WFS

Formation of sedimentary layers of white clay, Tamilnadu, India

Fossil site for wood fossils, Tamilnadu, India

Fossil site in Kerala, India

Fossil wood park maintained by geological survey of India at Tamilnadu

Cretaceous fossil sites india

Fossils in rack:-Cyad

Fossils in rack:-echiniderms

Fossils in rack:-Rastellum sp

Pre-historic seabed, Cretaceous period

Why Diplodocus did not put all her eggs in one basket

June 30th, 2014

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If you thought the largest dinosaurs to have walked the Earth produced the biggest eggs, you’d be mistaken. Scientists have discovered that both individual egg size and clutch size for the sauropods — which includes Diplodocus — were a lot smaller than might be expected for such enormous creatures.

A team of scientists have suggested reasons why the largest dinosaurs ever to have walked the Earth produced smaller eggs than might be expected.

One of the defining characteristics of the dinosaurs was their vast size, and the sauropods — a suborder of dinosaurs which includes the famous Diplodocus — were the largest of all.

Yet scientists have been puzzled at the relatively small size of sauropod eggs. Both individual egg size and clutch size are smaller than might be expected for such enormous creatures, relative to modern egg-laying animals.

Model diplodocus.
Credit: © Katja Xenikis / Fotolia

Researchers have now concluded that the substantial incubation time required for sauropod embryos to develop and hatch may have been an important constraint and that this could explain the small individual size of sauropod eggs.

The findings are published in the summer 2014 issue of the Paleontological Society’s journal, Paleobiology. The team, which included biologists from the University of Lincoln, UK, and George Mason University, Virginia, US, with lead researcher Professor Graeme Ruxton from the University of St Andrews, used data from modern birds and reptiles to investigate factors affecting clutch size in this group of dinosaurs.They estimated that the time from laying to hatching of eggs, which were incubated in underground nests, was between 65 and 82 days.

This long incubation time increases the risk of predation, which coupled with the relatively low temperatures expected in the nest, may have been a significant factor in limiting the egg and clutch size.

Having larger eggs than are in the fossil record may have been advantageous because of larger hatchling size but this may have been outweighed by the increased risk of predation during the egg stage.

Dr Charles Deeming, from the School of Life Sciences, University of Lincoln, UK, said: “We think that a long incubation period of sauropods is likely to have led to very high mortality through predation. We suggest that the females laid their eggs in small clutches, possibly in different nesting sites, as an adaptive strategy to mitigate the high predation risk associated with long time of exposure in the egg stage.”

Professor Ruxton, from the School of Biology at the University of St Andrews, added: “The living bird with the largest eggs, the ostrich, has to incubate its eggs for 42 days; during which time many eggs are lost to predators. An ostrich weighs about 100kg and lays a 1.5kg egg; a sauropod dinosaur might be 50 times heavier than an adult ostrich but its eggs were only a little heavier than an ostrich egg. Some people might find it a bit disappointing that giant dinosaurs didn’t lay equally giant eggs — but it’s very satisfying to think that we might finally understand why.”

There may also have been a finite limit to the period over which environmental temperatures are high enough for egg development.

The team believe their conclusions could be extended to other groups of dinosaurs.

A New Basal Hadrosauroid Dinosaur (Dinosauria: Ornithopoda) with Transitional Features from the Late Cretaceous of Henan Province, China

June 29th, 2014

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Southwestern Henan Province in central China contains many down-faulted basins, including the Xixia Basin where the Upper Cretaceous continental sediments are well exposed. The Majiacun Formation is a major dinosaur-bearing stratigraphic unit that occurs in this basin.

Methodology/Principal Findings

A new basal hadrosauroid dinosaur, Zhanghenglong yangchengensis gen. et sp. nov., is named based on newly collected specimens from the middle Santonian Majiacun Formation of Zhoujiagou Village, Xixia Basin. Two transitional features between basal hadrosauroids and hadrosaurids are attached to the diagnosis of the new taxon, namely five maxillary foramina consisting of four small scattered ones anteroposteriorly arranged in a row and a large one adjacent to the articular facet for the jugal, and dentary tooth crowns bearing both median and distally offset primary ridges. Zhanghenglong also displays a unique combination of plesiomorphic and derived features of hadrosauroids, and is clearly morphologically transitional between basal hadrosauroids and hadrosaurids. Furthermore, some measurement attributes in osteology are applied to the quantitative analysis of Zhanghenglong. For these attributes, the partition of the dataset on most hadrosauroid species resulting from model-based cluster analysis almost matches taxonomic separation between basal hadrosauroids and hadrosaurids. Data of Zhanghenglong on selected measurement attributes straddle the two combinations of intervals of partitioned datasets respectively related to basal hadrosauroids and hadrosaurids. This condition is similar to mosaic evolution of morphological characters present in the specimens of the taxon. The phylogenetic analysis of Hadrosauroidea recovers a clade composed of Zhanghenglong, Nanyangosaurus, and Hadrosauridae with an unresolved polytomy.

(A) Skull reconstruction of Z. yangchengensis in left lateral view. (B) Restoration of the head and the anterior part of the neck of Z. yangchengensis in left lateral view. (C) Skeleton reconstruction of Z. yangchengensis in left lateral view. Bones in white are preserved in the specimens of Z. yangchengensis (XMDFEC V0013 and V0014). Bones in grey are unknown. Abbreviations: d, dentary; f, frontal; j, jugal; l, lacrimal; mx, maxilla; na, nasal; pd, predentary; pmx, premaxilla; po, postorbital; prf, prefrontal; q, quadrate; qj, quadratojugal; sa, surangular; sq, squamosal.
doi:10.1371/journal.pone.0098821.g002

Maxilla of Zhanghenglong yangchengensis.
Right maxilla (XMDFEC V0013, holotype) in lateral (A), medial (B), dorsal (C), and anterior (D) views.
doi:10.1371/journal.pone.0098821.g003

Conclusions/Significance

Zhanghenglong is probably a relatively derived non-hadrosaurid hadrosauroid, based on the inferences made from the morphological comparisons, quantitative evaluation of measurements, and cladistic analysis. In combination with information on the stratigraphy, phylogeny and biogeography, the material of Zhanghenglong provides direct evidence for the hypothesis that hadrosaurids might have originated in Asia.

Citation: Xing H, Wang D, Han F, Sullivan C, Ma Q, et al. (2014) A New Basal Hadrosauroid Dinosaur (Dinosauria: Ornithopoda) with Transitional Features from the Late Cretaceous of Henan Province, China. PLoS ONE 9(6): e98821. doi:10.1371/journal.pone.0098821

Editor: David C. Evans, Royal Ontario Museum, Canada

Study sheds light on how one of Earth’s oldest reefs was formed

June 27th, 2014

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It is a remarkable survivor of an ancient aquatic world — now a new study sheds light on how one of Earth’s oldest reefs was formed.

Researchers have discovered that one of these reefs — now located on dry land in Namibia — was built almost 550 million years ago, by the first animals to have hard shells.

Scientists say it was at this point that tiny aquatic creatures developed the ability to construct hard protective coats and build reefs to shelter and protect them in an increasingly dangerous world.

These reefs were built by Cloudina ~548 million years ago, from the Nama Group, Namibia.
Credit: Fred Bowyer

They were the first animals to build structures similar to non-living reefs, which are created through the natural processes of erosion and sediment deposition.

The study reveals that the animals attached themselves to fixed surfaces — and to each other — by producing natural cement composed of calcium carbonate, to form rigid structures.

The creatures — known as Cloudina — built reefs in ancient seas that now form part of Namibia. Their fossilised remains are the oldest reefs of their type in the world.

Cloudina were tiny, filter-feeding creatures that lived on the seabed during the Ediacaran Period, which ended 541 million years ago. Fossil evidence indicates that animals had soft bodies until the emergence of Cloudina.

Findings from the study — led by scientists at the University of Edinburgh — support previous research which suggested that environmental pressures caused species to develop new features and behaviours in order to survive.

Researchers say animals may have developed the ability to build reefs to protect themselves against increased threats from predators. Reefs also provided access to nutrient-rich currents at a time when there was growing competition for food and living space.

Scientists say the development of hard biological structures — through a process called biomineralisation — sparked a dramatic increase in the biodiversity of marine ecosystems.

The study, published in the journal Science, was carried out in collaboration with University College London and the Geological Survey of Namibia. The work was supported by the Natural Environment Research Council, the University of Edinburgh and the Laidlaw Trust.

Professor Rachel Wood, Professor of Carbonate GeoScience at the University of Edinburgh, who led the study, said: “Modern reefs are major centres of biodiversity with sophisticated ecosystems. Animals like corals build reefs to defend against predators and competitors. We have found that animals were building reefs even before the evolution of complex animal life, suggesting that there must have been selective pressures in the Precambrian Period that we have yet to understand.”

Plate tectonics : movement of plates explained by scientists

June 26th, 2014

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A team of researchers including Scripps Institution of Oceanography, UC San Diego geophysicist Dave Stegman has developed a new theory to explain the global motions of tectonic plates on the earth’s surface.

The new theory extends the theory of plate tectonics — a kinematic description of plate motion without reference to the forces behind it — with a dynamical theory that provides a physical explanation for both the motions of tectonic plates as well as motion of plate boundaries. The new findings have implications for how scientists understand the geological evolution of Earth, and in particular, the tectonic evolution of western North America, in the past 50 million years.

The research, led by Monash University’s Wouter Schellart, is published in the July 16 issue of the journal Science.

The sinking of the Farallon plate beneath the North American continent over 30 million years created the geologic feature known as the Basin and Range Province, an area of the western United States that encompasses much of Nevada, seen here in a topographic model.
Credit: Mike Sandiford/University of Melbourne

These findings provide a new explanation as to why tectonic plates move along the Earth’s surface at the speeds that are observed, the details of which were previously not well-understood.

“The earth’s surface is covered with tectonic plates that move with respect to one another at centimeters per year,” Schellart said. “These plates converge at deep-sea trenches, plate boundaries where one plate sinks (subducts) below the other at so-called subduction zones. The velocities of these plates and the velocities of the boundaries between these plates vary significantly on Earth.”

Schellart and his team, including Stegman and Rebecca Farrington, Justin Freeman and Louis Moresi from Monash University, used observational data and advanced computer models to develop a new mathematical scaling theory, which demonstrates that the velocities of the plates and the plate boundaries depend on the size of subduction zones and the presence of subduction zone edges.

“The scalings for how subducted plates sink in the earth’s mantle are based on essentially the same fluid dynamics that describe how a penny sinks through a jar of honey,” said Stegman, who developed the computer models that helped the team reenact tens of millions of years of tectonic movement. “The computer models demonstrate that the subducted portion of a tectonic plate pulls on the portion of the plate that remains on the earth’s surface. This pull results in either the motion of the plate, or the motion of the plate boundary, with the size of the subduction zone determining how much of each.”

“In some ways, plate tectonics is the surface expression of dynamics in the earth’s interior but now we understand the plates themselves are controlling the process more than the mantle underneath. It means Earth is really more of a top-down system than the predominantly held view that plate motion is being driven from the bottom-up.”

This discovery explains why the Australian, Nazca and Pacific plates move up to four times faster than the smaller African, Eurasian and Juan de Fuca plates.

“It also provides explanations for the motions of the ancient Farallon plate that sank into the mantle below North and South America. This plate slowed down during eastward motion from about 10 centimeters (four inches) per year some 50 million years ago to only 2 centimeters (0.8 inches) per year at present,” Schellart said.

The decrease in plate velocity resulted from the decrease in subduction zone size, which decreased from 14,000 kilometers (8,700 miles) to only 1,400 kilometers (870 miles).

“This had a dramatic effect on the topography and the structure of the North American continent,” said Schellart. “Until 50 million years ago, the west coast of North America was characterized by a massive mountain chain similar to the present day Andes in South America, and ran from Canada in the north to southern Mexico in the south.”

As the subduction zone decreased in size, the compressive stresses along the west coast of North America decreased, resulting in destruction of the mountain range and formation of the Basin and Range province, a 2 million-square-kilometer (772,000-square-mile) area of elongated basins and ridges that characterizes the present-day western North American landscape.

Frictional melting help predict volcanic eruption behavior

June 25th, 2014

Riffin

A new discovery in the study of how lava dome volcanoes erupt may help in the development of methods to predict how a volcanic eruption will behave, say scientists at the University of Liverpool.

Volcanologists at the University have discovered that a process called frictional melting plays a role in determining how a volcano will erupt, by dictating how fast magma can ascend to the surface, and how much resistance it faces en-route.

Using friction experiments University of Liverpool scientists have shown that frictional melting plays a role in determining how a volcano will erupt.
Credit: Dr. Jackie Kendrick

The process occurs in lava dome volcanoes when magma and rocks melt as they rub against each other due to intense heat. This creates a stop start movement in the magma as it makes its way towards Earth’s surface. The magma sticks to the rock and stops moving until enough pressure builds up, prompting it to shift forward again (a process called stick-slip).

Volcanologist, Dr Jackie Kendrick, who lead the research said: “Seismologists have long known that frictional melting takes place when large tectonic earthquakes occur. It is also thought that the stick-slip process that frictional melting generates is concurrent to ‘seismic drumbeats’ which are the regular, rhythmic small earthquakes which have been recently found to accompany large volcanic eruptions.

“Using friction experiments we have shown that the extent of frictional melting depends on the composition of the rock and magma, which determines how fast or slow the magma travels to the surface during the eruption.”

Analysis of lava collected from Mount St. Helens, USA and the Soufrière Hills volcano in Montserrat by volcanology researchers from the University’s School of Environmental Sciences revealed remnants of pseudotachylyte, a cooled frictional melt. Evidence showed that the process took place in the conduit, the channel which lava passes through on its way to erupt.

Dr Kendrick, from the University’s School of Environmental Sciences, added: “The closer we get to understanding the way magma behaves, the closer we will get to the ultimate goal: predicting volcanic activity when unrest begins. Whilst we can reasonably predict when a volcanic eruption is about to happen, this new knowledge will help us to predict how the eruption will behave.

“With a rapidly growing population inhabiting the flanks of active volcanoes, understanding the behaviour of lava domes becomes an increasing challenge for volcanologists.”

J. E. Kendrick, Y. Lavallée, T. Hirose, G. Di Toro, A. J. Hornby, S. De Angelis, D. B. Dingwell. Volcanic drumbeat seismicity caused by stick-slip motion and magmatic frictional melting. Nature Geoscience, 2014; DOI: 10.1038/ngeo2146

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Study of ESA shows Earth’s changing magnetism

June 24th, 2014

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The first set of high-resolution results from ESA’s three-satellite Swarm constellation reveals the most recent changes in the magnetic field that protects our planet.

Launched in November 2013, Swarm is providing unprecedented insights into the complex workings of Earth’s magnetic field, which safeguards us from the bombarding cosmic radiation and charged particles.

Measurements made over the past six months confirm the general trend of the field’s weakening, with the most dramatic declines over the Western Hemisphere.

But in other areas, such as the southern Indian Ocean, the magnetic field has strengthened since January.

The latest measurements also confirm the movement of magnetic North towards Siberia.

These changes are based on the magnetic signals stemming from Earth’s core. Over the coming months, scientists will analyse the data to unravel the magnetic contributions from other sources, namely the mantle, crust, oceans, ionosphere and magnetosphere.

This will provide new insight into many natural processes, from those occurring deep inside our planet to space weather triggered by solar activity. In turn, this information will yield a better understanding of why the magnetic field is weakening.

“These initial results demonstrate the excellent performance of Swarm,” said Rune Floberghagen, ESA’s Swarm Mission Manager.

“With unprecedented resolution, the data also exhibit Swarm’s capability to map fine-scale features of the magnetic field.”

The first results were presented June 19, 2014 at the ‘Third Swarm Science Meeting’ in Copenhagen, Denmark.

Sofie Carsten Nielsen, Danish Minister of Higher Education and Science, highlighted the Danish contribution to the mission. Swarm continues the legacy of the Danish Ørsted satellite, which is still operational, as well as the German Champ mission. Swarm’s core instrument — the Vector Field Magnetometer — was provided by the Technical University of Denmark.

Changes in Earth’s magnetic field from January to June 2014 as measured by the Swarm constellation of satellites. These changes are based on the magnetic signals that stem from Earth’s core. Shades of red represent areas of strengthening, while blues show areas of weakening over the 6-month period.
Credit: ESA/DTU Space

Denmark’s National Space Institute, DTU Space, has a leading role — together with 10 European and Canadian research institutes — in the Swarm Satellite Constellation Application and Research Facility, which produces advanced models based on Swarm data describing each of the various sources of the measured field.

“I’m extremely happy to see that Swarm has materialised,” said Kristian Pedersen, Director of DTU Space.

Fossil tracks show how ancient sea reptiles swam

June 22nd, 2014

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Trackways formed on an ancient seabed have shed new light on how nothosaurs, ancient marine reptiles that lived during the age of the dinosaurs, propelled themselves through water. The evidence is described by a team from Bristol and China in Nature Communications today.

During the Mesozoic, 252-66 million years ago, the seas were ruled by a variety of marine reptiles. One of the earliest groups were the nothosaurs, voracious semi-aquatic hunters with elongate bodies and paddle-like limbs. They were the top predators of the Triassic coasts, some 245 million years ago.

Their mode of swimming has long been debated: did they row themselves along with a back-and-forth motion of their limbs, or did they ‘fly’ underwater, sweeping their forepaddles in a figure-eight motion like a modern penguin?

Scientists from the University of Bristol and colleagues in China studied trackways formed on an ancient seabed which were recently discovered in Yunnan, southwest China. The tracks consist of slots in the mud arranged in pairs, and in long series of ten to fifty that follow straight lines and sweeping curves.

The size and spacing of the paired markings indicate that they were created by the forelimbs of nothosaurs, representing animals ranging in size from over 3 metres to less than a metre in length.

They demonstrate that that these reptiles moved over the seafloor by rowing their forelimbs in unison, the first direct evidence of how these creatures propelled themselves in the water.

Two types of nothosaurs, the large Nothosaurus and the diminutive Lariosaurus, known from complete fossil skeletons from the Triassic of southern China, are the likely trackmakers.

Professor Qiyue Zhang from Chengdu Center of China Geological Survey, leader of the research, said: “We interpret the tracks as foraging trails. The nothosaur was a predator, and this was a smart way to feed. As its paddles scooped out the soft mud, they probably disturbed fishes and shrimps, which it snapped up with needle-sharp teeth.”

The tracks come from localities around Luoping in Yunnan, a well known site of exceptional fossil preservation that has yielded thousands of exquisite fossils of sea creatures, and occasional plants and small terrestrial animals blown in from the nearby islands.

Professor Michael Benton from the University of Bristol, one of the co-authors of the research, said: “When I first saw the site, I couldn’t believe the amazing quality of the fossils. It’s quite unusual to find skeletons of marine reptiles such as the nothosaurs so close to evidence of their tracks.”

Print impressions (lower slab) and the mould. Photograph taken within minutes of uncovering a new trackway, showing the imprint moulds on the overlying bed bottom and the imprints on the top of bed 107. The animal was moving from left to right.
Credit: © Chengdu Center of China Geological Survey.

Luoping and other sites in South China are shedding light on the recovery of life from the devastating Permo-Triassic mass extinction event which wiped out more than 90 per cent of all species on Earth. Nothosaurs and other marine reptiles were new members of the recovering ecosystems.

Co-author Professor Shixue Hu, also from Chengdu Center of China Geological Survey, said: “Here we see a detailed snapshot of how life was within 8 million years of the mass extinction. It took all that time for Earth to settle down from the cataclysm, and the arrival of these large, complex marine predators shows us the ecosystems had finally rebuilt themselves, and life could be said to have recovered from the crisis.”

New fossil find pinpoints the origin of jaws in vertebrates

June 18th, 2014

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Source: University of Cambridge

A major fossil discovery in Canada sheds new light on the development of the earliest vertebrates, including the origin of jaws, the first time this feature has been seen so early in the fossil record.

A key piece in the puzzle of the evolution of vertebrates has been identified, after the discovery of fossilised fish specimens, dating from the Cambrian period (around 505 million years old), in the Canadian Rockies. The fish, known as Metaspriggina, shows pairs of exceptionally well-preserved arches near the front of its body. The first of these pairs, closest to the head, eventually led to the evolution of jaws in vertebrates, the first time this feature has been seen so early in the fossil record.

Left: This is an illustration of Metaspriggina swimming. Drawing by: Marianne Collins. © Conway Morris and Caron. Right: This is a fossil of Metaspriggina from Marble Canyon — head to the left with two eyes, and branchial arches at the top. Photo by: Jean-Bernard Caron © ROM.
Credit: Left: Drawing by Marianne Collins / Copyright Conway Morris and Caron. Right: Photo by Jean-Bernard Caron / Copyright ROM.

Fish fossils from the Cambrian period are very rare and usually poorly preserved. This new discovery shows in unprecedented detail how some of the earliest vertebrates developed — the starting point of a story which led to animals such as later fish species, but also dinosaurs and mammals such as horses and even ourselves. The findings are published in the 11 June edition of the journal Nature.

Fossils of Metaspriggina were recovered from several locations including the Burgess Shale site in Canada’s Rocky Mountains, one of the richest Cambrian fossil deposits in the world. These fossils shed new light on the Cambrian ‘explosion’, a period of rapid evolution starting around 540 million years ago, when most major animal phyla originated.

Previously, only two incomplete specimens of Metaspriggina had been identified. During expeditions conducted by the Royal Ontario Museum in 2012, 44 new Burgess Shale fossils were collected near Marble Canyon in Kootenay National Park in British Columbia, which provide the basis for this study. Researchers from the University of Cambridge and the Royal Ontario Museum/University of Toronto used these fossils, along with several more specimens from the eastern United States, to reclassify Metaspriggina as one of the first vertebrates

The fossils, which date from 505 million years ago, also show clearly for the first time how a series of rod-like structures, known as the gill or branchial arches, were arranged in the earliest vertebrates. These arches have long been known to have played a key role in the evolution of vertebrates, including the origin of jaws, and some of the tiny bones in the ear which transmit sound in mammals. Until now, however, a lack of quality fossils has meant that the arrangement of these arches in the first vertebrates had been hypothetical.

Vertebrates first appear in the fossil record slightly earlier than these finds, but pinpointing exactly how they developed is difficult. This is because fossils of such animals are rare, incomplete and open to varying interpretations, as they show soft tissues which are difficult to identify with complete certainty.

The new fossils of Metaspriggina are remarkably well-preserved. The arrangement of the muscles shows these fish were active swimmers, not unlike a trout, and the animals saw the world through a pair of large eyes and sensed their surrounding environment with nasal structures.

“The detail in this Metaspriggina fossil is stunning,” said lead author Professor Simon Conway Morris of Cambridge’s Department of Earth Sciences. “Even the eyes are beautifully preserved and clearly evident.”

But it is the branchial arches which makes this discovery so important. Previously, they were thought to exist as a series of single arches, but Metaspriggina now shows that they in fact existed in pairs. The anteriormost pair of arches is also slightly thicker than the remainder, and this subtle distinction may be the very first step in an evolutionary transformation that in due course led to the appearance of the jaw. “Once the jaws have developed, the whole world opens,” said Professor Conway Morris. “Having a hypothetical model swim into the fossil record like this is incredibly gratifying.”

Earth may have underground ‘ocean’ three times that on surface

June 17th, 2014

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Source : The Guardian

After decades of searching scientists have discovered that a vast reservoir of water, enough to fill the Earth’s oceans three times over, may be trapped hundreds of miles beneath the surface, potentially transforming our understanding of how the planet was formed.

Three-quarters of the Earth’s water may be locked deep underground in a layer of rock, scientists say. Photograph: Blue Line Pictures/Getty Images

The water is locked up in a mineral called ringwoodite about 660km (400 miles) beneath the crust of the Earth, researchers say. Geophysicist Steve Jacobsen from Northwestern University in the US co-authored the study published in the journal science and said the discovery suggested Earth’s water may have come from within, driven to the surface by geological activity, rather than being deposited by icy comets hitting the forming planet as held by the prevailing theories.

“Geological processes on the Earth’s surface, such as earthquakes or erupting volcanoes, are an expression of what is going on inside the Earth, out of our sight,” Jacobsen said.

“I think we are finally seeing evidence for a whole-Earth water cycle, which may help explain the vast amount of liquid water on the surface of our habitable planet. Scientists have been looking for this missing deep water for decades.”

Jacobsen and his colleagues are the first to provide direct evidence that there may be water in an area of the Earth’s mantle known as the transition zone. They based their findings on a study of a vast underground region extending across most of the interior of the US.

Ringwoodite acts like a sponge due to a crystal structure that makes it attract hydrogen and trap water.

If just 1% of the weight of mantle rock located in the transition zone was water it would be equivalent to nearly three times the amount of water in our oceans, Jacobsen said.

The study used data from the USArray, a network of seismometers across the US that measure the vibrations of earthquakes, combined with Jacobsen’s lab experiments on rocks simulating the high pressures found more than 600km underground.

It produced evidence that melting and movement of rock in the transition zone – hundreds of kilometres down, between the upper and lower mantles – led to a process where water could become fused and trapped in the rock.

The discovery is remarkable because most melting in the mantle was previously thought to occur at a much shallower distance, about 80km below the Earth’s surface.

Jacobsen told the New Scientist that the hidden water might also act as a buffer for the oceans on the surface, explaining why they have stayed the same size for millions of years. “If [the stored water] wasn’t there, it would be on the surface of the Earth, and mountaintops would be the only land poking out,” he said.

5-Million-Year-Old Arctic Fox Ancestor Found in Tibet

June 15th, 2014

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Source : Livescience

By Tia Ghose, Staff Writer | LiveScience.com

The fossilized jawbone and teeth of a 5-million-year-old fox have been unearthed in Tibet.

The fox, Vulpes qiuzhudingi, is probably the ancestor of modern Arctic foxes. The discovery, along with several other fossils from cold-loving mammals, buttress the Out of Tibet hypothesis: That iconic ice-age mammals such as woolly mammoths, saber-toothed tigers and giant sloths first evolved for the cold weather in Tibet before fanning out over the steppes of Central Asia and into North America.

Out of Tibet

Several years ago, paleontologists excavating the Zanda Basin in Tibet unearthed a 3.7-million-year-old Woolly rhino fossil that not only was older than all other fossils of the species, but also was found much farther south than those prior specimens. At that time, The Arctic was much warmer than it is today, whereas the snowy, high Tibetan plateau was just a touch warmer, said study co-author Zhijie Jack Tseng, a paleontologist at the American Museum of Natural History in New York.

LiveScience.com/Xiaoming Wang – The Zanda Basin in Tibet.

That led the researchers to propose that the frigid, high-altitude climate of Tibet was a staging ground where many of the shaggy-coated, cold-loving megafauna first adapted to the cold. When Earth’s temperatures plunged at the onset of the last ice age about 2.6 million years ago, these cold-loving creatures emerged from the Tibetan plateau to colonize most of the Arctic and colder portions of North America.

Living relative

In 2006, the researchers also found a single tooth in the Zanda Basin, but couldn’t match it to a specific animal species. Over the next several years, they went on to find two other fossils that revealed the lower jaw and some of the teeth from ancient predatory Foxes, allowing them to identify the original tooth as well.

The fox fossils ranged from 3.6 million to 5 million years old, and the teeth looked a lot like those of the modern Arctic fox, which now lives across the Arctic, from Scandinavia and Russia in the west all the way to Greenland and Iceland.

“The arrangement of the cusps on the tooth are more or less in a straight line and pretty sharp,” Tseng told Live Science. “That meant that the fox was using that tooth for cutting and shearing meat,” just as the Arctic fox does today.

The discovery marks the first time that an older predecessor to a modern Arctic creature has been found in Tibet, buttressing the Out of Tibet hypothesis, Tseng said.

The team has also found other fossils from archaic, cold-adapted mammals throughout Tibet, such as ancient Snow leopards, wolf-sized dogs and hyenas. And, just like modern Arctic species that must subsist mainly on meat during the long, frosty winter months when plant-based food is almost nonexistent, these ancient animals were more carnivorous than similar animals that live in more temperate climates, Tseng said.

The findings were published Tuesday (June 10) in the journal Proceedings of the Royal Society B.