgadoi, e) Dromaeosaurus albertensis, f) Tyrannosaurus rex. | Ciara O'Donovan et al., Nature Ecology & Evolution

At the start of their research, the scientists thought that each of the four dinosaur groups would exhibit different dispersal patterns. They especially thought that would be the case for birds.

The researchers determined, however, that all of the animals shared a rapid initial expansion whereby the dinosaurs speciated quickly and moved over great distances. This was followed by a continual and gradual slow-down as the animals approached the critical Cretaceous-Tertiary boundary 66 million years ago.

Venditti explained: "As time went on, dinosaurs both moved less, and fewer new species were produced. The less they could move, the more likely it would have been that any speciation that did occur would be by specialization in the environment the dinosaurs were already living in."

"The idea that the dinosaurs were running out of space fits here," he continued. "The lack of space explains why the dinosaurs were less able to speciate to replace species that were going extinct. And species may have been going extinct owing to becoming specialized and therefore being vulnerable to changes within the environment."

The new information supports the conclusions of a prior University of Reading study that was published in 2016 in the journal Proceedings of the National Academy of Sciences. It found that 50 million years before the asteroid impact that occurred in the Yucatan peninsula 66 million years ago, dinosaurs were already in decline.

Nevertheless, the ancestors of today's birds survived.

"Where avian ancestors were not able to move to new environments owing to the lack of space by that time, they specialized to take advantage of a type of space previously unoccupied by dinosaurs — aerial space," O'Donovan said. "They were able to do this because they had feathered wings. In doing this, they would have been able to explore ecological opportunities that were previously inaccessible and would have been able to evade competition with their relatives on the ground."

It is possible that birds benefitted from the die-off in the same way that non-avian dinosaurs did after the Permian-Triassic extinction event.



Dinosaur-Era Bird Found Trapped in Amber

Monday, February 5, 2018

The amber containing the dinosaur-era bird had been polished partway through the body, allowing researchers to peer inside the skull and chest cavity and chemically map its exposed soft tissues. PHOTOGRAPH BY R.C. MCKELLAR, ROYAL SASKATCHEWAN MUSEU

The squashed remains of a small bird that lived 99 million years ago have been found encased in a cloudy slab of amber from Myanmar (Burma). While previous birds found in Burmese amber have been more visually spectacular, none of them have contained as much of the skeleton as this juvenile, which features the back of the skull, most of the spine, the hips, and parts of one wing and leg.

The newfound bird is also special because researchers can more clearly see the insides of the young prehistoric creature, says study co-author Ryan McKellar of the Royal Saskatchewan Museum in Regina, Canada.

“The amber is turbid, with lots of little wood particulates. It looks like it was produced on or near the forest floor,” McKellar says. This means the external view of the bird isn’t great, but the interior is much more exciting.

“When it was being prepared in Myanmar, they polished through the front half of the specimen, which gave us an exposed view into the chest cavity and the skull,” McKellar says.

The discovery adds to a remarkable collection of Cretaceous-period fossils from the amber deposits in northern Myanmar’s Hukawng Valley. In the past few years, the region has also yielded several beautiful bird wings, the spectacular feathered tail of a small carnivorous dinosaur, and the outline of an entire hatchling bird. In December, researchers even revealed ticks in amber that may have feasted on dinosaurs.

“This Myanmar fossil deposit is clearly game-changing. It’s arguably the more important breakthrough for understanding bird evolution right now,” says Julia Clarke, an expert on the evolution of birds and flight at the University of Texas at Austin.

“We used to think we’d never have a whole bird in Cretaceous amber, but now we have multiple examples.”


Lida Xing, lead author of the paper detailing the specimen in the journal Science Bulletin, says that when he first saw the newfound bird being sold for jewelry in Myanmar in 2015, his heart began to beat very fast.

The team was lucky to acquire the bird for the Dexu Institute of Paleontology in Chaozhou, China. Birds in amber can sometimes sell for up to $500,000, putting them beyond the reach of scientists, says Xing, a paleontologist at the China University of Geosciences in Beijing.

He estimates that this is only the second bird in Burmese amber that’s been described by scientists and published in a journal. But he thinks as many as six have been discovered so far, around half of which have disappeared into the hands of private collectors.

Based on their analysis, supported in part by National Geographic, the team says that the young bird fell into the Cretaceous tree resin either dead or alive, and moisture caused the resin to foam slightly, later creating the cloudy amber. Some of the bones and soft tissues were weathered away, and sediment got trapped inside the spaces.

An illustration shows the young Cretaceous bird trapped in tree resin, which would eventually fossilize into amber.  ILLUSTRATION BY CHEUNG CHUNG TAT

“A subsequent resin flow sealed the remains to protect them from further weathering or dissolution, but the amber was later squished, shattering many of the bones,” says McKellar. “All of this is now trapped in a wafer of amber about as large as a belt buckle.”

The bird itself is around 2.4 inches long and is perhaps slightly older than the 1.8-inch hatchling bird described last year. The structure of its feathers and skeleton suggests it was an enantiornithine, a type of primitive bird that went extinct with the non-avian dinosaurs 66 million years ago.

“Even though they are hatchlings, they already have a full set of flight feathers,” McKellar says. “They have a weakly developed rachis, or central shaft, so they may not have been excellent flyers.”

In life, the bird would have had teeth in its beak and would have been dark chestnut or walnut in color, with fuzzy feathers on its head and neck.


“It’s always exciting when a vertebrate fossil is found in amber, especially Cretaceous amber,” says George Poinar, a paleobiologist at Oregon State University in Corvallis, whose research on fossilized insects in amber inspired the plot of Jurassic Park.

Assigning it to the enantiornithine birds makes sense, he adds, as they were common at that time. But it’s a pity “that the two diagnostic features of that family are missing: the toothed beak and clawed fingers on the wings.”

Poinar speculates that the fledgling may have been attacked by a predator and knocked out of the nest into resin oozing from the same tree, and that some of the plant fragments and a cockroach also found trapped in the amber piece may have originated in the nest.

“Cockroaches are general scavengers, and finding them in nesting material would not be a surprise,” he says.

With time and luck, McKellar says, the team hopes to have a whole growth series of enantiornithine birds in Burmese amber. There’s certainly no shortage of raw material to comb through—in 2015 alone, an estimated 10 tons of amber were extracted from the Hukawng Valley.



Toward end of Ice Age, Human Beings Witnessed Fires Larger than Dinosaur Killers

Saturday, February 3, 2018

New research shows that some 12,800 years ago, an astonishing 10 percent of the Earth's land surface, or about 10 million square kilometers, was consumed by fires. Credit: © Oran Tantapakul / Fotolia

On a ho-hum day some 12,800 years ago, the Earth had emerged from another ice age. Things were warming up, and the glaciers had retreated.

Out of nowhere, the sky was lit with fireballs. This was followed by shock waves.

Fires rushed across the landscape, and dust clogged the sky, cutting off the sunlight. As the climate rapidly cooled, plants died, food sources were snuffed out, and the glaciers advanced again. Ocean currents shifted, setting the climate into a colder, almost "ice age" state that lasted an additional thousand years.

Finally, the climate began to warm again, and people again emerged into a world with fewer large animals and a human culture in North America that left behind completely different kinds of spear points.

This is the story supported by a massive study of geochemical and isotopic markers just published in the Journal of Geology.

The results are so massive that the study had to be split into two papers.

"Extraordinary Biomass-Burning Episode and Impact Winter Triggered by the Younger Dryas Cosmic Impact ~12,800 Years Ago" is divided into "Part I: Ice Cores and Glaciers" and "Part 2: Lake, Marine, and Terrestrial Sediments."

The paper's 24 authors include KU Emeritus Professor of Physics & Astronomy Adrian Melott and Professor Brian Thomas, a 2005 doctoral graduate from KU, now at Washburn University.

"The work includes measurements made at more than 170 different sites across the world," Melott said.

The KU researcher and his colleagues believe the data suggests the disaster was touched off when Earth collided with fragments of a disintegrating comet that was roughly 62 miles in diameter -- the remnants of which persist within our solar system to this day.

"The hypothesis is that a large comet fragmented and the chunks impacted the Earth, causing this disaster," said Melott. "A number of different chemical signatures -- carbon dioxide, nitrate, ammonia and others -- all seem to indicate that an astonishing 10 percent of the Earth's land surface, or about 10 million square kilometers, was consumed by fires."

According to Melott, analysis of pollen suggests pine forests were probably burned off to be replaced by poplar, which is a species that colonizes cleared areas.

Indeed, the authors posit the cosmic impact could have touched off the Younger Dryas cool episode, biomass burning, late Pleistocene extinctions of larger species and "human cultural shifts and population declines."

"Computations suggest that the impact would have depleted the ozone layer, causing increases in skin cancer and other negative health effects," Melott said. "The impact hypothesis is still a hypothesis, but this study provides a massive amount of evidence, which we argue can only be all explained by a major cosmic impact."

Story Source:

Materials provided by University of KansasNote: Content may be edited for style and length.

Journal References:

  1. Wendy S. Wolbach, Joanne P. Ballard, Paul A. Mayewski, Victor Adedeji, Ted E. Bunch, Richard B. Firestone, Timothy A. French, George A. Howard, Isabel Israde-Alcántara, John R. Johnson, David Kimbel, Charles R. Kinzie, Andrei Kurbatov, Gunther Kletetschka, Malcolm A. LeCompte, William C. Mahaney, Adrian L. Melott, Abigail Maiorana-Boutilier, Siddhartha Mitra, Christopher R. Moore, William M. Napier, Jennifer Parlier, Kenneth B. Tankersley, Brian C. Thomas, James H. Wittke, Allen West, James P. Kennett. Extraordinary Biomass-Burning Episode and Impact Winter Triggered by the Younger Dryas Cosmic Impact ∼12,800 Years Ago. 1. Ice Cores and GlaciersThe Journal of Geology, 2018; 000 DOI: 10.1086/695703
  2. Wendy S. Wolbach, Joanne P. Ballard, Paul A. Mayewski, Andrew C. Parnell, Niamh Cahill, Victor Adedeji, Ted E. Bunch, Gabriela Domínguez-Vázquez, Jon M. Erlandson, Richard B. Firestone, Timothy A. French, George Howard, Isabel Israde-Alcántara, John R. Johnson, David Kimbel, Charles R. Kinzie, Andrei Kurbatov, Gunther Kletetschka, Malcolm A. LeCompte, William C. Mahaney, Adrian L. Melott, Siddhartha Mitra, Abigail Maiorana-Boutilier, Christopher R. Moore, William M. Napier, Jennifer Parlier, Kenneth B. Tankersley, Brian C. Thomas, James H. Wittke, Allen West, James P. Kennett. Extraordinary Biomass-Burning Episode and Impact Winter Triggered by the Younger Dryas Cosmic Impact ∼12,800 Years Ago. 2. Lake, Marine, and Terrestrial SedimentsThe Journal of Geology, 2018; 000 DOI: 10.1086/695704


The Lost Continent of Laramidia

Tuesday, February 13, 2018

North America, 76 million years ago

In this article, we discuss the nature of North America in the Late Cretaceous Period. Between 100 and 70 million years ago, the entire continent was divided by a shallow sea. This sea was once filled with colossal marine lizards, long-necked plesiosaurs, toothed birds, and the occasional diving Pteranodon. The sea divided the land into two smaller continents: Appalachia in the east and Laramidia in the west. As residents of the eastern United States, we are saddened by the meager dinosaur fossils (so far) discovered in the east. However, the vast and exposed formations in the west tell an amazing story.

Fossil-bearing formations dot the landscape of Laramidia, from the North Slope of Alaska down into Mexico. Each formation exhibits a similar ecosystem to the other: there are always tyrannosaurs, horned dinosaurs (ceratopsians), duck-billed dinosaurs (hadrosaurs), and raptors (dromaeosaurs) among other creatures. However, there are always different species belonging to each group. Even formations of the same age, or nearly the same age, differ in their species when they occupy different latitudes on the continent. This suggests that there were multiple “mini-ecosystems” throughout Laramidia some seventy-five million years ago.

Around seventy million years ago, as continents shifted and climates grew colder, the sea began to dry up. This linked the mini-continents of Laramidia and Appalachia once again and opened vast new regions for land animals to inhabit. The fossils of this age suggest that the divided mini-ecosystems began to blend together. It was into this great new world that Tyrannosaurus rex appeared on the scene, occupying the role of top predator until the extinction of the dinosaurs sixty-five million years ago.

The divided continent of North America. Note that the column on the left displays only a small number of the dinosaurs in each ecosystems. Also note that the Kirtland Formation is slightly younger than the others displayed.

World’s oldest Moths also Roamed Jurassic Period, says Research

Saturday, January 13, 2018

Examples of the oldest wing and body scales of primitive moths from the Schandelah-1 core photographed with transmitted light (magnification 630x). The scales are part of palynological preparations and occur together with fossil pollen grains and other organic plant remains. Size of the images (h) approx. 85 micrometer (w) approx. 65 micrometer.  CREDIT Bas van de Schootbrugge, Utrecht University

An international team of scientists led by researchers from Utrecht University have found the oldest fossil remains of moths and butterflies known to date.

The fossil remains are more than 70 million years older than the oldest fossils of flowering plants and shed new light on the co-evolution between flowering plants and pollinating insects, researchers Timo van Eldijk and Bas van de Schootbrugge claim.

The fossil remains – wing and body scales – were isolated from a core of sediment drilled in northern Germany which straddles the mass-extinction event.

The researchers say the butterflies and moths seemed to have avoided the impact of the mass extinction event at the end of the Triassic era.

‘As the super continent Pangea started to break apart, biodiversity on land and in the oceans suffered a setback with many key species becoming extinct,’ says Master’s student Van Eldijk.

‘However, one major group of insects, the Lepidoptera moths and butterflies, appeared unaffected. Instead, this group diversified during a period of ecological turnover.’

Palaeontologist Bas van de Schootbrugge says the fossil remains contain distinctive hollow scales, and provide clear evidence that there was a group of moths sucking mouth-parts, as have the vast majority of living moths and butterflies.

Modern day butterflies are well known for their association with flowering plants and the butterfly ‘tongue’ has long been assumed to be an important adaptation for feeding on flowering plants.

‘This evidence has transformed our understanding of the evolutionary history of moths and butterflies as well as their resilience to extinction,’ says Van Eldijk.

‘By studying how insects and their evolution was affected by dramatic greenhouse warming at the start of the Jurassic era, we hope to provide insight into how insects might respond to the human-induced climate change challenges we face today.’


A Sub-Desert Savanna Spread Across Madrid 14 Million Years Ago

Thursday, November 30, 2017

A Sub-Desert Savanna Spread Across Madrid 14 Million Years Ago

The current landscape of Madrid city and its vicinity was really different 14 million years ago. A semi-desert savanna has been inferred for the center of the Iberian Peninsula in the middle Miocene. This ecosystem was characterized by a very arid tropical climatic regime with up to ten months of drought per year, according to a recent paper. Scientists reached such conclusions after comparing mammal fauna with Africa and Asia ones.

The Central Iberian Peninsula was characterised by a very arid savanna during the middle Miocene, according to a study led by the Complutense University of Madrid (UCM) that compares the mammal assemblages from different localities in Africa and South Asia with those that inhabited the Iberian central area 14 million years ago.

The results of this study, recently published in PLOS ONE, are the product of more than fifteen years of fieldwork and previous paleontological studies of the fossil vertebrate remains found at the Somosaguas paleontological site (Madrid), which allowed paleontologists to infer the type of environment that existed in the middle Miocene in the central part of the Iberian Peninsula. This fossil site is located at the Somosaguas Campus of the UCM, a particular feature as only two paleontological sites have been discovered up to now at university campuses worldwide (the other one being located in the USA).

The body size of every species is largely influenced by the environmental conditions of the habitat where each species lives. For example, elephants that inhabit humid places (such as those in Asian jungles) are smaller than elephants that live in dry places (such as those that inhabit in African savannahs).

“Based on this premise, the distribution of sizes within a mammal community can offer us valuable information about its climatic context,” explains Iris Menéndez, a researcher at the Department of Paleontology of the UCM and the Institute of Geosciences (UCM and CSIC).

In this study paleontologists have been able to infer that the centre of the Iberian Peninsula witnessed a very arid tropical climate with a high precipitation seasonality. After a brief wet period, the annual dry season could last up to 10 months. “These results confirm the previous inferences on the Savannahs environment of Somosaguas in the Miocene, but placing this habitat at their driest estimated, within the limits between the savanna and the desert,” says Menéndez.

This study compiled the information of climatic parameters for more than 60 current localities from Africa and Asia, including information of the body size of the mammalian species that inhabit these localities.

“For this purpose, we made a compilation of information on mammalian fauna lists, their body sizes, and climatic parameters for these localities, such as temperatures and precipitation. Based on this data, we developed statistical models suitable for the inference of different climatic parameters in the past,” says the UCM researcher.

“We included the information on the 26 mammal species found in the Somosaguas site, which allowed us to infer the environment by comparison with the extant assemblages,” she adds.

Somosaguas is a particularly interesting fossil site in the context of paleoecological and paleoclimatic studies because it was located at a turning point during the Miocene. At this time, there was a marked change from warm and relatively humid global conditions to colder and arid environments. This inflection point eventually led to the beginning of the Pleistocene glaciations.

Moreover, the Somosaguas fossil site, due to its location within a university campus, gives to the general public the opportunity to visit it and learn all the details of the investigations that have been carried out from the data collected in the successive excavation campaigns.

Story Source:

Materials provided by Universidad Complutense de MadridNote: Content may be edited for style and length.

Journal Reference:

  1. Iris Menéndez, Ana R. Gómez Cano, Blanca A. García Yelo, Laura Domingo, M. Soledad Domingo, Juan L. Cantalapiedra, Fernando Blanco, Manuel Hernández Fernández. Body-size structure of Central Iberian mammal fauna reveals semidesertic conditions during the middle Miocene Global Cooling EventPLOS ONE, 2017; 12 (10): e0186762 DOI: 10.1371/journal.pone.0186762