WFS News: Earth’s deepest forearc basin discovered

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Geologists have for the first time seen and documented the Banda Detachment fault in eastern Indonesia and worked out how it formed.

Lead researcher Dr Jonathan Pownall from The Australian National University (ANU) said the find will help researchers assess dangers of future tsunamis in the area, which is part of the Ring of Fire — an area around the Pacific Ocean basin known for earthquakes and volcanic eruptions.

“The abyss has been known for 90 years but until now no one has been able to explain how it got so deep,” Dr Pownall said.

“Our research found that a 7 km-deep abyss beneath the Banda Sea off eastern Indonesia was formed by extension along what might be Earth’s largest-identified exposed fault plane.”

Geologists have for the first time seen and documented the Banda Detachment fault in eastern Indonesia and worked out how it formed. Credit: Image courtesy of Australian National UniversityClose

Geologists have for the first time seen and documented the Banda Detachment fault in eastern Indonesia and worked out how it formed.Credit: Image courtesy of Australian National University

By analysing high-resolution maps of the Banda Sea floor, geologists from ANU and Royal Holloway University of London found the rocks flooring the seas are cut by hundreds of straight parallel scars.

These wounds show that a piece of crust bigger than Belgium or Tasmania must have been ripped apart by 120 km of extension along a low-angle crack, or detachment fault, to form the present-day ocean-floor depression.

Dr Pownall said this fault, the Banda Detachment, represents a rip in the ocean floor exposed over 60,000 square kilometres.

“The discovery will help explain how one of Earth’s deepest sea areas became so deep,” he said.

Professor Gordon Lister also from the ANU Research School of Earth Sciences said this was the first time the fault has been seen and documented by researchers.

“We had made a good argument for the existence of this fault we named the Banda Detachment based on the bathymetry data and on knowledge of the regional geology,” said Professor Lister.

Dr Pownall said he was on a boat journey in eastern Indonesia in July when he noticed the prominent landforms consistent with surface extensions of the fault line.

“I was stunned to see the hypothesised fault plane, this time not on a computer screen, but poking above the waves,” said Dr Pownall.

He said rocks immediately below the fault include those brought up from the mantle.

“This demonstrates the extreme amount of extension that must have taken place as the oceanic crust was thinned, in some places to zero,” he said.

Dr Pownall also said the discovery of the Banda Detachment fault would help assesses dangers of future tsunamis and earthquakes.

“In a region of extreme tsunami risk, knowledge of major faults such as the Banda Detachment, which could make big earthquakes when they slip, is fundamental to being able to properly assess tectonic hazards,” he said.

Citation:Australian National University. “Biggest exposed fault on Earth discovered.” ScienceDaily. ScienceDaily, 28 November 2016. <www.sciencedaily.com/releases/2016/11/161128132928.htm>

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WFS News: X-raying the Earth with waves from stormy weather bomb

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Using a detection network based in Japan, scientists have uncovered a rare type of deep-earth tremor that they attribute to a distant North Atlantic storm called a “weather bomb.”

The discovery marks the first time scientists have observed this particular tremor, known as an S wave microseism. And, as Peter Gerstoft and Peter D. Bromirski write in a related Perspective, their observation “gives seismologists a new tool with which to study Earth’s deeper structure,” one that will contribute to a clearer picture of Earth’s movements, even those originating from the atmosphere-ocean system.

Faint tremors called microseisms are phenomena caused by the sloshing of the ocean’s waves on the solid Earth floor during storms. Detectable anywhere in the world, microseisms can be various waveforms that move through the Earth’s surface and interior, respectively.

An Atlantic "weather bomb," or a severe, fast-developing storm, causes ocean swells that incite faint and deep tremors into the oceanic crust. These subtle waves run through the earth and can be detected in places as far away as Japan, where facilities using a method called "Hi-net" measure the amplitude of the storm's P and S waves for the first time. Credit: Kiwamu Nishida and Ryota Takagi

An Atlantic “weather bomb,” or a severe, fast-developing storm, causes ocean swells that incite faint and deep tremors into the oceanic crust. These subtle waves run through the earth and can be detected in places as far away as Japan, where facilities using a method called “Hi-net” measure the amplitude of the storm’s P and S waves for the first time.Credit: Kiwamu Nishida and Ryota Takagi

So far, however, scientists analyzing microseismic activity in the Earth have only been able to chart P waves (those that animals can feel before an earthquake), and not their more elusive S wave counterpart (those that humans feel during earthquakes).

Here, using 202 Hi-net stations operated by the National Research Institute for Earth Science and Disaster Prevention in Japan’s Chugoku district, Kiwamu Nishida and Ryota Takagi successfully detected not only P wave microseisms triggered by a severe and distant North Atlantic storm, known as a weather bomb, but also S wave microseisms, too.

What’s more, the authors determined both the direction and distance to these waves’ origins, providing insight into their paths as well as the earthly structures through which they traveled. In this way, the seismic energy travelling from this weather bomb storm through the Earth illuminated many dark patches of its interior. Nishida and Takagi’s findings not only offer a new means by which to explore the Earth’s internal structure, but they may also contribute to more accurate detection of earthquakes and oceanic storms.

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Ref: K. Nishida, R. Takagi. Teleseismic S wave microseisms. Science, 2016; 353 (6302): 919 DOI: 10.1126/science.aaf7573

Citaion:American Association for the Advancement of Science. “X-raying the Earth with waves from stormy weather ‘bombs’.” ScienceDaily. ScienceDaily, 25 August 2016. <www.sciencedaily.com/releases/2016/08/160825151609.htm>.

WFS News: Keratin and melanosomes preserved in 130-million-year-old bird fossil Eoconfuciusornis

New research from North Carolina State University, the Chinese Academy of Sciences and Linyi University has found evidence of original keratin and melanosome preservation in a 130-million-year-old Eoconfuciusornis specimen. The work extends the timeframe in which original molecules may preserve, and demonstrates the ability to distinguish between ancient microstructures in fossils.

Eoconfuciusornis, crow-sized primitive birds that lived in what is now China around 130 million years ago, are the earliest birds to have a keratinous beak and no teeth, like modern birds. Previous studies argued that the feathers of these and other ancient birds and dinosaurs preserved small, round structures interpreted to be melanosomes — pigment-containing organelles that, along with other pigments, give feathers their color. However, without additional evidence, it was not possible to prove that these structures weren’t just microbes that had coated the feather during decomposition and fossilization.

Eoconfuciusornis. Credit: Dr. Xiaoli Wang

   Eoconfuciusornis.   Credit: Dr. Xiaoli Wang

Yanhong Pan, associate research fellow at the Chinese Academy of Sciences and corresponding author of a paper describing the research and co-author Mary Schweitzer, NC State professor of biology with a joint appointment at the North Carolina Museum of Natural Sciences, examined feathers from an Eoconfuciusornisspecimen taken from the Jehol Biota site in northern China, which is renowned for excellent fossil preservation.

“If these small bodies are melanosomes, they should be embedded in a keratinous matrix, since feathers contain beta-keratin,” Schweitzer says. “If we couldn’t find the keratin, then those structures could as easily be microbes, or a mix of microbes and melanosomes — in either case, predictions of dinosaur shading would not be accurate.”

Pan, Schweitzer and their team used both scanning and transmission electron microscopy to get microscopic details of the feather’s surface and its internal structure. They also utilized immunogold labeling — in which gold particles are attached to antibodies that bind to particular proteins in order to make them visible in electron microscopy — to show that filaments within the feathers were keratin.

Finally, they mapped copper and sulfur to these feathers at high resolution. Sulfur was broadly distributed, reflecting its presence in both keratin and melanin molecules in modern feathers. However copper, which is only found in modern melanosomes, and not part of keratin, was only observed in the fossil melanosomes. These findings both support the identity of the melanosomes and indicate that there was no mixing or leaching during decomposition and fossilization.

“This study is the first to demonstrate evidence for both keratin and melanosomes, using structural, chemical and molecular methods,” says Pan. “These methods have the potential to help us understand — on the molecular level — how and why feathers evolved in these lineages.”

Citation:North Carolina State University. “Keratin and melanosomes preserved in 130-million-year-old bird fossil.” ScienceDaily. ScienceDaily, 21 November 2016.

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WFS News: Asteroid impacts could create niches for early life

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Scientists studying the Chicxulub crater have shown how large asteroid impacts deform rocks in a way that may produce habitats for early life.

Around 65 million years ago a massive asteroid crashed into the Gulf of Mexico causing an impact so huge that the blast and subsequent knock-on effects wiped out around 75 per cent of all life on Earth, including most of the dinosaurs. This is known as the Chicxulub impact.

Split drill cores collected from the peak ring of Chicxulub crater. The left two cores consist of basement granite. The right two cores are impact melt rocks that were created by the heat associated with the impact. Credit: E. Le Ber

Split drill cores collected from the peak ring of Chicxulub crater. The left two cores consist of basement granite. The right two cores are impact melt rocks that were created by the heat associated with the impact.Credit: E. Le Ber

In April and May 2016, an international team of scientists undertook an offshore expedition and drilled into part of the Chicxulub impact crater. Their mission was to retrieve samples from the rocky inner ridges of the crater — known as the ‘peak ring’ — drilling 506 to 1335 metres below the modern day sea floor to understand more about the ancient cataclysmic event.

Now, the researchers have carried out the first analysis of the core samples. They found that the impact millions of years ago deformed the peak ring rocks in such a way that it made them more porous, and less dense, than any models had previously predicted.

Porous rocks provide niches for simple organisms to take hold, and there would also be nutrients available in the pores, from circulating water that would have been heated inside the Earth’s crust. Early Earth was constantly bombarded by asteroids, and the team have inferred that this bombardment must have also created other rocks with similar physical properties. This may partly explain how life took hold on Earth.

The study, which is published today in the journal Science, also confirmed a model for how peak rings were formed in the Chicxulub crater, and how peak rings may be formed in craters on other planetary bodies.

The team’s new work has confirmed that the asteroid, which created the Chicxulub crater, hit the Earth’s surface with such a force that it pushed rocks, which at that time were ten kilometres beneath the surface, farther downwards and then outwards. These rocks then moved inwards again towards the impact zone and then up to the surface, before collapsing downwards and outwards again to form the peak ring. In total they moved an approximate total distance of 30 kilometres in a matter of a few minutes.

Professor Joanna Morgan, lead author of the study from the Department of Earth Science and Engineering, said: “It is hard to believe that the same forces that destroyed the dinosaurs may have also played a part, much earlier on in Earth’s history, in providing the first refuges for early life on the planet. We are hoping that further analyses of the core samples will provide more insights into how life can exist in these subterranean environments.”

The next steps will see the team acquiring a suite of detailed measurements from the recovered core samples to refine their numerical simulations. Ultimately, the team are looking for evidence of modern and ancient life in the peak-ring rocks. They also want to learn more about the first sediments that were deposited on top of the peak ring, which could tell the researchers if they were deposited by a giant tsunami, and provide them with insights into how life recovered, and when life actually returned to this sterilised zone after the impact.

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Citation:Imperial College London. “Asteroid impacts could create niches for early life, suggests Chicxulub crater study.” ScienceDaily. ScienceDaily, 17 November 2016.

WFS News: This oviraptorosaur may have met its end in a Chinese slush pit

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The workmen were building a high school, blasting out the site with dynamite in the southern Chinese city of Ganzhou when they saw it: the newly exposed fossil of a small, child-sized dinosaur. It was well preserved despite the construction, and it struck a curious pose: head elevated, neck arching upward, limbs splayed out to the side. The roughly meter-long fossil, researchers say today in Scientific Reports, represents a new species of oviraptorosaur, a group of feathered, birdlike dinosaurs that rapidly diversified in the few million years before an asteroid impact wiped out the dinosaurs 66 million years ago. Oviraptorosaurs inhabited much of the Northern Hemisphere, but they seem to have flourished in what is now Ganzhou. The new species, dubbed Tongtianlong limosus (or “muddy dragon on the road to heaven”), marks the sixth species of oviraptorosaur found in the Ganzhou area. T. limosus has slightly different skull features from its brethren, but a similarly short, deep, skull and a beak rather than teeth. Cretaceous-era Ganzhou was a hot, humid jungle with towering plants and the occasional mud pit, a richly diverse environment home to everything from duck-billed dinosaurs to long-nosed tyrannosaurs. Still, T. limosus may have met a sad end between 66 million and 72 million years ago: Its reaching neck and outstretched limbs hint at the final struggles of a creature hopelessly mired in mud.

Tongtianlong limosus (or “muddy dragon on the road to heaven”)

Tongtianlong limosus (or “muddy dragon on the road to heaven”)

 

Source: Article By Carolyn Gramling,Science mag.

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WFS News: Dinosaurs’ rise was ‘more gradual’

Researchers have discovered two small dinosaurs together with a lagerpetid, a group of animals that are recognized as precursors of dinosaurs. The discovery made in Brazil and reported in the Cell Press journal Current Biology on November 10 represents the first time that a dinosaur and a dinosaur precursor have ever been found together.

The new lagerpetid (Ixalerpeton) and saurischian dinosaur (Buriolestes) were unearthed from the ~230-million-year-old Carnian Santa Maria Formation — one of the oldest known rock units including dinosaur fossils anywhere in the world.

The skull of Buriolestes. Credit: Cabreira et al.

   The skull of Buriolestes.Credit: Cabreira et al.

“We now know for sure that dinosaurs and dinosaur precursors lived alongside one another and that the rise of dinosaurs was more gradual, not a fast overtaking of other animals of the time,” says Max Langer of Brazil’s Universidade de São Paulo.

The discovery clearly shows that these animals were contemporaries of each other during the earliest stages of dinosaurs’ evolution. The new lagerpetid specimen also preserves the first skull, scapular, and forelimb elements, plus associated vertebrae, known for the group, the researchers report. Tooth evidence also shows that the first dinosaurs most likely fed on “all kinds of small animals, but most probably not plants,” Langer says.

Those details help to reveal how dinosaurs acquired some of their characteristic anatomical traits. Their analysis also suggests that Buriolestes is one of the oldest known Sauropodomorpha, the group of long-necked dinosaurs that includes sauropods.

The two new animals have already helped to fill important gaps in the evolution of the key anatomical features of dinosaurs. But Langer and his colleagues aren’t done with them yet. They are using CT scans to characterize and describe the animals’ anatomy in even greater detail. They also hope to get an even more precise radioisotopic date on the oldest dinosaur-bearing rocks, and the search for more Triassic fossils continues.

Citation: Cell Press. “Dinosaurs’ rise was ‘more gradual,’ new fossil evidence suggests.” ScienceDaily. ScienceDaily, 10 November 2016. <www.sciencedaily.com/releases/2016/11/161110153112.htm>.

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Plate tectonics cannot explain dynamics of Earth and crust formation more than three billion years ago

The current theory of continental drift provides a good model for understanding terrestrial processes through history. However, while plate tectonics is able to successfully shed light on processes up to 3 billion years ago, the theory isn’t sufficient in explaining the dynamics of Earth and crust formation before that point and through to the earliest formation of planet, some 4.6 billion years ago. This is the conclusion of Tomas Naæraa of the Nordic Center for Earth Evolution at the Natural History Museum of Denmark, a part of the University of Copenhagen. His new doctoral dissertation has just been published by the journal Nature.

“Using radiometric dating, one can observe that Earth’s oldest continents were created in geodynamic environments which were markedly different than current environments characterised by plate tectonics. Therefore, plate tectonics as we know it today is not a good model for understanding the processes at play during the earliest episodes of Earths’s history, those beyond 3 billion years ago. There was another crust dynamic and crust formation that occurred under other processes,” explains Tomas Næraa, who has been a PhD student at the Natural History Museum of Denmark and the Geological Survey of Denmark and Greenland — GEUS.

“Plate tectonics theory can be applied to about 3 billion years of the Earth’s history. However, the Earth is older, up to 4.567 billion years old. We can now demonstrate that there has been a significant shift in the Earth’s dynamics. Thus, the Earth, under the first third of its history, developed under conditions other than what can be explained using the plate tectonics model,” explains Tomas Næraa. Credit: Image courtesy of University of Copenhagen

“Plate tectonics theory can be applied to about 3 billion years of the Earth’s history. However, the Earth is older, up to 4.567 billion years old. We can now demonstrate that there has been a significant shift in the Earth’s dynamics. Thus, the Earth, under the first third of its history, developed under conditions other than what can be explained using the plate tectonics model,” explains Tomas Næraa.
Credit: Image courtesy of University of Copenhagen

Plate tectonics is a theory of continental drift and sea floor spreading. A wide range of phenomena from volcanism, earthquakes and undersea earthquakes (and pursuant tsunamis) to variations in climate and species development on Earth can be explained by the plate tectonics model, globally recognized during the 1960’s. Tomas Næraa can now demonstrate that the half-century old model no longer suffices.

“Plate tectonics theory can be applied to about 3 billion years of the Earth’s history. However, the Earth is older, up to 4.567 billion years old. We can now demonstrate that there has been a significant shift in the Earth’s dynamics. Thus, the Earth, under the first third of its history, developed under conditions other than what can be explained using the plate tectonics model,” explains Tomas Næraa. Tomas is currently employed as a project researcher at GEUS.

Central research topic for 30 years

Since 2006, the 40-year-old Tomas Næraa has conducted studies of rocks sourced in the 3.85 billion year-old bedrock of the Nuuk region in West Greenland. Using isotopes of the element hafnium (Hf), he has managed to shed light upon a research topic that has puzzled geologists around the world for 30 years. Næraa’s instructor, Professor Minik Rosing of the Natural History Museum of Denmark considers Næraa’s dissertation a seminal work:

“We have come to understand the context of the Earth’s and continent’s origins in an entirely new way. Climate and nutrient cycles which nourish all terrestrial organisms are driven by plate tectonics. So, if the Earth’s crust formation was controlled and initiated by other factors, we need to find out what controlled climate and the environments in which life began and evolved 4 billion years ago. This fundamental understanding can be of great significance for the understanding of future climate change,” says Minik Rosing, who adds that: “An enormous job waits ahead, and Næraas’ dissertation is an epochal step.”

Journal Reference:

  1. T. Næraa, A. Scherstén, M. T. Rosing, A. I. S. Kemp, J. E. Hoffmann, T. F. Kokfelt, M. J. Whitehouse. Hafnium isotope evidence for a transition in the dynamics of continental growth 3.2 Gyr ago. Nature, 2012; 485 (7400): 627 DOI: 10.1038/nature11140

WFS News: Fossil clues to aftermath of dinosaur asteroid strike

Rapid recovery of Patagonian plant–insect associations after the end-Cretaceous extinction

The Southern Hemisphere may have provided biodiversity refugia after the Cretaceous/Palaeogene (K/Pg) mass extinction. However, few extinction and recovery studies have been conducted in the terrestrial realm using well-dated macrofossil sites that span the latest Cretaceous (late Maastrichtian) and early Palaeocene (Danian) outside western interior North America (WINA). Here, we analyse insect-feeding damage on 3,646 fossil leaves from the latest Maastrichtian and three time slices of the Danian in Chubut, Patagonia, Argentina (palaeolatitude approximately 50° S). We test the southern refugial hypothesis and the broader hypothesis that the extinction and recovery of insect herbivores, a central component of terrestrial food webs, differed substantially from WINA at locations far south of the Chicxulub impact structure in Mexico. We find greater insect-damage diversity in Patagonia than in WINA during both the Maastrichtian and Danian, indicating a previously unknown insect richness. As in WINA, the total diversity of Patagonian insect damage decreased from the Cretaceous to the Palaeocene, but recovery to pre-extinction levels occurred within approximately 4 Myr compared with approximately 9 Myr in WINA. As for WINA, there is no convincing evidence for survival of any of the diverse Cretaceous leaf miners in Patagonia, indicating a severe K/Pg extinction of host-specialized insects and no refugium. However, a striking difference from WINA is that diverse, novel leaf mines are present at all Danian sites, demonstrating a considerably more rapid recovery of specialized herbivores and terrestrial food webs. Our results support the emerging idea of large-scale geographic heterogeneity in extinction and recovery from the end-Cretaceous catastrophe.

a–l, Latest Cretaceous samples from the Lefipán Formation (a–c), and early Palaeocene samples8 from the Salamanca (d–i) and Peñas Coloradas (j–l) formations. a, Multiple, overlapping blotch mines containing centralized frass (DT299) on leaf morphotype LEF28 (LefW; MPEF-Pb 4776). b, Spheroidal galls with striated surfaces (DT303) on LEF2 (LefE; MPEF-Pb 4259). c, Margin feeding with thickened reaction tissue (DT12) on LEF23 (LefL; MPEF-Pb 4758). d, Serpentine mine with spheroidal terminal chamber (DT300) on Cissites patagonica (PL1; MPEF-Pb 6557). e, Elliptical gall positioned on the primary vein at the intersection with secondary veins (DT84) on Laurophyllum piatnitzkyi (PL1; MPEF-Pb 6555). f, Row of parallel-sided holes near the leaf margin (DT64) on Dryophyllum australis (PL1; MPEF-Pb 6560). g, Spheroidal galls with distinct outer rims positioned on the primary vein (DT117) of Cissites patagonica (PL2; MPEF-Pb 6567). h, Concentric rings of piercing and sucking marks surrounded by dark reaction tissue (DT118) on SA19 (PL2; MPEF-Pb 4072). i, Hole feeding surrounded by a wide rim of blotched reaction tissue (DT113) on SA43 (PL2; MPEF-Pb 6561). j, Serpentine mines that transition to blotch mines with internal, intestiniform trails (DT301) on Fagophyllum duseni (LF; MPEF-Pb 6547). k, Elongate, curvilinear patches of skeletonized tissue (DT20) on SA70 (LF; MPEF-Pb 6549). l, Deeply incised margin feeding damage (DT15) on Dryophyllum australis (LF; MPEF-Pb 6546). DT, damage type27 (new DTs defined in Supplementary Discussion).

a–l, Latest Cretaceous samples from the Lefipán Formation (a–c), and early Palaeocene samples8 from the Salamanca (d–i) and Peñas Coloradas (j–l) formations. a, Multiple, overlapping blotch mines containing centralized frass (DT299) on leaf morphotype LEF28 (LefW; MPEF-Pb 4776). b, Spheroidal galls with striated surfaces (DT303) on LEF2 (LefE; MPEF-Pb 4259). c, Margin feeding with thickened reaction tissue (DT12) on LEF23 (LefL; MPEF-Pb 4758). d, Serpentine mine with spheroidal terminal chamber (DT300) on Cissites patagonica (PL1; MPEF-Pb 6557). e, Elliptical gall positioned on the primary vein at the intersection with secondary veins (DT84) on Laurophyllum piatnitzkyi (PL1; MPEF-Pb 6555). f, Row of parallel-sided holes near the leaf margin (DT64) on Dryophyllum australis (PL1; MPEF-Pb 6560). g, Spheroidal galls with distinct outer rims positioned on the primary vein (DT117) of Cissites patagonica (PL2; MPEF-Pb 6567). h, Concentric rings of piercing and sucking marks surrounded by dark reaction tissue (DT118) on SA19 (PL2; MPEF-Pb 4072). i, Hole feeding surrounded by a wide rim of blotched reaction tissue (DT113) on SA43 (PL2; MPEF-Pb 6561). j, Serpentine mines that transition to blotch mines with internal, intestiniform trails (DT301) on Fagophyllum duseni (LF; MPEF-Pb 6547). k, Elongate, curvilinear patches of skeletonized tissue (DT20) on SA70 (LF; MPEF-Pb 6549). l, Deeply incised margin feeding damage (DT15) on Dryophyllum australis (LF; MPEF-Pb 6546). DT, damage type27 (new DTs defined in Supplementary Discussion).

Palaeontological evidence from both continental and marine deposits suggests that the Southern Hemisphere may have harboured biodiversity refugia in the wake of the bolide impact at Chicxulub, Mexico, 66.0 Myr ago (Ma)1,2,3,4. The extinction rate of Southern Hemisphere nannoplankton was lower than that of their Northern Hemisphere counterparts, and their populations recovered nearly immediately2. Nominally Mesozoic plant groups, including corystosperms and bennettitaleans, survived until at least the Palaeogene in Australia1,5. Palynological data from New Zealand revealed a sudden but short-lived disturbance, with low overall extinction rates6,7. In Patagonia, Argentina, palynomorphs from the latest Maastrichtian–early Danian Lefipán Formation exhibited low extinction, followed by the reappearances of Cretaceous pollen types3. Early Danian macrofloras from the Salamanca Formation in Patagonia are more diverse than comparable North American Palaeocene floras8,9,10. A number of surviving lineages from other plant3 and vertebrate11,12groups have also been identified, especially in Patagonia4, although marine invertebrate faunas in Antarctica underwent severe extinction13. K/Pg boundary sections in New Zealand have provided important insights into the response of terrestrial ecosystems6,7,14,15,16, but until recently there has not been a series of well-dated, heavily sampled continental macrofloral localities anywhere in the Southern Hemisphere that spans both the terminal Cretaceous and earliest Palaeogene.

Plant–insect interactions are fundamental components of terrestrial food webs, and their sensitivity to major environmental perturbations is well known from deep time as well as the modern world17,18,19,20. The diversity of insect-feeding damage on extant leaves in two tropical rainforests is positively correlated with the richness of insects that caused the damage, supporting the widespread use of insect damage on fossil leaves as a proxy for herbivorous insect diversity when suitable insect body fossils are absent21. In North Dakota, USA, insect-damage diversity on fossil leaves, especially specialized feeding such as mining and galling, declined considerably across the K/Pg boundary and remained low throughout WINA before increasing with the latest Palaeocene warming, approximately 9 Myr after the K/Pg boundary17,18,20. The only exception to this pattern is the early Palaeocene (about 65 Ma) Mexican Hat locality in south-eastern Montana, USA, which has typical low-diversity flora but anomalously high insect damage diversity for the time; this pattern is attributed to a short-lived interval of decoupled plant and insect diversity following the K/Pg mass extinction17,20.

Much less is known about the extinction and recovery of insect herbivores outside WINA. Late Palaeocene floras from Colombia are associated with low richness of plants and specialized insect-damage diversity as in Palaeocene WINA22, contrasting with high plant and insect-damage diversity on middle Palaeocene floras from France23 and Spitsbergen24. However, until now, no studies have investigated changes in insect-damage diversity based on terminal Cretaceous and early Palaeocene leaf floras from any non-WINA study area.

Full Text: http://www.nature.com/articles/s41559-016-0012

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Atom-by-atom growth chart for shells helps decode past climate

For the first time scientists can see how the shells of tiny marine organisms grow atom-by-atom, a new study reports. The advance provides new insights into the mechanisms of biomineralization and will improve our understanding of environmental change in Earth’s past.

Led by researchers from the University of California, Davis and the University of Washington, with key support from the U.S. Department of Energy’s Pacific Northwest National Laboratory, the team examined an organic-mineral interface where the first calcium carbonate crystals start to appear in the shells of foraminifera, a type of plankton.

“We’ve gotten the first glimpse of the biological event horizon,” said Howard Spero, a study co-author and UC Davis geochemistry professor. The findings were published in theProceedings of the National Academy of Sciences.

Foraminifera’s Final Frontier

The researchers zoomed into shells at the atomic level to better understand how growth processes may influence the levels of trace impurities in shells. The team looked at a key stage — the interaction between the biological ‘template’ and the initiation of shell growth. The scientists produced an atom-scale map of the chemistry at this crucial interface in the foraminifera Orbulina universa. This is the first-ever measurement of the chemistry of a calcium carbonate biomineralization template, Spero said.

Among the new findings are elevated levels of sodium and magnesium in the organic layer. This is surprising because the two elements are not considered important architects in building shells, said lead study author Oscar Branson, a former postdoctoral researcher at UC Davis who is now at the Australian National University in Canberra. Also, the greater concentrations of magnesium and sodium in the organic template may need to be considered when investigating past climate with foraminifera shells.

Calibrating Earth’s Climate

Most of what we know about past climate (beyond ice core records) comes from chemical analyses of shells made by the tiny, one-celled creatures called foraminifera, or “forams.” When forams die, their shells sink and are preserved in seafloor mud. The chemistry preserved in ancient shells chronicles climate change on Earth, an archive that stretches back nearly 200 million years.

The calcium carbonate shells incorporate elements from seawater — such as calcium, magnesium and sodium — as the shells grow. The amount of trace impurities in a shell depends on both the surrounding environmental conditions and how the shells are made. For example, the more magnesium a shell has, the warmer the ocean was where that shell grew.

Foraminifera are marine organisms whose shells, buried in marine sediments, provide a record of past climate stretching back 200 million years. A new study by UC Davis, University of Washington and Pacific Northwest National Lab applies material science techniques to understand how foraminifera build their shells, and may help improve our understanding of this climate record. Image shows the foraminiferan Orbulina universa. Credit: Howard Spero, UC Davis

Foraminifera are marine organisms whose shells, buried in marine sediments, provide a record of past climate stretching back 200 million years. A new study by UC Davis, University of Washington and Pacific Northwest National Lab applies material science techniques to understand how foraminifera build their shells, and may help improve our understanding of this climate record. Image shows the foraminiferan Orbulina universa.
Credit: Howard Spero, UC Davis

“Finding out how much magnesium there is in a shell can allow us to find out the temperature of seawater going back up to 150 million years,” Branson said.

But magnesium levels also vary within a shell, because of nanometer-scale growth bands. Each band is one day’s growth (similar to the seasonal variations in tree rings). Branson said considerable gaps persist in understanding what exactly causes the daily bands in the shells.

“We know that shell formation processes are important for shell chemistry, but we don’t know much about these processes or how they might have changed through time,” he said. “This adds considerable uncertainty to climate reconstructions.”

Atomic Maps

The researchers used two cutting-edge techniques: Time-of-Flight Secondary Ionization Mass Spectrometry (ToF-SIMS) and Laser-Assisted Atom Probe Tomography (APT). ToF-SIMS is a two-dimensional chemical mapping technique which shows the elemental composition of the surface of a polished sample. The technique was developed for the elemental analysis of complex polymer materials, and is just starting to be applied to natural samples like shells.

APT is an atomic-scale three-dimensional mapping technique, developed for looking at internal structures in advanced alloys, silicon chips and superconductors. The APT imaging was performed at the Environmental Molecular Sciences Laboratory, a U.S. Department of Energy Office of Science User Facility at the Pacific Northwest National Laboratory.

University of California – Davis. “Atom-by-atom growth chart for shells helps decode past climate.” ScienceDaily. ScienceDaily, 24 October 2016. <www.sciencedaily.com/releases/2016/10/161024170634.htm>.
@WFS,World Fossil Society,Riffin T Sajeev,Russel T Sajeev

Fossilized dinosaur brain tissue identified for the first time : WFS News

Researchers have identified the first known example of fossilised brain tissue in a dinosaur from Sussex. The tissues resemble those seen in modern crocodiles and birds.

An unassuming brown pebble, found more than a decade ago by a fossil hunter in Sussex, has been confirmed as the first example of fossilised brain tissue from a dinosaur.

The fossil, most likely from a species closely related toIguanodon, displays distinct similarities to the brains of modern-day crocodiles and birds. Meninges — the tough tissues surrounding the actual brain — as well as tiny capillaries and portions of adjacent cortical tissues have been preserved as mineralised ‘ghosts’.

The results are reported in a Special Publication of the Geological Society of London, published in tribute to Professor Martin Brasier of the University of Oxford, who died in 2014. Brasier and Dr David Norman from the University of Cambridge co-ordinated the research into this particular fossil during the years prior to Brasier’s untimely death in a road traffic accident.

The fossilised brain, found by fossil hunter Jamie Hiscocks near Bexhill in Sussex in 2004, is most likely from a species similar toIguanodon: a large herbivorous dinosaur that lived during the Early Cretaceous Period, about 133 million years ago.

Finding fossilised soft tissue, especially brain tissue, is very rare, which makes understanding the evolutionary history of such tissue difficult. “The chances of preserving brain tissue are incredibly small, so the discovery of this specimen is astonishing,” said co-author Dr Alex Liu of Cambridge’s Department of Earth Sciences, who was one of Brasier’s PhD students in Oxford at the time that studies of the fossil began.

According to the researchers, the reason this particular piece of brain tissue has been so well-preserved is that the dinosaur’s brain was essentially ‘pickled’ in a highly acidic and low-oxygen body of water — similar to a bog or swamp — shortly after its death. This allowed the soft tissues to become mineralised before they decayed away completely, so that they could be preserved.

“What we think happened is that this particular dinosaur died in or near a body of water, and its head ended up partially buried in the sediment at the bottom,” said Norman. “Since the water had little oxygen and was very acidic, the soft tissues of the brain were likely preserved and cast before the rest of its body was buried in the sediment.”

mage of specimen. See: https://www.youtube.com/watch?v=1T5_NlRs-5o Credit: Jamie Hiscocks

Image of specimen. See: https://www.youtube.com/watch?v=1T5_NlRs-5o    Credit: Jamie Hiscocks

Working with colleagues from the University of Western Australia, the researchers used scanning electron microscope (SEM) techniques in order to identify the tough membranes, or meninges, that surrounded the brain itself, as well as strands of collagen and blood vessels. Structures that could represent tissues from the brain cortex (its outer layer of neural tissue), interwoven with delicate capillaries, also appear to be present. The structure of the fossilised brain, and in particular that of the meninges, shows similarities with the brains of modern-day descendants of dinosaurs, namely birds and crocodiles.

In typical reptiles, the brain has the shape of a sausage, surrounded by a dense region of blood vessels and thin-walled vascular chambers (sinuses) that serve as a blood drainage system. The brain itself only takes up about half of the space within the cranial cavity.

In contrast, the tissue in the fossilised brain appears to have been pressed directly against the skull, raising the possibility that some dinosaurs had large brains which filled much more of the cranial cavity. However, the researchers caution against drawing any conclusions about the intelligence of dinosaurs from this particular fossil, and say that it is most likely that during death and burial the head of this dinosaur became overturned, so that as the brain decayed, gravity caused it to collapse and become pressed against the bony roof of the cavity.

“As we can’t see the lobes of the brain itself, we can’t say for sure how big this dinosaur’s brain was,” said Norman. “Of course, it’s entirely possible that dinosaurs had bigger brains than we give them credit for, but we can’t tell from this specimen alone. What’s truly remarkable is that conditions were just right in order to allow preservation of the brain tissue — hopefully this is the first of many such discoveries.”

“I have always believed I had something special. I noticed there was something odd about the preservation, and soft tissue preservation did go through my mind. Martin realised its potential significance right at the beginning, but it wasn’t until years later that its true significance came to be realised,” said paper co-author Jamie Hiscocks, the man who discovered the specimen. “In his initial email to me, Martin asked if I’d ever heard of dinosaur brain cells being preserved in the fossil record. I knew exactly what he was getting at. I was amazed to hear this coming from a world renowned expert like him.”

The research was funded in part by the Natural Environment Research Council (NERC) and Christ’s College, Cambridge.

Citation: University of Cambridge. “Fossilized dinosaur brain tissue identified for the first time.” ScienceDaily.ScienceDaily,27
October 2016.  <www.sciencedaily.com/releases/2016/10/161027175858.htm>
Key: WFS World Fossil Society,Riffin T Sajeev,Russel T Sajeev