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How Strike-Slip Faults Form, the Origin of Earthquakes

Strike-Slip Fault

Structural geologist Michele Cooke calls it the “million-dollar question” that underlies all work in her laboratory at the University of Massachusetts Amherst: what goes on deep in Earth as strike-slip faults form in the crust? This is the fault type that occurs when two tectonic plates slide past one another, generating the waves of energy we sometimes feel as earthquakes.

Geologists have been uncertain about the factors that govern how new faults grow, says Cooke. In recent years she and colleagues have offered the first systematic explorations of such fault evolution. In their new paper, she and her team of students provide experimental results to illustrate the process, with videos, and report on how they re-enact such events in wet clay in the lab. Details appear in the current online edition of Journal of Structural Geology.

Cooke says, “When I give talks to other geologists I put up a picture of a fault and ask, wouldn’t you love to be able to see exactly how that formed? Well, in my lab that’s what we do. We set up the conditions for faulting on a small scale and watch them unfold. People have done this before, but we’ve developed methods so we can see faults grow in very, very fine detail, at a finer resolution than anyone has documented before.”

The UMass Amherst researchers take a mechanical efficiency approach to understanding fault development. It states that faults in the crust reorganize in accord with “work optimization” principles, or what Cooke refers to as the “Lazy Earth” hypothesis. It focuses on fault systems’ effectiveness at transforming input energy into movement along the faults. Like lightning striking the closest object, when forming a fault Earth takes the easiest path.

For this National Science Foundation-supported work, the researchers load a tray with kaolin, also known as china clay, prepared so its viscosity and length scale to that of Earth’s crust. All the experiments involve two slabs of wet clay moving in opposite directions under one of three base boundary conditions, that is, different ways of “loading” the fault. One scenario begins with a pre-existing fault, another with localized displacement beneath the clay, and a third that is characterized by a displacement across a wider zone of shear beneath the clay.

Data from the two-hour experiments record strain localization and fault evolution that represents millions of years at the scale of tens of kilometers during strike-slip fault maturation. Cooke says, “We have captured very different conditions for fault formation in our experiments that represent a range of conditions that might drive faulting in the crust.”

She adds, “We found that faults do evolve to increase kinematic efficiency under different conditions, and we learned some surprising things along the way. One of them is that faults shut off along the way. We suspected this, but our experiment is the first to document it in detail. Another especially surprising finding is that fault irregularities, which are inefficient, persist rather than the system forming a straight, efficient fault.”

The authors, who include graduate students Alex Hatem and Kevin Toeneboehn, identify four stages in fault evolution: pre-faulting, localization, linkage and slip. The process starts simply, advances to a peak of complexity, after which complexity suddenly drops off and the fault simplifies again, lengthening into a “through-going” or continuous single, surface crack.

In videos by Hatem, shear strain is clearly seen to distort the crust along the area where two base plates meet. In the next stage numerous echelon faults develop. These are step-like fractures parallel to each other that get pulled length-wise as strain increases until they suddenly link. In the last stage, these join to form a final single fault. Cooke says, “We were very excited to see that portions of the faults shut off as the system reorganized, and also that the irregularities persisted along the faults.”

An interesting finding, but not a surprise is that for the most part all faults went through a similar process. Cooke says, “We tested the various extremes but came out of this with a common kind of evolution that’s true for all. If there’s not already a fault, then you see echelon faults, small faults parallel to each other but at an angle to the shear. Probably the most insightful bit is the details of fault evolution within those extremes. What you’re left with at the end is a long fault with abandoned segments on either side, which is something we see in the field all the time. It’s a nice confirmation that our lab experiments replicate what is going on within Earth.”

Another insight, the researchers say, results from measuring the kinematic or geometric efficiency, the percent of applied displacement expressed as slip on the faults. “An inefficient fault will have less slip and more deformation around the zones,” Cooke explains. “We can see it happening in the experiments and it supports the idea that faults evolve to become efficient and Earth optimizes work. This is the Lazy Earth; the efficiency is increasing even though the fault is becoming more complex.”

Finally the geologist adds, “We saw that when the faults eventually link up, they don’t necessarily make a perfectly straight fault. That tells me that irregularities can persist along mature faults because of the material. It’s an insight into how you get persistent irregularities that we see in the real earth’s crust. Structural geologists are surprised by irregularities, because if faults evolve to minimize work then all faults should be straight. But we have evidence now to show these irregularities persist. We have irregular faults that are active for millions of years.”

Reference:
Alexandra E. Hatem, Michele L. Cooke, Kevin Toeneboehn. Strain localization and evolving kinematic efficiency of initiating strike-slip faults within wet kaolin experiments. Journal of Structural Geology, 2017; 101: 96 DOI: 10.1016/j.jsg.2017.06.011

Note: The above post is reprinted from materials provided by University of Massachusetts at Amherst.

Study finds Earth’s magnetic field ‘simpler than we thought’

A snapshot of the 3D magnetic field structure simulated with the Glatzmaier-Roberts geodynamo model. Magnetic field lines are blue where the field is directed inward and yellow where directed outward. The rotation axis of the model Earth is vertical and through the center.

Scientists have identified patterns in the Earth’s magnetic field that evolve on the order of 1,000 years, providing new insight into how the field works and adding a measure of predictability to changes in the field not previously known.

The discovery also will allow researchers to study the planet’s past with finer resolution by using this geomagnetic “fingerprint” to compare sediment cores taken from the Atlantic and Pacific oceans.

Results of the research, which was supported by the National Science Foundation, were recently published in Earth and Planetary Science Letters.

The geomagnetic field is critical to life on Earth. Without it, charged particles from the sun (the “solar wind”) would blow away the atmosphere, scientists say. The field also aids in human navigation and animal migrations in ways scientists are only beginning to understand. Centuries of human observation, as well as the geologic record, show our field changes dramatically in its strength and structure over time.

Yet in spite of its importance, many questions remain unanswered about why and how these changes occur. The simplest form of magnetic field comes from a dipole: a pair of equally and oppositely charged poles, like a bar magnet.

“We’ve known for some time that the Earth is not a perfect dipole, and we can see these imperfections in the historical record,” said Maureen “Mo” Walczak, a post-doctoral researcher at Oregon State University and lead author on the study. “We are finding that non-dipolar structures are not evanescent, unpredictable things. They are very long-lived, recurring over 10,000 years – persistent in their location throughout the Holocene.

“This is something of a Holy Grail discovery,” she added, “though it is not perfect. It is an important first step in better understanding the magnetic field, and synchronizing sediment core data at a finer scale.”

Some 800,000 years ago, a magnetic compass’ needle would have pointed south because the Earth’s magnetic field was reversed. These reversals typically happen every several hundred thousand years.

While scientists are well aware of the pattern of reversals in the Earth’s magnetic field, a secondary pattern of geomagnetic “wobble” within periods of stable polarity, known as paleomagnetic secular variation, or PSV, may be a key to understanding why some geomagnetic changes occur.

The Earth’s magnetic field does not align perfectly with the axis of rotation, which is why “true north” differs from “magnetic north,” the researchers say. In the Northern Hemisphere this disparity in the modern field is apparently driven by regions of high geomagnetic intensity that are centered beneath North America and Asia.

“What we have not known is whether this snapshot has any longer-term meaning – and what we have found out is that it does,” said Joseph Stoner, an Oregon State University paleomagnetic specialist and co-author on the study.

When the magnetic field is stronger beneath North America, or in the “North American Mode,” it drives steep inclinations and high intensities in the North Pacific, and low intensities in Europe with westward declinations in the North Atlantic. This is more consistent with the historical record.

The alternate “European mode” is in some ways the opposite, with shallow inclination and low intensity in North Pacific, and eastward declinations in the North Atlantic and high intensities in Europe.

“As it turns out, the magnetic field is somewhat less complicated than we thought,” Stoner said. “It is a fairly simple oscillation that appears to result from geomagnetic intensity variations at just a few recurrent locations with large spatial impacts. We’re not yet sure what drives this variation, though it is likely a combination of factors including convection of the outer core that may be biased in configuration by the lowermost mantle.”

The researchers were able to identify the pattern by studying two high-resolution sediment cores from the Gulf of Alaska that allowed them to develop a 17,400-year reconstruction of the PSV in that region. They then compared those records with sediment cores from other sites in the Pacific Ocean to capture a magnetic fingerprint, which is based on the orientation of the magnetite in the sediment, which acts as a magnetic recorder of the past.

The common magnetic signal found in the cores now covers an area spanning from Alaska to Oregon, and over to Hawaii.

“Magnetic alignment of distant environmental reconstructions using reversals in the paleomagnetic record provides insights into the past on a scale of hundreds of thousands of years,” Walczak said. “Development of the coherent PSV stratigraphy will let us look at the record on a scale possibly as short as a few centuries, compare events between ocean basins, and really get down to the nitty-gritty of how climate anomalies are propagated around the planet on a scale relevant to human society.”

The magnetic field is generated within the Earth by a fluid outer core of iron, nickel and other metals that creates electric currents, which in turn produce magnetic fields. The magnetic field is strong enough to shield the Earth from solar winds and cosmic radiation. The fact that it changes is well known; the reasons why have remained a mystery.

Now this mystery may be a little closer to being solved.

Reference:
M.H. Walczak et al. A 17,000 yr paleomagnetic secular variation record from the southeast Alaskan margin: Regional and global correlations, Earth and Planetary Science Letters (2017). DOI: 10.1016/j.epsl.2017.05.022

Note: The above post is reprinted from materials provided by Oregon State University.

Ancient animal thought to be first air breather on land loses claim to fame

These are examples of zircon grains used in a University of Texas at Austin study that showed the animal thought to be the oldest land-based air breather is younger than thought. Grain numbers and ages are indicated by the numbers. Credit: University of Texas Jackson School of Geosciences

Some good scientific sleuthing by an undergraduate at The University of Texas at Austin has helped rewrite one of the earliest chapters in the planet’s evolutionary history. The research, led by the UT Jackson School of Geosciences, has shown that the millipede thought to be the world’s oldest known air-breathing land creature is in fact about 14 million years younger than previously thought and cannot be the original land breather.

The paper was published June 28 in the journal PLOS ONE. The study focuses on a species of millipede called Pneumodesmus newmani, which was thought to have been breathing air on solid ground during the late Silurian period some 428 million years ago. All other animal fossils discovered before this time have been from animals that lived and breathed under water.

The millipede fossil was discovered by an amateur paleontologist in 2004 in Aberdeenshire, Scotland, and dated by testing plant spores in sediment found in the general area, a method that contains a significant amount of scientific uncertainty compared with radiometric dating methods, said Elizabeth Catlos, a study author and associate professor in the Jackson School’s Department of Geological Sciences.

“The 428 million year age wasn’t obtained using radiometric techniques because no one could get the radioactive minerals out of these soils,” she said.

Catlos, who obtained the soil samples from co-author Michael Brookfield of the University of Massachusetts Boston, tasked Jackson School senior Stephanie Suarez, the paper’s lead author, with finding grain-sized zircons in the sediment that could be dated in the Jackson School’s Laser Ablation Inductively Coupled Plasma Mass Spectrometry Laboratory. Zircons are minerals that trap radioactive elements inside of them when they form, which can help scientists more accurately determine the age of rock or sediment where they’re found.

The zircon samples were from ancient volcanic ash beds directly above and below where the millipede specimen was found. Brookfield, who is from Scotland, said he has been collecting samples from the area since he was a teenager and has long been interested in more precisely dating the sediment where the well-known specimen was discovered.

This job was particularly challenging because the clay sediment Brookfield sent to the Jackson School was loose in plastic bags and unlike the solid rock that Catlos is used to studying. Suarez, who was introduced to the geosciences in high school as part to the Jackson School’s GeoFORCE outreach program, initially tried the standard method of heavy mineral separation, which involves crushing the rock and using bromoform (an organic solvent) to separate out heavier minerals.

“When I attempted it, the ashes clumped together, and no zircons sank to the bottom,” she said. “It was very messy and unsuccessful.”

Undeterred, Suarez combed scientific literature looking for ideas and came across a 2014 study led by Gregory Hoke of Syracuse University that pioneered a method of isolating nonclay components from clay-rich material by constructing and using an ultrasonic clay separator.

“I had to get creative,” Suarez said. “We have a very small sonicator in our lab that we use to clean thin sections. I used that, a Tupperware container and some hydrogen peroxide. It worked. I was very excited.”

Ultimately, Suarez was able to collect 74 zircons to be analyzed and dated. More than 10 of the zircons were younger than 428 million years ago, with the youngest being about 414 million years old. This places the specimen in a completely different geologic era, the Devonian, a classification that bursts the millipede’s uniqueness. Many fossils of land-breathing organisms, mainly insects and arthropods, have been recovered from this era.

Catlos expects the results to raise a few eyebrows, but she said the beauty of published science is that others can replicate the experiment. The handful of zircons found to be younger than 428 million years old definitely show that the Pneumodesmus newmani specimen was not the first organism on Earth to breathe air while on land.

“This wasn’t it,” Catlos said. “We have to keep looking.”

Note: The above post is reprinted from materials provided by University of Texas at Austin.

Forgotten archives reveal street-level impact of 1918 Puerto Rico earthquake and tsunami

Shoreline damage in Aguadilla, Puerto Rico is shown following the 1918 earthquake and tsunami. Credit: Courtesy of Roland LaForge

Repair petitions filed in the wake of the 1918 Puerto Rico earthquake and tsunami, stored and forgotten in the San Juan archives for nearly 100 years, are giving scientists a house-by-house look at the damage wrought by the magnitude 7.3 event.

In the journal Seismological Research Letters, seismologists Roland LaForge and William McCann describe how they used the records to trace the impact of the earthquake in Aguadilla, the town closest to the 1918 epicenter.

The researchers combed through handwritten and often heartbreaking petitions for funds to repair homes battered or washed away by the tsunami, or damaged by earthquake ground shaking. Together, the data provide a “pretty accurate picture to find out where the damage was, and how far the tsunami made it inland,” said LaForge.

At the south end of town, in particular, the tsunami’s three to four meter- high mark could be determined from repair petitions from houses closely clustered together — where some homes reported wave damage and some were untouched by the waves.

The address-level findings are consistent with a 1919 reconnaissance of the earthquake damage and more modern calculations of tsunami wave heights, the researchers say. But the new study provides more detailed “ground truth” of what happened during the 1918 quake, said LaForge, and could be useful in predicting which parts of Aguadilla would be mostly likely to suffer damage during the next major earthquake.

In the United States, the Caribbean and Latin America, LaForge said, “finding and interpreting written historical earthquake damage accounts is difficult and time consuming, but we have learned that researching these old earthquakes has become more important over time.”

The October 11, 1918 Puerto Rico earthquake and tsunami is the most recent damaging seismic event to affect the island. More than 100 people died, and the island sustained $4 million dollars (1918 dollars) in damage, especially in the towns of Aguadilla, Mayagüez, Aguada and Añasco.

As part of the relief efforts after the earthquake, residents whose homes were damaged or destroyed submitted petitions for repair funds to a Special Earthquake Commission established after the event. Inspectors came out to review the damage claimed in each petition, and funds were awarded based on their recommendations.

McCann, a former professor at the University of Puerto Rico, stumbled across boxes of these petitions, unsealed for nearly 100 years, in the General Archive in San Juan, Puerto Rico. He later mentioned them to LaForge, who had worked with the U.S. Bureau of Reclamation and Puerto Rico Electric Power Authority on seismic hazard studies of dams on the island.

The two received a grant from the National Earthquake Hazards Reduction Program (NEHRP) to digitize and study more than 6000 pages of the petitions and other records and photographs related to the earthquake. Although 275 petitions were known to be received from Aguadilla, only 88 (32%) were discovered in the San Juan archives. Most of these appear to be petitions to repair damage rather than replacement of entire homes.

“The layout of the town is pretty much the same as it was in 1918,” LaForge explained. “And we had these detailed damage descriptions by neighborhood and street and address in some cases. We thought if we can match up these addresses with modern-day addresses to know where they were, we could get a pretty good picture of where the damage was and how severe it was.”

The petitions marked other losses as well. “Reading through the actual reports was very poignant at times,” LaForge said. “Some of these people lost family members, or knew people who drowned. You get a real idea of what people went through.”

LaForge hopes that other researchers — students at the University of Puerto Rico, perhaps — will use the digitized petition data to learn more about the earthquake and tsunami impact in other towns such as Mayagüez. “The dataset in general is a real gold mine.”

The Seismological Society of America, which publishes Seismological Research Letters, will hold a joint conference in April 2018 with the Latin American and Caribbean Seismological Commission in San Juan, Puerto Rico. The site of the Seismology of the Americas meeting was chosen in part to commemorate the 100th anniversary of the 1918 earthquake.

Reference:
Roland LaForge and William McCann. Address-level Effects in Aguadilla, Puerto Rico, from the 1918 Mw 7.3 Earthquake and Tsunami. Seismological Research Letters, July 2017 DOI: 10.1785/0220170044

Note: The above post is reprinted from materials provided by Seismological Society of America.

Kinect scan of T. rex skull addresses paleontological mystery

Researchers demonstrate their scanning technique, with a user holding a monopod-mounted Kinect at close range from a T. Rex skull. Credit: Courtesy of the researchers

Last year, a team of forensic dentists got authorization to perform a 3-D scan of the prized Tyrannosaurus rex skull at the Field Museum of Natural History in Chicago, in an effort to try to explain some strange holes in the jawbone.

Upon discovering that their high-resolution dental scanners couldn’t handle a jaw as big as a tyrannosaur’s, they contacted the Camera Culture group at MIT’s Media Lab, which had recently made headlines with a prototype system for producing high-resolution 3-D scans.

The prototype wasn’t ready for a job that big, however, so Camera Culture researchers used $150 in hardware and some free software to rig up a system that has since produced a 3-D scan of the entire five-foot-long T. rex skull, which a team of researchers — including dentists, anthropologists, veterinarians, and paleontologists — is using to analyze the holes.

The Media Lab researchers report their results in the latest issue of the journal PLOS One.

“A lot of people will be able to start using this,” says Anshuman Das, a research scientist at the Camera Culture group and first author on the paper. “That’s the message I want to send out to people who would generally be cut off from using technology — for example, paleontologists or museums that are on a very tight budget. There are so many other fields that could benefit from this.”

Das is joined on the paper by Ramesh Raskar, a professor of media arts and science at MIT, who directs the Camera Culture group, and by Denise Murmann and Kenneth Cohrn, the forensic dentists who launched the project.

The system uses a Microsoft Kinect, a depth-sensing camera designed for video gaming. The Kinect’s built-in software produces a “point cloud,” a 3-D map of points in a visual scene from which short bursts of infrared light have been reflected back to a sensor. Free software called MeshLab analyzes the point cloud and infers the shape of the surfaces that produced it.

A high-end commercial 3-D scanner costs tens of thousands of dollars and has a depth resolution of about 50 to 100 micrometers. The Kinect’s resolution is only about 500 micrometers, but it costs roughly $100. And 500 micrometers appears to be good enough to shed some light on the question of the mysterious holes in the jaw of the T. rex skull.

Cretaceous conundrum

Discovered in 1990, the Field Museum’s T. rex skeleton, known as Sue, is the largest and most complete yet found. For years, it was widely assumed that the holes in the jaw were teeth marks, probably from an attack by another tyrannosaur. Ridges of growth around the edges of the holes show that Sue survived whatever caused them.

But the spacing between the holes is irregular, which is inconsistent with bite patterns. In 2009, a group of paleontologists from the University of Wisconsin suggested that the holes could have been caused by a protozoal infection, contracted from eating infected prey, that penetrated Sue’s jaw from the inside out.

The 3-D scan produced by the MIT researchers and their collaborators sheds doubt on both these hypotheses. It shows that the angles at which the holes bore through the jaw are inconsistent enough that they almost certainly weren’t caused by a single bite. But it also shows that the holes taper from the outside in, which undermines the hypothesis of a mouth infection.

One of the great advantages of 3-D scans is that they can be shared remotely. The Field Museum limits the time that researchers can spend with Sue’s skull, so the Wisconsin paleontologists’ analysis was largely based on photographs. But photographs don’t permit the comparison of the holes’ diameters at the inner and outer surfaces.

And if researchers working with a scan needed to examine a particular feature in close detail, they could use a 3-D printer to build a replica. To demonstrate this capacity, Das and his colleagues used their scan of Sue’s skull to produce a few models of it, at one-eighth the actual size.

Remote research

Das envisions that Kinect scans could prove as useful in other fields, such as archaeology and anthropology, as they could in paleontology. An archaeologist who unearths a large, fragile, artifact in a remote corner of the world could scan it and immediately share the scan with colleagues around the world.

“It’s that critical size,” Das says. “If it’s something really small, you can use a 3-D scanner. But if you have something stationary that’s difficult to move, you just put on the [Kinect] rig and walk around.”

Indeed, when Das scanned Sue’s skull, he mounted the Kinect in a modified camera harness and wore it on his chest. The space in which he performed the scan was irregularly shaped and presented various immovable obstacles, so it took him some time to find a route that would permit him to maintain a fixed distance from the skull as he walked around. But once he identified the route, the scan itself took about two minutes.

In ongoing work, Das, Murmann, Cohrn, Raskar, and a team of collaborators including the Wisconsin paleontologists, are looking at fragmentation patterns at the edges of the holes and at the holes’ depths and diameters, to see if they can infer anything about the shape, hardness, and velocity of whatever object might have caused them.

Note: The above post is reprinted from materials provided by Massachusetts Institute of Technology. Original written by Larry Hardesty.

360° Bryce Canyon

Bryce Canyon National Park is a National Park located in southwestern Utah in the United States. The major feature of the park is Bryce Canyon, which despite its name, is not a canyon, but a collection of giant natural amphitheaters along the eastern side of the Paunsaugunt Plateau. Bryce is distinctive due to geological structures called hoodoos, formed by frost weathering and stream erosion of the river and lake bed sedimentary rocks. The red, orange, and white colors of the rocks provide spectacular views for park visitors. Bryce sits at a much higher elevation than nearby Zion National Park. The rim at Bryce varies from 8,000 to 9,000 feet (2,400 to 2,700 m).

The Bryce Canyon area was settled by Mormon pioneers in the 1850s and was named after Ebenezer Bryce, who homesteaded in the area in 1874. The area around Bryce Canyon became a National Monument in 1923 and was designated as a National Park in 1928. The park covers 35,835 acres (55.992 sq mi; 14,502 ha; 145.02 km2) and receives substantially fewer visitors than Zion National Park (nearly 4.3 million in 2016) or Grand Canyon National Park (nearly 6 million in 2016), largely due to Bryce’s more remote location. In 2016, Bryce Canyon received 2,365,110 recreational visitors, representing an increase of 35% from the prior year.

How did plesiosaurs swim with such long necks?

Representative Image: Plesiosaur attack, artwork.

When dinosaurs ruled the land, plesiosaurs ruled the oceans. Famous for their incredibly long necks – some of which were up to 7 metres long – plesiosaurs have remained an evolutionary mystery for hundreds of years. Pernille V. Troelsen, a PhD student at Liverpool John Moores University, UK is simulating plesiosaur locomotion with a 3D model to understand how they could swim with such long necks.

“A steady neck would be more hydrodynamic than a bent neck, and due to the pressure on a bent neck, plesiosaurs would probably only bend them when moving at slow speeds or when floating,’ says Ms Troelsen.

She reveals that not only increasing the bend in a plesiosaurs neck would have a big effect on the production of ‘hydrodynamic drag’, but the location of the bending may also play a large role. She adds that plesiosaurs would likely have had a more patient hunting style similar to today’s crocodiles and snakes.

“We have some ideas about why they had long necks and they mainly concern feeding strategies, but we still don’t fully understand how they moved,” explains Ms Troelsen. “These were extremely successful animals that existed for 140 million years, but we don’t have any living equivalents to compare with”.

Several possible theories suggest that plesiosaurs may have developed long necks to extend their feeding range. By laying immobile on the sea floor or floating at the surface and using their protruding necks to hunt, they may have been able to sneak up on their prey more easily, or simply been more effective at snapping up fast-moving prey.

To test the hydrodynamic effects of different neck bending degrees and locations, Ms Troelsen created a digital 3D model based on a simplified plesiosaur body shape and uses computational fluid dynamics to visualise and determine how bending the neck affects the flow of water around the animal.

To improve these 3D models for in future, Ms Troelsen will be looking at fossil evidence for more information about the shape and bendiness of plesiosaur necks: “Further studies will include digitized neck vertebrae from actual plesiosaurs which will allow us to have an even more realistic approach.”

Ms Troelsen believes that these and future results will provide deeper insights into this mysterious group of marine reptiles: “We hope that we can shed some light on the biomechanical implications of having such a long neck and learn more about the lifestyle and evolutionary history of plesiosaurs.”

Note: The above post is reprinted from materials provided by Society for Experimental Biology.

Through fossil leaves, a step towards Jurassic Park

Ginkgo fossil. Credit: Stephen McLoughlin

For the first time, researchers have succeeded in establishing the relationships between 200-million-year-old plants based on chemical fingerprints. Using infrared spectroscopy and statistical analysis of organic molecules in fossil leaves, they are opening up new perspectives on the dinosaur era.

The unique results stem from a collaboration between researchers at Lund University, the Swedish Museum of Natural History in Stockholm, and Vilnius University.

“We have solved many questions regarding these extinct plants’ relationships. These are questions that science has long been seeking answers to,” says Vivi Vajda, a professor at the Department of Geology at Lund University and active at the Swedish Museum of Natural History.

The researchers have collected fossil leaves from rocks in Sweden, Australia, New Zealand and Greenland. Using molecular spectroscopy and chemical analysis, the fossil leaves were then compared with the chemical signatures from molecules in plant leaves picked at the Botanical Garden in Lund.

The use of genetic DNA analysis in modern research to determine relationships is not possible on fossil plants. The oldest DNA fragments ever found are scarcely one million-years-old. Therefore, the scientists searched for organic molecules to see what these could reveal about the plants’ evolution and relationships.

The molecules were found in the waxy membrane, which covers the leaves and these showed to differ between various species. The membrane has been preserved in the fossil leaves, some of which are 200 million-years-old.

Using infrared spectroscopy, the researchers carried out analyses in several stages. Firstly, they examined leaves from living plants that have relatives preserved in the fossil archive. The analysis showed that the biomolecular signatures were similar among plant groups, much in the same way as shown by modern genetic DNA analysis.

When the method was shown to work on modern plants, the researchers went on to analyse their extinct fossil relatives. Among others, they examined fossil leaves from conifers and several species of Ginkgo. The only living species of Ginkgo alive today is Ginkgo biloba, but this genus was far more diverse during the Jurassic.

“The results from the fossil leaves far exceeded our expectations, not only were they full of organic molecules, they also grouped according to well-established botanical relationships, based on DNA analysis of living plants i.e. Ginkgoes in one group, conifers in another,” says Vivi Vajda.

Finally, when the researchers had shown that the method gave consistent results, they analysed fossils of enigmatic extinct plants that have no living relatives to compare them with Among others, they examined Bennettites and Nilssonia, plants that were common in the area that is now Sweden during the Triassic and Jurassic around 250-150 million years ago. The analysis showed that Bennettites and Nilssonia are closely related. On the other hand, they are not closely related to cycads, which many researchers had thought until now.

Per Uvdal, Professor of Chemical Physics at Lund University and one of the researchers who conducted the study, considers that the overall results are astounding.

“The great thing about the biomolecules in the leaves’ waxy membranes is that they are so much more stable than DNA. As they reflect, in an indirect way, a plants DNA they can preserve information about the DNA. Therefore, the biomolecules can tell us how one plant is related in evolutionary terms to other plants,” he says.

The researchers are now going to extend their studies to more plant groups.

Reference:
Vivi Vajda, Milda Pucetaite, Stephen McLoughlin, Anders Engdahl, Jimmy Heimdal, Per Uvdal. Molecular signatures of fossil leaves provide unexpected new evidence for extinct plant relationships. Nature Ecology & Evolution, 2017; DOI: 10.1038/s41559-017-0224-5

Note: The above post is reprinted from materials provided by Lund University.

Scientists discover a new mineral “Nataliyamalikite”

Representative Image

In the harshest of environments in far-east Russia, Monash scientists have played a leading role in the discovery of a new mineral, which could revolutionise the future of the mining industry.

The mineral – Nataliyamalikite – is new, and did not exist before, explains Professor Joël Brugger, the lead author in a recently published paper in American Mineralogist.

It contains thallium, a rare heavy metal most famous for its qualities as a poison.

“The discovery of this new mineral means we will be able to better understand how metals are extracted from deep-seated sources within our planet, and concentrated at shallow levels to form economic ore deposits,” Professor Brugger said.

“This will give us a unique insight into the processes responsible for the geochemical evolution of our planet.

“And this understanding is required to sustain mining – a key to Australia’s ongoing economic prosperity,” Professor Brugger said.

A significant part of the recently published paper is about the formal description and naming of the new mineral (a process overseen by the International Mineralogical Association).

“Our Russian colleague was the first to see the mineral under the electron microscope,” Professor Brugger said.

“However, Monash was key to making the naming of the new mineral possible: we combined state-of-the-art sample preparation at our Monash Centre for Electronic Microscopy facility, along with the unique capabilities of the Australian Synchrotron, to obtain the crystal structure of the mineral.

“Understanding the crystal structure is akin to getting the full genome of the new mineral,” Professor Brugger said.

“And in the case of Nataliyamalikite this was incredibly difficult as the grains are tiny and almost invisible.”

The new mineral was discovered in the Kamchatka Peninsula – one of the most active volcanic zones in the world, featuring 160 volcanoes including 29 that are active.

According to Professor Brugger, who spent six weeks in the region, it is also one of the few remaining wild oases on this planet, a result of politics (off-limit for a long time due to its military significance for the Soviets) as well as geographical isolation (no road connection to mainland Russia) and harsh climate.

Around 150 new minerals are discovered around the world every year, and the recently published article by Professor Brugger marks the official birth of one of them. Read Professor Brugger’s article here.

Note: The above post is reprinted from materials provided by Monash University.

Gigantic crocodile with T. rex teeth was a top land predator of the Jurassic in Madagascar

A paleoartistic restoration of the head of Razanandrongobe sakalavae. Unlike extant crocodilians, this terrestrial predator had a deep skull. Credit: Fabio Manucci\

Little is known about the origin and early evolution of the Notosuchia, hitherto unknown in the Jurassic period. New research on fossils from Madagascar, published in the peer-reviewed journal PeerJ by Italian and French paleontologists, begin to fill the gap in a million-year-long ghost lineage.

Deep and massive jaw bones armed with enormous serrated teeth that are similar in size and shape to those of a T-rex strongly suggest that these animals fed also on hard tissue such as bone and tendon. The full name of the predatory crocodyliform (nicknamed ‘Razana’) is Razanandrongobe sakalavae, which means “giant lizard ancestor from Sakalava region”.

A combination of anatomical features clearly identify this taxon as a Jurassic notosuchian, close to the South American baurusuchids and sebecids, that were highly specialized predators of terrestrial habits, different from present-day crocodilians in having a deep skull and powerful erect limbs. “Like these and other gigantic crocs from the Cretaceous, ‘Razana’ could outcompete even theropod dinosaurs, at the top of the food chain”, says Cristiano Dal Sasso, of the Natural History Museum of Milan.

Razanandrongobe sakalavae is by far the oldest—and possibly the largest—representative of the Notosuchia, documenting one of the earliest events of exacerbated increase in body size along the evolutionary history of the group.

“Its geographic position during the period when Madagascar was separating from other landmasses is strongly suggestive of an endemic lineage. At the same time, it represents a further signal that the Notosuchia originated in southern Gondwana”, remarks co-author Simone Maganuco.

Reference:
Dal Sasso et al. (2017), Razanandrongobe sakalavae, a gigantic mesoeucrocodylian from the Middle Jurassic of Madagascar, is the oldest known notosuchian. PeerJ 5:e3481; DOI: 10.7717/peerj.3481

Note: The above post is reprinted from materials provided by PeerJ.

Dinosaurs’ loss was frogs’ gain

The frog Hyla sanchiangensis from eastern China is a descendant of one of three lineages (Hyloidea) that made it through Earth’s last mass extinction 66 million years ago to flourish worldwide today. It’s ancestors diversified out of South America. Credit: Image courtesy of Peng Zhang, Sun Yat-Sen University

Most of the frogs alive today owe a big thank you to the asteroid or comet that delivered the coup de grace to the dinosaurs.

A new study by Chinese and American biologists shows that if the calamity had not wiped the planet clean of most terrestrial life 66 million years ago, 88 percent of today’s frog species wouldn’t be here. Nearly nine out of 10 species of frog today have descended from just three lineages that survived the mass extinction.

The results, to be published this week in the journal Proceedings of the National Academy of Sciences, are a surprise, because previous studies of frog evolution pinpointed the blossoming of the main frog lineages today to about 35 million years earlier, in the middle of the Mesozoic era.

The new analysis of 95 genes from frogs within 44 of 55 living families shows that these three lineages started to take off precisely at the boundary between the Cretaceous and Paleogene periods — the K-Pg boundary, formerly called the KT boundary — when the last mass extinction occurred, and not 100 million years ago.

According to herpetologist and co-author David Wake, a University of California, Berkeley professor of the graduate school and a curator of the Museum of Vertebrate Zoology, new frog species likely radiated rapidly throughout the world because so many environmental niches were available after the animals occupying them disappeared.

“We think the world was quite impoverished as a result of the KT event, and when the vegetation came back, angiosperms dominated. That’s when trees evolved to their full flowering,” Wake said. “Frogs started becoming arboreal. It was the arboreality that led to the great radiation in South America in particular.”

Trees are an ideal habitat for frogs not only because they allow them to escape from terrestrial predators, but also because their fallen leaves provide protection while the frogs are on the ground, breeding habitat and plenty of food, such as insects. Trees and other flowering plants took off in the late Cretaceous, and were ready for exploitation by frogs after they recovered from the extinction.

Another adaptation that became popular was direct development, that is, producing young without a tadpole stage, which is standard for about half of all frog species today.

“The majority of the frogs that thrive now are thriving because of direct development of eggs in terrestrial situations,” he said. “It is a combination of direct development and use of arboreal habitat that accounts for a great deal of the radiation.”

Previous genetic analyses of frog evolution focused on mitochondrial DNA and how long the molecular clock had been ticking for mitochrondrial genes. However, analysis of molecular evolution in mitochondrial DNA often produces dates for lineage divergence that are too old. In the case of frogs, such analysis pinpointed the radiation of most living frogs at about 100 million years ago, which was a puzzle, since Earth’s environment was stable at that time. A changing environment typically drives evolution.

The new analysis, based on data assembled primarily by graduate student Yan-Jie Feng at Sun Yat-Sen University in Guangzhou, China, focused on the sequences of 95 genes located on chromosomes in the nucleus and how they changed over time. He and his colleagues gathered genetic data from 156 frog species and combined this with earlier information about two genes from 145 different frogs, for a total of 301 distinct frog species from all 55 families of frogs. The data were calibrated using 20 dates derived from fossils and Earth historical events.

The team, which includes scientists from the Florida Museum of Natural History at the University of Florida and the University of Texas, Austin, concluded that perhaps 10 groups of frogs survived the extinction, but only three of them (Hyloidea, Microhylidae, and Natatanura) flourished and diversified to claim habitats and niches around the world.

Nothing other than luck distinguishes the survivors, Wake said. Remnants of the other surviving lineages are scattered in isolated spots around the world, but are just as diverse today in their habitats and breeding strategies as the 88 percent.

Two of the three surviving lineages that subsequently radiated widely came out of Africa, which remained intact as the continents shifted around over the ensuing eons, with the breakup of Pangea and then Gondwana to form the continents we see today. The African rift zone and mountain building in West Africa generated new habitats for the evolving frogs, Wake noted. The third, Hyloidea, radiated throughout what became South America.

Today’s frogs, comprising more than 6,700 known species, as well as many other animal and plant species are under severe stress around the world because of habitat destruction, human population explosion and climate change, possibly heralding a new period of mass extinction. The new study provides one clear message for future generations.

“These frogs made it through on luck, perhaps because they were either underground or could stay underground for long periods of time,” Wake said. “This certainly draws renewed attention to the positive aspects of mass extinctions: They provide ecological opportunity for new things. Just wait for the next grand extinction and life will take off again. In which direction it will take off, you don’t know.”

Reference:
Yan-Jie Feng et al. Phylogenomics reveals rapid, simultaneous diversification of three major clades of Gondwanan frogs at the Cretaceous–Paleogene boundary. PNAS, 2017 DOI: 10.1073/pnas.1704632114

Note: The above post is reprinted from materials provided by University of California – Berkeley. Original written by Robert Sanders.

Why does a Yellowstone microorganism prefer meager rations over rich ones?

Credit: Arizona State University

Arizona State University geoscientist Everett Shock has collaborated with a team of life scientists from Montana State University to discover a puzzle at the junction of geochemistry and biology.

The puzzle, which has no solution yet, is: Why would a microorganism thriving in a hot spring draw its energy from low-quality sources instead of rich ones?

Shock, who is a professor in geochemistry in ASU’s School of Earth and Space Exploration and the School of Molecular Sciences, has long studied questions of habitability as they apply to life on Earth, and to the potential for life on other planets.

“The team isolated this organism, which is a member of the Acidianus genus, from a hot spring in Yellowstone National Park and cultured it in the laboratory,” he said. “There it was given a choice of three different geochemical energy supplies.”

This microbe, Shock said, can get energy from combining hydrogen with sulfur, or hydrogen with iron, or sulfur with iron. In the experiments the team carried out, hydrogen and sulfur supplied the least energy, while hydrogen and iron provided the most.

“Surprisingly, the organism grew best on the lowest energy supply—and it grew the worst with the richest energy material,” Shock said.

The scientists’ report was published July 3 in Nature Geoscience. The lead author is Maximiliano Amenabar of Montana State University; besides Shock, the other authors are Eric Roden (University of Wisconsin), and John Peters and Eric Boyd (both Montana State).

Rich diet: Genetically costly?

“The results were quite counterintuitive,” said Shock. “It’s only natural to expect that in any environment, the ‘big deal’ energy sources will be supporting the most organisms, and the feeble sources—well, you wonder if they are supporting anything at all.”

It turns out, he explained, that in a genetic sense, it may be costly for the organism to go after the big-energy supply.

“It’s like mining,” he said. “You can have a rich ore deposit, but if extracting it costs more than you can get for it, it’s not worth pursuing.”

And in microorganism terms, Shock said, “biological cost may come down to availability. Perhaps the low-energy source is more reliable in nature than the high-energy one.”

Shock suggested that reliability could “tune” the microorganism’s metabolism to the energy source that’s always available.

But apparently not exclusively, he added. “The organism is also capable of using these other energy sources. However, maybe using them takes more work, so the organism grows more slowly with them.”

The focus of future research on this organism will be to assess in detail the energetic costs. Its recently completed genome will aid the research..

Shock concluded, “We don’t know for sure why this organism thrives best on low-energy food sources—but now the task becomes finding that out.”

Reference:
Maximiliano J. Amenabar et al. Microbial substrate preference dictated by energy demand rather than supply, Nature Geoscience (2017). DOI: 10.1038/ngeo2978

Note: The above post is reprinted from materials provided by Arizona State University.

Dinosaur find in outback Queensland

Savannasaurus is part of the sauropod family. Credit: Travis R. Tischler and Australian Age of Dinosaurs Museum of Natural History

The remains of what might be the most complete sauropod dinosaur ever found in Australia have been uncovered by a team including a Swinburne palaeontologist.

The team has discovered four teeth, at least 10 interconnected neck vertebrae, and several vertebrae, shoulder and limb bones, all from one animal.

The dig was co-supervised by Dr Stephen Poropat, a postdoctoral fellow in palaeontology at Swinburne.

The discovery was made on a property north-east of the small Queensland town of Winton. In 2015, grazier Bob Elliott found fragments of dinosaur bone in one of his paddocks. It was not until the site was excavated, however, that the significance of the find was realised.

“This just might be the most complete sauropod ever found in Australia,” says Dr Poropat.

“We probably have more than 25 per cent of the skeleton, which is phenomenal.”

Sauropod dinosaurs were the largest animals ever to have lived on land, with some exceeding 30 metres in length, and others achieving heights of 13 metres.

Two weeks of digging at the site revealed the bones of the sauropod dinosaur, now nicknamed ‘Judy’ after Mr Elliott’s mother, Judy Elliott. She and her husband Dvid Elliott founded the Australian Age of Dinosaurs Museum in Winton in 2002, and she has coordinated the digs for more than a decade.

The fact that so many bones of “Judy” are preserved has led Dr Poropat to believe that this specimen will give scientists a better understanding of Australia’s Cretaceous sauropods.

“We will be able to understand many aspects of this sauropod’s anatomy, simply because we have so much of its skeleton.

“By studying its teeth and neck in particular, we might be able to shed light on how it fed. Better yet, we might just have direct evidence of this too, since a section of the site between the chest and the hips preserves what might be gut contents.”

If the team can prove that the stomach contents were preserved, they will be the first found in a sauropod dinosaur.

Dr Poropat says the findings may lead to even more questions.

“We still have a lot to learn about many aspects of sauropod behaviour, physiology, and – in the case of Australia’s sauropods in particular – skeletal anatomy.

“This new specimen will probably prompt more questions than it answers, but it will still provide us with a unique snapshot of the life – and death – of at least one sauropod individual that roamed Australia 95 million years ago.”

What do these findings tell us?

  • The teeth and neck of this sauropod might shed light on how it fed.
  • The possible gut contents found at the site might reveal exactly what this dinosaur ate.
  • This dinosaur, which was about 12 metres long, was not fully mature when it died: neither of the shoulder girdles was fused, as is common in older animals.

The team will return to the site in August 2017 to continue the dig and uncover more bones.

Note: The above post is reprinted from materials provided by Swinburne University of Technology.

3-D scanning fossils to help researchers around the world study mastodons

The Virtual Curation Laboratory 3-D scanned this mastodon jaw fragment with an abscess, which was excavated near Yorktown, Virginia. Credit: Brian McNeill, University Public Affairs

Boxes upon boxes filled with the fossilized remains of a mastodon that died in Virginia more than 18,000 years ago are being hauled up the steps to Virginia Commonwealth University’s Virtual Curation Laboratory, where the massive Ice Age animal’s fossils—including the tip of a tusk, a very worn tooth, toe bones, a rib bone and a mandible—are slated to be 3-D scanned.

“Mastodon,” said Bernard Means, Ph.D., director of the lab, which specializes in 3-D scanning and printing of historic and archaeological objects. “It’s what’s for breakfast.”

The fossils, dating to 16,260 B.C., were excavated from a site near Yorktown between July 2015 and last November and are the most significant mastodon remains to be found east of the Blue Ridge Mountains.

The mastodon’s tooth was first discovered in 1983 by a bricklayer named Lawnell Hart, who then enlisted the help of College of William and Mary geology professor Jerre Johnson, Ph.D. Hart and Johnson visited the site again and found additional fossils, but the property owners would not grant them permission to conduct a proper excavation.

“After we discovered the remains, we did a stratigraphic study, looking at what’s the sequence of sediments and so forth … but the owner would not let us dig it up,” said Johnson, as he dropped off a sampling of fossils at VCU. “And, as a result, 38 years went by. In my cabinet, I kept that stupid fragment of the jaw and this tooth that was cavity ridden.”

Hart died in 2011, but Johnson, now a professor emeritus of geology at William and Mary, kept hoping that one day he could return to the site and recover the fossils. In 2015, the site’s new property owners granted him permission, and Johnson, along with a team of volunteers, excavated a staggering quantity of the mastodon’s remains, which suggest that the animal was hunted and butchered by pre-Clovis American Indians during the last Ice Age.

“It’s gratifying,” Johnson said. “It’s really neat that we have enough parts to basically reconstruct what we think the animal had when it was alive—arthritis and an impacted tooth. We probably know its predator. These are really neat discoveries.”

Johnson loaned the fossils to the Virtual Curation Laboratory, which is part of the School of World Studies in the College of Humanities and Sciences, so the specimens could be 3-D scanned and shared with researchers around the world.

“The forefront of research in both archaeology and paleontology is to do detailed metrical analyses of items and also to make comparisons,” Means said. “So by 3-D scanning these objects, you can make very accurate measurements and easily compare them to other specimens around the world. It allows you to make virtual comparisons, so you can avoid the trouble of trying to bring everybody together. That’s been a tremendous boon.”

This week, Means and his students 3-D scanned several of the mastodon fossils excavated by Johnson, including the tip of the tusk and the jaw fragment with an abscess.

Yet those are just some of the mastodon remains that the Virtual Curation Laboratory has scanned lately. In fact, the 3-D scanning of Ice Age animal remains, and mastodons in particular, has become one of the lab’s two major areas of focus, with the other being 3-D-scanning artifacts associated with enslaved people.

Earlier this month, Means visited the Museum of the Middle Appalachians and a paleontology dig in Saltville, Virginia, as part of the 100th anniversary of the first research dig conducted at the site in 1917 by the Carnegie Museum of Natural History, of Pittsburgh. Means was invited to scan a variety of Ice Age animal fossils found at Saltville, as well as other artifacts.

“I’m currently 3-D printing a baby mastodon tusk that I scanned [from the 1917 excavations],” Means said. “It’s in two pieces. It’s really cute. I also scanned part of a mastodon tusk that was misidentified in 1917 as a crocodile tooth.”

Last year, Means took a trip to the Western Science Center in Hemet, California, to 3-D scan the museum’s collection of mastodon fossils, including parts of “Max,” the museum’s prized 13,500-year-old specimen.

Means also scanned a plushy toy of “Max,” which he has lately been 3-D printing as a miniature mastodon riding on a surfboard. “He’s a California mastodon,” Means said.

Also last summer, Means visited the National Constitution Center in Philadelphia to 3-D scan archeological artifacts dating to the 18th century in Philadelphia, and Means’ lab’s 3-D-printed replicas were included in an exhibition in January. “I had actually scanned a mastodon’s remains as part of the Philadelphia project,” Means said. “They have a mastodon tooth that belonged to Ben Franklin. Somebody told me about it, and I was like, ‘Can I scan that?'”

During the first week in August, Means will return to the Western Science Center to take part in an exhibit and conference titled “Valley of the Mastodons,” which will feature researchers from across the country who will study the museum’s dozens of mastodons.

The Virtual Curation Laboratory began focusing on Ice Age animal remains, including mastodons, in partnership with the Virginia Museum of Natural History, at which Means is a research associate.

“I started also scanning other Ice Age stuff that they have, partly just because I thought it was kind of cool,” Means said. He went on to 3-D scan the museum’s mastodon casts and real fossils, which were excavated at Saltville and a site in Darke County, Ohio.

More recently, Means has been 3-D scanning fossils of a giant ground sloth in the museum’s collection, as part of a project to re-create its skeleton. Certain bones on the right and left are missing, however, and Means has been 3-D scanning the other side’s bones, thereby allowing him to make a mirror image model. With the 3-D-printed replica, the museum can make a cast of the needed bone—a process much faster and less labor intensive than sculpting the missing part from scratch.

Part of the idea, Means said, is that 3-D scanning and printing of mastodon fossil replicas can be a great way to teach and get people excited about paleontology.

“Everybody who’s involved with this Ice Age research, they’re all very interested in education and especially STEM education, so they really want 3-D printed replicas [of the fossils],” he said. “One of the items I scanned [last week] in Saltville is something they use when they go to school groups and they’re a little nervous about bringing it with them. It’s a mastodon rib that shows major damage and then healing. Those are kind of unusual, so it’s better to take a replica rather than the original.”

The focus on mastodons, Means said, is partly because it’s simply a fascinating Ice Age animal.

“They were only present in North America,” he said. “They weren’t present anywhere else in the world. They ate vegetation but their teeth are very different than elephants and mammoths. Other elephants have sort of ridged teeth, while mastodons had these blocky poked teeth. In fact, there was a debate during the Colonial period about whether they might have been carnivorous.”

A number of VCU students are also working with mastodons this year. Isabel Griffin, a junior in the School of the Arts, is doing an Undergraduate Research Opportunities Program fellowship with Means this summer that involves using 3-D digital models of objects, such as mastodon fossils, to create illustrations.

“Basically, I’m exploring how 3-D technology can be used in archaeological illustration,” she said. “I intend to make a guide that parallels Brian Dillon’s ‘The Student’s Guide to Archaeological Illustrating’ that explains how 3-D technology can simplify the processes in each of the contexts outlined in the book.”

Kristen Egan, a senior anthropology major who interned in the lab in the spring, was one of several VCU students who presented their research into mastodons and Ice Age animals at this spring’s Undergraduate Research Opportunities Program poster symposium. Egan’s poster, “The Founding Fathers Search for Megafauna,” describes how Thomas Jefferson and other founding fathers were greatly interested in giant Ice Age animals such as the mastodon.

“The founding fathers took the discovery of megafauna in America as a symbol for this country, which told the rest of the world that America is bigger and more powerful than Europe and can sustain more than just large insects,” she wrote. “The megafauna helped to shape America’s ideology of power, strength, and separation from Europe.”

At the symposium, Egan brought along a 3-D-printed replica of a mastodon tooth that she painted in Mean’s lab.

“People were really drawn to it,” she said. “Having a 3-D-printed mastodon tooth, it really brought everything to another level where people can really relate to [the research]. You become a little bit more passionate and interested when you can hold something in your hand.”

Note: The above post is reprinted from materials provided by Virginia Commonwealth University.

Can satellites be used as an early warning system for landslides?

Credit: Newcastle University

Researchers are working hard to use satellite data to accurately map the movement of the earth before a landslide in a bid to develop a life-saving early warning system.

The team from Newcastle University (UK), Chengdu University of Technology, Tongji University, China Academy of Space Technology and Wuhan University (China) have been tracking the devastating events of last week when a massive landslide struck Xinmo Village, Maoxian County, Sichuan Province in China.

Triggered by heavy rain, the Maoxian landslide swept away homes in Xinmo village, blocking a 2km section of river and burying 1,600 meters of road. The collapsed rubble was estimated to be about eight million cubic meters.

Three days later, a second landslide hit Xinmo Village and almost at the same time, a third landslide occurred in Shidaguan Town, 20km away from Xinmo Village.

Using ESA’s Sentinel-1 satellite radar mission – which comprises a constellation of two polar-orbiting satellites, operating day and night in all-weather conditions – the research team were able to capture before and after images of the landslides.

This provides vital information about the extent of the disaster which can be used to assess the damage and future risk in the area.

Detecting and mapping active landslides

Professor Zhenhong Li, Professor of Imaging Geodesy at Newcastle University, explains:

“It is still hard, if not impossible, to detect a landslide using traditional techniques, especially in mountain areas. Using the satellite radar data, we were able to efficiently detect and map the active landslide over a wide region, identifying the source of the landslide and also its boundaries.

“Going forward, we can use this information to set up real-time monitoring systems – such as GPS, Beidou and Galileo – for those sites and whenever we detect abnormal behaviour, the system can send out an early warning message.

“In fact, while we were monitoring the Maoxian landslides we managed to identify over 10 other active landslides in the same region and forwarded this information to the relevant agencies.”

Living with the constant threat of a landslide

Sichuan province is prone to earthquakes, including the devastating Great Wenchuan Earthquake of 2008 when a 7.9 magnitude quake hit the area, killing over 70,000 people.

Professor Li says their data suggests the Maoxian (Shidaguan) landslide had been sliding for at least six months before it failed.

“When you consider this sort of timescale it suggests that a landslide Early Warning System is not only possible but would also be extremely effective,” says Professor Li.

“If we can detect movement at a very early stage then in many cases it is likely we would have time put systems in place to save lives.”

Professor Li and the team have been working on active faults and landslides in Southwest China for over ten years and have identified several active landslides in the area south to Maoxian County but this is the first time they have studied the Maoxian region.

Ultimately, the team hope to use the technology to detect and map active landslides in the whole region of SW China, and then build a landslide database.

Note: The above post is reprinted from materials provided by Newcastle University.

Flysch Rock Formation, Zumaia Spain

Flysch is a sequence of sedimentary rocks that is deposited in a deep marine facies in the foreland basin of a developing orogen. Flysch is typically deposited during an early stage of the orogenesis. When the orogen evolves, the foreland basin becomes shallower and molasse is deposited on top of the flysch. It is therefore called a syn-orogenic sediment (deposited contemporaneously with mountain building).

Flysch Formation

Flysch is a sequence of sedimentary rocks that is deposited in a deep marine facies in the foreland basin of a developing orogen. Flysch is typically deposited during an early stage of the orogenesis. When the orogen evolves, the foreland basin becomes shallower and molasse is deposited on top of the flysch. It is therefore called a syn-orogenic sediment (deposited contemporaneously with mountain building).

The name flysch was introduced in geologic literature by the Swiss geologist Bernhard Studer in 1827. Studer used the term for the typical alternations of sandstone and shale in the foreland of the Alps. The name comes from the German word fliessen, which means to flow, because Studer thought flysch was deposited by rivers. The insight that flysch is actually a deep marine sediment typical for a particular plate tectonic setting came only much later.

Sedimentological properties

Flysch consists of repeated sedimentary cycles with upwards fining of the sediments. At the bottom of each cycle are sometimes coarse conglomerates or breccias, which gradually evolve upwards into sandstone and shale/mudstone. Flysch typically consists of a sequence of shales rhythmically interbedded with thin, hard, graywacke-like sandstones. Typically the shales do not contain many fossils, the coarser sandstones often have fractions of micas and glauconite.

Flysch is formed under deep marine circumstances, in a quiet and low-energetic depositional environment. The coarser layers (which require higher energy) are disruptions in these circumstances, caused by pulsewise flows of mass transport from the forming orogenic wedge. In many cases the mass transports are represented in the record by turbidites.

Tectonics

Flysch deposits form at convergent plate boundaries at the stage of continental collision, often in remnant ocean basins that are present along the same boundary. The sedimentary material in the flysch is derived from the forming mountains and deposited along the axis of the new mountain chain into remnant ocean basin. The same ocean basin is in the process of subducting under the orogenic wedge. As subduction continues, the flysch sediments are scraped off the down-going oceanic plate and are accreted onto the orogenic wedge. As a result, flysch deposits are often highly deformed by thrust faulting and folding.

 

Ancient South Carolina whale yields secrets to filter feeding’s origins

This photograph shows Coronodon havensteini teeth. Credit: Geisler et al.

The blue whale is the largest animal that has ever lived. And yet they feed almost exclusively on tiny crustaceans known as krill. The secret is in the baleen, a complex filter-feeding system that allows the enormous whales to strain huge volumes of saltwater, leaving only krill and other small organisms behind. Now, researchers who have described an extinct relative of baleen whales in Current Biology on June 29 offer new insight into how baleen first evolved.

The findings shed light on a long-standing debate about whether the first baleen whales were toothless suction feeders or toothed whales that used their teeth like a sieve to filter prey out of water, the researchers say. The teeth of the newly discovered species of mysticete, called Coronodon havensteini, lend support to the latter view.

“We know from the fossil record that the ancestors of baleen whales had teeth,” says Jonathan Geisler of the New York Institute of Technology College of Osteopathic Medicine. “However, the transition from teeth to baleen is controversial. Our study indicates that early toothed whales used spaces between their large complex teeth for filtering and that baleen gradually replaced teeth over millions of years.”

The new whale species was found in the early 2000s by a scuba diver in South Carolina’s Wando River. He was looking for shark teeth and found the fossilized whale instead. The whale, which lived some 30 million years ago, was later recognized as a representative of a new transitional species.

“The skull of this species indicates that it split off very early in mysticete whale evolution, and our analyses confirm that evolutionary position,” Geisler says.

Geisler and his colleagues realized that meant the whale could offer important clues about the teeth to baleen transition. The whale under study also had other interesting features. It was larger than other toothed mysticetes, with a skull nearly one meter long. Its large molars in comparison to other whales further suggested an unusual feeding behavior.

Closer examination of the shape and wear on the whale’s teeth led the researchers to conclude that the whale used its front teeth to snag prey. But the whale’s large, back molars were used in filter feeding, by expelling water through open slots between the closed teeth.

“The wear on the molars of this specimen indicates they were not used for shearing food or for biting off chunks of prey,” he says. “It took us quite some time to come to the realization that these large teeth were framing narrow slots for filter feeding.”

As confirmation, the researchers found wear on the hidden cusps bordering those slots between the teeth.

The findings offer another example of a broader evolutionary pattern in which body parts (in this case teeth) that evolved for one function are later co-opted for another function. The researchers say they are now examining closely related species from the Charleston, SC, area in search of additional evidence.

Reference:
Jonathan H. Geisler, Robert W. Boessenecker, Mace Brown, Brian L. Beatty. The Origin of Filter Feeding in Whales. Current Biology, 2017; DOI: 10.1016/j.cub.2017.06.003

Note: The above post is reprinted from materials provided by Cell Press.

Size not important for fish in the largest mass extinction of all time

Fishes in Triassic seas of China 8 million years after the extinction crisis. Painting ‘Lobster lunch of Luoping’. Credit: Brian Choo

Understanding modern biodiversity and extinction threats is important. It is commonly assumed that being large contributes to vulnerability during extinction crises.

However, researchers from the University of Bristol and the Chengdu Center of the China Geological Survey, have found that size played no role in the extinction of fish during the largest mass extinction of all time.

The study focused on the evolution of bony fishes during the Permian-Triassic mass extinction 252 million years ago. During this crisis, as many as 90 percent of all species on Earth were killed by massive climate change triggered by huge volcanic eruptions in Russia.

The erupted gases led to worldwide acid rain and atmospheric warming of as much as 20 degrees centigrade. This killed plants, and soil was stripped by rainfall and washed into the sea. Oceans were also heated and life fled from the tropics.

It was expected that a key feature in extinction would have been body size: the large animals would suffer heat and starvation stress first. However, in the new paper, published today in Palaeontology, it is shown that larger fish were no more likely to go extinct than small fish.

The study used a detailed summary of all information on fossil fish through a span of over 100 million years, from well before to well after the disaster. Body size information was identified for over 750 of these fishes, and multiple calculations were carried out to allow for variations in the shape of the evolutionary tree and the exact dating of all the species. The result was clear – body size did not provide any advantages or disadvantages to fish during the crisis.

Lead researcher Dr Mark Puttick from the Natural History Museum and University of Bristol’s School of Earth Sciences, explained: “These results continue the trend of recent studies that suggest body size played no role in determining which species survive or go extinct. This is the opposite result we would expect, but provides increasing support for previous studies that show body size plays no role in extinction selectivity.”

The team explored the largest dataset used in an analysis of this type and applied a range of computational evolutionary models to understand these patterns in deep time. The models take account of uncertainties in the quality of the fossil data and the reconstructed evolutionary tree, and the result was clear.

Professor Michael Benton, also from the University of Bristol, added: “These are exciting results. What is important also is that we were able to deploy new methods in the study that take greater account of uncertainties.

“The methods are based around a detailed evolutionary tree so, unlike most previous work in the field, we paid attention to the relationships of all the species under consideration.”

Professor Shixue Hu, leader of the China Geological Survey: “It’s great to see this new analytical work. We were able to include many new fossils from our exceptional biotas in China, and we can see the full impact of the extinction and the subsequent recovery of life during the Triassic.”

Reference:
Mark N. Puttick et al. Body length of bony fishes was not a selective factor during the biggest mass extinction of all time, Palaeontology (2017). DOI: 10.1111/pala.12309

Note: The above post is reprinted from materials provided by University of Bristol.

Rare, exceptionally preserved fossil reveals lifestyle of ancient armor-plated reptile

A life reconstruction of Eusaurosphargis dalsassoi based on new specimen PIMUZ A/III 4380. Credit: Beat Scheffold; Palaeontological Institute and Museum, University of Zurich, Switzerland

An exceptionally-preserved fossil from the Alps in eastern Switzerland has revealed the best look so far at an armoured reptile from the Middle Triassic named Eusaurosphargis dalsassoi. The fossil is extremely rare in that it contains the animal’s complete skeleton, giving an Anglo-Swiss research team a very clear idea of its detailed anatomy and probable lifestyle for the first time, according to a paper published in Scientific Reports today.

At just 20 cm long, the specimen represents the remains of a juvenile. Yet large portions of its body were covered in armour plates, with a distinctively spiky row around each flank, protecting the animal from predators. Today’s girdled lizards, found in Africa, have independently evolved a very similar appearance even though they are not closely related to Eusaurosphargis.

The new fossil, found in the Prosanto Formation at Ducanfurgga, south of Davos in Switzerland, is not the first material of Eusaurosphargis to be discovered. The species was originally described in 2003 based on a partially complete and totally disarticulated specimen from Italy. This was found alongside fossils of fishes and marine reptiles, leading scientists to believe that Eusaurosphargis was an aquatic animal.

However, the detail preserved in the new specimen shows a skeleton without a streamlined body outline and no modification of the arms, legs or tail for swimming. This suggests that the reptile was in fact most probably adapted to live, at least mostly, on land, even though all of its closest evolutionary relatives lived in the water.

“Until this new discovery we thought that Eusaurosphargis was aquatic, so we were astonished to discover that the skeleton actually shows adaptations to life on the land,” says Dr James Neenan, research fellow at Oxford University Museum of Natural History and co-author of the new paper about Eusaurosphargis dalsassoi. “We think this particular animal must have washed into the sea from somewhere like a beach, where it sank to the sea floor, was buried and finally fossilised.”

The findings from the research team are published in Scientific Reports as ‘A new, exceptionally preserved juvenile specimen of Eusaurosphargis dalsassoi (Diapsida) and implications for Mesozoic marine diapsid phylogeny’.

Reference:
‘A new, exceptionally preserved juvenile specimen of Eusaurosphargis dalsassoi (Diapsida) and implications for Mesozoic marine diapsid phylogeny’ Scientific Reports (2017). DOI: 10.1038/s41598-017-04514-x

Note: The above post is reprinted from materials provided by University of Oxford.

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