High-speed video footage of leaping lizards supports a 40-year-old hypothesis about how theropod dinosaurs, like the velociraptors of Jurassic Park fame, adjusted the angle of their tails to stay stable when jumping.
Source : Nature Video
Mars, too, has macroweather
Weather, which changes day-to-day due to constant fluctuations in the atmosphere, and climate, which varies over decades, are familiar. More recently, a third regime, called “macroweather,” has been used to describe the relatively stable regime between weather and climate.
A new study by researchers at McGill University and UCL finds that this same three-part pattern applies to atmospheric conditions on Mars. The results, published in Geophysical Research Letters, also show that the sun plays a major role in determining macroweather.
The research promises to advance scientists’ understanding of the dynamics of Earth’s own atmosphere — and could provide insights into the weather of Venus, Saturn’s moon Titan, and possibly the gas giants Jupiter, Saturn, Uranus and Neptune.
The scientists chose to study Mars for its wealth of data with which to test their theory that a transitional “macroweather” regime exists on other planets. They used information collected from Viking — a Mars lander mission during the 1970s and 1980s — and more recent data from a satellite orbiting Mars.
By taking into account how the sun heats Mars, as well as the thickness of the planet’s atmosphere, the scientists predicted that Martian temperature and wind would fluctuate similarly to Earth’s — but that the transition from weather to macroweather would take place over 1.8 Martian days (about two Earth days), compared with a week to 10 days on Earth.
“Our analysis of the data from Mars confirmed this prediction quite accurately,” said Shaun Lovejoy, a physics professor at McGill University in Montreal and lead author of the paper. “This adds to evidence, from studies of Earth’s atmosphere and oceans, that the sun plays a central role in shaping the transition from short-term weather fluctuations to macroweather.” The findings also indicate that weather on Mars can be predicted with some skill up to only two days in advance, compared to Earth’s 10 days.
Co-author Professor Jan-Peter Muller from the UCL Mullard Space Science Laboratory, said: “We’re going to have a very hard time predicting the weather on Mars beyond two days given what we have found in weather records there, which could prove tricky for the European lander and rover!”
Reference:
Shaun Lovejoy, J.-P. Muller, J. P. Boisvert. On Mars too expect macroweather. Geophysical Research Letters, 2014; DOI: 10.1002/2014GL061861
Note : The above story is based on materials provided by McGill University.
Rocky Mountain storms lead to new findings about hailstones
Hailstones from three Rocky Mountain storms formed around biological material, then bounced around the clouds picking up layers of ice, according to a new Montana State University study.
The discovery of a biological embryo extends previous findings about the formation of snow and rain, applies to hailstones globally and provides basic information about a little-studied topic, said the researchers who published their findings Nov. 6 in the Journal of Geophysical Research: Atmospheres.
“This is the first paper to really show that biological material makes hailstones,” said John Priscu, a renowned polar scientist and professor in MSU’s Department of Land Resources and Environmental Sciences. “Despite the millions in dollars of damage the storm caused in Bozeman (Mont.), the damaging hailstones provided us with a better understanding of hailstone formation, which will help us understand the role of aerosol particles in the formation of precipitation.”
Alex Michaud – MSU doctoral student and first author of the paper—normally studies Antarctic microorganisms with Priscu, but he took on a side project after hailstones pummeled Bozeman, Mont., on June 30, 2010.
“If it weren’t for his inquisitive nature of how things work, no good would have come from the devastating storm,” Priscu said.
Once the storm subsided, Michaud collected hailstones and stored them in an MSU freezer at minus 22 degrees Fahrenheit. The hailstones averaged 1.5 inches in diameter. Then Michaud gathered hailstones from two more area storms that occurred in 2010 and 2011. Those averaged about half an inch in diameter.
Examining some 200 hailstones in MSU’s Subzero Science and Engineering Research Facility showed that the hailstones formed around a biological embryo, Michaud said. Analyzing stable isotopes of water in an Ohio State University laboratory showed that most of the hailstone embryos froze at relatively warm temperatures, generally above 6.8 degrees Fahrenheit, which corroborates freezing temperatures of biological embryos recovered from the middle of hailstones.
Two different research methods showed that a warm temperature of ice nucleation indicates biological material is the likely nuclei, Michaud said. He added that hailstones grow in such a way that makes them a nice model system for studying atmospheric ice nucleation and cloud processes.
Among those providing direction and advice to Michaud were Priscu and David Sands, both co-authors on the published paper and internationally known researchers.
Priscu was chief scientist and one of three directors of a historic U.S. expedition that drilled through half a mile of Antarctic ice and found microorganisms living in a subglacial lake in January 2013. Michaud was part of the Whillans Ice Stream Subglacial Access Research Drilling project (WISSARD) and is about to head to Antarctica for its next phase.
Sands, a professor in MSU’s Department of Plant Sciences and Plant Pathology, conducted and published previous research that gained widespread attention for showing that active airborne bacteria were involved in the formation of rain and snow over several continents. Michaud’s hailstone study builds upon his work.
Co-author John Dore, associate research professor in MSU’s Department of Land Resources and Environmental Sciences, conducted low-level phosphate analyses to validate hailstone decontamination procedures. The presence of phosphates indicates contamination that originated on the ground. Dore also analyzed stable isotope data and developed temperature calibrations for the hailstone layer formation, and participated in many discussions about hail and how the research pieces fit together.
Co-authors outside of MSU were Deborah Leslie and W. Berry Lyons in the School of Earth Sciences and Byrd Polar Research Center at The Ohio State University. Lyons is a long-time collaborator of Priscu’s, and Leslie received her Ph.D. in Lyons’ lab. She analyzed stable isotopes from the melted hailstone embryos to estimate the temperatures that the hailstone embryos froze in the clouds.
In addition to his co-authors, Michaud said former MSU postdoctoral researcher Brent Christner and MSU affiliate Cindy Morris provided important assistance by helping him develop ideas and discuss data. Christner is also part of the WISSARD project. Morris collaborated with Sands on previous research about the formation of rain and snow.
Michaud also consulted with fellow hailstone researcher Tina Santl Temkiv, a postdoctoral researcher at Aarhus University in Denmark. She is in the university’s Department of Bioscience where Michaud was last spring through the National Science Foundation’s Integrative Graduate Education and Research Traineeship (IGERT) program.
“It was very coincidental that she published two hailstone microbiology papers two years before me and we ended up at the same university for a few months. Plus, we are the only ones to work on hailstone microbiology since a 1973 paper in Nature,” Michaud said, noting that the two jokingly established the first hailstone microbiology research center at Aarhus.
Reference:
Alexander B. Michaud et al: Biological ice nucleation initializes hailstone formation. Journal of Geophysical Research: Atmospheres 2014; DOI: 10.1002/2014JD022004
Note : The above story is based on materials provided by Montana State University
Clues to one of Earth’s oldest craters revealed
The Sudbury Basin located in Ontario, Canada is one of the largest known impact craters on Earth, as well as one of the oldest due to its formation more than 1.8 billion years ago.
Researchers who took samples from the site and subjected them to a detailed geochemical analysis say that a comet may have hit the area to create the crater.
“Our analysis revealed a chondritic platinum group element signature within the crater’s fallback deposits; however, the distribution of these elements within the impact structure and other constraints suggest that the impactor was a comet. Thus, it seems that a comet with a chondritic refractory component may have created the world-famous Sudbury basin,” said Joe Petrus, lead author of the Terra Nova paper.
Reference: DOI: 10.1111/ter.12125
Note : The above story is based on materials provided by Wiley
Latrines, sewers show varied ancient Roman diet
Archaeologists picking through latrines, sewers, cesspits and trash dumps at Pompeii and Herculaneum have found tantalizing clues to an apparently varied diet there before the eruption of Mount Vesuvius destroyed those Roman cities in 79 A.D.
Much of what residents didn’t digest or left on their plates went down into latrine holes, became remnants in cesspits built up over the centuries or was thrown away in local dumps. At a three-day conference ending Friday in Rome, archaeologists discussed their discoveries, including gnawed-on fish bones and goose eggshells that were possibly ancient delicacies for the elite.
“We just have small glimpses of the environment, but some are quite curious,” Mark Robinson, a professor of environmental archaeology at Oxford University Museum of Natural History, told the conference.
Here’s some of the curiosities the experts discussed:
ROMANS LIKED EATING LOCAL
Much of what the inhabitants ate was local. Archaeologists noted that some types of mollusk shells found in the sewers of Herculaneum came from the ancient town’s beach. Notable exceptions include grain, which was likely imported from Egypt; dates from the Middle East and northern Africa; and pepper spice from India. Although flour left no traces across such a long time, grain weevils apparently survived the milling process, ending up in a Herculaneum sewer that served a block of shops and home.
PORK PLEASED ROMAN PALATES THEN AND NOW
Today’s Romans are big on pork—pork slices known as porchetta are a popular filling for lunchtime sandwiches. Trash dumps from roughly the 1st century B.C. and the early 1st century A.D. in the Pompeii neighborhood of Porta Stabia yielded an abundance of pig bones, a sure sign that pork was popular then, noted Michael MacKinnon from the University of Winnipeg. Particularly tasty mollusks known as telline were popular on ancient tables; now telline as an ingredient for a seafood sauce is a much sought-after item on present-day Roman menus.
A CHICKEN IN EVERY POT?
That’s not clear but lots of chicken eggs were consumed, judging by the numerous pieces of eggshell found. Erica Rowan, an archaeologist at the University of Exeter who worked on the Herculaneum sewer, also reported finding two fragments of goose egg shell, possibly the remnants of a meal consumed by the elite. But for the most part, it appeared that both rich and not-so-rich Romans in these cities ate much the same food, especially fish.
HORS D’OEUVRES FOR THE DEITIES
Being buried for centuries in the sewers and cesspits helped preserve food traces—Vesuvius’ eruption also carbonized some food for posterity. Bite-sized, carbonized, cake-like breads—”nibbles for the gods” is how Robinson referred to them—were discovered at a disused kiln in Pompeii. Pieces of votive cups were also found, prompting archaeologists to view the nibbles as possible offerings to ancient Roman deities.
ANCIENT RECYCLING
Robinson also reported finding a scallop shell that held rouge, serving as a kind of women’s compact.
Note : The above story is based on materials provided by © 2014 The Associated Press. All rights reserved.
Seismic Hazard in the Puget Lowland, Washington State, USA
Boulder, Colo., USA – Seismic hazards in the Puget Lowland of northwestern Washington include deep earthquakes associated with the Cascadia subduction zone and shallow earthquakes associated with crustal faults across the region. Research presented in Geosphere this month establishes not only that one of the more prominent crustal faults, the Darrington-Devils Mountain fault zone, displays evidence of strong earthquakes in the past, but that it will likely be a source of strong earthquakes in the future.
Paleoseismic investigations on the Darrington-Devils Mountain fault zone by Stephen F. Personius and colleagues, using three-dimensional trenching, document a large-magnitude (M 6.7 to 7.0) earthquake about 2,000 years ago and show evidence of a similar earthquake about 8,000 years ago.
An additional surprising result is evidence indicating that the sense of slip on the fault zone during these earthquakes was primarily right-lateral, with a smaller component of north-side-up vertical slip. Holocene north-side-up, right-lateral oblique slip is opposite the south-side-up, left-lateral oblique sense of slip inferred from deformation of Eocene and older rocks along the fault zone. According Personius and colleagues, the cause of this slip reversal is unknown, but may be related to ongoing clockwise rotation of northwestern Washington State into a position more favorable to right-lateral slip in the current stress field.
Note : The above story is based on materials provided by The Geological Society of America
Lava continues to flow toward Hawaii’s Pahoa “Video”
Lava flowing from the Kilauea volcano in Hawaii slows but continues to threaten the village of Pahoa. Rough Cut
Video Source: Reuters
140-million-year-old dinosaur tooth found in Malaysia
While still unsure of the exact species of dinosaur, lead researcher Masatoshi Sone from the University of Malaya said the discovery means “it is plausible that large dinosaur fossil deposits still remain in Malaysia”.
“We started the programme to look for dinosaur fossils two years ago. We are very excited to have found the tooth of the dinosaurian order called Ornithischian in central Pahang state” last year, he said.
Researchers from Japan’s Waseda University and Kumamoto University also took part in the project.
Ornithischian, or “bird-hipped”, is a major group comprised of herbivous dinosaurs such as triceratops.
The dinosaur would have been about as big as a horse, Sone said.
The darkened tooth fossil—13-mm-long (0.5-inches) and 10.5-mm-wide—was discovered in a sedimentary rock formation by a team of Malaysian and Japanese palaeontologists.
It was found close to where the first Malaysian dinosaur fossil, estimated to be at least 75 million years old, was discovered in 2012.
That fossil was found to belong to a fish-eating predator belonging to the family of dinosaur known as Spinosaurid, believed to be semi-aquatic.
The exact location of the discoveries is being kept secret in order to preserve it.
Note : The above story is based on materials provided by AFP
Blowholes and caves surprise on Nullarbor geological survey
La Trobe University expert says Dr Shannon Burnett says he had always thought of the Nullabor Plain as “just a big desert”.
“However, as I started studying and collecting data for my honors project in 2011, I became intrigued as flank margin caves [forming on margins of enclosing ridges] are normally found on islands, but this is the first time they have been found on a continental setting,” he says.
Dr Burnett has been gathering data on the region’s blowholes with the help of the Victorian Speleological Society.
They carried out aerial surveys and subsequent ground confirmation expeditions and also considered data collected from previous surveys carried out by the Western Australian Cavers.
Dr Burnett found the blowholes in two bands, one along the coast and the other about 75km inland, in a 25−30km wide band incorporating 1,307 features.
He believes the cave porosity is much greater than the blowhole density because the blowholes blow draughts of up to 70km/h indicating they are connected by extensive cave systems of small un-enterable passages.
He says the blowhole draughts are caused by barometric pressure and not tidal influences.
Air survey uncovers blowholes
“We chose areas to survey that we believed had a high density of features or had one or more significant features,” Dr Burnett says.
“I had the use of a retired pilot with an ultra-light aircraft who flew in a systematic pattern so that the whole search area could be covered.
“When the pilot spotted a blowhole, he marked the position with a GPS for the ground team to physically verify and accurately locate.
“Because of accessibility issues on the Nullarbor, previous data [was] biased around roads and the Trans-Continental railway, however the systematic coverage of the large and defined search areas by the ultra-light aircraft has almost eliminated bias.”
Dr Burnett says it was too difficult to access and explore the Nullarbor’s northern regions and satellite imagery wasn’t an option as he didn’t have the budget for paid satellite imagery and the blowholes are too small to be seen on free satellite services.
He says more surveys and expeditions will be conducted, especially as these flank margin caves represent an unrecognised potential petroleum reservoir.
Note : The above story is based on materials provided by Science Network WA
Raw: Lava Burns on Local Hawaii Road
Video from the Big Island of Hawaii shows lava from the Kilauea Volcano burning on a local road. The lava’s leading edge remains 500 feet from Pahoa Village Road. However, several lobes of lava broke out and advanced on Sunday. (Nov. 10)
Video provided by AP
Understanding the 1989 Loma Prieta Earthquake in an Urban Context
Despite the absence of primary surface rupture from the 1989 Loma Prieta earthquake, patterns of damage to pavement and utility pipes can be used to assess ground deformation near the southwest margin of the densely populated Santa Clara or “Silicon” Valley, California, USA. Schmidt and colleagues utilized more than 1,400 damage sites as an urban strain gage to determine relationships between ground deformation and previously mapped faults.
Post-earthquake surveys of established monuments and the concrete channel lining of Los Gatos Creek reveal belts of deformation consistent with regional geologic structure. The authors conclude that reverse movement largely along preexisting faults, probably enhanced significantly by warping combined with enhanced ground shaking, produced the widespread ground deformation.
Such damage, with a preferential NE-SW sense of shortening, occurred in response to the 1906 and 1989 earthquakes and will likely repeat itself in future earthquakes in the region.
Note : The above story is based on materials provided by The Geological Society of America
Volcano hazards and the role of westerly wind bursts in El Niño
On 27 June, lava from Kīlauea, an active volcano on the island of Hawai`i, began flowing to the northeast, threatening the residents in Pāhoa, a community in the District of Puna, as well as the only highway accessible to this area. Scientists from the U.S. Geological Survey’s Hawaiian Volcano Observatory (HVO) and the Hawai`i County Civil Defense have been monitoring the volcano’s lava flow and communicating with affected residents through public meetings since 24 August. Eos recently spoke with Michael Poland, a geophysicist at HVO and a member of the Eos Editorial Advisory Board, to discuss how he and his colleagues communicated this threat to the public.
Drilling a Small Basaltic Volcano to Reveal Potential Hazards
Drilling into the Rangitoto Island Volcano in the Auckland Volcanic Field in New Zealand offers insight into a small monogenetic volcano, and may improve understanding of future hazards.
From AGU’s journals: El Niño fades without westerly wind bursts
The warm and wet winter of 1997 brought California floods, Florida tornadoes, and an ice storm in the American northeast, prompting climatologists to dub it the El Niño of the century. Earlier this year, climate scientists thought the coming winter might bring similar extremes, as equatorial Pacific Ocean conditions resembled those seen in early 1997. But the signals weakened by summer, and the El Niño predictions were downgraded. Menkes et al. used simulations to examine the differences between the two years.
The El Niño-Southern Oscillation is defined by abnormally warm sea surface temperatures in the eastern Pacific Ocean and weaker than usual trade winds. In a typical year, southeast trade winds push surface water toward the western Pacific “warm pool”–a region essential to Earth’s climate. The trade winds dramatically weaken or even reverse in El Niño years, and the warm pool extends its reach east.
Scientists have struggled to predict El Niño due to irregularities in the shape, amplitude, and timing of the surges of warm water. Previous studies suggested that short-lived westerly wind pulses (i.e. one to two weeks long) could contribute to this irregularity by triggering and sustaining El Niño events.
To understand the vanishing 2014 El Niño, the authors used computer simulations and examined the wind’s role. The researchers find pronounced differences between 1997 and 2014. Both years saw strong westerly wind events between January and March, but those disappeared this year as spring approached. In contrast, the westerly winds persisted through summer in 1997.
In the past, it was thought that westerly wind pulses were three times as likely to form if the warm pool extended east of the dateline. That did not occur this year. The team says their analysis shows that El Niño’s strength might depend on these short-lived and possibly unpredictable pulses.
Note : The above story is based on materials provided by American Geophysical Union
‘Dark magma’ could explain mystery volcanoes
“It’s a very provocative paper … a bit speculative,” says Thomas Duffy, a geoscientist at Princeton University who was not involved with the study. “But it’s taking us in an important step on the road to understanding the deep Earth.”
Most volcanoes form because tectonic plates, vast sections of Earth’s crust, smash against or slide underneath each other. The pushing and melting there feed the volcanoes in the infamous Ring of Fire around the Pacific Ocean. But hot spot–spawned volcanoes like Hawaii’s are a different breed. They are nowhere near tectonic plate edges, and yet millions of years ago they spewed out so much lava that they nearly blanketed whole continents with molten rock or covered the globe with soot. Geologists believe the source of this magma is coming from just above Earth’s outer core, but they’re not exactly sure how.
Alexander Goncharov, a geophysicist at the Carnegie Institution for Science in Washington, D.C., and colleagues think that there are patches of magma—remnants from an early molten stage of our planet’s history—quilted around the outer core. Because the bottom of Earth’s mantle is nearly 3000 kilometers below the surface—about a 3-day journey if you could drive there by car—temperatures and pressures reach such hellish extremes that the atomic structures of these magmas are different from those they would have at lesser pressures. Duffy says that “can really change physical properties a lot,” including the way the material looks and absorbs heat.
To test how magma might behave near the core, Goncharov and his colleagues squeezed a sliver of a dark, opaque glass, made from iron and silicate to mimic the composition of deep Earth magmas, between two diamonds to simulate pressures near the core. The team then shined an infrared light through the glass and measured how much light passed through. As the pressure increased, so did the amount of light the glass absorbed, and the team saw a change in the atomic structure of the glass, the researchers report online today in Nature Communications.
Goncharov says that means magmas at high pressures in the lower mantle must be sponging up heat emanating from the core. As these patches of magma around the core get hotter, they start to act as a door for heat to pass into the mantle by convection. The heated mantle rocks then move up through the planet in a massive plume until they erupt on the surface, creating large volcanoes in strange places like Hawaii, Yellowstone, Easter Island, and Mount Etna, and some of the most violent eruptions.
If the team is right, its work could illuminate a key part of Earth’s geology. Duffy says these plumes are “one of the most important things to understand,” because the movement of heat powers many processes on the planet. For one, Earth’s magnetic field depends on how the core spins and flows inside the planet. As a result, Duffy says, “the way heat flows from the core to the mantle could potentially affect the way Earth’s magnetic field evolves over time.”
Not everybody is ready to get behind Goncharov and his colleagues’ new hypothesis. “There are two fundamental limitations of the paper,” Duffy says. “First that they’re studying a glass and not [melted rock], and there’s the fact that [the experiment] is at room temperature and not high temperature.” Until scientists perform the experiment with molten rock heated to about 3200°C, Duffy says, they can’t be sure how the magma really behaves.
And geologists still contest whether the pockets of magma around Earth’s outer core actually exist. To probe Earth’s interior, scientists rely on seismic waves from large earthquakes that have to travel through 3000 kilometers of rock. At that depth, the measurements become “a little bit ambiguous,” Duffy says. “And there’s a question as to why the liquid wouldn’t just all drain [away].” Because these dark magma pockets float above the core, it’s a bit like imagining an ocean rising tens of kilometers above sea level. “It’s not impossible,” he says, “but the idea that there’s melt in the deep
mantle is controversial.”
Reference:
Motohiko Murakami,Alexander F. Goncharov,Naohisa Hirao,Ryo Masuda,Takaya Mitsui,Sylvia-Monique Thomas& Craig R. Bina , http://dx.doi.org/10.1038/NCOMMS6428
Note: The above story is based on materials provided by American Association for the Advancement of Science. The original article was written by Angus Chen.
Kīlauea, 1790 and today
The footprints, made by warriors and their families, appear along a major trail in use at the time. Today, the area is one of the most visited parts of Hawai’i Volcanoes National Park.
The explosive eruption resulted from the violent interaction of groundwater with hot rocks. Such explosive eruptions have happened frequently in Kīlauea’s past and will probably occur in the future when the caldera collapses down to the water table, some 600 m (2000 ft) below the summit of the volcano.
The 1790 eruption of Kīlauea was explosive, and its major impacts were in the summit area of the volcano. The eruption taking place now at Kīlauea is effusive, says Swanson, producing a flow of lava that erupts without explosion. This flow is erupting from a site named Pu’u ‘Ō’ō on the east rift zone, far from the summit area, and lava has to flow many kilometers (several miles) before reaching inhabited areas.
Explosive eruptions are very hazardous; the 1790 fatalities bear witness to this fact. Lava flows are not very hazardous to life but can be exceedingly destructive to property. Explosive eruptions are brief but terrifying. Lava flows often last for months or more and are captivating to the viewer. Kīlauea has both types of eruptions, but not at the same time.
Violent explosive eruptions from the summit of Kīlauea are geologically common. They are generally clustered into periods lasting a few centuries. It has been about 200 years since the most recent major explosion, which culminated about 300 years of frequent explosive eruptions. In the past 200 years, Kīlauea has produced many lava flows similar to the present one; small explosions took place in 1924 and, on an even smaller scale, during the past 6 years.
The general public is unaware of Kīlauea’s explosive nature, because the volcano has erupted mainly lava flows in recent times. Kīlauea will almost certainly become explosive at some future time, producing conditions similar to those of 1790. However, according to Swanson, there is no reason to think that a period of violent eruptions will resume any time soon. The public can probably expect more lava flows in the near future, such as those of the past three decades from Pu’u ‘Ō’ō.
Reference:
D. A. Swanson, S. J. Weaver, B. F. Houghton. Reconstructing the deadly eruptive events of 1790 CE at K lauea Volcano, Hawai’i. Geological Society of America Bulletin, 2014; DOI: 10.1130/B31116.1
Note : The above story is based on materials provided by Geological Society of America.
Archaeologists discover remains of Ice Age infants in Alaska
The remains of two Ice Age infants, buried more than 11,000 years ago at a site in Alaska, represent the youngest human remains ever found in northern North America, according to a new paper published in the Proceedings of the National Academy of Sciences.
The site and its artifacts provide new insights into funeral practices and other rarely preserved aspects of life among people who inhabited the area thousands of years ago, according to Ben Potter, a researcher at the University of Alaska Fairbanks and the paper’s lead author.
Potter led the archaeological team that made the discovery in fall of 2013 at an excavation of the Upward Sun River site, near the Tanana River in central Alaska. The researchers worked closely with local and regional Native tribal organizations as they conducted their research. The National Science Foundation funded the work.
Potter and his colleagues note that the human remains and associated burial offerings, as well as inferences about the time of year the children died and were buried, could lead to new thinking about how early societies were structured, the stresses they faced as they tried to survive, how they treated the youngest members of their society, and how they viewed death and the importance of rituals associated with it.
Potter made the new find on the site of a 2010 excavation, where the cremated remains of another 3-year-old child were found. The bones of the two infants were found in a pit directly below a residential hearth where the 2010 remains were found.
“Taken collectively, these burials and cremation reflect complex behaviors related to death among the early inhabitants of North America,” Potter said.
In the paper, Potter and his colleagues describe unearthing the remains of the two children in a burial pit under a residential structure about 15 inches below the level of the 2010 find. The radiocarbon dates of the newly discovered remains are identical to those of the previous find–about 11,500 years ago–indicating a short period of time between the burial and cremation, perhaps a single season.
Also found within the burials were unprecedented grave offerings. They included shaped stone points and associated antler foreshafts decorated with abstract incised lines, representing some of the oldest examples of hafted compound weapons in North America.
“The presence of hafted points may reflect the importance of hunting implements in the burial ceremony and with the population as whole,” the paper notes.
The researchers also examined dental and skeletal remains to determine the probable age and sex of the infants at the time of the death: One survived birth by a few weeks, while the other died in utero. The presence of three deaths within a single highly mobile foraging group may indicate resource stress, such as food shortages, among these early Americans.
Such finds are valuable to science because, except in special circumstances like those described in the paper, there is little direct evidence about social organization and mortuary practices of such early human cultures, which had no written languages.
The artifacts–including the projectile points, plant and animal remains–may also help to build a more complete picture of early human societies and how they were structured and survived climate changes at the end of the last great Ice Age. The presence of two burial events–the buried infants and cremated child–within the same dwelling could also indicate relatively longer-term residential occupation of the site than previously expected.
The remains of salmon-like fish and ground squirrels in the burial pit indicate that the site was likely occupied by hunter-gatherers between June and August.
“The deaths occurred during the summer, a time period when regional resource abundance and diversity was high and nutritional stress should be low, suggesting higher levels of mortality than may be expected give our current understanding” of survival strategies of the period, the authors write.
Reference:
Ben A. Potter, Joel D. Irish, Joshua D. Reuther, and Holly J. McKinney. New insights into Eastern Beringian mortuary behavior: A terminal Pleistocene double infant burial at Upward Sun River. PNAS, November 10, 2014 DOI: 10.1073/pnas.1413131111
Note : The above story is based on materials provided by University of Alaska Fairbanks. The original article was written by Marmian Grimes.
Discovery of a dinosaur tail in northern Mexico
A team of paleontologists have discovered the fossilized remains of a 72 million-year-old dinosaur tail in a desert in northern Mexico. It’s the first ever found in the country.
Source: AFP
A/C came standard on armored dinosaur models
Berlin, Germany (November, 2014) – Sweating, panting, moving to the shade, or taking a dip are all time-honored methods used by animals to cool down. The implicit goal of these adaptations is always to keep the brain from overheating. Now a new study shows that armor-plated dinosaurs (ankylosaurs) had the capacity to modify the temperature of the air they breathed in an exceptional way: by using their long, winding nasal passages as heat transfer devices.
Led by paleontologist Jason Bourke, a team of scientists at Ohio University used CT scans to document the anatomy of nasal passages in two different ankylosaur species. The team then modeled airflow through 3D reconstructions of these tubes. Bourke found that the convoluted passageways would have given the inhaled air more time and more surface area to warm up to body temperature by drawing heat away from nearby blood vessels. As a result, the blood would be cooled, and shunted to the brain to keep its temperature stable.
Modern mammals and birds use scroll-shaped bones called conchae or turbinates to warm inhaled air. But ankylosaurs seem to have accomplished the same result with a completely different anatomical construction.
“There are two ways that animal noses transfer heat while breathing,” says Bourke. “One is to pack a bunch of conchae into the air field, like most mammals and birds do–it’s spatially efficient. The other option is to do what lizards and crocodiles do and simply make the nasal airway much longer. Ankylosaurs took the second approach to the extreme.”
Lawrence Witmer, who was also involved with the study, said, “Our team discovered these ‘crazy-straw’ airways several years ago, but only recently have we been able to scientifically test hypotheses on how they functioned. By simulating airflow through these noses, we found that these stretched airways were effective heat exchangers. They would have allowed these multi-tonne beasts to keep their multi-ounce brains from overheating.”
Like our own noses, ankylosaur noses likely served more than one function. Even as it was conditioning the air it breathed, the convoluted passageways may have added resonance to the low-pitched sounds the animal uttered, allowing it to be heard over greater distances.
Note : The above story is based on materials provided by Society of Vertebrate Paleontology
Brahmaputra River
The Brahmaputra is a trans-boundary river and one of the major rivers of Asia. Majuli is the Riverine island formed by River Brahmaputra in Assam in India.
With its origin in the Angsi Glacier, located on the northern side of the Himalayas in Burang County of Tibet as the Yarlung Tsangpo River, it flows across southern Tibet to break through the Himalayas in great gorges (including the Yarlung Tsangpo Grand Canyon) and into Arunachal Pradesh (India) where it is known as Dihang or Siang. It flows southwest through the Assam Valley as Brahmaputra and south through Bangladesh as the Jamuna (not to be mistaken with Yamuna of India). In the vast Ganges Delta it merges with the Padma, the main distributary of the Ganges, then the Meghna, before emptying into the Bay of Bengal.
About 1,800 miles (2,900 km) long, the Brahmaputra is an important river for irrigation and transportation. The average depth of the river is 124 feet (38 m) and maximum depth is 380 feet (120 m). The river is prone to catastrophic flooding in spring when the Himalayan snows melt. The average discharge of the river is about 19,300 cubic metres per second (680,000 cu ft/s), and floods can reach over 100,000 cubic metres per second (3,500,000 cu ft/s). It is a classic example of a braided river and is highly susceptible to channel migration and avulsion. It is also one of the few rivers in the world that exhibit a tidal bore. It is navigable for most of its length.
The river drains the Himalaya east of the Indo-Nepal border, southern-central portion of the Tibetan plateau above the Ganges basin, south-eastern portion of Tibet, the Patkai-Bum hills, the northern slopes of the Meghalaya hills, the Assam plains and the northern portion of Bangladesh. The basin, especially south of Tibet is characterized by high levels of rainfall. Kangchenjunga (8,586m) is the only peak above 8,000m and the highest point within the Brahmaputra basin.
The Brahmaputra’s upper course was long unknown, and its identity with the Yarlung Tsangpo was only established by exploration in 1884–86. This river is often called Tsangpo-Brahmaputra river.
The lower reaches are sacred to Hindus. While most rivers on the Indian subcontinent have female names, this river has a rare male name, as it means “son of Brahma” in Sanskrit (putra means “son”).
Note : The above story is based on materials provided by Wikipedia
Duck-billed dinosaurs were no sitting ducks, research shows
If you ever find yourself wandering lost in Jurassic Park or time-warped back 70 million years, University of Alberta paleontologists Scott Persons and Phil Currie are two guys you would want with you. The two scientists have just published a new paper on tyrannosaur avoidance strategies, looking into how other dinosaurs coexisted with the colossal carnivores and offering new insight into a prehistoric mystery of survival.
“When it comes to avoiding predators, big animals have it hard,” says lead author Scott Persons, a graduate student in the Department of Biological Sciences. “When trouble comes, tiny creatures can hide in the bushes, run up a tree or escape inside a burrow, but an animal the size of a big herbivorous dinosaur couldn’t exactly conceal itself behind the nearest shrub or beneath a convenient rock or tree root.”
Instead, most families of plant-eating dinosaurs evolved specific adaptations to help them cope with their meat-eating adversaries. Some, like Triceratops, evolved big horns that made them too dangerous to attack. Others evolved bony suits of spiky armour that turned them into walking fortresses. A few others evolved lightweight bodies and extra-long legs that gave them the speed to reliably outrun predators. But one group has always appeared virtually defenceless: the hadrosaurs—better known as the duck-billed dinosaurs.
“Hadrosaurs have no horns, no tusks, no big claws and no armour,” says Persons. “They were social animals and lived in large herds. But safety in numbers only goes so far, and to a T. Rex, a big herd of unarmed hadrosaurs would seem like a buffet.”
And yet, hadrosaurs did not simply survive alongside tyrannosaurs—they thrived. In the badlands of Alberta and in many other dinosaur fossil beds across North America and Asia, hadrosaur bones outnumber all other large dinosaur fossils combined. What were they doing right?
“If duck-bills couldn’t hide and couldn’t fight, maybe they could run,” Persons explains. “Compared with other herbivorous heavyweights, hadrosaurs do have proportionately longer leg bones, which indicates faster running. But hadrosaur limb proportions still seem downright poky when you compare them to tyrannosaurs.”
A breakthrough came when Persons looked beyond the bones and considered muscles. Using digital modelling techniques and muscle insertion clues from skeletons, Persons was able to estimate the size and shape of the primary leg muscles of hadrosaurs and tyrannosaurs. He found that both groups had adaptations to support a supersized set of running muscles.
“Their primary running muscle is called the caudofemoralis, and it’s positioned at the base of the tail,” Persons says. “Both hadrosaurs and their predators had an expanded caudofemoralis, but there was a critical difference: in hadrosaurs the muscle was expanded downwards, whereas in tyrannosaurs it was expanded upwards. The upward-expanded muscles attached high on the thigh; the downward-expanded muscles attached low. These up versus down expansions were not just two equally good solutions to the same problem. They imparted two very different running abilities.”
“Imagine we go to the Dino Derby,” Persons muses. “In a race between a tyrannosaur and a hadrosaur, it used to be that the smart money was all on the tyrannosaur. Well, bang! The race begins and, sure enough, with longer legs the tyrannosaur bursts out of the starting gate and into an early lead. With a high attachment, it only takes a short, quick contraction of the caudofemoralis muscle to pull the leg through a single long stride. The low attachment of the hadrosaur only permits shorter, slower strides. The tyrannosaur leaves the duck-bill in its dust. But . . . suppose the race isn’t just a quick sprint. Suppose it’s a full lap or two around the track. Although the tyrannosaur has a higher top speed, it cannot keep up the pace. The low attachment of the hadrosaur’s caudofemoralis gives the muscle great leverage. That translates into much better endurance. It’s like a prehistoric version of Aesop’s fable: the slow but steady hadrosaur wins the race.”
How did superior endurance running keep hadrosaurs from becoming easy pickings for faster tyrannosaurs? Here the U of A researchers draw a comparison with modern zebras. Like hadrosaurs, zebras are often the most abundant big herbivores in their environments, despite having no horns or armour. And although zebras are fast, their top speed is well below that of the lions and cheetahs that prey on them.
“But big cats have terrible endurance and tire out quickly,” Persons concludes. “Zebras can avoid being caught if they start to run before the cats can sneak into their very short effective striking distance. An alert herd can help with that. I think endurance running could have been an even better predator avoidance strategy for hadrosaurs. After all, the limitations of big size work both ways. Zebras have to be on the lookout for stealthy cats lurking in tall grass, but hadrosaurs had only to spot predators that were the size of billboards.”
Persons’ and Currie’s research in the Faculty of Science was published this week in a special compendium of research papers on hadrosaurs produced by Indiana University Press.
Note : The above story is based on materials provided by University of Alberta
Why Iceland formed so differently from the gentle early Earth
If we can find minerals that formed during the period we are interested in, they can give us clues about the origin and evolution of the magmas from which they crystallized. That information, in turn, can provide valuable evidence of the conditions on the Earth’s surface at the time the magma was generated. This insight into ancient environments is critical to understanding when conditions on Earth were first hospitable to life.
A new study compares Hadean Earth (more than four billion years ago) to the modern Earth that we are familiar with today. This is not a new idea; people have long thought that Hadean Earth might be similar to modern Iceland, where magmatism runs rampant, volcanoes are active, the crust is anomalously thick, and rocks associated with continents (rhyolite, granite) are found in the ocean (seemingly out of place). The study demonstrates just how different Iceland and the Hadean really are, but how similar the Hadean may have been to other environments that are more typical of modern Earth.
Researchers found this out by analyzing zircon, a mineral that crystallizes in the kinds of magmas associated with continental crust. Zircons have been analyzed from all around the world, in many different magmatic and tectonic environments, and from all chapters of Earth’s history. However, until recently, zircons from Iceland have not been the focus of rigorous study. The conclusion, when Hadean zircons were compared to Icelandic zircons? Magmas in the Hadean Earth were likely formed in environments much cooler and wetter (some might say, more hospitable) than the magmatic environments of modern Iceland.
“Zircon is a phenomenal research tool—a reliable little time capsule,” said Lafayette College geoscientist Tamara Carley, who did the research while finishing her doctorate at Vanderbilt University. “It can tell you a lot about magmatic conditions at the time of its crystallization.”
The research was recently published in the scientific journal Earth and Planetary Science Letters.
Finding the early rocks
The challenge in researching early Earth is the paucity of information available. Earth’s earliest rocks have been all but lost to the geologic record, and have been severely altered or totally destroyed by surficial and tectonic processes that continue to shape our planet today. Traditionally, this absence of rocks from the oldest chapter of Earth’s history led researchers to believe that early Earth was covered in a harsh environment, like a global lava ocean, that would be totally inhospitable to rocks and life alike.
In the 1980s, however, the vision of early Earth began to change. Researchers discovered zircon crystals that had crystallized in magmas during the Hadean, then survived Earth’s tumultuous geologic history for more than four billion years. The age of the crystals was confirmed using dating techniques that measure the proportion of radioactive and radiogenic isotopes (parent and daughter isotopes) inside the crystals. Isotopes decay in a predictable fashion over millions or billions of years, and zircon does a good job of locking in this valuable evidence, providing researchers with an accurate clock of the age of the crystals.
Carley’s group did a literature review of the oxygen isotope and trace element geochemistry data teased from these ancient zircon crystals. They then compared the published Hadean results to their new Icelandic findings. Upon realizing just how different Icelandic and Hadean zircons are (and thus, how different their formation environments were), they scoured the literature for zircons that acted as a better modern analogue for the Hadean. They considered the Andes in South America; the Cascade Mountains, the Sierra Nevada Mountains and the Yellowstone Hotspot in western North America; the Mid-Atlantic Ridge; and volcanic rocks in the East African Rift Zone.
The Hadean has temperatures and other compositional clues that are more similar to zircons from subduction zones magmas, generated in areas where one tectonic plate is forced beneath the other when they collide, as happens in places like the Cascades and the Andes. They concluded that Iceland is most similar to other rift environments, which perhaps isn’t much of a surprise since it sits atop a rift itself.
From their look at other researchers’ published work, Carley said her team concurs with what the other researchers found: zircons from the Hadean crystallized at relatively low magmatic temperatures. Furthermore, oxygen isotope ratios measured in the zircon crystals acts as evidence that low-temperature surface water played a role in the generation of the magmas from which they grew. Icelandic zircons, on the other hand, crystallized at much higher temperatures, and have isotopic evidence of hot, hydrothermal waters playing a role in magma genesis. Zircons from Iceland and the Hadean tell very different stories, about their respective environments of origin. Zircons from subduction zone volcanoes (like the Cascades) are more in line with zircons from the Hadean.
“It’s pretty compelling evidence that Earth was cool enough, and perhaps wet enough early on in its history that the thought of early life isn’t crazy,” Carley said.
How similar is Iceland?
Iceland is a standout location on modern Earth, Carley pointed out. It sits at the junction of a mid-ocean ridge and a hotspot, making it a location of elevated heat and magma generation. It has more rhyolite and granite (rocks associated with continental crust) than is common in an oceanic setting. It also features an extra-thick crust, estimated to be about 16 to 19 miles thick (25 to 30 kilometers) compared to the average oceanic crust, which is 4.4 miles (seven kilometers) thick.
Differences also show up after comparing not-so-subtle differences in chemistry between the Icelandic and the ancient zircon populations. In an ideal world, a zircon mineral would only contain three elements: zirconium, oxygen, and silicon. However, trace amounts of other elements (like titanium and uranium) can be trapped in the mineral as it grows. The specific element and its composition all depends on the conditions of the magma as the zircon crystallizes. In this case, titanium was one element that helped give the game away. In comparing hundreds of Icelandic and Hadean zircons, Carley’s research team found that Icelandic zircons consistently were richer in titanium. This told them that the Icelandic zircons grew in hotter magmas compared to the Hadean zircons, which grew in cooler magmas.
Even more exciting than the temperature story told by titanium was the water story told by oxygen isotope ratios, locked in the zircon crystal structure. The zircon record revealed to Carley and her research team that liquid water (essential to life as we know it on Earth) played a major role in both Icelandic and ancient magmas.
But the waters were very different in both cases. In the Hadean, the water involved in the magma generating process appear to be cool, like we see at modern-day subduction zones (like the Cascadeds and the Andes), as opposed to very hot, like we see in Iceland with its active, high-temperature, hydrothermal systems. “It become clear to us that Iceland is very dissimilar to the Hadean,” Carley said. “We need to change the conversation, and we need to stop saying that Iceland is a modern analogue for the Hadean.”The field, she added, could benefit from examining zircons from other locations on Earth, such as collisional zones where subduction does not occur, and juvenile subduction zones that form volcanic islands. These are research directions she said she hopes to pursue in the future.
Reference:
Tamara L. Carley, Calvin F. Miller, Joseph L. Wooden, Abraham J. Padilla, Axel K. Schmitt, Rita C. Economos, Ilya N. Bindeman, Brennan T. Jordan, “Iceland is not a magmatic analog for the Hadean: Evidence from the zircon record,” Earth and Planetary Science Letters, Volume 405, 1 November 2014, Pages 85-97, ISSN 0012-821X, dx.doi.org/10.1016/j.epsl.2014.08.015.
Note : The above story is based on materials provided by Astrobio.net
This story is republished courtesy of NASA’s Astrobiology Magazine.