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

Fossil Egg Links Dinosaurs to Modern Birds

November 19th, 2012

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Researchers have discovered a series of dinosaur eggs with a unique characteristic: they are oval in shape. The discovery supports the theory that birds and non-avian theropods, dinosaurs from the Cretaceous Period, could have a common ancestor.

Before her death in December 2010, Nieves López Martínez, palaeontologist of the Complutense University of Madrid, was working on the research of dinosaur eggs with a very peculiar characteristic: an ovoid, asymmetrical shape. Together with Enric Vicens, palaeontologist of the Universitat Autònoma de Barcelona, the two scientists conducted an exhaustive analysis of their discovery, recently published in the journal Palaeontology.

Researchers have discovered a series of dinosaur eggs with a unique characteristic: they are oval in shape. The discovery supports the theory that birds and non-avian theropods, dinosaurs from the Cretaceous Period, could have a common ancestor. (Credit: Image courtesy of Universitat Autònoma de Barcelona

The new type of dinosaur egg has been given the scientific name ofSankofa pyrenaica. The eggs were discovered in the Montsec area of Lleida, in two sites located on either side of the Terradets pass in Spain.

The South Pyrenean area is rich in dinosaur egg sites, most of which correspond to sauropod eggs from the upper Cretaceous, dating back more than 70 million years ago. During that period, the area was a coastal area full of beaches and deltas which won land from the sea through sediment accumulation. Sand and mud from that period gave way, millions of years later, to the sandstone and marl where dinosaur remains now can be found. On the beach ridges and flat coastal lands is where a large group of dinosaurs laid their eggs.

The sites where the discoveries were made correspond to the upper Cretaceous, between the Campanian and Maastrichtian periods, some 70 to 83 million years ago. The fossils found belong to small eggs measuring some 7 centimeters tall and 4 cm wide, while the eggshell was on average 0.27mm thick. Most of the eggs found were broken in small fragments, but scientists also discovered more or less complete eggs, which can be easily studied in sections. The eggs found at the sites all belong to the same species. The main difference when compared to other eggs from the same period is their asymmetrical shape, similar to that of chicken eggs. The more complete samples clearly show an oval form rarely seen in eggs from the upper Cretaceous period and similar to modern day eggs.

Their shape is a unique characteristic of theropod eggs from the upper Cretaceous period and suggests a connection with bird eggs. Non avian dinosaur eggs are symmetrical and elongated. Asymmetry in bird eggs is associated to the physiology of birds: they take on this shape given the existence of only one oviduct which can form only one egg at a time. In this case the isthmus, the region in the oviduct creating the eggshell membrane, is what gives the egg its asymmetrical shape. Thanks to this shape, the wider end contains a bag of air which allows the bird to breathe in the last stages of its development. This evolutionary step was still relatively underdeveloped in dinosaurs.

Thus, the egg discovered by UCM and UAB researchers may represent the missing link between dinosaurs and birds. Only one other egg, discovered in Argentina and corresponding to a primitive bird from the same period, has similar characteristics. The discover supports the theory that non avian theropods, the dinosaurs of the Cretaceous period, and birds could have had a common ancestor

Why Some Earthquakes Result in Faster Shaking : A Tabletop Fault Model

November 18th, 2012

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The more time it takes for an earthquake fault to heal, the faster the shake it will produce when it finally ruptures, according to a new study by engineers at the University of California, Berkeley, who conducted their work using a tabletop model of a quake fault.

“The high frequency waves of an earthquake — the kind that produces the rapid jolts — are not well understood because they are more difficult to measure and more difficult to model,” said study lead author Gregory McLaskey, a former UC Berkeley Ph.D. student in civil and environmental engineering. “But those high frequency waves are what matter most when it comes to bringing down buildings, roads and bridges, so it’s important for us to understand them.”

While the study, to be published in the Nov. 1 issue of the journal Natureand funded by the National Science Foundation, does nothing to bring scientists closer to predicting when the next big one will hit, the findings could help engineers better assess the vulnerabilities of buildings, bridges and other structures when a fault does rupture.

“The experiment in our lab allows us to consider how long a fault has healed and more accurately predict the type of shaking that would occur when it ruptures,” said Steven Glaser, UC Berkeley professor of civil and environmental engineering and principal investigator of the study. “That’s important in improving building designs and developing plans to mitigate for possible damage.”

To create a fault model, the researchers placed a Plexiglas slider block against a larger base plate and equipped the system with sensors. The design allowed the researchers to isolate the physical and mechanical factors, such as friction, that influence how the ground will shake when a fault ruptures.

It would be impossible to do such a detailed study on faults that lie several miles below the surface of the ground, the authors said. And current instruments are generally unable to accurately measure waves at frequencies higher than approximately 100 Hertz because they get absorbed by the earth.

“There are many people studying the properties of friction in the lab, and there are many others studying the ground motion of earthquakes in the field by measuring the waves generated when a fault ruptures,” said McLaskey. “What this study does for the first time is link those two phenomena. It’s the first clear comparison between real earthquakes and lab quakes.”

Noting that fault surfaces are not smooth, the researchers roughened the surface of the Plexiglas used in the lab’s model.

“It’s like putting two mountain ranges together, and only the tallest peaks are touching,” said McLaskey, who is now a postdoctoral researcher with the U.S. Geological Survey in Menlo Park.

As the sides “heal” and press together, the researchers found that individual contact points slip and transfer the resulting energy to other contact points.

“As the pressing continues and more contacts slip, the stress is transferred to other contact points in a chain reaction until even the strongest contacts fail, releasing the stored energy as an earthquake,” said Glaser. “The longer the fault healed before rupture, the more rapidly the surface vibrated.”

“It is elegant work,” said seismologist John Vidale, a professor at the University of Washington who was not associated with the study. “The point that more healed faults can be more destructive is dismaying. It may not be enough to locate faults to assess danger, but rather knowing their history, which is often unknowable, that is key to fully assessing their threat.”

Glaser and McLaskey teamed up with Amanda Thomas, a UC Berkeley graduate student in earth and planetary sciences, and Robert Nadeau, a research scientist at the Berkeley Seismological Laboratory, to confirm that their lab scenarios played out in the field. The researchers used records of repeating earthquakes along the San Andreas fault that Nadeau developed and maintained. The data were from Parkfield, Calif., an area which has experienced a series of magnitude 6.0 earthquakes two to three decades apart over the past 150 years.

Thomas and McLaskey explored the records of very small, otherwise identically repeating earthquakes at Parkfield to show that the quakes produced shaking patterns that changed depending on the time span since the last event, just as predicted by the lab experiments.

In the years after a magnitude 6.0 earthquake hit Parkfield in 2004, the small repeating earthquakes recurred more frequently on the same fault patches.

“Immediately after the 2004 Parkfield earthquake, many nearby earthquakes that normally recurred months or years apart instead repeated once every few days before decaying back to their normal rates,” said Thomas. “Measurements of the ground motion generated from each of the small earthquakes confirmed that the shaking is faster when the time from the last rupture increases. This provided an excellent opportunity to verify that ground motions observed on natural faults are similar to those observed in the laboratory, suggesting that a common underlying mechanism — fault healing — may be responsible for both.”

Understanding how forcefully the ground will move when an earthquake hits has been one of the biggest challenges in earthquake science.

“What makes this study special is the combination of lab work and observations in the field,” added Roland Burgmann, a UC Berkeley professor of earth and planetary sciences who reviewed the study but did not participate in the research. “This study tells us something fundamental about how earthquake faults evolve. And the study suggests that, in fact, the lab setting is able to capture some of those processes correctly.”

Glaser said the next steps in his lab involve measuring the seismic energy that comes from the movement of the individual contact points in the model fault to more precisely map the distribution of stress and how it changes in the run-up to a laboratory earthquake event

“Sauroniops pachytholus” DINO NAMED AFTER LORD OF THE RINGS’

November 17th, 2012

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Earlier this year a team of palaeontologists came into the possession of what appeared to be a 95 million-year-old skull cap from a previously unknown dinosaur. Further analysis showed that the bone likely belonged to a carcharodontosaurid — an offshoot of the familiarAllosaurus. Given its unique domed skull, the researchers concluded that it was in fact a newly discovered species, one they’ve decided to name after the demonic Sauron from the Lord of the Rings series.

Sauroniops pachytholus

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It’s full name is Sauroniops pachytholus, a massive bipedal carcharodontosaur that lived during the Cretaceous period. The paleontologists, Andrea Cau, Fabio Dalla Vecchia, and Matteo Fabbri, felt that the single fragment provided enough evidence to warrant the classification of an entirely new species, and their work describing the new dinosaur has since been published inActa Palaeontologica Polonica.

WATCH VIDEO: From a tiny, tough guy T. rex to a mummified duck-billed dino, take a look at these stories and more in these dinosaur videos.

Interestingly, the discovery now adds credence to the hypothesis that a fourth large theropod existed in the Cenomanian of Morocco together withCarcharodontosaurus, Deltadromeus, and Spinosaurus(yes, all four of them at the same time — must have been a nice place to visit).

Unfortunately, however, the limited bone fragment reveals achingly little about Sauron. That said, the researchers speculate that it was more than 30 feet in length, and that it was probably just as large as the Carcharodontosaurus. The palaeontologists are obviously hoping to find more fossils to be absolutely sure.

There’s also the prominent bump on its head. Brian Switek from Smithsonian offers some theories as to its function:

Why did such a large theropod have a prominent bump on its head? In other theropod lineages, such as the abelisaurids, bumps, knobs and horns are common forms of ornamentation. Perhaps the same was true for Sauroniops — thanks to Acrocanthosaurus and the sail-backed Concavenator, we know that carcharodontosaurs showed off with visual signals. Then again, Cau and coauthors speculate that the dome might have been a sexual signal or might have even been used in head-butting behavior. I think the last hypothesis is unlikely, especially since we don’t know what the microstructure of the dome looks like and there’s no evidence of pathology, but it’s still a distant possibility

Penn Dixie (Hamburg Natural History Society ) Fossils

November 16th, 2012

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Phacops rana, enrolled specimens collected from the Windom Shale by Dan Cooper

Phacops rana, enrolled specimens collected from the Windom Shale by Dan Cooper

Tetradactyl Footprints of an Unknown Affinity Theropod Dinosaur from the Upper Jurassic of Morocco

November 15th, 2012

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In this work the study surface where the footprints were registered was examined carefully. The study surface may or may be not the tracking surface (the surface where the dinosaur stepped) . All the surfaces with true footprints in Iouaridène syncline have been found in the hard layers (red siliceous levels) with mud cracks . The undertracks and underprints are in resistant layers with ripples. The number of hard layers varies from the northwest area of the syncline, about 20 layers, to the southeast area, where there are places with one hard layer. Currently, in the soft levels (shales) footprints have not been found in the soft levels (shales).

Holotype of Boutakioutichnium atlasicus.
A) outline. B) photograph.

The footprints studied in this work were registered after the formation of mud cracks. The cracks are deformed by the dinosaur feet so that the sides of the tracks were moved upward and outward . Sometimes they were also bent, but usually the deformation is closer to an elastic than plastic type. Under the foot, the cracks are broken in small fragments. In the Iouaridène syncline there are also some theropod footprints crossed by mud cracks produced after the dinosaur steps . In the footprint hole, the small rims and the displacement of the mud cracks are due to the dry layer below (elastic or almost) of the tracking surface, were there was a soft zone (of plastic or fluid) mud.

In general, the footprint depth is less than 5 cm, therefore the feet do not get any deeper into the mud. Only some footprints (7IGR6.6, 8IGR1.24 footprint, for instance) show collapse structures in the proximal part of the digit III. This occurs because the mud is accumulated in the interdigital area among the digits.

Most of the footprint shafts have been interpreted as direct structures . Therefore the footprints are considered true footprints and although not all are not an accurate representation of the foot, there are also some elite tracks or stamps . he footprint outline is not always easy to see because sometimes the physical features of the mud cracks do not allow the foot to print it well. The footprint outline does not fit exactly with the foot shape because the mud cracks move as coarse fragments and their behavior is not completely plastic. Nonetheless, in some footprints the diagnostic features as the digits margins, the digital pads and the claws marks are clearly distinghished.

Jaouad Nouri¹, Ignacio Díaz-Martínez²^,³, Félix Pérez-Lorente²^,³^*

1 Faculté des Sciences, Université Mohamed V, Rabat, Morocco, 2 Facultad de Ciencas, Universidad de La Rioja, Logroño, La Rioja, España, 3 Fundación Patrimonio Paleontológico de La Rioja, Enciso, La Rioja, España

2011 Virginia Earthquake Triggered Landslides at Extraordinary Distances

November 14th, 2012

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The 2011 Mineral, Virginia M-5.8 earthquake was felt over an extraordinarily large area. A new study details landslides triggered by the earthquake at distances four times greater and over an area 20 times larger than previously

The study, to be published in the December issue of the Bulletin of the Seismological Society of America(BSSA), describes physical confirmation of previous observations that ground shaking from earthquakes in the eastern U.S. travels farther than in the western U.S, a plate-boundary region.

The star indicates the epicenter; large crosses are landslide limits; the small cross represents the largest landslide observed; triangles represent seismic recording stations with station codes indicated (see Table 1 for station names and codes); and dash-double-dot lines are state boundaries. The bold line shows a best-fit ellipse centered at the epicenter and passing through the observed limits (dashed where inferred beyond limits); the dotted line shows a polygon enclosing the observed landslides; the circle around the epicenter indicates the previous maximum distance limit for M 5.8 earthquake (Keefer, 1984); filled circles show maximum (1500 km2) and average (219 km2) areas expected to experience landslides for an M 5.8 earthquake based on previous studies (Keefer, 1984, 2002; Rodríguez et al., 1999). Sinuous solid line shows Blue Ridge Parkway, which extends along the crest of the Blue Ridge. Abundant susceptible slopes exist from the Blue Ridge to the west and north; few susceptible slopes are present to the south and east. (Credit: BSSA Vol. 102:6

U.S. Geological Survey scientists Randall W. Jibson, who is scheduled to present his findings on Nov. 6 at the annual meeting of the Geological Society of America, and co-author Edwin L. Harp painstakingly mapped rock falls to determine the distance limits from the epicenter to compare with previously documented earthquakes.

The 2011 Virginia earthquake was the largest earthquake in the eastern U.S. since 1897. Although it did not produce large, damaging landslides, it did trigger small landslides of rock and soil from steep slopes.

Because landslides can occur without earthquake shaking, Jibson and Harp looked for evidence of recent physical disruption that could be attributed to the quake. From August 25 though September 3, Jibson and Harp made detailed observations by driving outward from the epicentral area in transects; they stopped frequently to get on their hands and knees to overturn rocks to see whether there was green grass underneath — a sign that the rock could have fallen during the quake. As they drove, they inspected highly susceptible slopes until they had reached an apparent limit for a particular area.

“We’ve been doing this for more than 30 years and have developed a consistent observational standard that isn’t dependent on the observers,” Jibson said. “We are confident we can accurately compare limits for different earthquakes.”

The authors noted that Hurricane Irene passed near the area a few days after the quake, and they identified small rainfall-triggered debris flows that were quite distinct from rock falls triggered by the quake.

Landslide limits were documented along the Blue Ridge Parkway from near Harpers Ferry, West Virginia, southwestward to within 30 km of the Virginia-North Carolina border as well as on transects northwestward through the Appalachian Mountains into West Virginia. The limits to the east and south of the Blue Ridge are less well constrained owing to a lack of susceptible slopes. The authors propose an estimated elliptical area had there been equally susceptible landscape yielding evidence in all areas.

There is sufficient documented evidence, say Jibson and Harp, to suggest the need to revise the established distance limits for the occurrence of landslides in different tectonic environments.

For the eastern U.S., the documented landslides from the 2011 Virginia earthquake suggest that ground motion is stronger and travels farther parallel to the Appalachian Mountains than perpendicular to them, which is consistent with other sources of intensity information such as the U.S. Geological Survey’s Did You Feel It? map.

Not all historical post-earthquake landslide investigations have been conducted at the same level of detail, and so they might not be directly comparable with the current study. Also, very few earthquakes in stable continental interiors, where ground motion is known to travel farther than in plate-boundary regions, have had thorough documentations of triggered landslides, noted the authors.

“Even taking differential landslide reporting into account,” wrote the authors, “the landslide limits from the 2011 Virginia earthquake are extraordinary.”

The study is titled, “Extraordinary Distance Limits of Landslides Triggered by the 2011 Mineral, Virginia Earthquake.”

Greenland Rocks Provide Evidence of Earth Formation Process

November 12th, 2012

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Rocks dating back 3.4 billion years from south-west Greenland’s Isua mountain range have yielded valuable information about the structure of Earth during its earliest stages of development. In these rocks, which witnessed the first billion years of Earth’s history, a French-Danish team led by researchers from the ‘Magmas and Volcanoes’ Laboratory (CNRS / Université Blaise Pascal / IRD) have highlighted a lack of neodymium-142, an essential chemical element for the study of Earth’s formation.

View of the Isua range (south-west Greenland) taken in August 2010 during the sampling mission. (Credit: © Hanika Rizo

This deficit supports the hypothesis that between 100 and 200 million years after its formation, Earth was made up of an ocean of molten magma, which gradually cooled. The work, which was carried out in collaboration with the Laboratoire de Géologie de Lyon (CNRS / Université Lyon 1 / ENS de Lyon) and the University of Copenhagen, was published on 1 November 2012, in the journal Nature.

Earth is believed to have formed 4.58 billion years ago, by accretion of material in the Solar System. The heat produced by the accretion process, as well as by the decay of radioactive elements, caused this material to melt. As a result, 100 to 200 million years after its formation, Earth must have been made up of an ocean of molten magma, in the center of which a metallic core formed. The ocean gradually cooled. Earth’s crust then appeared, and the process of continental drift began. The crystallization of the molten magma is likely to have been accompanied by the chemical layering of Earth: concentric layers with distinct chemical compositions became differentiated. It is the signature of these primordial inhomogeneities that the researchers found in the Isua rocks.

The scientists were interested in a key chemical element, the isotope neodymium-142, formed by the decay of a now vanished radioactive isotope called samarium-146. The abundance of neodymium-142 is almost identical in all terrestrial rocks. Only two exceptions have been discovered to date, in Canada and Greenland, in certain rocks dating back 3.7 billion years. The composition of these rocks shows evidence of the primordial inhomogeneities that formed as the magma ocean crystallized.

In 2003, for the first time, two groups of French researchers observed an excess of neodymium-142 in certain rocks in the same region. If such excess can be found in some layers of the primordial Earth, it means that other layers must be depleted in this isotope. However, until these new findings by the French-Danish team, such neodymium-142 deficits remained hypothetical for nine years. Using a sophisticated method, thermal ionization mass spectrometry, the researchers carried out a very detailed analysis of the concentration of neodymium-142 in Isua rock samples. They discovered a neodymium-142 deficit of 10.6 parts per million, which lends weight to the ‘magma ocean’ theory.

These findings should help to improve models of the internal dynamics of Earth during its early stages of development. By discovering a neodymium-142 deficit in relatively young rocks, formed around a billion years after the crystallization of the magma ocean, the researchers have shown that the primordial inhomogeneities persisted longer than predicted before being eliminated by convective motion in Earth’s mantle. In order to obtain more comprehensive data, the scientists now intend to study the composition of other rocks of similar age outcropping for example in Canada, South Africa and China.

This study was mainly funded by an ERC Starting Grant.

New Computational Method for Timing the Tree of Life

November 11th, 2012

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With its deeply embedded roots, sturdy trunk and dense profusion of branches, the Tree of Life is a structure of nearly unfathomable complexity and beauty. While major strides have been made to establish the evolutionary hierarchy encompassing every living species, the project is still in its infancy.

At Arizona State University’s Biodesign Institute, Sudhir Kumar has been filling in the Tree of Life by developing sophisticated methods and bioinformatics tools. His latest research, which appeared on the advance online edition of the Proceedings of the National Academy of Sciences will uniquely enable scientists to analyze very large datasests to set time to the multitude of branching points (nodes) on the tree, each representing a point of species divergence from a common ancestor. The new method differs significantly from currently used techniques and excels in providing results of equal or greater accuracy at speeds of 1000 times or faster.

For the proper study of evolutionary history, two components are key: the relationships between organisms (known as phylogeny) and their times of divergence. As Kumar explains, the powerful technique for estimating the time of divergence between species was initially realized over four decades ago, when the concept of molecular clocks was introduced. Initially the idea rested on the assumption that alterations in either the amino acid sequences of proteins or the nucleotide sequences of DNA between various species accumulate at a uniform rate over time and can be used to evaluate divergence times. The resulting phylogenetic structure is known as a “TimeTree,” that is, a tree of life scaled to time.

Prior to the use of molecular clocks, morphological changes between species were the primary means of identifying divergence times. Since then, molecular clocks have proved a vital tool for evolutionary biologists, supplementing the fossil record and providing a powerful means to time the divergence of species.

But there is a complication. The rate of change measured by molecular clocks can vary — sometimes radically — between groups of species. Rather than an ordered world running on a universal clock time, the Tree of Life is more like an antiques shop where clocks run at different speeds in different species.

Many approaches for dealing with this conundrum have been applied successfully, but their complexity rises exponentially with the number of species involved. Often such calculations swallow vast amounts of computing time, even for data sets of modest size.

By contrast, the new simplified method (known as RelTime) produces rapid results. Its main purpose is to estimate relative times of divergence. This avoids the need to use the fossil record, which is otherwise required in order to obtain absolute times.

“If, for example, we can establish that human and chimp divergence is 5 times younger than the human and monkey divergence, that would be very useful,” Kumar says. “What our method can do is to generate such relative time information for every divergence in the Tree of Life — without using the fossil record or other complicated model parameters. ” Once relative times for all the nodes on the tree of life are established, fossil calibration points for which a high degree of confidence exists can be applied post hoc to add the absolute time dimension.

Kumar points out that rapid DNA sequencing has allowed for huge datasets of comparative molecular sequences to be generated. Analyses of even a few hundred sequences through current methods however can severely strain computer resources and more massive data sets now being generated can not be solved in reasonable time through current methods, so a fresh approach was needed.

Using RelTime and restricting the analysis to relative divergence times produces results for large phylogenetic trees in hours rather than days. It can also deliver better accuracy, particularly when datasets are enormous and species of interest are from vastly different groups.

“The uses of such technique are only limited by one’s imagination. They can be used to estimate the origin of familiar species, emergence of human pathogens, and so forth,” Kumar says. “The method is applicable wherever you work with sequences and trees.”

RelTime may also help sort out troubling disparities between divergence times based on the fossil record versus those established through the use of molecular data. Examples of dramatic discrepancies between fossils and sequence change measurements have provoked spirited debate, particularly concerning the adaptive radiation of mammals posited to have occurred at the time of dinosaur extinction some 65 million years ago and the divergence of specific animal phyla believed to date to the beginning of the Cambrian period (~500-600 Mya). In both cases, for example, the molecular dates are about 50 percent older than fossil dates.

The ongoing Timetree of Life project will have important ramifications for many fields of research, providing deep insights into comparative biology, as well as generating data of relevance for paleontologists, geologists, geochemists, and climatologists. Establishing a comparative biological timeline synchronized with Earth history will enable scientists working in diverse areas to explore the long-term development of the biosphere and investigate the evolutionary underpinnings of all life.

Xenoceratops: Canada’s Newest Horned Dinosaur

November 10th, 2012

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Scientists have named a new species of horned dinosaur (ceratopsian) from Alberta, Canada. Xenoceratops foremostensis (Zee-NO-Sare-ah-tops) was identified from fossils originally collected in 1958. Approximately 20 feet long and weighing more than 2 tons, the newly identified plant-eating dinosaur represents the oldest known large-bodied horned dinosaur from Canada.

Research describing the new species is published in the October 2012 issue of the Canadian Journal of Earth Sciences.

“Starting 80 million years ago, the large-bodied horned dinosaurs in North America underwent an evolutionary explosion,” said lead author Dr. Michael Ryan, curator of vertebrate paleontology at The Cleveland Museum of Natural History. “Xenoceratops shows us that even the geologically oldest ceratopsids had massive spikes on their head shields and that their cranial ornamentation would only become more elaborate as new species evolved.”

Artist reconstruction of Canada’s oldest ceratopsid, Xenoceratops foremostensis (Zee-NO-Sare-ah-tops), from southern Alberta 78 million years ago. The new species of horned dinosaur was identified from fossils originally collected in 1958. Approximately 20 feet long and weighing more than 2 tons, the newly identified plant-eating dinosaur represents the oldest known large-bodied horned dinosaur from Canada. Research describing the new species is published in the October 2012 issue of the Canadian Journal of Earth Sciences. (Credit: © Julius T. Csotonyi 2012)

Xenoceratops (Xeno + ceratops) means “alien horned-face,” referring to the strange pattern of horns on its head and the scarcity of horned dinosaur fossils from this part of the fossil record. It also honors the Village of Foremost, located close to where the dinosaur was discovered.Xenoceratops had a parrot-like beak with two long brow horns above its eyes. A large frill protruded from the back of its skull featuring two huge spikes.

“Xenoceratops provides new information on the early evolution of ceratopsids, the group of large-bodied horned dinosaurs that includes Triceratops,” said co-author Dr. David Evans of the Royal Ontario Museum and University of Toronto. “The early fossil record of ceratopsids remains scant, and this discovery highlights just how much more there is to learn about the origin of this diverse group.”

The new dinosaur is described from skull fragments from at least three individuals from the Foremost Formation originally collected by Dr. Wann Langston Jr. in the 1950s, and is currently housed in the Canadian Museum of Nature in Ottawa, Canada. Ryan and Evans stumbled upon the undescribed material more than a decade ago and recognized the bones as a new type of horned dinosaur. Evans later discovered a 50-year-old plaster field jacket at the Canadian Museum of Nature containing more skull bones from the same fossil locality and had them prepared in his lab at the Royal Ontario Museum.

This dinosaur is just the latest in a series of new finds being made by Ryan and Evans as part of their Southern Alberta Dinosaur Project, which is designed to fill in gaps in our knowledge of Late Cretaceous dinosaurs and study their evolution. This project focuses on the paleontology of some of the oldest dinosaur-bearing rocks in Alberta, which is less intensely studied than that of the famous badlands of Dinosaur Provincial Park and Drumheller.

“This discovery of a previously unknown species also drives home the importance of having access to scientific collections,” says co-author Kieran Shepherd, curator of paleobiology for the Canadian Museum of Nature, which holds the specimen. “The collections are an untapped source of new material for study, and offer the potential for many new discoveries.”

Xenoceratops was identified by a team comprising palaeontologists Dr. Michael J. Ryan, curator of vertebrate paleontology at The Cleveland Museum of Natural History; and Dr. David Evans, curator, vertebrate palaeontology of the Department of Natural History at the Royal Ontario Museum; as well as Kieran Shepherd, curator of paleobiology for the Canadian Museum of Nature.

Mohorovičić Discontinuity

November 6th, 2012

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What is the Mohorovičić Discontinuity?

The Mohorovicic Discontinuity, or “Moho”, is the boundary between the crust and the mantle. The red line in the drawing below shows its location.

In geology the word “discontinuity” is used for a surface at which seismic waves change velocity. One of these surfaces exists at an average depth of 8 kilometers beneath the ocean basin and at an average depth of about 32 kilometers beneath the continents. At this discontinuity, seismic waves accelerate. This surface is known as the Mohorovicic Discontinuity or often simply referred to as the “Moho”.

Thickness of Earth’s crust by USGS – since the Moho is at the base of the crust this map also shows depth to Moho.

How Was the Moho Discovered?

The Mohorovicic Discontinuity was discovered in 1909 by Andrija Mohorovicic , a Croatian seismologist. Mohorovicic realized that the velocity of a seismic wave is related to the density of the material that it is moving through. He interpreted the acceleration of seismic waves observed within Earth’s outer shell as a compositional change within the earth. The acceleration must be caused by a higher density material being present at depth.

The lower density material immediately beneath the surface is now commonly referred to as “Earth’s crust”. The higher density below the crust became known as “Earth’s mantle”. Through careful density calculations Mohorovicic determined that the basaltic oceanic crust and the granitic continental crust are underlain by a material which has a density similar to an olivine-rich rock such as peridotite.

How Deep is the Moho?

The Mohorovicic Discontinuity marks the lower limit of Earth’s crust. As stated above it occurs at an average depth of about 8 kilometers beneath the ocean basins and 32 kilometers beneath continental surfaces. Mohorovičić was able to use his discovery to study thickness variations of the crust. He discovered that the oceanic crust has a relatively uniform thickness while continental crust is thickest under mountain ranges and thinner under plains.

The map below illustrates the thickness of Earth’s crust. Note how the thickest areas (red and dark brown) are beneath some of Earth’s important mountain ranges such as: Andes (west side of South America), Rockies (Western North America), Himalayas (north of India in South-central Asia) and Urals (north-south trending between Europe and Asia)

Has Anyone Ever Seen the Moho?

No one has ever been deep enough into the earth to see the Moho and no wells have ever been drilled deep enough to penetrate it. Drilling wells to that depth is very expensive and very difficult because of the extreme temperature and pressure conditions. The deepest well that has been drilled to date was located on the Kola Peninsula of the Soviet Union. It was drilled to a depth of about 12 kilometers. Drilling to the Moho through oceanic crust has also been unsuccessful.

There are a few rare locations where mantle material has been brought to the surface by tectonic forces. At these locations, rock that used to be at the crust – mantle boundary is present. A photo of rock from one of these locations is shown at right.

Contributor: Hobart King