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July 18, 2011, 8:37 AM CT

What keeps the Earth cooking?

What keeps the Earth cooking?
A main source of the 44 trillion watts of heat that flows from the interior of the Earth is the decay of radioactive isotopes in the mantle and crust. Scientists using the KamLAND neutrino detector in Japan have measured how much heat is generated this way by capturing geoneutrinos released during radioactive decay.

Credit: Lawrence Berkeley National Laboratory




What spreads the sea floors and moves the continents? What melts iron in the outer core and enables the Earth's magnetic field? Heat. Geologists have used temperature measurements from more than 20,000 boreholes around the world to estimate that some 44 terawatts (44 trillion watts) of heat continually flow from Earth's interior into space. Where does it come from?.

Radioactive decay of uranium, thorium, and potassium in Earth's crust and mantle is a principal source, and in 2005 researchers in the KamLAND collaboration, based in Japan, first showed that there was a way to measure the contribution directly. The trick was to catch what KamLAND dubbed geoneutrinos � more precisely, geo-antineutrinos � emitted when radioactive isotopes decay. (KamLAND stands for Kamioka Liquid-scintillator Antineutrino Detector.)

"As a detector of geoneutrinos, KamLAND has distinct advantages," says Stuart Freedman of the U.S. Department of Energy's Lawrence Berkeley National Laboratory (Berkeley Lab), which is a major contributor to KamLAND. Freedman, a member of Berkeley Lab's Nuclear Science Division and a professor in the Department of Physics at the University of California at Berkeley, leads U.S. participation. "KamLAND was specifically designed to study antineutrinos. We are able to discriminate them from background noise and detect them with very high sensitivity.".........

Posted by: William      Read more         Source


July 18, 2011, 8:29 AM CT

Non-Africans are part Neanderthal

Non-Africans are part Neanderthal
Some of the human X chromosome originates from Neanderthals and is found exclusively in people outside Africa, as per an international team of scientists led by Damian Labuda of the Department of Pediatrics at the University of Montreal and the CHU Sainte-Justine Research Center. The research was reported in the recent issue of Molecular Biology and Evolution.

"This confirms recent findings suggesting that the two populations interbred," says Dr. Labuda. His team places the timing of such intimate contacts and/or family ties early on, probably at the crossroads of the Middle East.

Neanderthals, whose ancestors left Africa about 400,000 to 800,000 years ago, evolved in what is now mainly France, Spain, Gera number of and Russia, and are thought to have lived until about 30,000 years ago. Meanwhile, early modern humans left Africa about 80,000 to 50,000 years ago. The question on everyone's mind has always been whether the physically stronger Neanderthals, who possessed the gene for language and may have played the flute, were a separate species or could have interbred with modern humans. The answer is yes, the two lived in close association.

"In addition, because our methods were totally independent of Neanderthal material, we can also conclude that prior results were not influenced by contaminating artifacts," adds Dr. Labuda.........

Posted by: William      Read more         Source


May 29, 2011, 2:39 PM CT

Seeing hidden building blocks of life

Seeing hidden building blocks of life
A diamond surrounded by air, and a glass of water. Both contain carbon and oxygen. If they are embedded inside another object, without access for a chemical probe, it is a difficult task to distinguish between even simple chemical bonds. A new synchrotron X-ray technique has made this now possible.

Credit: Simo Huotari (University of Helsinki)

Researchers from Finland and France have developed a new synchrotron X-ray technique that may revolutionize the chemical analysis of rare materials like meteoric rock samples or fossils. The results have been published on 29 May 2011 in Nature Materials as an advance online publication.

Life, as we know it, is based on the chemistry of carbon and oxygen. The three-dimensional distribution of their abundance and chemical bonds has been difficult to study up to now in samples where these elements were embedded deep inside other materials. Examples are tiny inclusions of possible water or other chemicals inside martian rock samples, fossils buried inside a lava rock, or minerals and chemical compounds within meteorites.

X-ray tomography, which is widely used in medicine and material science, is sensitive to the shape and texture of a given sample but cannot reveal chemical states at the macroscopic scale. For instance graphite and diamond both consist of pure carbon, but they differ in the chemical bond between the carbon atoms. This is why their properties are so radically different. Imaging the variations in.

atomic bonding has been surprisingly difficult, and techniques for imaging of chemical bonds are highly desirable in a number of fields like engineering and research in physics, chemistry, biology, and geology.........

Posted by: William      Read more         Source


May 19, 2011, 9:00 AM CT

Bird, crocodile family trees split earlier than thought

Bird, crocodile family trees split earlier than thought
This is a reconstruction of X. sapingensis, based on the fossil.

Credit: Sterling Nesbitt

A fossil unearthed in China in the 1970s of a creature that died about 247 million years ago, originally believed to be a distant relative of both birds and crocodiles, turns out to have come from the crocodile family tree after it had already split from the bird family tree, as per research led by a University of Washington paleontologist.

The only known specimen of Xilousuchus sapingensis has been reexamined and is now classified as an archosaur. Archosaurs, characterized by skulls with long, narrow snouts and teeth set in sockets, include dinosaurs as well as crocodiles and birds.

The new examination dates the X. sapingensis specimen to the early Triassic period, 247 million to 252 million years ago, said Sterling Nesbitt, a UW postdoctoral researcher in biology. That means the creature lived just a short geological time after the largest mass extinction in Earth's history, 252 million years ago at the end of the Permian period, when as much as 95 percent of marine life and 70 percent of land creatures perished. The evidence, he said, places X. sapingensis on the crocodile side of the archosaur family tree.

"We're marching closer and closer to the Permian-Triassic boundary with the origin of archosaurs," Nesbitt said. "And today the archosaurs are still the dominant land vertebrate, when you look at the diversity of birds".........

Posted by: William      Read more         Source


March 31, 2011, 11:00 PM CT

Mesopotamian cIties in Iraqi Marshes?

Mesopotamian cIties in Iraqi Marshes?
Explore the marshlands-turned-desert that is giving archaeologists insight into the earliest modern civilizations in this photo gallery.

Credit: National Science Foundation

Learn more about the Iraqi marshes and the origins of Mesopotamian cities in this photo gallery and video.

Three National Science Foundation-supported scientists recently undertook the first non-Iraqi archaeological investigation of the Tigris-Euphrates delta in nearly 20 years. Archeologists Jennifer Pournelle and Carrie Hritz, with geologist Jennifer Smith, carried out the study late last year to look for links between wetland resources and the emergence of Mesopotamian cities.

"Mesopotamia"--Greek for "the land between the rivers"--is an area about 300 miles long and 150 miles wide straddling the Tigris and Euphrates rivers, which now run through Iraq, northeastern Syria, southeastern Turkey and southwestern Iran. It is broadly considered a cradle of civilization, because urban societies first developed there, about six thousand years ago.

Alexander the Great conquered Mesopotamia in 332 B.C.

"This is an important project because it has the potential to shed new light on the processes by which civilization rose in the Near East," said John Yellen, an NSF program director for archeological research.

The scientists proposed the project to probe how the area's gulf shoreline and marshes contributed to the economic foundation of Mesopotamian cities. Specifically, they wanted to investigate archaeological sites from 5,000 B.C. to Islamic times to learn more about how wetland resources contributed to the locale's towns and cities during the early- to mid-Holocene period.........

Posted by: William      Read more         Source


March 26, 2011, 10:09 PM CT

Algae and bacteria hogged oxygen after ancient mass extinction

Algae and bacteria hogged oxygen after ancient mass extinction
A distant view of the field area in the Nanpanjiang Basin in south China where limestone contained evidence of a slow recovery of marine animal populations after the mass extinction 250 million years ago.
A mass extinction is hard enough for Earth's biosphere to handle, but when you chase it with prolonged oxygen deprivation, the biota ends up with a hangover that can last millions of years.

Such was the situation with the greatest mass extinction in Earth's history 250 million years ago, when 90 percent of all marine animal species were wiped out, along with a huge proportion of plant, animal and insect species on land.

A massive amount of volcanism in Siberia is widely credited with driving the disaster, but even after the immense outpourings of lava and toxic gases tapered off, oxygen levels in the oceans, which had been depleted, remained low for about 5 million years, slowing life's recovery there to an unusual degree.

The reason for the lingering low oxygen levels has puzzled scientists, but now Stanford scientists have figured out what probably happened. By analyzing the chemical composition of some then-underwater limestone beds deposited over the course of the recovery in what is now southern China, they have determined that while it took several million years for most ecosystems in the ocean to recover, tiny single-celled algae and bacteria bounced back much more quickly.

In fact, as per biogeochemist Katja Meyer, the tiny organisms rebounded to such an extent that the bigger life forms couldn't catch a break - much less their breath - because the little ones were enjoying a sustained population explosion.........

Posted by: William      Read more         Source


March 1, 2011, 10:21 PM CT

World's oldest Pteranodon?

World's oldest Pteranodon?
Fossilized bones discovered in Texas from a flying reptile that died 89 million years ago appears to be the earliest occurrence of the prehistoric creature known as Pteranodon.

Previously, Pteranodon bones have been found in Kansas, South Dakota and Wyoming in the Niobrara and Pierre geological formations. This likely Pteranodon specimen is the first of its kind found in Texas, as per paleontologist Timothy S. Myers at Southern Methodist University in Dallas, who identified the reptile. The specimen was discovered north of Dallas by an amateur fossil hunter who found various bones belonging to the left wing.

Pteranodon was a type of pterosaur that lived about the same time as some dinosaurs, about 100 million to 65 million years ago. The only reptiles to dominate the ancient skies, pterosaurs had broad leathery wings and slim torsos.

Adult pterosaur, toothless variety with about a 12-foot wing span.

The specimen identified by Myers is an adult pterosaur of the toothless variety and while larger than most birds, wasn't among the largest pterosaurs, Myers said, noting it had a wing span between 12 and 13 feet, or 3.6 to 4 meters. It was discovered in the Austin Group, a prominent rock unit in Texas that was deposited around 89 million years ago, early in the geological time period called the Late Cretaceous.........

Posted by: William      Read more         Source


February 22, 2011, 7:55 AM CT

Oldest Fossils of Large Seaweeds

Oldest Fossils of Large Seaweeds
Almost 600 million years ago, before the rapid evolution of life forms known as the Cambrian explosion, a community of seaweeds and worm-like animals lived in a quiet deep-water niche near what is now Lantian, a small village in south China.

Then they simply died, leaving some 3,000 nearly pristine fossils preserved between beds of black shale deposited in oxygen-free and unbreathable waters.

Researchers from the Chinese Academy of Sciences, Virginia Tech in the United States and Northwest University in Xi'an, China report the discovery of the fossils in this week's issue of the journal Nature

In addition to ancient versions of algae and worms, the Lantian biota--named for its location--included macrofossils with complex and puzzling structures.

In all, researchers have identified some 15 species at the site.

The fossils suggest that structural diversification of macroscopic eukaryotes--the earliest versions of organisms with complex cell structures--may have occurred only tens of millions of years after the Snowball Earth event that ended 635 million years ago.

Snowball Earth proposes that the Earth's surface became almost, or completely, frozen at least once during the planet's history.

The presence of macroscopic eukaryotes in the highly organic-rich black shale suggests that, despite the overall oxygen-free conditions, brief oxygenation of the oceans did come and go, as per H. Richard Lane, program director in the National Science Foundation (NSF)'s Division of Earth Sciences, which funded the research.........

Posted by: William      Read more         Source


February 21, 2011, 7:54 AM CT

Testing the limits of where humans can live

Testing the limits of where humans can live
These are stone artifacts, mostly tips for spears and harpoons, found on the Kuril Islands.

Credit: Photo credit: Coby Phillips, U. Washington.

On an isolated segment of islands in the Pacific Ring of Fire, residents endure volcanoes, tsunamis, dense fog, steep cliffs and long and chilly winters.

Sounds homey, huh?

At least it might be for inhabitants of the Kuril Islands, an 810-mile archipelago that stretches from Japan to Russia. The islands, formed by a collision of tectonic plates, are nearly abandoned today, but anthropologists have learned that thousands of people have lived there on and off as far back as at least 6000 B.C., persevering despite natural disasters.

"We want to identify the limits of adaptability, or how much resilience people have," said Ben Fitzhugh, associate professor of anthropology at the University of Washington. "We're looking at the islands as a yardstick of humans' capacity to colonize and sustain themselves".

Understanding what made residents stay and how they survived could inform how we adapt to modern vulnerabilities, including climate change. The findings also have implications for how we rebound from contemporary catastrophes, such as the Indonesian tsunami in 2004, hurricanes Katrina and Rita and last year's earthquake in Haiti.

Fitzhugh is leading an international team of anthropologists, archaeologists, geologists and earth and atmospheric researchers in studying the history of human settlement on the Kuril Islands.........

Posted by: William      Read more         Source


February 14, 2011, 6:52 AM CT

Archaeologists find hidden African side

Archaeologists find hidden African side
In West African practice, placing metal and pointed objects at the doorway helps deter harmful spirits from entering. These were found buried at the entrance to the slave quarters, until now known only as a potting shed -- its most recent use.

Credit: UMD

One of North America's most famous Revolutionary-era buildings � a lone-surviving testament to an Enlightenment ideal � has a hidden West African face, University of Maryland archaeologists have discovered.

Their excavation at the 1785 Wye �Orangery� on Maryland's Eastern Shore � the only 18th century greenhouse left in North America � reveals that African American slaves played a sophisticated, technical role in its construction and operation. They left behind tangible cultural evidence of their involvement and spiritual traditions.

Frederick Douglass, who lived there as a young man, made it famous through his autobiography. But the team concludes that he failed to appreciate the slaves� full contribution.

"For years, this famous Enlightenment structure has been recognized for its European qualities, but it has a hidden African face that we've unearthed," says University of Maryland archaeologist Mark Leone, who led the excavation. "Concealed among the bricks of the furnace that controlled the greenhouse temperature, we found embedded a symbol used in West African spirit practice. An African American slave built the furnace, and left an historic signature".

His team also found African charms buried at the entrance to a part of the Wye greenhouse that once served as living quarters for the slaves who maintained the building.........

Posted by: William      Read more         Source


February 3, 2011, 7:56 AM CT

Earliest cemetery in Middle East

Earliest cemetery in Middle East
The Middle Epipalaeolithic site of 'Uyun al-Hammam, with inset showing the location of the site and other Early and Middle Epipalaeolithic sites discussed in the text.
Anthropologists at the University of Toronto and the University of Cambridge have discovered the oldest cemetery in the Middle East at a site in northern Jordan. The cemetery includes graves containing human remains buried alongside those of a red fox, suggesting that the animal was possibly kept as a pet by humans long before dogs ever were.

The 16,500-year-old site at 'Uyun al-Hammam was discovered in 2000 by an expedition led by University of Toronto professor Edward (Ted) Banning and Lisa Maher, an assistant professor of anthropology at U of T and research associate at the University of Cambridge. "Recent archaeological excavations have uncovered the remains of at least 11 individuals - more than known from all other sites of this kind combined," says Banning, of U of T's Department of Anthropology.

Prior research had identified the earliest cemeteries in the region in a somewhat later period (the Natufian, ca. 15,000-12,000 years ago). These were notable for instances of burials of humans with dogs. One such case involved a woman buried with her hand on a puppy, while another included three humans buried with two dogs along with tortoise shells. However, this new research shows that some of these practices occurred earlier.

Most of the individuals buried at the Jordan site were found with what are known as "grave goods," such as stone tools, a bone spoon, animal parts, and red ochre (an iron mineral). One grave contained the skull and right upper arm bone of a red fox, with red ochre adhered to the skull, along with bones of deer, gazelle and wild cattle. Another nearby grave contained the nearly complete skeleton of a red fox, missing its skull and right upper arm bone, suggesting that portions of a single fox had been moved from one grave to another in prehistoric times.........

Posted by: William      Read more         Source


January 28, 2011, 7:43 AM CT

Dinosaurs survived mass extinction by 700,000 years

Dinosaurs survived mass extinction by 700,000 years
University of Alberta scientists determined that a fossilized dinosaur bone found in New Mexico confounds the long established paradigm that the age of dinosaurs ended between 65.5 and 66 million years ago.

The U of A team, led by Larry Heaman from the Department of Earth and Atmospheric Sciences, determined the femur bone of a hadrosaur as being only 64.8 million years old. That means this particular plant eater was alive about 700,000 years after the mass extinction event a number of paleontologists believe wiped all non-avian dinosaurs off the face of earth, forever.

Heaman and his colleagues used a new direct-dating method called U-Pb (uranium-lead) dating. A laser beam unseats minute particles of the fossil, which then undergo isotopic analysis. This new technique not only allows the age of fossil bone to be determined but potentially can distinguish the type of food a dinosaur eats. Living bone contains very low levels of uranium but during fossilization (typically less than 1000 years after death) bone is enriched in elements like uranium. The uranium atoms in bone decay spontaneously to lead over time and once fossilization is complete the uranium-lead clock starts ticking. The isotopic composition of lead determined in the hadrosaur's femur bone is therefore a measure of its absolute age.........

Posted by: William      Read more         Source


January 27, 2011, 10:53 PM CT

Humans may have left Africa for Eurasia earlier than believed

Humans may have left Africa for Eurasia earlier than believed
These small hand axes are at least 100,000 years old. A team of scientists found these tools in the United Arab Emirates.
Researchers have discovered new evidence suggesting that modern humans first left Africa to explore Eurasia much earlier than previously thought.

An international team of researchers has uncovered a tool kit that indicates that modern humans, who looked and perhaps behaved much like us, must have lived in eastern Arabia about 100,000 to 125,000 years ago. The collection of small hand axes, scrapers and other tools was found in Jebel Faya, United Arab Emirates. A report about the discovery appears in the journal Science.

The people who made these tools "are our ancestors, I have no doubt about that," said Hans-Peter Uerpmann, of the University of Tubingen in Gera number of, who collaborated on the project, at a press teleconference Wednesday.

But the findings still do not prove definitively that modern humans made these tools, as the scientists did not find human remains near them, said Ted Goebel, anthropologist at Texas A&M University, who was not involved in the study. They potentially could have been made by Neanderthals or Neanderthal-like hominids, who were already in Eurasia at that time, Goebel said.

Prior research suggested that modern humans first left Africa along the coast by way of the Indian Ocean rim about 60,000 years ago, based on genetic evidence.........

Posted by: William      Read more         Source


January 26, 2011, 6:59 AM CT

Evolution by mistake

Evolution by mistake
Just like erasing misspellings on a whiteboard, organisms have evolved mechanisms to deal with errors that pop up when genetic information is translated into proteins. Joanna Masel (left) and Etienne Rajon discovered that such errors help organisms adapt to evolutionary challenges. Here, they write "GATTACA" on a whiteboard, for the 1997 movie spelled with letters of the genetic alphabet.

Credit: Beatriz Verdugo/UANews

Charles Darwin based his groundbreaking theory of natural selection on the realization that genetic variation among organisms is the key to evolution.

Some individuals are better adapted to a given environment than others, making them more likely to survive and pass on their genes to future generations. But exactly how nature creates variation in the first place still poses somewhat of a puzzle to evolutionary biologists.

Now, Joanna Masel, associate professor in the UA's department of ecology and evolutionary biology, and postdoctoral fellow Etienne Rajon discovered the ways organisms deal with mistakes that occur while the genetic code in their cells is being interpreted greatly influences their ability to adapt to new environmental conditions � in other words, their ability to evolve.

"Evolution needs a playground in order to try things out," Masel said. "It's like in competitive business: New products and ideas have to be tested to see whether they can live up to the challenge".

The finding is reported in a paper reported in the journal Proceedings of the National Academy of Sciences

In nature, it turns out, a number of new traits that, for example, enable their bearers to conquer new habitats, start out as blunders: mistakes made by cells that result in altered proteins with changed properties or functions that are new altogether, even when there is nothing wrong with the gene itself. Sometime later, one of these mistakes can get into the gene and become more permanent.........

Posted by: Jaison      Read more         Source


January 25, 2011, 7:34 AM CT

new light on dawn of the dinosaurs

new light on dawn of the dinosaurs
Careful dating of new dinosaur fossils and volcanic ash around them by scientists from UC Davis and UC Berkeley casts doubt on the idea that dinosaurs appeared and opportunistically replaced other animals. Instead -- at least in one South American valley -- they seem to have existed side by side and gone through similar periods of extinction.

Geologists from Argentina and the United States announced earlier this month the discovery of a new dinosaur that roamed what is now South America 230 million years ago, at the beginning of the age of the dinosaurs. The newly discovered Eodramaeus, or "dawn runner," was a predatory dinosaur that walked (or ran) on two legs and weighed 10 to 15 pounds. The new fossil was described in a paper by Ricardo Martinez of the Universidad Nacional de San Juan, Argentina, and his colleagues in the journal Science Jan. 14.

The fossils come from a valley in the foothills of the Andes in northwestern Argentina. More than 200 million years ago, it was a rift valley on the western edge of the supercontinent Pangaea, surrounded by volcanoes. It's one of the few places in the world where a piece of tectonically active continental margin has been preserved, said Isabel Montañez, a UC Davis geology professor and a co-author of the Science paper.........

Posted by: William      Read more         Source


January 22, 2011, 6:38 AM CT

Learing evolution using cloud computing

Learing evolution using cloud computing
(From left) Bina Ramamurthy, Jessica Poulin and Katharina Dittmar say Pop! World's visual appeal makes the mathematical analysis of evolution more captivating for students than conventional representations.

Credit: University at Buffalo

\ An innovative, educational computing platform developed by University at Buffalo faculty members and hosted by the cloud (remote, high-capacity, scalable servers) is helping UB students understand parts of evolutionary biology on an entirely new level. Soon, high-school and middle-school students will benefit from the same tool as well.

Pop! World, developed by UB faculty members with a $250,000 National Science Foundation grant, takes advantage of cloud computing, which allows programs to run on remote servers instead of through departmental or institutional servers. That feature allows resource-intensive programs to serve a number of users regardless of their physical location without sacrificing speed or quality of service.

"The cloud serves as a way to distribute resources for free without limits on how a number of people can access it and with no regard to what kind of computer you are downloading to," says Jessica Poulin, PhD, research assistant professor in the Department of Biological Sciences in the College of Arts and Sciences, who developed Pop! World with principal investigator Bina Ramamurthy, PhD, research associate professor in the Department of Computer Science and Engineering in the School of Engineering and Applied Sciences, and Katharina Dittmar, PhD, assistant professor of biological sciences. "Everybody can get there."........

Posted by: William      Read more         Source


January 11, 2011, 7:00 AM CT

New species of flying reptile identified

New species of flying reptile identified
The fossilized pterosaur jawbone found on Hornby Island, British Columbia (Photo courtesy U. Alberta)
Persistence paid off for a University of Alberta paleontology researcher, who after months of pondering the origins of a fossilized jaw bone, finally identified it as a new species of pterosaur, a flying reptile that lived 70 million years ago.

Victoria Arbour says she was stumped when the small piece of jaw bone was first pulled out of of a fossil storage cabinet in the U of A's paleontology department.

"It could have been from a dinosaur, a fish or a marine reptile," said Arbour. ".

Arbour, a PhD student in paleontology, says the first clue to the fossil's identify came after she compared it to known species of pterosaurs, "I found a previously published paper describing the teeth of a previously discovered pterosaur and ours was very close," said Arbour.

"The teeth of our fossil were small and set close together," said Arbour. "They reminded me of piranha teeth, designed for pecking away at meat." That led Arbour to believe her new species, named Gwawinapterus beardi was a scavenger of the late Cretaceous. "It had a wing span of about 3 metres and patrolled the sky and set down to feed on the leftover kills made by predator dinosaurs of the time such as Albertosaurus."

The fossil is not only a new species it's the first pterosaur of any kind to be found in British Columbia. It was found on Hornby Island, off the coast of Vancouver Island.........

Posted by: William      Read more         Source


January 7, 2011, 7:08 AM CT

humans first wore clothes 170,000 years ago

humans first wore clothes 170,000 years ago
Neanderthal man
A new University of Florida study following the evolution of lice shows modern humans started wearing clothes about 170,000 years ago, a technology which enabled them to successfully migrate out of Africa.

Principal investigator David Reed, associate curator of mammals at the Florida Museum of Natural History on the UF campus, studies lice in modern humans to better understand human evolution and migration patterns. His latest five-year study used DNA sequencing to calculate when clothing lice first began to diverge genetically from human head lice.

Funded by the National Science Foundation, the study is available online and appears in this month's print edition of Molecular Biology and Evolution.

"We wanted to find another method for pinpointing when humans might have first started wearing clothing," Reed said. "Because they are so well adapted to clothing, we know that body lice or clothing lice almost certainly didn't exist until clothing came about in humans".

The data shows modern humans started wearing clothes about 70,000 years before migrating into colder climates and higher latitudes, which began about 100,000 years ago. This date would be virtually impossible to determine using archaeological data because early clothing would not survive in archaeological sites.........

Posted by: William      Read more         Source


January 7, 2011, 7:05 AM CT

Widespread Ancient Ocean "Dead Zones" Challenged Early Life

Widespread Ancient Ocean
Little Horse Canyon near Orr Ridge, Utah: many of the study samples were collected nearby.

The oceans became oxygen-rich as they are today about 600 million years ago, during Earth's Late Ediacaran Period. Before that, most researchers believed until recently, the ancient oceans were relatively oxygen-poor for the preceding four billion years.

Now biogeochemists at the University of California-Riverside (UCR) have found evidence that the oceans went back to being "anoxic," or oxygen-poor, around 499 million years ago, soon after the first appearance of animals on the planet.

They remained anoxic for two to four million years.

The scientists suggest that such anoxic conditions may have been commonplace over a much broader interval of time.

"This work is important at a number of levels, from the steady growth of atmospheric oxygen in the last 600 million years, to the potential impact of oxygen level fluctuations on early evolution and diversification of life," said Enriqueta Barrera, program director in the National Science Foundation (NSF)'s Division of Earth Sciences, which funded the research.

The scientists argue that such fluctuations in the oceans' oxygen levels are the most likely explanation for what drove the explosive diversification of life forms and rapid evolutionary turnover that marked the Cambrian Period some 540 to 488 million years ago.........

Posted by: William      Read more         Source


December 29, 2010, 6:41 AM CT

Secrets of an Ancient Tel Aviv Fortress

Secrets of an Ancient Tel Aviv Fortress
An aerial view of the remains of the Tel Qudadi fortress
(Photo: Leon Mauldin)
Tel Qudadi, an ancient fortress located in the heart of Tel Aviv at the mouth of the Yarkon River, was first excavated more than 70 years ago - but the final results of neither the excavations nor the finds were ever published. Now, research on Tel Qudadi by archaeologists at Tel Aviv University has unpeeled a new layer of history, indicating that there is much more to learn from the site, including evidence that links ancient Israel to the Greek island of Lesbos.

"The secrets of this ancient fortress are only beginning to be revealed," Dr. Alexander Fantalkin and Dr. Oren Tal of Tel Aviv University's Department of Archaeology say. Their new research was recently reported in the Palestine Exploration Quarterly and BABESH: Annual Papers on Mediterranean Archaeology.

Well developed laws at sea

It was previously believed that the fortress was established during the 10th century B.C.E. at the behest of King Solomon, in order to protect the approach from the sea and prevent possible hostile raids against inland settlements located along the Yarkon River. The establishment of the fortress at Tel Qudadi was taken then as evidence of the existence of a developed maritime policy in the days of the United Monarchy in ancient Israel.

In another reconstruction, it was suggested that the fortress was erected sometime in the 9th century B.C.E. and could be attributed to the Kingdom of Israel. Now a careful re-evaluation of the finds conducted by Tel Aviv University scientists indicates that the fortress cannot be dated earlier than the late 8th - early 7th centuries B.C.E., much later than previously suggested.........

Posted by: William      Read more         Source


December 24, 2010, 1:13 PM CT

Back to the Dead

Back to the Dead
Prof. Zvi Ben-Avraham examines the top of the first extracted core of the drilling project.
They'll drill through four ice ages, epic sandstorms, mankind's migration from Africa to the New World, and the biggest droughts in history. Tel Aviv University is heading an international study that for the first time will dig deep beneath the Dead Sea, 500 meters (about a third of a mile) down under 300 meters (about a fifth of a mile) of water. Drilling with a special rig, the scientists will look back in time to collect a massive amount of information about climate change and earthquake patterns.

The study, led by Prof. Zvi Ben-Avraham of Tel Aviv University's Minerva Dead Sea Research Center, "aims to get a complete record in unprecedented resolution - at one year intervals - of the last 500 thousand years," says Prof. Ben-Avraham.

A crazy sandstorm 365,250 years ago?

Looking at the core sample to be dug about five miles offshore near Ein Gedi, the scientists hope to pinpoint particular years in Earth history to discover the planet's condition. They'll be able to see what the climate was like 365,250 years ago, for instance, or determine the year of a catastrophic earthquake.

This is by far the largest Earth sciences study of its kind in Israel. The evidence will help the world's climatologists calibrate what they know about climate change from other geological samples - and may lead to better predictions of what's in store for Middle East weather. For example, are currently increasing dry and hot periods in the region something new, or are they part of some larger cyclical pattern? What they find should also shed light on earthquake patterns - important information for Israelis, Jordanians and Palestinians who live on or around the fault line that passes through the Dead Sea region.........

Posted by: William      Read more         Source


December 19, 2010, 8:42 PM CT

Deciphering 3 billion-year-old genomic fossils

Deciphering 3 billion-year-old genomic fossils
The figure shows the evolution of gene families in ancient genomes across the Tree of Life. The sizes of the little pie charts scale with the number of evolutionary events in lineages, slices indicate event types: gene birth (red), duplication (blue), horizontal gene transfer (green), and loss (yellow). The Archean Expansion period (3.33 to 2.85 billion years ago) is highlighted in green.

Credit: Lawrence David

About 580 million years ago, life on Earth began a rapid period of change called the Cambrian Explosion, a period defined by the birth of new life forms over a number of millions of years that ultimately helped bring about the modern diversity of animals. Fossils help palaeontologists chronicle the evolution of life since then, but drawing a picture of life during the 3 billion years that preceded the Cambrian Period is challenging, because the soft-bodied Precambrian cells rarely left fossil imprints. However, those early life forms did leave behind one abundant microscopic fossil: DNA.

Because all living organisms inherit their genomes from ancestral genomes, computational biologists at MIT reasoned that they could use modern-day genomes to reconstruct the evolution of ancient microbes. They combined information from the ever-growing genome library with their own mathematical model that takes into account the ways that genes evolve: new gene families can be born and inherited; genes can be swapped or horizontally transferred between organisms; genes can be duplicated in the same genome; and genes can be lost.

The researchers traced thousands of genes from 100 modern genomes back to those genes' first appearance on Earth to create a genomic fossil telling not only when genes came into being but also which ancient microbes possessed those genes. The work suggests that the collective genome of all life underwent an expansion between 3.3 and 2.8 billion years ago, during which time 27 percent of all presently existing gene families came into being.........

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December 9, 2010, 7:57 AM CT

Lost civilization under Persian Gulf?

Lost civilization under Persian Gulf?
once fertile landmass now submerged beneath the Persian Gulf may have been home to some of the earliest human populations outside Africa, as per an article published recently in Current Anthropology

Jeffrey Rose, an archaeologist and researcher with the University of Birmingham in the U.K., says that the area in and around this "Persian Gulf Oasis" may have been host to humans for over 100,000 years before it was swallowed up by the Indian Ocean around 8,000 years ago. Rose's hypothesis introduces a "new and substantial cast of characters" to the human history of the Near East, and suggests that humans may have established permanent settlements in the region thousands of years before current migration models suppose.

In recent years, archaeologists have turned up evidence of a wave of human settlements along the shores of the Gulf dating to about 7,500 years ago. "Where before there had been but a handful of scattered hunting camps, suddenly, over 60 new archaeological sites appear virtually overnight," Rose said. "These settlements boast well-built, permanent stone houses, long-distance trade networks, elaborately decorated pottery, domesticated animals, and even evidence for one of the oldest boats in the world".

But how could such highly developed settlements pop up so quickly, with no precursor populations to be found in the archaeological record? Rose believes that evidence of those preceding populations is missing because it's under the Gulf.........

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November 18, 2010, 7:49 AM CT

On-site assessments in archaeology

On-site assessments in archaeology
Kristin Poduska of Duke University.

Credit: Kristin Poduska

The ability to tell the difference between crystals that formed naturally and those formed by human activity can be important to archaeologists in the field. This can be a crucial bit of information in determining the ancient activities that took place at a site, yet archaeologists often wait for months for the results of laboratory tests.

Now, however, an international team of physicists, archaeologists and materials researchers has developed a process that can tell in a matter of minutes the origin of samples thousands of years old. The new device is easily portable and works by "lifting off" the spectral fingerprint of a material with infrared light.

The first material tested was the mineral calcite, usually found in rocks such as limestone, which forms over millions years in sediments. These rocks can also contain the mineralized shells of sea creatures. Archaeological sites may also feature calcite that was a part of ash, plaster, or other building materials.

In the latest issue of the journal Advanced Materials, on-line today, Stefano Curtarolo, associate professor of mechanical engineering and materials sciences and physics at Duke University, and Kristin Poduska, associate professor of physics at Memorial University in Newfoundland, and their colleagues at the Weizmann Institute of Science in Israel, describe the new approach, which has already been successfully tested in archeological sites in Israel.........

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November 9, 2010, 10:38 PM CT

Oldest Fossil Shrimp Preserved With Muscles

Oldest Fossil Shrimp Preserved With Muscles
One of America's favorite seafood is shrimp. Did you know that they fossilize as well? Rodney Feldmann, professor emeritus, and Carrie Schweitzer, associate professor, from Kent State University's Department of Geology report on the oldest fossil shrimp known to date in the world. The creature in stone is as much as 360 million years old and was found in Oklahoma. Even the muscles of the fossil are preserved. Their study will be published in Journal of Crustacean Biology.

"The oldest known shrimp previous to this discovery came from Madagascar," Feldmann said. "This one is way younger, having an age of 'only' 245 million years, making the shrimp from Oklahoma 125 million years older".

The fossil shrimp, having a length of about 3 inches, was found by fellow paleontologist Royal Mapes of Ohio University and his students. Feldmann and Schweitzer named the fossil after him: Aciculopoda mapesi.

The discovery is also one of the two oldest decapods ('ten footed') to which shrimp, crabs and lobsters belong. The other decapod, Palaeopalaemon newberryi, is of similar age and was found in Ohio and Iowa. "The shrimp from Oklahoma might, thus, be the oldest decapod on earth," Feldmann explained.

The fossil is a very important step in unraveling the evolution of decapods. However, more finds are necessary. "The common ancestor of the two species can probably be found in rocks that once formed the old continent Laurentia," Schweitzer said. "Nowadays, these rocks can be found primarily in North America and Greenland. Who's going to find it? Possibly by one of the numerous amateur collectors, who often graciously donate specimens to science".........

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November 8, 2010, 7:59 AM CT

Oldest ground-edge implement discovered

Oldest ground-edge implement discovered
The oldest ground-edge stone tool in the world has been discovered in Northern Australia by a Monash University researcher and a team of international experts.

Evidence for stone tool-use among our earliest hominid ancestors dates to 3.4 million years ago, however, the first use of grinding to sharpen stone tool edges such as axes is clearly linked to modern humans, otherwise known as Homo sapiens sapiens.

Monash University archaeologist and member of the team who made the discovery, Dr Bruno David said while there have been reports of much older axes being found in New Guinea, the implements were not ground.

"This suggests that axe technology evolved into the later use of grinding for the sharper, more symmetrical and maintainable edges this generates," said Dr David.

"The ground-axe fragment is dated to 35,000 years ago, which pre-dates the oldest examples of ground-edge implements dated to 22,000-30,000 years ago from Japan and Northern Australia".

Archaeological excavations undertaken in May 2010 at Nawarla Gabarnmang in Northern Australia uncovered the artefact.

Nawarla Gabarnmang is a large rock-shelter in Jawoyn Aboriginal country in southwestern Arnhem Land. The discovery of the rock-shelter was made by Ray Whear and Chris Morgan from the Jawoyn Association while flying by helicopter on 15 June 2006.........

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