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

Slow Earthquakes: It’s All in the Rock Mechanics

June 24th, 2013

Riffin

Earthquakes that last minutes rather than seconds are a relatively recent discovery, according to an international team of seismologists. Researchers have been aware of these slow earthquakes, only for the past five to 10 years because of new tools and new observations, but these tools may explain the triggering of some normal earthquakes and could help in earthquake prediction.

“New technology has shown us that faults do not just fail in a sudden earthquake or by stable creep,” said Demian M. Saffer, professor of geoscience, Penn State. “We now know that earthquakes with anomalous low frequencies — slow earthquakes — and slow slip events that take weeks to occur exist.”

These new observations have put a big wrinkle into our thinking about how faults work, according to the researchers who also include Chris Marone, professor of geosciences, Penn State; Matt J. Ikari, recent Ph.D. recipient, and Achim J. Kopf, former Penn State postdoctural fellow, both now at the University of Bremen, Germany. So far, no one has explained the processes that cause slow earthquakes.

The researchers thought that the behavior had to be related to the type of rock in the fault, believing that clay minerals are important in this slip behavior to see how the rocks reacted. Ikari performed laboratory experiments using natural samples from drilling done offshore of Japan in a place where slow earthquakes occur. The samples came from the Integrated Ocean Drilling Program, an international collaborative. The researchers reported their results recently in Nature Geoscience.

These samples are made up of ocean sediment that is mostly clay with a little quartz.

“Usually, when you shear clay-rich fault rocks in the laboratory in the way rocks are sheared in a fault, as the speed increases, the rocks become stronger and self arrests the movement,” said Saffer. “Matt noticed another behavior. Initially the rocks reacted as expected, but these clays got weaker as they slid further. They initially became slightly stronger as the slip rate increased, but then, over the long run, they became weaker.”

The laboratory experiments that produced the largest effect closely matched the velocity at which slow earthquakes occur in nature. The researchers also found that water content in the clays influenced how the shear occurred.

“From the physics of earthquake nucleation based on the laboratory experiments we would predict the size of the patch of fault that breaks at tens of meters,” said Saffer. “The consistent result for the rates of slip and the velocity of slip in the lab are interesting. Lots of things point in the direction for this to be the solution.”

The researchers worry about slow earthquakes because there is evidence that swarms of low frequency events can trigger large earthquake events. In Japan, a combination of broadband seismometers and global positioning system devices can monitor slow earthquakes.

For the Japanese and others in earthquake prone areas, a few days of foreknowledge of a potential earthquake hazard could be valuable and save lives.

For slow slip events, collecting natural samples for laboratory experiments is more difficult because the faults where these take place are very deep. Only off the north shore of New Zealand is there a fault that can be sampled. Saffer is currently working to arrange a drilling expedition to that fault.

The National Science Foundation and the Deutsche Forschungsgemeinschaft supported this work.

Oddest Couple Share 250 Million Year Old Burrow

June 23rd, 2013

Riffin

Scientists from South Africa, Australia and France have discovered a world first association while scanning a 250 million year old fossilised burrow from the Karoo Basin of South Africa.

The burrow revealed two unrelated vertebrate animals nestled together and fossilised after being trapped by a flash flood event. Facing harsh climatic conditions subsequent to the Permo-Triassic (P-T) mass extinction, the amphibian Broomistega and the mammal forerunner Thrinaxodon cohabited in a burrow.

Artist impression of Broomistega seeking shelter in Thrinaxodon’s burrow. (Credit: Image courtesy of University of the Witwatersrand)

Scanning shows that the amphibian, which was suffering from broken ribs, crawled into a sleeping mammal’s shelter for protection. This research suggests that short periods of dormancy, called aestivation, in addition to burrowing behaviour, may have been a crucial adaptation that allowed mammal ancestors to survive the P-T extinction.

The international team of scientists was led by Dr Vincent Fernandez from Wits University, South Africa and the European Synchrotron Radiation Facility (ESRF) in Grenoble, France. The other authors from Wits University include Prof. Bruce Rubidge (Director of the newly formed Palaeosciences Centre of Excellence at Wits), Dr Fernando Abdala and Dr Kristian Carlson. Other authors include Dr Della Collins Cook (Indiana University); Dr Adam Yates (Museum of Central Australia) and Dr. Paul Tafforeau (ESRF).

After many impressive results obtained on fossils, synchrotron imaging has led to revived interest in the studies of the numerous fossilised burrows discovered in the Karoo Basin of South Africa and dated to 250 million years ago. The first attempt to investigate one of these burrow-casts surprisingly revealed a world-first association of two unrelated animals.

The fossil was recovered from sedimentary rock strata in the Karoo Basin. It dates from 250 million years ago, at the beginning of the Triassic Period. At that time, the ecosystem was recovering from the Permo-Triassic mass extinction that wiped out most of life on Earth. In the Pangea Supercontinent context, what is now South Africa was an enclave in the southern half called Gondwana. It was the scene of pronounced climatic warming and increased seasonality marked by monsoonal rainfall. To survive this harsh environment, many animals, including mammal-like reptiles (mammal forerunners), developed a digging behaviour, attested by the numerous fossilised burrow casts discovered in the Karoo Basin. These casts have long been thought to enclose fossilised remains, triggering interest from palaeontologists. Early this year, an international group of scientists started to research the contents of these burrows using X-ray synchrotron computed microtomography.

Two burrow casts were selected from the collection at Wits to be scanned using the state-of-the-art facility at the European Synchrotron Radiation Facility (ESRF). Using the unique properties of the X-ray beam which enables non-destructive probing, the scan of the first burrow started to reveal the skull of a mammal-like reptile called Thrinaxodon, an animal previously reported in another burrow.

As the scan progressed, the three-dimensional reconstruction displayed results beyond expectations: the mammal-like reptile was accompanied by an amphibian Broomistega, belonging to the extinct group of Temnospondyl.

“While discovering the results we were amazed by the quality of the images,” says lead author Fernandez, “but the real excitement came when we discovered a second set of teeth completely different from that of the mammal-like reptile. It was really something else.”

Besides the pristine preservation of the two skeletons, the team focused on the reasons explaining such an unusual co-habitation. Fernandez explains: “Burrow-sharing by different species exists in the modern world, but it corresponds to a specific pattern. For example, a small visitor is not going to disturb the host. A large visitor can be accepted by the host if it provides some help, like predator vigilance. But neither of these patterns corresponds to what we have discovered in this fossilised burrow.”

The scientists gathered all the information to try to reconstitute the events that led to this incredible fossil aggregation, testing scenarios one after another. “It’s a fascinating scientific question: what caused the association of these two organisms in the burrow? One of the more obvious possibilities is a predator-prey interaction, but we inspected both skeletons looking for tooth marks or other evidence implying predation, ultimately finding no support for one having attempted to feed on the other,” says Carlson.

His colleague, Cook, adds that the consecutive broken ribs resulted from a single, massive trauma. The amphibian clearly survived the injury for some time because the fractures were healing, but it was surely quite handicapped. According to Fernandez this Broomistega is the first complete skeleton of this rare species that has been discovered. “It tells us that this individual was a juvenile and mostly aquatic at that time of its life,” he says.

The scientists eventually concluded that the amphibian crawled into the burrow in response to its poor physical condition but was not evicted by the mammal-like reptile.

Numerous Thrinaxodon specimens have been found in South Africa, many of them fossilised in a curled-up position. Abdala says: “I have always been fascinated by the preservation of Thrinaxodon fossils in a curled-up position that show even tiny bones of the skeleton preserved. It’s as if they were peacefully resting in shelters at the time of death.”

The shelters prevented disturbance of the skeletal remains from scavengers and weathering. “We also think it might reflect a state of torpor called aestivation in response to aridity and absence of food resources,” Abdala says.

Piecing all the clues together, the team finally elucidated the enigmatic association, concluding that “the mammal-like reptile, Thrinaxodon, was most probably aestivating in its burrow, a key adaptation response together with a burrowing behaviour which enabled our distant ancestors to survive the most dramatic mass extinction event. This state of torpor explains why the amphibian was not chased out of the burrow,” says Rubidge.

Both animals were finally entrapped in the burrow by a sudden flood and preserved together in the sediments for 250 million years.

Tafforeau says: “Thanks to the unique possibilities for high quality imaging of fossils developed during the last decade at the ESRF, these unique specimens remain untouched, protected by their mineral matrix. Who knows what kind of information we’ll be able to obtain from them in the future and which would have been completely lost if the specimen had been prepared out of its burrow cast?”

Himalayan Tsunami 2013 : Nature’s Fury OR Human negligence?

June 22nd, 2013

Riffin

Melting glaciers and rising temperatures are forming a potentially destructive combination in the deep ravines of Nepal’s Himalayan foothills, and the Phulping Bridge — on the Araniko Highway linking Kathmandu with the Chinese border — is a good place to see just how dangerous the pairing can be.

A bare concrete pillar stands there, little noticed by the drivers of trucks, laden with Chinese goods, that rattle along at high speeds across the bridge, about 110 km from Kathmandu. The pillar is all that’s left of the original Phulping Bridge, which was swept away by floodwaters in July 1981. The deluge was not caused, as is common, by monsoon rain, but by the bursting of a glacial lake. The force of the raging torrent was strong enough to dislodge boulders 30 m across. They still lie in the Bhote Koshi River.

Flood in Kedarnath

Glacial-lake outbursts, as they’re known, are not new. They occur every time the natural dams of ice or accumulated rocky deposits that hold back glacial lakes give way because of seismic activity, erosion or simple water pressure. Millions of cubic meters of meltwater can be released as a result, sometimes over the course of a few days or — far more frighteningly — in a matter of minutes. During the past century, at least 50 glacial-lake outbursts were recorded in the Himalayas, according to data maintained by the Kathmandu-based International Centre for Integrated Mountain Development (ICIMOD). But what is new is that the lakes are forming and growing much more quickly because the glaciers are melting faster than ever.

Kedarnath Area In Mud

The potential of a Himalayan tsunami is a hazard of global warming that has yet to be given much attention by outsiders, but it is a daily preoccupation of ICIMOD program coordinator Pradeep Mool. He told TIME that there were some 20,000 glacial lakes in the Hindu Kush Himalayan region, extending from Afghanistan to Burma. In some parts of the Himalayas, like the Dudh Koshi area in eastern Nepal, the melt rate is alarmingly high.

“Almost all the glaciers [in Dudh Koshi] are retreating at rates of 10 to 59 m annually,” Mool says, “but the rate for some has accelerated during the last half-decade to 74 m annually.” He explained that this had created 24 new glacial lakes in the area, which now had a total of 34 such bodies of water. At least 10 of them are considered dangerous.

Violent River Mandakini

Research by a team from the University of Milan, released this month, found that in the past 50 years glaciers in the Everest region had shrunk by 13% and the snow line was now seen about 180 m higher up. Sudeep Thakuri, a researcher with the team, says the melting was most likely caused by warming temperatures and was certain to continue. Since 1992, premonsoon and winter temperatures in the Everest region have increased by 0.6ºC.

Earthquakes also add to the risk. “Earthquakes could act as major triggers for glacial-lake outbursts,” Mool says. He feels that much better monitoring of the lakes is needed to get a proper assessment of the dangers.

aftermath

Down in the Bhote Koshi Valley, villagers now rely on text messages for warnings of potential floods, landslides and other hazards. The power station near the village of Jhirpu Phulpingkatt will issue a warning of a glacial-lake outburst, but people in the area will only have a few minutes’ notice before the floodwaters arrive, and only glacial-lake outbursts in Nepali territory can be immediately detected. There are at least six glacial lakes close by in Tibet that lie outside the warning system, and their outbursts will be detected only when the waters enter Nepali territory, according to the plant’s acting manager Janak Raj Pant. But regardless of where an outburst originates, he says, “All of us would have to run for our lives.” Seaborne tsunamis have already unleashed enough terror this century. Let’s hope that no comparable disasters dwell in the Himalayas’ icy ravines.

man Vs Nature

New ‘Embryonic’ Subduction Zone Found

June 22nd, 2013

Riffin

A new subduction zone forming off the coast of Portugal heralds the beginning of a cycle that will see the Atlantic Ocean close as continental Europe moves closer to America.

Published in Geology, new research led by Monash University geologists has detected the first evidence that a passive margin in the Atlantic ocean is becoming active. Subduction zones, such as the one beginning near Iberia, are areas where one of the tectonic plates that cover Earth’s surface dives beneath another plate into the mantle — the layer just below the crust.

$NOAA/NGDC image of the Atlantic crustal age of the ocean floor. Geologists have detected the first evidence that a passive margin in the Atlantic ocean is becoming active. The team mapped the ocean floor and found it was beginning to fracture, indicating tectonic activity around the apparently passive South West Iberia plate margin. (Credit: Mr. Elliot Lim and Mr. Jesse Varner, CIRES & NOAA/NGDC)$

NOAA/NGDC image of the Atlantic crustal age of the ocean floor. Geologists have detected the first evidence that a passive margin in the Atlantic ocean is becoming active. The team mapped the ocean floor and found it was beginning to fracture, indicating tectonic activity around the apparently passive South West Iberia plate margin. (Credit: Mr. Elliot Lim and Mr. Jesse Varner, CIRES & NOAA/NGDC)

Lead author Dr João Duarte, from the School of Geosciences said the team mapped the ocean floor and found it was beginning to fracture, indicating tectonic activity around the apparently passive South West Iberia plate margin.

“What we have detected is the very beginnings of an active margin — it’s like an embryonic subduction zone,” Dr Duarte said.

“Significant earthquake activity, including the 1755 quake which devastated Lisbon, indicated that there might be convergent tectonic movement in the area. For the first time, we have been able to provide not only evidences that this is indeed the case, but also a consistent driving mechanism.”

The incipient subduction in the Iberian zone could signal the start of a new phase of the Wilson Cycle — where plate movements break up supercontinents, like Pangaea, and open oceans, stabilise and then form new subduction zones which close the oceans and bring the scattered continents back together.

This break-up and reformation of supercontinents has happened at least three times, over more than four billion years, on Earth. The Iberian subduction will gradually pull Iberia towards the United States over approximately 220 million years.

The findings provide a unique opportunity to observe a passive margin becoming active — a process that will take around 20 million years. Even at this early phase the site will yield data that is crucial to refining the geodynamic models.

“Understanding these processes will certainly provide new insights on how subduction zones may have initiated in the past and how oceans start to close,” Dr Duarte said.

Feeding Mechanics in Spinosaurid Theropods and Extant Crocodilians

June 21st, 2013

Riffin

A number of extant and extinct archosaurs evolved an elongate, narrow rostrum. This longirostrine condition has been associated with a diet comprising a higher proportion of fish and smaller prey items compared to taxa with broader, more robust snouts. The evolution of longirostrine morphology and a bulbous anterior rosette of premaxillary teeth also occurs in the spinosaurid theropod dinosaurs, leading to suggestions that at least some members of this clade also had a diet comprising a notable proportion of fish or other small vertebrates. Here we compare the rostral biomechanics of the spinosaurs Baryonyx walkeri and Spinosaurus c.f. S. aegyptiacus to three extant crocodilians: two longistrine taxa, the African slender-snouted crocodile Mecistops cataphractus and the Indian gharial Gavialis gangeticus; and the American alligator Alligator mississippiensis.

Using computed tomography (CT) data, the second moments of area and moments of inertia at successive transverse slices along the rostrum were calculated for each of the species. Size-independent results tested the biomechanical benefits of material distribution within the rostra. The two spinosaur rostra were both digitally reconstructed from CT data and compared against all three crocodilians. Results show that African slender-snouted crocodile skulls are more resistant to bending than an equivalent sized gharial. The alligator has the highest resistances to bending and torsion of the crocodiles for its size and greater than that of the spinosaurs. The spinosaur rostra possess similar resistance to bending and torsion despite their different morphologies. When size is accounted for, B. walkeri performs mechanically differently from the gharial, contradicting previous studies whereas Spinosaurus does not. Biomechanical data support known feeding ecology for both African slender-snouted crocodile and alligator, and suggest that the spinosaurs were not obligate piscivores with diet being determined by individual animal size.

Species tested for second moments of area and moments of inertia.

: Figure 2. Lateral and ventral views of Baryonyx walkeri (NHMUK VP R9951) through the stages of digital preparation.

Lateral and ventral views of Baryonyx walkeri (NHMUK VP R9951) through the stages of digital preparation.

The digital preparation of Spinosaurus indet.

Citation: Cuff AR, Rayfield EJ (2013) Feeding Mechanics in Spinosaurid Theropods and Extant Crocodilians. PLoS ONE 8(5): e65295. doi:10.1371/journal.pone.0065295

Editor: Andrew A. Farke, Raymond M. Alf Museum of Paleontology, United States of America

Scientists Date Prehistoric Bacterial Invasion Still Present in Today’s Plant and Animal Cells

June 20th, 2013

Riffin

Long before Earth became lush, when life consisted of single-celled organisms afloat in a planet-wide sea, bacteria invaded the ancient ancestors of plants and animals and took up permanent residence. One bacterium eventually became the mitochondria that today power all plant and animal cells; another became the chloroplast that turns sunlight into energy in green plants.

A transmission electron microscope image of mitochondria in a lung cell. Some 1.2 billion years ago, proteobacteria invaded the one-celled ancestors of all plants and animals, giving these cells a powerhouse to fuel their proliferation in the ocean and on land. (Credit: Public domain image by Louisa Howard)

A new analysis by two University of California, Berkeley, graduate students more precisely pinpoints when these life-changing invasions occurred, placing the origin of photosynthesis in plants hundreds of millions of years earlier than once thought.

“When you are talking about these really ancient events, scientists have estimated numbers that are all over the board,” said coauthor Patrick Shih. Estimates of the age of eukaryotes — cells with a nucleus that evolved into all of today’s plants and animals — range from 800 million years ago to 3 billion years ago.

“We came up with a novel way of decreasing the uncertainty and increasing our confidence in dating these events,” he said. The two researchers believe that their approach can help answer similar questions about the origins of ancient microscopic fossils.

Shih and colleague Nicholas Matzke, who will earn their Ph.Ds this summer in plant and microbial biology and integrative biology, respectively, employed fossil and genetic evidence to estimate the dates when bacteria set up shop as symbiotic organisms in the earliest one-celled eukaryotes. They concluded that a proteobacterium invaded eurkaryotes about 1.2 billion years ago, in line withearlier estimates.

They found that a cyanobacterium — which had already developed photosynthesis — invaded eukaryotes 900 million years ago, much later than some estimates, which are as high as 2 billion years ago.

Previous estimates used hard-to-identify microbial fossilsor ambiguous chemical markers in fossils to estimate the time when bacteria entered ancestral eurkaryotic cells, probably first as parasites and then as symbionts. Shih and Matzke realized that they could get better precision by studying today’s mitochondria and chloroplasts, which from their free-living days still retain genes that are evolutionarily related to genes currently present in plant and animal DNA.

“These genes, such as ATP synthase — a gene critical to the synthesis of the energy molecule ATP — were present in our single-celled ancestors and present now, and are really, really conserved,” Matzke said. “These go back to the last common ancestor of all living things, so it helps us constrain the tree of life.”

Since mitochrondrial, chloroplast and nuclear genes do not evolve at exactly the same rate, the researchers used Bayesian statistics to estimate the rate variation as well as how long ago the bacteria joined forces with eukaryotes. They improved their precision by focusing on plant and animal fossils that have more certain dates and identities than microbial fossils.

The paper appeared online on June 17 in advance of publication in the journal Proceedings of the National Academy of Sciences. Matzke also is a member of UC Berkeley’s Center for Theoretical Evolutionary Genomics.

How Diving Mammals Evolve Underwater Endurance?

June 18th, 2013

Riffin

Scientists at the University of Liverpool have shed new light on how diving mammals, such as the sperm whale, have evolved to survive for long periods underwater without breathing.

The team identified a distinctive molecular signature of the oxygen-binding protein myoglobin in the sperm whale and other diving mammals, which allowed them to trace the evolution of the muscle oxygen stores in more than 100 mammalian species, including their fossil ancestors.

Myoglobin, which gives meat its red colour, is present in high concentrations in elite mammalian divers, so high that the muscle is almost black in colour. Until now, however, very little was known about how this molecule is adapted in champion divers.

Proteins tend to stick together at high concentrations, impairing their function, so it was unclear how myoglobin was able to help the body store enough oxygen to allow mammals, such as whales and seals, to endure underwater for long periods of time without breathing. Elite mammalian divers can hold their breath for over an hour while they hunt in the depths of the oceans, while land mammals, such as humans, can hold their breath for only a few minutes.

Dr Michael Berenbrink, from the University’s Institute of Integrative Biology, who led the international team, explains: “We studied the electrical charge on the surface of myoglobin and found that it increased in mammals that can dive underwater for long periods of time. We were surprised when we saw the same molecular signature in whales and seals, but also in semi-aquatic beavers, muskrats and even water shrews.

“By mapping this molecular signature onto the family tree of mammals, we were able to reconstruct the muscle oxygen stores in extinct ancestors of today’s diving mammals. We were even able to report the first evidence of a common amphibious ancestor of modern sea cows, hyraxes and elephants that lived in shallow African waters some 65 million years ago.”

Dr Scott Mirceta, PhD student on the project, added: “Our study suggests that the increased electrical charge of myoglobin in mammals that have high concentrations of this protein causes electro-repulsion, like similar poles of two magnets. This should prevent the proteins from sticking together and allow much higher concentrations of the oxygen-storing myoglobin in the muscles of these divers.”

“We are really excited by this new find, because it allows us to align the anatomical changes that occurred during the land-to-water transitions of mammals with their actual physiological diving capacity. This is important for understanding the prey items that were available to these extinct animals and their overall importance for past aquatic ecosystems.”

The research, funded by the Biotechnology and Biological Sciences Research Council (BBSRC), could also help improve understanding of a number of human diseases where protein aggregation is a problem, such as Alzheimer’s and diabetes, and could inform the development of artificial blood substitutes.

Dr Berenbrink added: “This finding illustrates the strength of combining molecular, physiological and evolutionary approaches to biological problems and, for the first time, allows us to put ‘flesh’ onto the bones of these long extinct divers.”

Fossil Kangaroo Teeth Reveal Mosaic of Pliocene Ecosystems in Queensland

June 17th, 2013

Riffin

The teeth of a kangaroo and other extinct marsupials reveal that southeastern Queensland 2.5-5-million-years ago was a mosaic of tropical forests, wetlands and grasslands and much less arid than previously thought. The chemical analysis of tooth enamel that suggests this diverse prehistoric habitat is published June 12 in the open access journal PLOS ONE by Shaena Montanari from the American Museum of Natural History and colleagues from other institutions.

The carbon isotope ratios present in these fossil teeth revealed that the extinct kangaroo ate plants similar to those consumed by present-day kangaroos in temperate and tropical regions, rather than the plants that now grow in this region. The fossils examined also suggest that different animals in the area occupied specialized dietary niches and did not rely on identical sources of food. As the authors explain, “This period, the Pliocene, is critical to understand the origins and evolution of Australia’s unique modern animals. It is during this time that the Australian fauna first began to take on its modern appearance and distinctiveness, with many modern Australian marsupials, such as the agile wallaby Macropus gracilis, first appearing in Pliocene fossil deposits.”

Montanari adds, “It is vital for us to understand what types of environments Australian megafauna thrived in during the Pliocene. Obtaining detailed environmental records from this time can help us find the drivers of the subsequent extinctions of many of these large marsupials.”

An Extraordinary Gobioid Fish Fossil from Southern France

June 16th, 2013

Riffin

The classification of gobioid fishes is still under discussion. Several lineages, including the Eleotridae and Butidae, remain difficult to characterize because synapomorphies are rare (Eleotridae) or have not yet been determined (Butidae). Moreover, the fossil record of these groups is scarce.

Results

Exceptionally well-preserved fish fossils with otoliths in situ from uppermost Oligocene sediments (≈23–24 Mio. y. ago) in Southern France provide the most in-depth description of a fossil gobioid to date. The species was initially described as Cottus aries Agassiz, then transferred to †Lepidocottus Sauvage, and subsequently assigned to Gobius. Based on a comparative analysis of meristic, osteological and otolith data, this species most likely is a member of the family Butidae. This discovery is important because it represents the first record of a fossil butid fish based on articulated skeletons from Europe.

Significance

The Butidae and Eleotridae are currently distributed in W-Africa, Madagascar, Asia and Australia, but they do not appear in Europe and also not in the Mediterranean Sea. The new results indicate that several species of the Butidae thrived in Europe during the Oligocene and Early Miocene. Similar to the recent Butidae and Eleotridae, these fishes were adapted to a wide range of salinities and thrived in freshwater, brackish and marginal marine habitats. The fossil Butidae disappeared from Europe and the Mediterranean and Paratethys areas during the Early Miocene, due probably to their lack of competitiveness compared to other Gobioidei that radiated during this period of time. In addition, this study documents the great value of otoliths for gobioid systematics.

Method for counting scales

Osteology, scales and otolith of †Lepidocottus aries (Agassiz).

Details of the osteology of †Lepidocottus aries (Agassiz).

Citation: Gierl C, Reichenbacher B, Gaudant J, Erpenbeck D, Pharisat A (2013) An Extraordinary Gobioid Fish Fossil from Southern France. PLoS ONE 8(5): e64117. doi:10.1371/journal.pone.0064117

Editor: Laurent Viriot, Team ‘Evo-Devo of Vertebrate Dentition’, France

When Will the Next Megathrust Hit the West Coast of North America?

June 15th, 2013

Riffin

Understanding the size and frequency of large earthquakes along the Pacific coast of North America is of great importance, not just to scientists, but also to government planners and the general public. The only way to predict the frequency and intensity of the ground motion expected from large and giant “megathrust ” earthquakes along Canada’s west coast is to analyze the geologic record.

There is a Fault line known as the Juan du Fuca plate. This is a Subduction plate, the exact same type of fault line that caused yesterday’s quake in Japan

A new study published today in the Canadian Journal of Earth Sciences presents an exceptionally well-dated first record of earthquake history along the south coast of BC. Using a new high-resolution age model, a team of scientists meticulously identified and dated the disturbed sedimentary layers in a 40-metre marine sediment core raised from Effingham Inlet. The disturbances appear to have been caused by large and megathrust earthquakes that have occurred over the past 11,000 years.

One of the co-authors of the study, Dr. Audrey Dallimore, Associate Professor at Royal Roads University explains: “Some BC coastal fjords preserve annually layered organic sediments going back all the way to deglacial times. In Effingham Inlet, on the west coast of Vancouver Island, these sediments reveal disturbances we interpret were caused by earthquakes. With our very detailed age model that includes 68 radiocarbon dates and the Mazama Ash deposit (a volcanic eruption that took place 6800 yrs ago); we have identified 22 earthquake shaking events over the last 11,000 years, giving an estimate of a recurrence interval for large and megathrust earthquakes of about 500 years. However, it appears that the time between major shaking events can stretch up to about a 1,000 years.

“The last megathrust earthquake originating from the Cascadia subduction zone occurred in 1700 AD. Therefore, we are now in the risk zone of another earthquake. Even though it could be tomorrow or perhaps even centuries before it occurs, paleoseismic studies such as this one can help us understand the nature and frequency of rupture along the Cascadia Subduction Zone, and help Canadian coastal communities to improve their hazard assessments and emergency preparedness plans.”

“This exceptionally well-dated paleoseismic study by Enkin et al., involved a multi-disciplinary team of Canadian university and federal government scientists, and a core from the 2002 international drill program Marges Ouest Nord Américaines (MONA) campaign,” says Dr. Olav Lian, an associate editor of the Canadian Journal of Earth Sciences, professor at the University of the Fraser Valley and Director of the university’s Luminescence Dating Laboratory. “It gives us our first glimpse back in geologic time, of the recurrence interval of large and megathrust earthquakes impacting the vulnerable BC outer coastline. It also supports paleoseismic data found in offshore marine sediment cores along the US portion of the Cascadia Subduction Zone, recently released in an important United States Geological Survey (USGS) paleoseismic study by a team of researchers led by Dr. Chris Goldfinger of Oregon State University.

In addition to analyzing the Effingham Inlet record for earthquake events, this study site has also revealed much information about climate and ocean changes throughout the Holocene to the present. These findings also clearly illustrate the importance of analyzing the geologic record to help today’s planners and policy makers, and ultimately to increase the resiliency of Canadian communities. ”