links for 2008-12-19

Danish Arctic Research Dates End of Ice Age to 11,711 Years Ago

Well cool! Urm, pun not intended. Archaeologists seldom need quite that precision, but just to know that we’re closer to 12KYA than 11 is useful. Now on to that whole “Younger Dryas” event.

Danish Arctic research dates Ice Age

The result of a Danish ice drilling project has become the international standard for the termination of the last glacial period. It ended precisely 11,711 years ago.

Jørgen Peder Steffensen of the Niels Bohr Institute showing the exact point in the ice cap where the last Ice Age ended – 11,711 years ago. – Foto: Niels Bohr Instituttet

A Danish ice drilling project has conclusively ended the discussion on the exact date of the end of the last ice age.

The extensive scientific study shows that it was precisely 11,711 years ago – and not the indeterminate figure of ‘some’ 11,000 years ago – that the ice withdrew, allowing humans and animals free reign.

According to the Niels Bohr Institute (NBI) in Copenhagen, the very precise dating of the end of the last Ice Age has made Denmark the owner of the “Greenwich Mean Time” of the end of the last glacial period and beginning of the present climate – the so-called International Standard Reference.

Kilometres of ice
It took several thousand years to warm up the earth and melt the kilometre thick ice caps that covered large parts of the northern hemisphere during the last glacial period and as a result the transition from Ice Age to the current period has lacked a clearly defined point in time.

The answer has now been found in the NordGrip drilling project in Greenland.

“Our new, extremely detailed data from the examination of the ice cores shows that in the transition from the ice age to our current warm, interglacial period the climate shift is so sudden that it is as if a button was pressed”, explains ice core researcher Jørgen Peder Steffensen, Centre for Ice and Climate at NBI at the University of Copenhagen.

Ice core reference
When ice cores, that are formed by annual snowfall that is compressed into ice, are drilled out and analysed, the three kilometre ice cap in Greenland has acted like a filing cabinet of the climate detail of past geological periods.

“It is the first time an ice core has been used as an international standard reference for a geological period and it is a great recognition of our extremely detailed scientific data”, Jørgen Peder Steffensen said.

Woolly-Mammoth Gene Study Changes Extinction Theory

More fodder, more grist for that mill.

Woolly-Mammoth Gene Study Changes Extinction Theory

Credit: Penn State
by Staff Writers
University Park PA (SPX) Jun 13, 2008
A large genetic study of the extinct woolly mammoth has revealed that the species was not one large homogenous [sic–ed.] group, as scientists previously had assumed, and that it did not have much genetic diversity.

“The population was split into two groups, then one of the groups died out 45,000 years ago, long before the first humans began to appear in the region,” said Stephan C. Schuster, associate professor of biochemistry and molecular biology at Penn State University and a leader of the research team.

“This discovery is particularly interesting because it rules out human hunting as a contributing factor, leaving climate change and disease as the most probable causes of extinction.” The discovery will be published later this week in the early online edition of the Proceedings of the National Academy of Sciences (PNAS).
The research marks the first time scientists have dissected the structure of an entire population of extinct mammal by using the complete mitochondrial genome — all the DNA that makes up all the genes found in the mitochondria structures within cells.

Data from this study will enable testing of the new hypothesis presented by the team, that there were two groups of woolly mammoth — a concept that previously had not been recognized from studies of the fossil record.

The scientists analyzed the genes in hair obtained from individual woolly mammoths — an extinct species of elephant adapted to living in the cold environment of the northern hemisphere. The bodies of these mammoths were found throughout a wide swathe of northern Siberia. Their dates of death span roughly 47,000 years, ranging from about 13,000 years ago to about 60,000 years ago.

Schuster and Webb Miller, professor of biology and computer science and engineering at Penn State, led the international research team, which includes Thomas Gilbert at the University of Copenhagen in Denmark and other scientists in Australia, Belgium, France, Italy, Russia, Spain, Sweden, the United Kingdom, and the United States.

The team includes experts in the fields of genome evolution, ancient DNA, and mammoth paleontology, as well as curators from various natural-history museums.
Another important finding for understanding the extinction processes is that the individuals in each of the two woolly-mammoth groups were related very closely to one another. “This low genetic divergence is surprising because the woolly mammoth had an extraordinarily wide range: from Western Europe, to the Bering Strait in Siberia, to Northern America,” Miller said.

“The low genetic divergence of mammoth, which we discovered, may have degraded the biological fitness of these animals in a time of changing environments and other challenges.”
Our study suggests a genetic divergence of the two woolly-mammoth groups more than 1-million years ago, which is one quarter the genetic distance that separates Indian and African elephants and woolly mammoths,” Miller said. The research indicates that the diversity of the two woolly-mammoth populations was as low centuries ago as it is now in the very small populations of Asian elephants living in southern India.

“The low genetic divergence of the elephants in southern Indian has been suggested as contributing to the problems of maintaining this group as a thriving population,” Schuster said. Intriguingly, the mitochondrial genomes revealed by the researchers are several times more complete than those known for the modern Indian and African Elephants combined.

Whereas studies before this research had analyzed only short segments of the DNA of extinct species, this new study generated and compared 18 complete genomes of the extinct woolly mammoth using mitochondrial DNA, an important material for studying ancient genes.

This achievement is based on an earlier discovery of the team led by Miller, Schuster, and co-author Thomas Gilbert, which was published last year and that revealed ancient DNA survives much better in hair than in any other tissue investigated so far.
This discovery makes hair, when it is available, a more powerful and efficient source of DNA for studying the genome sequences of extinct animals. Moreover, mammoth hair is found in copious quantities in cold environments and it is not regarded as fossil material of enormous value like bone or muscle, which also carries anatomical information.

“We also discovered that the DNA in hair shafts is remarkably enriched for mitochondrial DNA, the special type of DNA frequently used to measure the genetic diversity of a population,” Miller said. The team’s earlier study also showed that hair is superior for use in molecular-genetic analysis because it is much easier than bone to decontaminate.

Not only is hair easily cleaned of external contamination such as bacteria and fungi, its structure also protects it from degradation, preventing internal penetration by microorganisms in the environment.

An important aspect of the new study is that the hair samples it used had been stored in various museums for many years before being analyzed by the researchers, yet the scientists were able to obtain lots of useful DNA from them. “One of our samples originates from the famous Adams mammoth, which was found in 1799 and has been stored at room temperatures for the last 200 years,” Schuster said.

This research technique opens the door for future projects to target interesting specimens that were collected a long time ago and are no longer available from modern species, the scientists said. Even the molecular analysis of entire collections seems now possible, an effort that the team calls “Museomics.”

“We plan to continue using our techniques to untangle the secrets of populations that lived long ago and to learn what it might have taken for them to survive,” Schuster said. “Many of us also have a personal interest in learning as much as we can about how any species of large mammal can go extinct.”
The research was supported, in large part, by Penn State University, Roche Applied Sciences, and a private sponsor. Additional support was provided by the National Human Genome Research Institute, Marie Curie Actions, the Australian Research Council, the Russian Foundation for Basic Research, and the Pennsylvania Department of Health. [via ARCH-L]

Well, it largely rules out hunting in the 45KYA extinction. Probably. 😉

Let’s see how the use of DNA from hair holds up. That’s a factor, too. Though this appearing in the National Academy of Sciences is heartening, as that implies it has gone through the initial vetting process.

New Dates for Clovis

From the, “Now That It Has Been Published, We Can Talk About This” Department

This is how it is done, folks. Peer-reviewed prior to hitting the press.

A new bone collagen radiocarbon (14C) dating technique, resample some things, sample others for the first time (!) and away you go. [Side note: only 22 sites with Clovis or Clovis-like material had been directly dated prior to this study.]

The summary and the article by Waters and Stafford, both from the current issue of Science.

Redefining the Age of Clovis: Implications for the Peopling of the Americas [Waters and Stafford, Science 23 February 2007]
[abstract] The Clovis complex is considered to be the oldest unequivocal evidence of humans in the Americas, dating between 11,500 and 10,900 radiocarbon years before the present (14C yr B.P.). Adjusted14C dates and a reevaluation of the existing Clovis date record revise the Clovis time range to 11,050 to 10,800 14C yr B.P. In as few as 200 calendar years, Clovis technology originated and spread throughout North America. The revised age range for Clovis overlaps non-Clovis sites in North and South America. This and other evidence imply that humans already lived in the Americas before Clovis. [emphasis added –ed.]

For nearly 50 years, it has been generally thought that small bands of humans carrying a generalized Upper Paleolithic tool kit entered the Americas around 11,500 radiocarbon years before the present (14C yr B.P.) and that these first immigrants traveled southward through the ice-free corridor separating the Laurentide and Cordilleran Ice Sheets. These people developed the distinctive lithic, bone, and ivory tools of Clovis and then quickly populated the contiguous United States. Clovis humans and their descendants then rapidly populated Central America and reached southernmost South America by 10,500 14C yr B.P.

Identifying when the Clovis complex first appeared and knowing the complex’s duration is critical to explaining the origin of Clovis, evaluating the Clovis-first model of colonization of the Americas, determining the role of humans in the extinction of late Pleistocene megafauna, and assessing whether people inhabited the Americas before Clovis. We determined a more accurate time span for Clovis by analyzing the revised existing Clovis 14C date record and reporting high-precision accelerator mass spectrometry (AMS) 14C ages from previously dated Clovis sites. Our AMS 14C dates are on culturally specific organic matter—bone, ivory, and seeds—that accelerator mass spectrometers can date accurately to precisions of ±30 years at 11,000 14C yr B.P. (…)

Here is a popular-press article in the Houston Chronicle, “A&M find may shatter land-bridge migrant theory: A&M research raises migration doubt.” (I’m linking to the Chron because Eric Berger actually spoke with the researchers.)

links for 2007-01-30

Dinosaurs Identified in Southern Nevada

Pretty neat, though some may be curious why it takes Montana State to come down here and do the work when there are (supposedly) several institutions devoted to such and similar investigations already present in southern Nevada. Yes, I can imagine why you might wonder that, you clever wonderer about such things you… Yes, these are the people who eliminated a previous position of mine (and others) because they did not have anything for me to do. Now they are touting how wonderful it is to do research and find things.

Well done, Mr. Bonde, et. al, well done.

DINOSAUR DISCOVERY Las Vegas Review Journal
Fossil remains are first for Nevada

A fierce 6-foot-long raptor once roamed what is now southern Nevada about 100 million years ago based on fossilized dinosaur remains, the first ever documented in the state, found northeast of the Las Vegas Valley.

“This is the first dinosaur stuff [a technical term only real scientists are allowed to use –ed.] described in the state of Nevada from a time period not well-known in North America,” said Josh Bonde, of Fallon, the Montana State University researcher who found and documented the fossilized remains over the past year.

Bonde, a 26-year-old graduate student at Montana State University-Bozeman, will announce the find today with officials from Springs Preserve and the Nevada State Museum when they unveil plans for a new museum building that will house some of the newly found fossils at the preserve, near U.S. Highway 95 and Valley View Boulevard. (…)

Petrified remains of at least five types of dinosaurs from the Cretaceous Period were uncovered and recorded during a series of shallow digs and prospecting ventures beginning in March 2005 through this summer. (…)

The fossils include a femur from a 6-foot-long, meat-eating dromaeosaur, commonly known as a raptor or running lizard of the genus Deinonychus. (more)

Please pardon me while I retire to my corner and mutter dark things about former employers.

News From 1421exposed.com

Just in case anyone is still following the Bosnian pyramids [the background is getting stranger, though it is still ‘nonsense’ (a technical term edited for our occasional PG rating)], the Flores “Hobbit” (not a new species) and the ‘Chinese discovery’ of North America in 1421, I have a (very) brief update on the last.

This came over the electronic threshold a bit ago…

Considerable new material has been added to the www.1421exposed.com website including:
Gavin Menzies Cartographic Fiction: The Case Of The Chinese “Discovery” of Australia – Associate Professor W.A.R. (Bill) Richardson
Walrus Pitch & Other Novelties: Gavin Menzies & the Far North – Kirsten Seaver
1421 and all that Junk – Emeritus Professor Victor Prescott
Fathoming the Unfathomable: Even Leviathans have Limits – Dr. Stephen Davies, Museum Director Hong Kong Maritime Museum
Did the Chinese Circumnavigate the World in 1421? or Why Menzies’ 1421 Won’t Sail – Captain P. J. Rivers, FRGS FNI MRIN ACII ACI Arb, Master Mariner
1418 Map a Fake – Dr. Geoff Wade
PLUS – the full transcript of the Australian Broadcasting Corporation’s 4-Corners documentary “Junk History” in which Menzies, his agent, and the publisher reveal Menzies did not write the book!
AND – an expose of Paul Chiasson’s “The Island of Seven Cities” completely refuting his claims. This includes aerial photos from 1931, 1947, 1953, 1969, 1975, 1984, and 1993 which show the gradual development of the features identified in the book as fire, roads, and geological exploration take their toll on the area. Articles by Andrew Hanam, an expert on the area, and Lynn Baechler, who actually carried out the geological exploration, detail the events. 16 photos of specific features, showing their recent origin, provide clear supporting evidence.
____________________________________________
Michael Ross
Editor and Webmaster
1421exposed.com

And look, not one mention of politics! 🙂

Killer kangaroo, demon duck of doom roamed Outback

I ask you, what’s not to love here?

Killer kangaroo, demon duck of doom roamed Outback [Reuters]
A team of Australian paleontologists say they have found the fossilized remains of a fanged killer kangaroo and what they describe as a “demon duck of doom”.

A University of New South Wales team said the fearsome fossils were among 20 previously unknown species uncovered at a site in northwest Queensland state.

Professor Michael Archer said on Wednesday the remains of a meat-eating kangaroo with wolf-like fangs were found as well as a galloping kangaroo with long forearms that could not hop like a modern kangaroo. (more)

Dinosaur is Dead Ringer for Potter Dragon

Heh, I love it! via garret.

Dinosaur is dead ringer for Potter dragon [Times Online UK]
A new species discovered in the US has been named Dracorex hogwartsia, much to the delight of the author J. K. Rowling.

“The 66 million-year-old dragon-like monster has been given the title Dracorex hogwartsia because it resembles the kind of fantastical creature encountered by the teenage wizard.

The nearly complete skull of the previously unknown dinosaur was found by three friends during a fossil-collecting trip in South Dakota. (…)

Robert Bakker, a well known paleontologist [sic, it’s a BBC article –ed.], agreed that the new beast would not look out of place in a Potter book. “Honouring an author with a species name is rare. But it should be done more often,” he said. “The creature is a very special dinosaur that seems at home in a Harry Potter adventure. It was a plant-eater, about as heavy as the warhorse of a medieval knight. (more)”

Children’s Museum of Indianapolis where they had a big unveiling on May 22, 2006. Hey, Bakker was there too! (He’s on their advisory board.) Ohhh, he is sporting a heretofore uncategorized cowboy hat as well… And the Museum has t-shirts.

The new species flummoxes old theories. The combination of a flat forehead and a multitude of spikes and lumps have never been seen before. Dracorex hogwartsia is an exceptionally advanced species.

“This feeds the pachycephalosaur family tree to the wood chipper,” noted Bakker and Dr. Robert Sullivan, another member of The Children’s Museum’s Scientific Advisory Board of Paleontologists. Fierce debates have raged about whether the pachys butted each other, but since no good neck bones had been found, conclusive evidence was lacking. The Children’s Museum Paleo Lab personnel scored a [C]retaceous triumph when they pieced together four nearly complete neck vertebrae for Dracorex hogwartsia. Special anti-twist joints and enlarged muscle attachments seem to show that these dinosaurs indulged in violent kinetic exercises. “They were head-bangers!”

According to the museum’s Scientific Advisory Board, “Children’s museums don’t find new species. That’s for the “adult” institutions. But The Children’s Museum of Indianapolis combines first-rate scientific exploration within a kid-friendly environment. [Inside Indiana Business]

12,000-Year-Old Mammoth and Camel Bones Found in NW Kansas

Well… this is pretty cool! If they find tools associated with camel butchering this summer it will be beyond petty expletives. But, an unworked chunk of crypto-crystalline silicate does not an archaeological site make. There will be a lot of attention paid to the stratigraphy on this excavation.

12,000-Year-Old Bones Found in Kansas [AP via Yahoo! News]
GOODLAND, Kan. – Scientists say mammoth and camel bones unearthed in northwest Kansas that date back 12,200 years could be part of “one of the most important archaeological sites in North America.”

The bones, found last June in Sherman County near the Colorado border, were alongside a piece of stone that archaeologists say was the kind used in tools that humans once used to butcher animals.

Archaeological geologist Rolfe Mandel of the Kansas Geological Survey [and the University of Kansas –ed.] said carbon-14 dating completed last week shows the bones are between 12,200 and 12,300 years old, which could mean humans lived on the Great Plains 1,300 years earlier than previously thought.

Mandel said if excavations this summer verify the finding of the stone tool, it would make the archaeological site among the oldest in the New World.

“It would be one of the most important sites in North America,” he said. [emphasis added]