In death of dinosaurs, it was all about the asteroid -- not volcanoes

Illustrated scene of dinosaurs and asteroid (stock image).

Volcanic activity did not play a direct role in the mass extinction event that killed the dinosaurs, according to an international, Yale-led team of researchers. It was all about the asteroid.

In a break from a number of other recent studies, Yale assistant professor of geology & geophysics Pincelli Hull and her colleagues argue in a new research paper in Science that environmental impacts from massive volcanic eruptions in India in the region known as the Deccan Traps happened well before the Cretaceous-Paleogene extinction event 66 million years ago and therefore did not contribute to the mass extinction.

Most scientists acknowledge that the mass extinction event, also known as K-Pg, occurred after an asteroid slammed into Earth. Some researchers also have focused on the role of volcanoes in K-Pg due to indications that volcanic activity happened around the same time.

"Volcanoes can drive mass extinctions because they release lots of gases, like SO2 and CO2, that can alter the climate and acidify the world," said Hull, lead author of the new study. "But recent work has focused on the timing of lava eruption rather than gas release."

To pinpoint the timing of volcanic gas emission, Hull and her colleagues compared global temperature change and the carbon isotopes (an isotope is an atom with a higher or lower number of neutrons than normal) from marine fossils with models of the climatic effect of CO2 release. They concluded that most of the gas release happened well before the asteroid impact -- and that the asteroid was the sole driver of extinction.

"Volcanic activity in the late Cretaceous caused a gradual global warming event of about two degrees, but not mass extinction," said former Yale researcher Michael Henehan, who compiled the temperature records for the study. "A number of species moved toward the North and South poles but moved back well before the asteroid impact."

Added Hull, "A lot of people have speculated that volcanoes mattered to K-Pg, and we're saying, 'No, they didn't.'"

Recent work on the Deccan Traps, in India, has also pointed to massive eruptions in the immediate aftermath of the K-Pg mass extinction. These results have puzzled scientists because there is no warming event to match. The new study suggests an answer to this puzzle, as well.

"The K-Pg extinction was a mass extinction and this profoundly altered the global carbon cycle," said Yale postdoctoral associate Donald Penman, the study's modeler. "Our results show that these changes would allow the ocean to absorb an enormous amount of CO2 on long time scales -- perhaps hiding the warming effects of volcanism in the aftermath of the event."

The International Ocean Discovery Program, the National Science Foundation, and Yale University helped fund the research.

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Materials provided by Yale University. Original written by Jim Shelton. Note: Content may be edited for style and length.

In death of dinosaurs, it was all about the asteroid -- not volcanoes

Illustrated scene of dinosaurs and asteroid (stock image).

Volcanic activity did not play a direct role in the mass extinction event that killed the dinosaurs, according to an international, Yale-led team of researchers. It was all about the asteroid.

In a break from a number of other recent studies, Yale assistant professor of geology & geophysics Pincelli Hull and her colleagues argue in a new research paper in Science that environmental impacts from massive volcanic eruptions in India in the region known as the Deccan Traps happened well before the Cretaceous-Paleogene extinction event 66 million years ago and therefore did not contribute to the mass extinction.

Most scientists acknowledge that the mass extinction event, also known as K-Pg, occurred after an asteroid slammed into Earth. Some researchers also have focused on the role of volcanoes in K-Pg due to indications that volcanic activity happened around the same time.

"Volcanoes can drive mass extinctions because they release lots of gases, like SO2 and CO2, that can alter the climate and acidify the world," said Hull, lead author of the new study. "But recent work has focused on the timing of lava eruption rather than gas release."

To pinpoint the timing of volcanic gas emission, Hull and her colleagues compared global temperature change and the carbon isotopes (an isotope is an atom with a higher or lower number of neutrons than normal) from marine fossils with models of the climatic effect of CO2 release. They concluded that most of the gas release happened well before the asteroid impact -- and that the asteroid was the sole driver of extinction.

"Volcanic activity in the late Cretaceous caused a gradual global warming event of about two degrees, but not mass extinction," said former Yale researcher Michael Henehan, who compiled the temperature records for the study. "A number of species moved toward the North and South poles but moved back well before the asteroid impact."

Added Hull, "A lot of people have speculated that volcanoes mattered to K-Pg, and we're saying, 'No, they didn't.'"

Recent work on the Deccan Traps, in India, has also pointed to massive eruptions in the immediate aftermath of the K-Pg mass extinction. These results have puzzled scientists because there is no warming event to match. The new study suggests an answer to this puzzle, as well.

"The K-Pg extinction was a mass extinction and this profoundly altered the global carbon cycle," said Yale postdoctoral associate Donald Penman, the study's modeler. "Our results show that these changes would allow the ocean to absorb an enormous amount of CO2 on long time scales -- perhaps hiding the warming effects of volcanism in the aftermath of the event."

The International Ocean Discovery Program, the National Science Foundation, and Yale University helped fund the research.

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Story Source:

Materials provided by Yale University. Original written by Jim Shelton. Note: Content may be edited for style and length.

When penguins ruled after dinosaurs died

When penguins ruled after dinosaurs died

What waddled on land but swam supremely in subtropical seas more than 60 million years ago, after the dinosaurs were wiped out on sea and land?

Fossil records show giant human-sized penguins flew through Southern Hemisphere waters -- along side smaller forms, similar in size to some species that live in Antarctica today.

Now the newly described Kupoupou stilwelli has been found on the geographically remote Chatham Islands in the southern Pacific near New Zealand's South Island. It appears to be the oldest penguin known with proportions close to its modern relatives.

It lived between 62.5 million and 60 million years ago at a time when there was no ice cap at the South Pole and the seas around New Zealand were tropical or subtropical.

Flinders University PhD palaeontology candidate and University of Canterbury graduate Jacob Blokland made the discovery after studying fossil skeletons collected from Chatham Island between 2006 and 2011.

He helped build a picture of an ancient penguin that bridges a gap between extinct giant penguins and their modern relatives.

"Next to its colossal human-sized cousins, including the recently described monster penguin Crossvallia waiparensis, Kupoupou was comparatively small -- no bigger than modern King Penguins which stand just under 1.1 metres tall," says Mr Blokland, who worked with Professor Paul Scofield and Associate Professor Catherine Reid, as well as Flinders palaeontologist Associate Professor Trevor Worthy on the discovery.

"Kupoupou also had proportionally shorter legs than some other early fossil penguins. In this respect, it was more like the penguins of today, meaning it would have waddled on land.

"This penguin is the first that has modern proportions both in terms of its size and in its hind limb and foot bones (the tarsometatarsus) or foot shape."

As published in the US journal Palaeontologica Electronica, the animal's scientific name acknowledges the Indigenous Moriori people of the Chatham Island (Rēkohu), with Kupoupou meaning 'diving bird' in Te Re Moriori.

The discovery may even link the origins of penguins themselves to the eastern region of New Zealand -- from the Chatham Island archipelago to the eastern coast of the South Island, where other most ancient penguin fossils have been found, 800km away.

University of Canterbury adjunct Professor Scofield, Senior Curator of Natural History at the Canterbury Museum in Christchurch, says the paper provides further support for the theory that penguins rapidly evolved shortly after the period when dinosaurs still walked the land and giant marine reptiles swam in the sea.

"We think it's likely that the ancestors of penguins diverged from the lineage leading to their closest living relatives -- such as albatross and petrels -- during the Late Cretaceous period, and then many different species sprang up after the dinosaurs were wiped out," Professor Scofield says

"It's not impossible that penguins lost the ability to fly and gained the ability to swim after the extinction event of 66 million years ago, implying the birds underwent huge changes in a very short time. If we ever find a penguin fossil from the Cretaceous period, we'll know for sure."

BACKGROUND: The new species is based on the fossilised bones of five partial skeletons. Another two specimens showed a second larger penguin species was also present on the main Chatham Island but there was not enough material to formally name it. All of the described skeletons were collected between 2006 and 2011 by a group led by Monash University palaeontologist Jeffrey Stilwell. Dr Alan Tennyson from Te Papa Tongarewa the Museum of New Zealand and Professor Julia Clark from University of Texas at Austin were in the group and are also-coauthors of the paper. The species is named after Associate Professor Stilwell with all specimens now cared for by Te Papa.

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Materials provided by Flinders University. Note: Content may be edited for style and length.

First evidence of feathered polar dinosaurs found in Australia

First evidence of feathered polar dinosaurs found in Australia

A cache of 118 million-year-old fossilized dinosaur and bird feathers has been recovered from an ancient lake deposit that once lay beyond the southern polar circle.

Feathered dinosaur fossils are famous, but known from a handful of localities worldwide. Examples from the Southern Hemisphere are especially rare, and mainly include only isolated feathers.

An international team of scientists has analyzed a collection of 10 such fossil feathers found in Australia, which reveal an unexpected diversity of tufted hair-like 'proto-feathers' from meat-eating dinosaurs, together with downy body feathers, and wing feathers from primitive birds that would have been used for flight.

Uniquely, the fossil feathers from Australia were all entombed in fine muddy sediments that accumulated at the bottom of a shallow lake close to the South Pole during the Age of Dinosaurs.

"Dinosaur skeletons and even the fragile bones of early birds have been found at ancient high-latitudes before. Yet, to date, no directly attributable integumentary remains have been discovered to show that dinosaurs used feathers to survive in extreme polar habitats," said Dr Benjamin Kear from Uppsala University in Sweden, a leading author on the study.

"These Australian fossil feathers are therefore highly significant because they came from dinosaurs and small birds that were living in a seasonally very cold environment with months of polar darkness every year."

The fossil feathers were discovered in the Koonwarra Fish Beds Geological Reserve, which is a heritage listed site 145 km southeast of Melbourne in Victoria, Australia.

"Fossil feathers have been known from Koonwarra since the early 1960s, and were recognized as evidence of ancient birds, but have otherwise received very little scientific attention. Our study is thus the first to comprehensively document these remains, which include new specimens that were examined using cutting-edge technologies," said Dr Thomas Rich of the Melbourne Museum in Australia, who has led numerous expeditions to the Koonwarra locality.

A suite of advanced microscopic and spectroscopic techniques was employed to determine the anatomy and preservation of the Koonwarra fossil dinosaur and bird feathers.

"The Koonwarra feathers are preserved in incredible detail," said fossil bird expert Professor Patricia Vickers-Rich of Monash University and the Swinburne University of Technology in Melbourne.

"There are even tiny filament-like structures that would have 'zipped' the feather vanes together, just as in the flight feathers of modern birds."

However, unlike the structurally complex feathers of birds today, which are characterized by interlocking branches called barbs and barbules, different kinds of small dinosaurs had coverings that comprised much more simpler hair-like 'proto-feathers'.

"Dinosaur 'proto-feathers' would have been used for insulation," said Dr Martin Kundrát, of Pavol Jozef Safarik University in Slovakia, a leading author on the study.

"The discovery of 'proto-feathers' at Koonwarra therefore suggests that fluffy feather coats might have helped small dinosaurs keep warm in ancient polar habitats."

Microscopic remains of possible melanosomes ? cellular structures that contain colour pigments ? were also detected on several of the fossil feathers found at Koonwarra.

These traces occurred across the uniformly dark feather surfaces, as well as in distinct bands that might represent original patterning from the polar dinosaurs and birds.

Melanic residues have been reported on fossil feathers from elsewhere around the world, and are widely acknowledged as indicators of dinosaur colouration.

The densely packed fossil melanosomes occurring on the Koonwarra feathers could suggest dark colours that perhaps assisted in camouflage, visual communication, and/or heat absorbance in cold polar climates.

Possible preservation of biomolecules was also assessed, but proved to be too degraded, and were apparently lost during weathering of the rock.

The Koonwarra fossil feathers provide the first record of dinosaur integument from the ancient polar regions, and hint what was once a global distribution of feathered dinosaurs and early birds.

Some of the fossil feathers found at Koonwarra are on display in the '600 Million Years' exhibition at the Melbourne Museum in Australia.

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Materials provided by Uppsala University. Note: Content may be edited for style and length.