Filter-feeding pterosaurs were the flamingos of the Late Jurassic

August 31, 2019

The scans revealed many microscopic food remains including foraminifera (small amoeboid protists with external shells), small shells of marine invertebrates and possible remains of polychaete worms. Credit: Qvarnström mfl.

Modern flamingoes employ filter feeding and their feces are, as a result, rich in remains of microscopically-small aquatic prey. Very similar contents are described from more than 150 million year old pterosaur droppings in a recent paper in PeerJ. This represents the first direct evidence of filter-feeding in Late Jurassic pterosaurs and demonstrates that their diet and feeding environment were similar to those of modern flamingoes.

Pterosaurs were a diverse group of flying reptiles that roamed the skies during the age of dinosaurs. Skeletal fossils suggest that they, just like modern birds, adapted to diverse lifestyles and feeding habits. Direct evidence on diets such as gut contents, however, are rare and only known from a few pterosaur species.

Coprolites, that is fossil droppings, are surprisingly common fossils and they potentially hold valuable information on the diet of extinct animals. Unfortunately, it is often difficult to know which animal produced which dropping.

In a recent paper, researchers from Uppsala University and the Polish Academy of Sciences describe the contents of three coprolites collected from a surface with abundant pterosaur footprints in the Wierzbica Quarry in Poland. The coprolites’ size, shape and association to the tracks suggest that they were produced by pterosaurs, most probably belonging to a group called Ctenochasmatidae.

The fossil droppings were scanned using synchrotron microtomography, which works in a similar way to a CT-scanner in a hospital but with much stronger x-ray beams. This makes it possible to image the contents of fossils in three dimensions. The scans of the pterosaur coprolites revealed many microscopic food remains including foraminifera (small amoeboid protists with external shells), small shells of marine invertebrates and possible remains of polychaete worms.

“A reasonable explanation for how a pterosaur big enough to have produced the droppings ingested such small prey is through filter feeding,” says Martin Qvarnström, PhD student at Uppsala University and one of the authors of the article.

Some ctenochasmid pterosaurs are thought to have been filter feeders. Pterodaustro, which comes from the Cretaceous and is thus slightly younger than the Polish coprolites, possessed a sieving basket consisting of many long, thin teeth and was certainly a filter feeder. Older ctenochasmids did not possess such an obvious sieving basket, but some had elongated snouts with many slender teeth, also interpreted as adaptations for filter feeding. These pterosaurs were around at the time the droppings were made, and as the footprints from the site have also been attributed to ctenochasmids it is likely that such pterosaurs produced both the droppings and the footprints.

The modern Chilean flamingo, which is a filter feeder, can produce droppings full of foraminifera when feeding in coastal wetlands.

“The similar contents of the droppings of these flamingos and the pterosaur coprolites could be explained by similar feeding environments and mesh sizes of the filter-feeding apparatus. It appears therefore that the pterosaurs which produced the footprints and droppings found in Poland were indeed the flamingos of the Late Jurassic,” says Martin Qvarnström.

Reference:
Martin Qvarnström, Erik Elgh, Krzysztof Owocki, Per E. Ahlberg, Grzegorz Niedźwiedzki. Filter feeding in Late Jurassic pterosaurs supported by coprolite contents. PeerJ, 2019; 7: e7375 DOI: 10.7717/peerj.7375

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

Ancient Tsunamis: Deducing the scale of tsunamis from the ’roundness’ of deposited gravel

August 25, 2019

Scientists from Tokyo Metropolitan University and Ritsumeikan University have found a link between the “roundness” distribution of tsunami deposits and how far tsunamis reach inland. They sampled the “roundness” of gravel from different tsunamis in Koyadori, Japan, and found a common, abrupt change in composition approximately 40% of the “inundation distance” from the shoreline, regardless of tsunami magnitude. Estimates of ancient tsunami size from geological deposits may help inform effective disaster mitigation.

Tsunamis are one of nature’s most devastating hazards; understanding their scale and mechanism is of paramount scientific and socio-economic importance. Nevertheless, despite our best efforts to study and understand them, their infrequent occurrence can make quantitative studies difficult; tsunami-causing seismic events around subduction zones (where one tectonic plate dips underneath another plate) recur once every 100 to 1,000 years, significantly reducing the number of accurately documented events. It is highly desirable that we gain some understanding by looking at geological deposits instead. However, despite some success in finding the number and age of past events, it is not yet possible to estimate the magnitude of ancient tsunamis, particularly in narrow coastal lowlands like the Sanriku Coast in Japan, struck by the 2011 Tohoku earthquake and tsunami.

Therefore, Assistant Professor Daisuke Ishimura from Tokyo Metropolitan University and Postdoctoral Fellow Keitaro Yamada from Ritsumeikan University carried out studies of gravel samples collected from bore holes and the trench in Koyadori, situated in the middle of the Sanriku coastline. Geological samples were taken corresponding to three tsunami events (AD 1611, 1896 and 2011) whose magnitudes are known, specifically their “inundation distance,” or how far they reach inland. They used automated image analysis to study how “round” each gravel particle was in their samples, giving 10 to 100 times more data than existing, manual methods. Comparing distributions with measurements of modern beach and fluvial (river) gravels, they found that they could map the number ratio between beach and fluvial gravel. They discovered that this ratio suddenly changed at a certain distance away from the sea. This point was named the “Tsunami Gravel Inflection Point” (TGIP); it is thought to arise from “run-up” (incoming) waves bringing beach material inland and “return” waves drawing inland material towards the sea. Although the TGIP occurred at different locations for each event, they found that it was always approximately 40% of the inundation distance. They applied this finding to samples corresponding to even older tsunamis, providing estimates for the size of events along the Sanriku Coast going back approximately 4,000 years for the first time.

Although the researchers believe this ratio is specific to the local topography, the same analysis may be applied to characterize other tsunami-prone locations. An accurate estimate of the extent of ancient tsunamis will expand the number of events available for future research to study the mechanisms behind tsunamis, helping to inform effective disaster mitigation and the planning of coastal communities.

Reference:
Daisuke Ishimura, Keitaro Yamada. Palaeo-tsunami inundation distances deduced from roundness of gravel particles in tsunami deposits. Scientific Reports, 2019; 9 (1) DOI: 10.1038/s41598-019-46584-z

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

Detecting hydrothermal vents in volcanic lakes

August 25, 2019

Steep crater wall of Ngozi volcano in the Poroto Ridge Forest Reserve, Tanzania. Credit: Egbert Jolie/GFZ

Geothermal manifestations at Earth’s surface can be mapped and characterized by a variety of well-established exploration methods. However, mapping hydrothermal vents in aquatic environments is more challenging as conventional methods can no longer be applied. In fact, chemical composition of lake water may indicate inflow of fluids from a volcanic system, but it does not provide spatial information on the location of hydrothermal vents, their abundance and current state of activity.

Changes in the behaviour of hydrothermal vents may be indicative of changes in the volcanic system underneath, thus being a useful precursor for the next generation of early warning systems. Increased volcanic activity beneath volcanic lakes could also trigger increased gas input, in particular CO2, which could again result in catastrophic gas outbursts as reported from Lake Nyos or Lake Monoun in Cameroon. New exploration approaches will help improving site-specific risk assessment and monitoring concepts by taking a closer look at hydrothermal vents.

The study describes an integrated approach of (1) bathymetry, (2) thermal mapping of the lake floor, and (3) gas emission measurements at the water surface, which was tested successfully at Lake Ngozi in Tanzania. Multiple hydrothermal feed zones could be identified by hole-like structures and increased lake floor temperatures, in combination with increased CO2 emissions from the lake surface. The developed approach has the advantage that (1) it does not require a complex technical setup, (2) data can be obtained in-situ, and (3) it is transferable to other volcanic lakes for mapping hydrothermal feed sources.

Further research activities at volcanic lakes and in shallow marine environments with hydrothermal activity (e.g., Iceland, Italy) are currently in preparation with partners from the Scientific Diving Centre (SDC) at the Technical University Bergakademie Freiberg, Germany, and the Marine & Freshwater Research Institute in Reykjavík, Iceland. This will also include research related to future offshore geothermal exploration.

Data related to this study have been collected complementary to a geothermal exploration project, which was coordinated by the author, who has previously been with BGR in Hanover, Germany.

Reference:
Egbert Jolie. Detecting gas-rich hydrothermal vents in Ngozi Crater Lake using integrated exploration tools. Scientific Reports, 2019; 9 (1) DOI: 10.1038/s41598-019-48576-5

Note: The above post is reprinted from materials provided by GFZ GeoForschungsZentrum Potsdam, Helmholtz Centre.

Atacama Desert microbes may hold clues to life on Mars

August 25, 2019

Picture taken at one of the sites inspected in the Coastal Range of the Atacama Desert. On this picture Professor Azua-Bustos and González-Silva are donning sterile suites and using sterile collecting materials in order to avoid the contamination of the sites studied. Credit: Margarita Azua

Microbial life on Mars may potentially be transported across the planet on dust particles carried by wind, according to a study conducted in the Atacama Desert in North Chile, a well-known Mars analogue. The findings are published in Scientific Reports.

Armando Azua-Bustos and colleagues investigated whether microbial life could move across the Atacama Desert using on wind-driven dust particles They sought to determine where these microorganisms originate, which may have implications for microbial life in extreme environments.

The authors collected 23 bacterial and eight fungal species from three sampling sites across two regions of the Atacama traversing its hyperarid core, which in addition to its extreme aridity is known for having highly saline/oxidizing soils and extremely high UV radiation. Only three of the species were shared among transects, suggesting that there are different airborne ecosystems in different parts of the desert.

Bacterial and fungal species identified from the samples included Oceanobacillus oncorhynchi, a bacterium first described in aquatic environments, and Bacillus simplex, which originates from plants. These observations indicate that microbes may arrive at the hyperarid core from the Pacific Ocean and the Coastal Range of the desert.

The authors found that microbial cells collected in the morning tended to come from nearby areas, whereas in the afternoon, marine aerosols and microbial life on dust particles were carried by the wind from remote locations. This finding suggests that microbial life is able to efficiently move across the driest and most UV irradiated desert on Earth. Potential microbial life on Mars may similarly spread over, the authors speculate.

Reference:
Aeolian transport of viable microbial life across the Atacama Desert, Chile: Implications for Mars, Scientific Reports (2019). DOI: 10.1038/s41598-019-47394-z

Note: The above post is reprinted from materials provided by Nature Publishing Group.

Underground links between quakes and eruptions of Japan’s biggest active volcano

August 25, 2019

A picture of Mt. Aso, including locations of eastern and western clusters. Credit: Aso Geopark Promotion Council

The threat of explosive volcanic eruptions looms over many cities around the world. Earthquakes, another major geological hazard, are known to have some relationships with the occurrence of volcanic eruptions. Although they often precede volcanic events, the mechanisms of these relationships are not yet well understood.

Mount Aso in Kyushu, Japan, is one of the largest active volcanoes in the world and has experienced major earthquakes and eruptions as recently as 2016. Researchers at Kyushu University’s International Institute for Carbon-Neutral Energy Research (I2CNER) have been investigating the relationships among these events to better understand what are happening under the surface and to help predict future disasters. In particular, for a new study published in Geophysical Research Letters, they investigated “very long period” (VLP) seismic waves, which can represent pressure changes in subsurface hydrothermal systems.

“We analyzed continuous VLP seismicity data recorded from January 2015 to December 2016, a period that includes both large earthquakes and eruptions of Mount Aso,” explains lead author of the study Andri Hendriyana. “Using on this dataset, we developed a differential-time back-projection method to accurately locate VLP events, and detected over 18,000 reliable VLP events.”

Using this method, two distinct clusters of these seismic events were identified in the subsurface below the caldera of Mount Aso. For most of the observation period, VLP activity was almost entirely confined to the eastern cluster. However, after the Kumamoto earthquakes on April 2016, VLP activity abruptly shifted to the western cluster for about five months. Then, in September 2016, one month before the largest eruption of Mount Aso during the study period, VLP events migrated back to the eastern cluster. After the large eruption on October 8, 2016, VLP seismicity stopped temporarily. Together, these observations show that VLP events are affected by the occurrence of earthquakes and are related to volcanic eruptions. VLP seismicity is considered to be directly related to pressure variations associated with magmatic activity.

“We interpret the migration of VLP activity after the earthquakes as a response to permeability enhancement or to fractures opening because of extension associated with the Kumamoto earthquakes,” says senior author Takeshi Tsuji. He expects this method to be applied in further studies of Mount Aso as well as other volcanoes worldwide.

“The information obtained from this new monitoring approach could reveal new details about the dynamic behavior within Aso and other volcanoes after earthquakes, and could provide important information for prevention and mitigation of future disasters.”

Reference:
Andri Hendriyana, Takeshi Tsuji. Migration of Very Long Period Seismicity at Aso Volcano, Japan, Associated With the 2016 Kumamoto Earthquake. Geophysical Research Letters, 2019; DOI: 10.1029/2019GL082645

Note: The above post is reprinted from materials provided by Kyushu University, I2CNER.

20-million-year-old skull suggests complex brain evolution in monkeys, apes

August 25, 2019

An exceptional fossil skull of Chilecebus carrascoensis, a 20-million-year-old primate from the Andes mountains of Chile. Credit: © AMNH/N. Wong and M. Ellison

It has long been thought that the brain size of anthropoid primates — a diverse group of modern and extinct monkeys, humans, and their nearest kin — progressively increased over time. New research on one of the oldest and most complete fossil primate skulls from South America shows instead that the pattern of brain evolution in this group was far more checkered. The study, published today in the journal Science Advances and led by researchers from the American Museum of Natural History, the Chinese Academy of Sciences, and the University of California Santa Barbara, suggests that the brain enlarged repeatedly and independently over the course of anthropoid history, and was more complex in some early members of the group than previously recognized.

“Human beings have exceptionally enlarged brains, but we know very little about how far back this key trait started to develop,” said lead author Xijun Ni, a research associate at the Museum and a researcher at the Chinese Academy of Sciences. “This is in part because of the scarcity of well-preserved fossil skulls of much more ancient relatives.”

As part of a long-term collaboration with John Flynn, the Museum’s Frick Curator of Fossil Mammals, Ni spearheaded a detailed study of an exceptional 20-million-year-old anthropoid fossil discovered high in the Andes mountains of Chile, the skull and only known specimen of Chilecebus carrascoensis.

“Through more than three decades of partnership and close collaboration with the National Museum of Chile, we have recovered many remarkable new fossils from unexpected places in the rugged volcanic terrain of the Andes,” Flynn said. “Chilecebus is one of those rare and truly spectacular fossils, revealing new insights and surprising conclusions every time new analytical methods are applied to studying it.”

Previous research by Flynn, Ni, and their colleagues on Chilecebus provided a rough idea of the animal’s encephalization, or the brain size relative to body size. A high encephalization quotient (EQ) signifies a large brain for an animal of a given body size. Most primates have high EQs relative to other mammals, although some primates — especially humans and their closest relatives — have even higher EQs than others. The latest study takes this understanding one step further, illustrating the patterns across the broader anthropoid family tree. The resulting “PEQ” — or phylogenetic encephalization quotient, to correct for the effects of close evolutionary relationships — for Chilecebus is relatively small, at 0.79. Most living monkeys, by comparison, have PEQs ranging from 0.86 to 3.39, with humans coming in at an extraordinary 13.46 and having expanded brain sizes dramatically even compared to nearest relatives. With this new framework, the researchers confirmed that cerebral enlargement occurred repeatedly and independently in anthropoid evolution, in both New and Old World lineages, with occasional decreases in size.

High-resolution x-ray computed tomography (CT) scanning and 3D digital reconstruction of the inside of Chilecebus’ skull gave the research team new insights into the anatomy of its brain. In modern primates, the size of the visual and olfactory centers in the brain are negatively correlated, reflecting a potential evolutionary “trade-off,” meaning that visually acute primates typically have weaker senses of smell. Surprisingly, the researchers discovered that a small olfactory bulb in Chilecebus was not counterbalanced by an amplified visual system. This finding indicates that in primate evolution the visual and olfactory systems were far less tightly coupled than was widely assumed.

Other findings: The size of the opening for the optic nerve suggests that Chilecebus was diurnal. Also, the infolding (sulcus) pattern of the brain of Chilecebus, although far simpler than in most modern anthropoids, possesses at least seven pairs of sulcal grooves and is surprisingly complex for such an ancient primate.

“During his epic voyage on the Beagle, Charles Darwin explored the mouth of the canyon where Chilecebus was discovered 160 years later. Shut out of the higher cordillera by winter snow, Darwin was inspired by ‘scenes of the highest interest’ his vista presented. This exquisite fossil, found just a few kilometers east of where Darwin stood, would have thrilled him,” said co-author André Wyss from the University of California Santa Barbara.

Reference:
Xijun Ni, John J. Flynn, André R. Wyss and Chi Zhang. Cranial endocast of a stem platyrrhine primate and ancestral brain conditions in anthropoids. Science Advances, 2019 DOI: 10.1126/sciadv.aav7913

Note: The above post is reprinted from materials provided by American Museum of Natural History.

Making biominerals: Nature’s recipe is old, evolved more than once

August 25, 2019

A Desmoceras fossil. A cephalopod that thrived in the early Cretaceous, 146 to 100 million years ago. Note the fossilized biomineral nacre or mother of pearl. Credit: Pupa Gilbert

In recent years, scientists have teased out many of the secrets of biomineralization, the process by which sea urchins grow spines, mollusks build their shells and corals make their skeletons, not to mention how mammals and other animals make bones and teeth.

The materials that animals make from scratch to build protective shells, razor sharp teeth, load-bearing bones and needlelike spines are some of the hardest and most durable substances known. The recipe for making those materials was one of nature’s closely held secrets, but powerful new analytical tools and microscopes have peeled back much of the mystery, showing, at the nanoscale, exactly how a wide array of animals use precisely the same mechanisms and starter chemicals to make the biomineral structures they depend on.

Now, in a report published today (Aug. 19, 2019) in the Proceedings of the National Academy of Sciences (PNAS), a team led by Pupa Gilbert, a University of Wisconsin–Madison professor of physics, shows that the recipe for making shells, spines, and coral skeletons is not only the same across many modern animal lineages, but is ancient—dating back 550 million years—and evolved independently more than once.

The findings are important because they help stitch together an evolutionary narrative of biomineralization. The fuller picture of a process ubiquitous to animal life on our planet not only tells us something important about our world, but the details may one day be harnessed by humans to produce harder, lighter, more durable materials; tools that never need sharpening; more faithful biomedical implants; and the possibility of human intervention in things like rebuilding the world’s coral reefs.

“The finding that biomineralization evolved independently multiple times, using the same mechanism, tells us that there is a strong physical or chemical reason for doing so,” says Gilbert, a world expert on the process of biomineralization. “If one organism starts making its biomineral that way, it outcompetes all others that either don’t make biomineral or make them differently, it doesn’t get eaten, and gets to transmit that good idea down the lineage.”

The new PNAS report builds on a series of seminal discoveries by Gilbert and her colleagues. In past studies, the Wisconsin physicist has shown that the process of biomineralizations works the same in vastly different classes of animals, ranging from mollusks like abalone, to echinoderms such as sea urchins, and to cnidaria, a large group of animals that includes corals, jellyfish, and sea anemones. These phyla, or broad groups of animals, have no common ancestor that was already biomineralizing, thus they must have evolved biomineralization mechanisms independently. Therefore, Gilbert says, “it is extremely surprising that when they started biomineralizing in the Cambrian (more than 500 million years ago) these three phyla started doing it in precisely the same way: using attachment of amorphous nanoparticles.”

“Biomineralization illustrates both the unity and diversity of nature,” explains Andrew Knoll, a professor of natural history and of Earth and planetary sciences at Harvard University, and a corresponding co-author of the new report. “Biomineralized skeletons may have evolved as many as twenty times within animals alone. That means that no two of these biomineralizing groups share a common ancestor that, itself, fashioned a biomineralized skeleton.”

Gilbert and her colleagues have shown that different biominerals form beginning with amorphous calcium carbonate nanoparticles, which are produced in cells and are the critical starter chemical for all of the materials that form in the biomineralization process, be it the nacre, or mother-of-pearl, that lines an abalone shell or the rock-grinding teeth of a sea urchin. “More than one biomineral forms by these amorphous precursor nanoparticles,” says Gilbert. “It doesn’t matter if it is a sea urchin spicule, a tooth, a spine, nacre, or coral. All of these systems have the same amorphous precursors.

“Amorphous calcium carbonate nanoparticles,” adds Gilbert, “are stabilized in confinement, and reversibly so. Thus, crystals don’t nucleate and grow at the wrong place and time, but they can and do at the right place and time, that is, on the growing surface of a shell, a coral skeleton, a sea urchin spine.”

The ability of many animals to make hard, protective or defensive structures, says Knoll, was likely a broad response to the evolution of carnivores, reflected in a “burst of biomineralization” seen in fossils from the Cambrian period, beginning some 541 million years ago.

The microscopic particles of calcium carbonate produced in animal cells are the same stuff that forms “lime” deposits in pipes and plumbing fixtures. In an animal, it is transformed at the site of biomineralization by attaching to the site and forming crystals in which individual atoms are neatly aligned to make a lattice, a scaffold of sorts for whatever structure an animal is building. The process has been teased out by Gilbert’s team using a novel microscope that employs the soft X-rays produced by synchrotron radiation to observe at the nanoscale how the structures come together as they are formed.

Gilbert’s team went back in time applying the same techniques to probe the deep fossil record in three distinct phyla, or broad groups of related animals, going as far back as 550 million years to sample the oldest known animal biomineral: the Cloudina skeleton with its characteristic series of funnels nestled into one another.

Gilbert notes that while animal remains undergo significant changes in the process of fossilization, the nanoparticle biomineralization signature remains intact and is observed by cracking open fossils and using a scanning electron microscope to probe the site of the fracture for the telltale signs of nanoparticles during the original crystallization process. “We stepped back in time as far as possible, to the very first fossils, and biomineralization by particle attachment looks the same as in modern animals.”

The biomineralization story unraveled by Gilbert and her colleagues may inform the development of novel materials useful for industry.

“We don’t know how to make amorphous calcium carbonate or any other material form a space-filling solid and then crystallize, but cells in marine organisms do,” Gilbert explains. “What we learn from them, we can reproduce in the lab and in industry, and make materials that are far better than the sum of their parts, as all biominerals are.”

Reference:
Pupa U. P. A. Gilbert et al. Biomineralization by particle attachment in early animals, Proceedings of the National Academy of Sciences (2019). DOI: 10.1073/pnas.1902273116

Note: The above post is reprinted from materials provided by University of Wisconsin-Madison.

Scientists discover new way to reconstruct what extinct animals looked like

August 25, 2019

Fig. 1. 10 million-year-old fossil frog from Libros, Spain and X-ray map showing elevated levels of copper and zinc in the internal organs. Fossil photograph copyright the Natural History Museum, London. X-ray fluorescence map. Credit: Valentina Rossi

Scientists could be set to reveal the most accurate depictions of ancient vertebrates ever made after a world-first discovery at University College Cork (UCC) in Ireland.

UCC palaeontologists have discovered a new way to reconstruct the anatomy of ancient vertebrate animals, analyzing the chemistry of fossilized melanosomes from internal organs.

The study, published today in the journal Proceedings of the National Academy of Sciences of the United States of America, was led by UCC’s Valentina Rossi and her supervisor Dr. Maria McNamara in collaboration with an international team of chemists from the US and Japan.

The team used cutting-edge synchrotron techniques to analyze the chemistry of the fossil and modern melanosomes using X-rays, allowing them to peer inside the anatomy of fossils and uncover hidden features.

Until recently, most studies on fossil melanin have focused on the skin and feathers, whereas here the pigment is linked to visible color. Unexpectedly, the new study also showed that melanin is abundant in internal organs of modern amphibians, reptiles, birds and mammals, and their fossil counterparts.

“This discovery is remarkable in that it opens up a new avenue for reconstructing the anatomy of ancient animals. In some of our fossils we can identify skin, lungs, the liver, the gut, the heart, and even connective tissue,” said senior author Dr. Maria McNamara.

“What’s more, this suggests that melanin had very ancient functions in regulating metal chemistry in the body going back tens, if not hundreds, of millions of years.”

The team made the initial discovery of internal melanosomes last year on fossil frogs. “After the pilot study, we had a hunch that these features would turn out to be more widespread across vertebrates. But we never guessed that the chemistry would be different in different organs,” Rossi said.

The advent of new synchrotron X-ray analysis techniques “allows us to harness the energy of really fast-moving electrons to detect minute quantities of different metals in the melanosomes.”

The fossils are so well-preserved that even the melanin molecule can be detected.

Reference:
Valentina Rossi et al. Tissue-specific geometry and chemistry of modern and fossilized melanosomes reveal internal anatomy of extinct vertebrates, Proceedings of the National Academy of Sciences (2019). DOI: 10.1073/pnas.1820285116

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

Obsidian : What is obsidian? Why obsidian is black?

August 17, 2019

What is Obsidian?

Obsidian Rock

Color: Deep black or blackish green
Fracture: Conchoidal
Mohs scale hardness: 5 – 6
Luster: Vitreous
Specific gravity: c. 2.4
Optical properties: Translucent

Obsidian is a volcanic glass that occurs naturally as an extrusionary igneous rock.

Obsidian is a massive glass of volcanoes. This word is’ huge,’ but it does mean in geology that stone (obsidian is rocky, not a mineral) is homogeneous, though this is connected to geologies. Laying, slitting, leavening, phenocrysts, etc. is lacking. It is simply an unconditional piece of volcanic glass. Obsidian solidification (on earth) in most instances was subaerial. Underwater volcanic glass has alternative names such as tachyllite and hyaloclastic.

The volcanic glass and obsidian are therefore not synonymous, although you can often freely use both terms. You certainly do not use “volcanic glass” rather than “obsidian,” but be careful about it—volcanic glass isn’t always obsidian.

Volcano glass is an igneous rock made up of a magmatic content mainly uncrypted. Most of it is not crystallized because the crystals had two difficult problems which restricted their growth. It’s time the first. Large crystals have to develop for a long moment. When viscous magma is removed from a volcano and cools quickly, there’s very little. I gave a subtle indication of what might be the second issue. It is the viscosity of magma / lava. The crystals are very difficult to form if the magmatic body is thick and viscous, because they don’t have new material, when almost nothing can move inside the magma body.

So obsidian forms from viscous magma only? Often yes, but not always. The structure of most obsidians is rhyolitic. The thickest lava has the largest concentration of silica. Why does this matter? Since silica polymerizes magma. There are many bridges (chemical connections) between silica oxygen anions (SiO2), which is why it is so difficult to relocate this magma. If the water has many electrons (cations), it is less viscous, because the frame system of silica is broken by these cations.

How Obsidian is Formed?

Obsidian is created when the volcano’s felsic lava cools quickly with minimal crystal growth. The chemicals (hodium silica content) produce a elevated viscosity that shapes a natural glass from lava when rapidly drying. The chemical composition is often discovered on the edges of rhyolitic lava flows recognized as obsidian flows. The absence of crystal growth is explained by the inhibition of atomic diffusion by this high-viscous lava. Obsidian is difficult, fragile and amorphous and therefore has strong corners of fractures. The instruments for slicing and piercing were previously used and were used as operative scalpel blades experimentally.

The obsidian is the rock created by fast-cooled lava, the material father. Extensive obsidian formation can happen if felsic magma quickly recools on the corners of a volcanic dome or felsic lava stream, or if lava cools during abrupt water or wind touch. Obsidian can be intrusive when felsic lava cools on the edges of a deck.

Obsidian consists of approximately 70% or more of the silicone (silicone dioxide) that has been uncristallised. It is like granite and rhyolite, which were also initially frozen, chemically. As obsidian is not mineral crystals, it is not a real “stone” technically obsidian. It is actually a congealed fluid with small quantities of microscopic and impure microscopy. Obsidian with a typical hardness of 5 to 5.5 is comparatively gentle on the level of mineral hardness. In contrast, quartz (silicium dioxide crystallized) is of 7.0 hardness.

Why Obsidian is Black?

Pure obsidian is generally black, although the colour differs with the existence of impurity. The jade could be light gray to black with iron and other transformation components. The majority of black obsidians are magnetite-nanoinclusions, iron oxide. Very few obsidian specimens are almost colorless. In some rocks, the incorporation of the mineral cristobalitis in the black glass of tiny, yellow, radially grouped rocks produces a blotchy (snowflaking) image.

Obsidian can include patterns of gas bubbles from the lava flow that align with layers created during molten rock before cooling. These bubbles could generate exciting impacts like a golden blade (obsidian blade). The inclusion of magnetite nanoparticles, which create a thin-film interference, causes an iridescent, rainbow-like shine. Mexican colorful rainbow obsidian contains hedenbergite oriented nanorods which cause rainbow strewning effects via interference with thin films.

The various colors of obsidian are a result of several factors. There are very few clear obsidian types, or microscopic mineral crystals. Obsidian red or brown usually results in small crystals or hematite or limonite (iron oxide) inclusions. The jet-black types of obsidian are probable to generate abundant microscopic crystals of minerals such as magnet, hornblende, pyroxene, plagioclase, and biotites in combination with smaller pieces of rocken. The distinctive blue, green, violet or bronze colours of the rainbow obsidian may be obtained from a microscope of multiple feldspar kinds.

Where Obsidian is Found?

Obsidian can be discovered in places with rhyolitical temperatures. You can find it in Argentina, Australia, Chile, Azerbaijan, Armenia, Guatemala, Iceland, Mexico, New Zealand, Iceland, Peru, Greece, El Salvador, Turkey, Kenya, Mexico, Peru and New Zealand. In Cascade Range of the west of north America and in the south of California’s Sierra Nevada, Obsidian streams can be discovered within Newberry Volcano calderas and Medicine Lake Volcano. Yellowstone National Park is situated between Mammoth Hot Springs and the Norris Geyser Basin and has an obsidian mountain ranges and reservoirs in many other Western US States such as Arizona, Colorado, New Mexico, Texas, Utah, Washington, Oregon, and Idaho. The southern countries of Virginia, as well as Pennsylvania and North Carolina are also subject to obsidian.

In the main Mediterranean there are only four significant deposits: Lipari, Pantelleria, Palmarola and Monte Arci. Milos and Gyali were former suppliers in the Aegean.

The most significant springs in Central Anatolia, one of the main sources in the prehistorical Middle East, were the city Acıgöl and the Göllü Dağ volcano.

Superdeep diamonds confirm ancient reservoir deep under Earth’s surface

August 17, 2019

Diamonds from the Juina area: most of these are superdeep diamonds. Credit: Graham Pearson

Analyses show that gases found in microscopic inclusions in diamonds come from a stable subterranean reservoir at least as old as the Moon, hidden more than 410 km below sea level in the Earth’s mantle.

Scientists have long suspected that an area of the Earth’s mantle, somewhere between the crust and the core, contains a vast reservoir of rock, comparatively undisturbed since the planet’s formation. Until now, there has been no firm proof if or where it exists. Now an international group of scientists has measured helium isotopes contained in superdeep diamonds brought to the surface by violent volcanic eruptions, to detect the footprints of this ancient reservoir. This work will be presented to scientists for the first time on Friday 23rd August at the Goldschmidt conference in Barcelona, after publication today (15 August) in the journal Science.

After the formation of the Earth, violent geological activity and extra-terrestrial impacts disrupted the young planet, meaning that almost nothing of the Earth’s original structure remains. Then in the 1980’s geochemists noted that in some basalt lavas from particular locations the ratio of the helium 3 to helium 4 isotope was higher than expected, mirroring the isotope ratio found in extremely old meteorites which had fallen to Earth. This indicates that the lava had carried the material from some kind of reservoir deep in the Earth, with a composition which hasn’t changed significantly in the last 4 billion years. “This pattern has been observed in “Ocean Island Basalts,” which are lavas coming to the surface from deep in the Earth, and form islands such as Hawaii and Iceland” said research leader Dr. Suzette Timmerman, from the Australian National University. “The problem is that although these basalts are brought to the surface, we only see a glimpse of their history. We don’t know much about the mantle where their melts came from.”

To address this problem, Timmerman’s team looked at helium isotope ratios in superdeep diamonds. Most diamonds are formed between 150 to 230 km below the Earth’s crust, before being carried to the surface by melts. Very occasionally some ‘superdeep’ diamonds (created between 230 and 800 km below the Earth’s surface) are brought to the surface. These superdeep diamonds are recognizably different from normal diamonds.

Suzette Timmerman said, “Diamonds are the hardest, most indestructible natural substance known, so they form a perfect time capsule that provides us a window into the deep Earth. We were able to extract helium gas from twenty-three super-deep diamonds from the Juina area of Brazil. These showed the characteristic isotopic composition that we would expect from a very ancient reservoir, confirming that the gases are remnants of a time at or even before the Moon and Earth collided. From the geochemistry of the diamonds, we know that they formed in an area called the “transition zone,” which is between 410 and 660 km below the surface of the Earth. This means that this unseen reservoir, left over from the Earth’s beginnings, must be in this area or below it.

“Questions remain about the form of this reservoir; is it a large single reservoir, or are there multiple smaller ancient reservoirs? Where exactly is the reservoir? What is the complete chemical composition of this reservoir? But with this work, we are beginning to home in on what is probably the oldest remaining comparatively undisturbed material on Earth,” she says.

Commenting, Professor Matthew Jackson (University of California, Santa Barbara) said, “There has been a lot of work focused on identifying the location of primordial reservoirs in the deep Earth. So this is an interesting result, with a lot of potential to “map out” where elevated 3He/4He domains are located in the Earth’s deep interior. Helium can diffuse rapidly at mantle conditions, so it will be important to evaluate whether the ancient helium signature reflects compositions trapped at diamond-formation depths, or the composition of the host lava that transported to diamonds to the surface. This work is an important step towards understanding these reservoirs, and points the way to further research.”

Reference:
S. Timmerman el al., “Primordial and recycled helium isotope signatures in the mantle transition zone,” Science (2019). science.sciencemag.org/cgi/doi … 1126/science.aax5293

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

Dinosaur brains from baby to adult

August 17, 2019

Head posture if the lateral (horizontal) semi-circular canal is parallel to the ground, in hatching (A), juvenile (B) and adult (C) Psittacosaurus lutjiatunensis. Images not to scale. Credit: Claire Bullar and IVPP.

New research by a University of Bristol palaeontology post-graduate student has revealed fresh insights into how the braincase of the dinosaur Psittacosaurus developed and how this tells us about its posture.

Psittacosaurus was a very common dinosaur in the Early Cretaceous period — 125 million years ago — that lived in eastern Asia, especially north-east China.

Hundreds of samples have been collected which show it was a beaked plant-eater, an early representative of the Ceratopsia, which had later relatives with great neck frills and face horns, such as Triceratops.

The babies hatched out as tiny, hamster-sized beasts and grew to two metres long as adults.

As they grew, the brain changed in shape, from being crammed into the back of the head, behind the huge eyes in the hatchling, to being longer, and extending under the skull roof in the adults.

The braincase also shows evidence for a change in posture as the animals grew. There is good evidence from the relative lengths of the arms and legs, that baby Psittacosaurus scurried about on all fours, but by the age of two or three, they switched to a bipedal posture, standing up on their elongate hind legs and using their arms to grab plant food.

Claire Bullar from the University of Bristol’s School of Earth Sciences led the new research which has been published this week in PeerJ.

She said: “I was excited to see that the orientation of the semi-circular canals changes to show this posture switch.

“The semi-circular canals are the structures inside our ears that help us keep balance, and the so-called horizontal semi-circular canal should be just that — horizontal — when the animal is standing in its normal posture.

“This is just what we see, with the head of Psittacosaurus pointing down and forwards when it was a baby — just right for moving on all-fours. Then, in the teen or adult, we see the head points exactly forwards, and not downwards, just right for a biped.”

Co-supervisor Dr Qi Zhao from the Institute of Vertebrate Palaeontology and Palaeoanthropology (IVPP) in Beijing, where the specimens are housed, added: “It’s great to see our idea of posture shift confirmed, and in such a clear-cut way, from the orientation of the horizontal ear canal.

“It’s also amazing to see the results of high-quality CT scanning in Beijing and the technical work by Claire to get the best 3D models from these scan data.”

Professor Michael Ryan of Carleton University, Ottawa, Canada, another collaborator, said: “This posture shift during growth from quadruped to biped is unusual for dinosaurs, or indeed any animal. Among dinosaurs, it’s more usual to go the other way, to start out as a bipedal baby, and then go down on all fours as you get really huge.

“Of course, adult Psittacosaurus were not so huge, and the shift maybe reflects different modes of life: the babies were small and vulnerable and so probably hid in the undergrowth, whereas bipedalism allowed the adults to run faster and escape their predators.”

Professor Michael Benton, also from the University of Bristol’s School of Earth Sciences and another collaborator, added: “This is a great example of classic, thorough anatomical work, but also an excellent example of international collaboration.

“The Bristol Palaeobiology Research Group has a long-standing collaboration with IVPP, and this enables the mix of excellent specimens and excellent research.

“Who would have imagined we could reconstruct posture of dinosaurs from baby to adult, and with multiple lines of evidence to confirm we got it right.”

Reference:
Claire M. Bullar, Qi Zhao, Michael J. Benton, Michael J. Ryan. Ontogenetic braincase development in Psittacosaurus lujiatunensis (Dinosauria: Ceratopsia) using micro-computed tomography. PeerJ, 2019; 7: e7217 DOI: 10.7717/peerj.7217

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

Ancient feces reveal how ‘marsh diet’ left Bronze Age Fen folk infected with parasites

August 17, 2019

Microscopic eggs of fish tapeworm (left), giant kidney worm (centre), and Echinostoma worm (right) from the Must Farm excavation. Black scale bar represents 20 micrometres. Credit: Marissa Ledger

New research published today in the journal Parasitology shows how the prehistoric inhabitants of a settlement in the freshwater marshes of eastern England were infected by intestinal worms caught from foraging for food in the lakes and waterways around their homes.

The Bronze Age settlement at Must Farm, located near what is now the fenland city of Peterborough, consisted of wooden houses built on stilts above the water. Wooden causeways connected islands in the marsh, and dugout canoes were used to travel along water channels.

The village burnt down in a catastrophic fire around 3,000 years ago, with artefacts from the houses preserved in mud below the waterline, including food, cloth, and jewellery. The site has been called “Britain’s Pompeii.”

Also preserved in the surrounding mud were waterlogged “coprolites” — pieces of human faeces — that have now been collected and analysed by archaeologists at the University of Cambridge. They used microscopy techniques to detect ancient parasite eggs within the faeces and surrounding sediment.

Very little is known about the intestinal diseases of Bronze Age Britain. The one previous study, of a farming village in Somerset, found evidence of roundworm and whipworm: parasites spread through contamination of food by human faeces.

The ancient excrement of the Anglian marshes tells a different story. “We have found the earliest evidence for fish tapeworm, Echinostoma worm, and giant kidney worm in Britain,” said study lead author Dr Piers Mitchell of Cambridge’s Department of Archaeology.

“These parasites are spread by eating raw aquatic animals such as fish, amphibians and molluscs. Living over slow-moving water may have protected the inhabitants from some parasites, but put them at risk of others if they ate fish or frogs.”

Disposal of human and animal waste into the water around the settlement likely prevented direct faecal pollution of the fenlanders’ food, and so prevented infection from roundworm — the eggs of which have been found at Bronze Age sites across Europe.

However, water in the fens would have been quite stagnant, due in part to thick reed beds, leaving waste accumulating in the surrounding channels. Researchers say this likely provided fertile ground for other parasites to infect local wildlife, which — if eaten raw or poorly cooked — then spread to village residents.

“The dumping of excrement into the freshwater channel in which the settlement was built, and consumption of aquatic organisms from the surrounding area, created an ideal nexus for infection with various species of intestinal parasite,” said study first author Marissa Ledger, also from Cambridge’s Department of Archaeology.

Fish tapeworms can reach 10m in length, and live coiled up in the intestines. Heavy infection can lead to anemia. Giant kidney worms can reach up to a metre in length. They gradually destroy the organ as they become larger, leading to kidney failure. Echinostoma worms are much smaller, up to 1cm in length. Heavy infection can lead to inflammation of the intestinal lining.

“As writing was only introduced to Britain centuries later with the Romans, these people were unable to record what happened to them during their lives. This research enables us for the first time to clearly understand the infectious diseases experienced by prehistoric people living in the Fens,” said Ledger.

The Cambridge team worked with colleagues at the University of Bristol’s Organic Chemistry Unit to determine whether coprolites excavated from around the houses were human or animal. While some were human, others were from dogs.

“Both humans and dogs were infected by similar parasitic worms, which suggests the humans were sharing their food or leftovers with their dogs,” said Ledger.

Other parasites that infect animals were also found at the site, including pig whipworm and Capillaria worm. It is thought that they originated from the butchery and consumption of the intestines of farmed or hunted animals, but probably did not cause humans any harm.

The researchers compared their latest data with previous studies on ancient parasites from both the Bronze Age and Neolithic. Must Farm tallies with the trend of fewer parasite species found at Bronze Age compared with Neolithic sites.

“Our study fits with the broader pattern of a shrinking of the parasite ecosystem through time,” said Mitchell. “Changes in diet, sanitation and human-animal relationships over millennia have affected rates of parasitic infection.” Although he points out that infections from the fish tapeworm found at Must Farm have seen a recent resurgence due to the popularity of sushi, smoked salmon and ceviche.

“We now need to study other sites in prehistoric Britain where people lived different lifestyles, to help us understand how our ancestors’ way of life affected their risk of developing infectious diseases,” added Mitchell.

The Must Farm site is an exceptionally well-preserved settlement dating to 900-800 BC (the Late Bronze Age). The site was first discovered in 1999. The Cambridge Archaeological Unit carried out a major excavation between 2015 and 2016, funded by Historic England and Forterra Building Products Ltd.

Reference:
Marissa L. Ledger, Elisabeth Grimshaw, Madison Fairey, Helen L. Whelton, Ian D. Bull, Rachel Ballantyne, Mark Knight, Piers D. Mitchell. Intestinal parasites at the Late Bronze Age settlement of Must Farm, in the fens of East Anglia, UK (9th century B.C.E.). Parasitology, 2019; 1 DOI: 10.1017/S0031182019001021

Note: The above post is reprinted from materials provided by University of Cambridge. The original story is licensed under a Creative Commons License.

Magnified Sand : Magnified Photos Shows How Sand Looks like

August 14, 2019

Magnified-sand grains Sand that is magnified up to 300 times

Magnified Sand

Comparing something to a grain of sand is generally meant to imply it’s tiny or meaningless, but the amazing images of Dr. Gary Greenberg produced using a microlens are aimed at turning this stereotype on his head. His pictures of tiny grains of up to 300-fold magnified colourful rocks show it under a microscope can be a hypocrisy.

Depending on where it comes from, Sand structure can differ dramatically. The Hawaiian coastal beach sands, where Dr. Greenberg is situated, are the topics of his incredible microphotography. The tiny rocks in his pictures are full of vestiges of different big and small tropical ocean species. The sand on other shores may include a completely distinct collection of stones, minerals and organic matter based on the temperature, surfing circumstances and marine environment.

The grains originate from various coasts all over the globe, from Okinawa, from Japan to Maui, from Hawaii to Smith Mountain Lake, from Va. Each fragment is distinctive and extremely lovely in personality.

Greenberg’s website explains that he spent his life “revealing the secret beauty of nature.” Using high-quality microscopes, he creates “spectacular worldscapes beyond our daily perception— worlds where reality is seen as abstract form and colour, motion and texture.”

I am fascinated by the complexity and individuality produced by a mixture of nature and the frequent crashing of surfing on a beach every moment I look through my microscope.’

Professor Greenberg, who searches through thousands of small stones with acupuncture instruments to discover and organize the most ideal samples, then utilizes a painful method to produce his pictures.

He’s been looking for notable sand grains like these to photograph the globe for five years.

He said:’ Extreme close-up photography usually provides a very small field depth so I had to create a fresh method for making the photos I wished.

I take dozens of pictures at separate focal points and then add them to create my images using software.

Even though the images look easy, it may take hours to photograph each grain of it in a manner I am pleased with.

Magnified sand grains Sand that is magnified up to 300 times

1 of 11

Credit: Sand Grains

Jurassic world of volcanoes found in central Australia

August 14, 2019

Volatile elements in magma, primarily water, drive explosive volcanic eruptions, like this eruption of Anak Krakatau in Lampung, Indonesia, in 2018. Experimental geochemists from Washington University in St. Louis have discovered compelling evidence that magmas may be wetter than once thought. Credit: Shutterstock

An international team of subsurface explorers from the University of Adelaide in Australia and the University of Aberdeen in Scotland have uncovered a previously undescribed ‘Jurassic World’ of around 100 ancient volcanoes buried deep within the Cooper-Eromanga Basins of central Australia.

The Cooper-Eromanga Basins in the north-eastern corner of South Australia and south-western corner of Queensland is Australia’s largest onshore oil and gas producing region of Australia. But, despite about 60 years of petroleum exploration and production, this ancient Jurassic volcanic underground landscape has gone largely unnoticed.

Published in the journal Gondwana Research, the researchers used advanced subsurface imaging techniques, analogous to medical CT scanning, to identify the plethora of volcanic craters and lava flows, and the deeper magma chambers that fed them. They’ve called the volcanic region the Warnie Volcanic Province, with a nod to Australian cricket legend Shane Warne.

The volcanoes developed in the Jurassic period, between 180 and 160 million years ago, and have been subsequently buried beneath hundreds of meters of sedimentary — or layered — rocks.

The Cooper-Eromanga Basins are now a dry and barren landscape but in Jurassic times, the researchers say, would have been a landscape of craters and fissures, spewing hot ash and lava into the air, and surrounded by networks of river channels, evolving into large lakes and coal-swamps.

“While the majority of Earth’s volcanic activity occurs at the boundaries of tectonic plates, or under the Earth’s oceans, this ancient Jurassic world developed deep within the interior of the Australian continent,” says co-author Associate Professor Simon Holford, from the University of Adelaide’s Australian School of Petroleum.

“Its discovery raises the prospect that more undiscovered volcanic worlds reside beneath the poorly explored surface of Australia.”

The research was carried out by Jonathon Hardman, then a PhD student at the University of Aberdeen, as part of the Natural Environment Research Council Centre for Doctoral Training in Oil and Gas.

The researchers say that Jurassic-aged sedimentary rocks bearing oil, gas and water have been economically important for Australia, but this latest discovery suggests a lot more volcanic activity in the Jurassic period than previously supposed.

“The Cooper-Eromanga Basins have been substantially explored since the first gas discovery in 1963,” says co-author Associate Professor Nick Schofield, from the University of Aberdeen’s Department of Geology and Petroleum Geology.

“This has led to a massive amount of available data from underneath the ground but, despite this, the volcanics have never been properly understood in this region until now. It changes how we understand processes that have operated in Earth’s past.”

The researchers have named their discovery the Warnie Volcanic Province after one of the drill holes that penetrated Jurassic volcanic rocks (Warnie East-1), itself named after a nearby waterhole), but also in recognition of the explosive talent of former Australian cricketer Shane Warne.

“We wrote much of the paper during a visit to Adelaide by the Aberdeen researchers, when a fair chunk was discussed and written at Adelaide Oval during an England vs Cricket Australia XI match in November 2017. Inspired by the cricket, we thought Warnie a good name for this once fiery region,” says Associate Professor Holford.

Reference:
Jonathon P.A. Hardman, Simon P. Holford, Nick Schofield, Mark Bunch, Daniel Gibbins. The Warnie volcanic province: Jurassic intraplate volcanism in Central Australia. Gondwana Research, 2019; 76: 322 DOI: 10.1016/j.gr.2019.06.012

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

Researchers study largest impact crater in the US, buried for 35 million years

August 14, 2019

The 21 shocked and unshocked zircon crystals dated in this study were separated from this ~30 cubic centimeters of unconsolidated late Eocene sediment obtained from Ocean Drilling Project site 1073, hole A. Credit: Biren/ASU

About 35 million years ago, an asteroid hit the ocean off the East Coast of North America. Its impact formed a 25-mile diameter crater that now lies buried beneath the Chesapeake Bay, an estuary in Virginia and Maryland. From this impact, the nearby area experienced fires, earthquakes, falling molten glass droplets, an air blast and a devastating tsunami.

While the resulting “Chesapeake Bay impact crater” is now completely buried, it was discovered in the early 1990s by scientific drilling. It now ranks as the largest known impact crater in the U.S., and the 15th largest on Earth.

When the asteroid hit, it also produced an impact ejecta layer, which includes tektites (natural glass formed from debris during meteorite impacts) and shocked zircon crystals which were thrown out of the impact area. Scientists refer to this layer as the “North American tektite strewn field,” which covers a region of roughly 4 million square miles, about 10 times the size of Texas. Some ejecta landed on land while the rest immediately cooled on contact with seawater and then sank to the ocean floor.

A team of researchers, including Arizona State University School of Earth and Space Exploration scientist and lead author Marc Biren, along with co-authors Jo-Anne Wartho, Matthijs Van Soest and Kip Hodges, has obtained drilling samples from the Ocean Drilling Project site 1073 and dated them with the “uranium-thorium-helium technique” for the first time.

Their research was recently published in the international journal Meteoritics & Planetary Science.

“Determining accurate and precise ages of impact events is vital in our understanding of the Earth’s history,” Biren said. “In recent years, for example, the scientific community has realized the importance of impact events on Earth’s geological and biological history, including the 65 million years old dinosaur mass extinction event that is linked to the large Chicxulub impact crater.”

The team studied zircon crystals in particular because they preserve evidence of shock metamorphism, which is caused by shock pressures and high temperatures associated with impact events. The dated crystals were tiny, about the thickness of a human hair.

“Key to our investigation were zircon — or to be more precise: zirconium silicate — crystals that we found in the oceanic sediments of a borehole, which is located almost 400 kilometers (250 miles) northeast of the impact site, in the Atlantic Ocean,” says co-author Wartho, who began the study when she was a lab manager at the Mass Spectrometry Lab at ASU.

For this study, Biren worked with co-authors Wartho (now working at GEOMAR Helmholtz Centre for Ocean Research Kiel), Van Soest and Hodges to prepare samples for analysis and to date zircon crystals with the uranium-thorium-helium dating method. Biren then identified and processed shocked zircon fragments for imaging and chemical analysis with an electron microprobe.

“This research adds a tool for investigators dating terrestrial impact structures,” Biren said. “Our results demonstrate the uranium-thorium-helium dating method’s viability for use in similar cases, where shocked materials were ejected away from the crater and then allowed to cool quickly, especially in cases where the sample size is small.”

Reference:
M. B. Biren, J.-A. Wartho, M. C. VAN Soest, K. V. Hodges, H. Cathey, B. P. Glass, C. Koeberl, J. W. Horton, W. Hale. (U-Th)/He zircon dating of Chesapeake Bay distal impact ejecta from ODP site 1073. Meteoritics & Planetary Science, 2019; 54 (8): 1840 DOI: 10.1111/maps.13316

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

Meteorite strikes made life on Earth possible

August 14, 2019

Representative Image: An example of a Pallasite meteorite (from the Esquel fall) on display in the Vale Inco Limited Gallery of Minerals at the Royal Ontario Museum. Credit: Captmondo/Wikimedia

Meteorites from the far reaches of the solar system delivered large amounts of water, carbon and volatile substances to the Earth. Only then could the Earth host life. Dr. María Isabel Varas-Reus, Dr. Stephan König, Aierken Yierpan and Professor Dr. Ronny Schönberg from Tübingen University’s Isotope Geochemistry Group, and Dr. Jean-Pierre Lorand from the Université de Nantes, provide evidence for this scenario in a new study. Using a method recently developed at the University of Tübingen, the researchers measured selenium isotopes in rocks derived from the Earth’s mantle. Identical isotope signatures in these rocks and in certain types of meteorites revealed the origin of the selenium as well as large amounts of water and other vital substances. The study has been published in the latest Nature Geoscience.

Strictly speaking, there shouldn’t be any selenium in the Earth’s mantle. “It is attracted to iron. That is why, in the early history of our planet, it went down into the iron-rich core,” Dr. María Isabel Varas-Reus explains. There was no more selenium in the Earth’s outer layer. “The previous selenium signatures were completely erased there. The selenium found in the Earth’s mantle today must therefore have been added after the formation of the Earth’s core. Geologically speaking, “at the last moment of the formation of the Earth, after our moon had also formed,” Varas-Reus adds. It’s hard to say exactly when—it could have been between 4.5 and 3.9 billion years ago.

Complex measurements

In various places, the research team took samples of mantle rocks, which have been brought to the surface by plate tectonic processes and had remained unchanged with regard to its selenium isotope composition since the formation of the Earth. The researchers determined the isotope signature of the selenium in these rocks. Isotopes are atoms of the same chemical element with different weights. “It has been possible for some time now to measure selenium isotopes in high concentrations—for example in samples from rivers,” says Varas-Reus. “However, the selenium concentration in high-temperature rocks is very low. Samples must be dissolved out at high temperatures, and selenium is volatile. This makes the measurements difficult.” But recently it became possible to measure selenium isotopes in high-temperature rocks. Dr. Stephan König and his group of researchers developed a complex method as part of his ERC grant, the O2RIGIN project funded by the European Research Council.

It has long been suspected that meteorites added substances to the Earth’s mantle. “But we thought they were meteorites from the inner solar system,” Varas-Reus says. “So we were very surprised that the selenium isotope signature of the Earth’s mantle closely matched a certain type of meteorite from the outer solar system. These are carbonaceous chondrites from the solar system beyond the asteroid belt, from the area of the planets Jupiter, Saturn, Uranus and Neptune. The selenium isotope signatures of various meteorites were collected by the geologist Dr. Jabrane Labidi, a former O2RIGIN collaborator, in a previous study.

The research team was also able to quantify what else—apart from selenium—these meteorites brought with them when they hit the early Earth. “According to our calculations, around 60 percent of the water on Earth today comes from this source. That is the only way oceans could eventually form,” says Varas-Reus. Volatile substances from the meteorites contributed to the formation of the earth’s protective atmosphere. “This created the conditions for life on Earth to develop in its present form.”

Reference:
María Isabel Varas-Reus et al. Selenium isotopes as tracers of a late volatile contribution to Earth from the outer Solar System, Nature Geoscience (2019). DOI: 10.1038/s41561-019-0414-7

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

Giant penguin fossil found in New Zealand

August 14, 2019

Canterbury Museum researcher Vanesa De Pietri (L) said the discovery reinforces the theory that penguins attained great size early in their evolution

The fossilised remains of a huge penguin almost the size of an adult human have been found in New Zealand’s South Island, scientists announced Wednesday.

The giant waddling sea bird stood 1.6 metres (63 inches) high and weighed 80 kilograms, about four times heavier and 40cm taller than the modern Emperor penguin, researchers said.

Named “crossvallia waiparensis”, it hunted off New Zealand’s coast in the Paleocene era, 66-56 million years ago.

An amateur fossil hunter found leg bones belonging to the bird last year and it was confirmed as a new species in research published this week in Alcheringa: An Australasian Journal of Palaeontology.

Canterbury Museum researcher Vanesa De Pietri said it was the second giant penguin from the Paleocene era found in the area.

“It further reinforces our theory that penguins attained great size early in their evolution,” she said.

Scientists have previously speculated that the mega-penguins eventually died out due to the emergence of other large marine predators such as seals and toothed whales.

New Zealand is well known for its extinct giant birds, including the flightless moa, which was up to 3.6-metres tall, and Haast’s eagle, which had a wingspan of three metres.

Just last week, Canterbury Museum announced the discovery of a prodigious parrot that was one metre tall and lived about 19 million years ago.

Reference:
Gerald Mayr et al. Leg bones of a new penguin species from the Waipara Greensand add to the diversity of very large-sized Sphenisciformes in the Paleocene of New Zealand, Alcheringa: An Australasian Journal of Palaeontology (2019). DOI: 10.1080/03115518.2019.1641619

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

Aquamarine : The World’s Largest Aquamarine Gem – Dom Pedro Aquamarine

August 13, 2019

The Dom Pedro aquamarine obelisk by gem sculptor Bernd Munsteiner

What is Aquamarine?

Aquamarine is a blue or cyan variety of beryl. It happens in most locations where normal beryl is produced. Sri Lanka’s deposits of gem-gravel placer contain aquamarine. Green-yellow beryl is sometimes referred to as chrysolite aquamarine, as happening in Brazil. Aquamarine’s deep blue version is called maxixe. Maxixe is frequently discovered in the Madagascar nation. When exposed to sunlight or undergoing heat treatment, its color fades to white, although the color returns with irradiation.

Aquamarine’s pale blue colour is ascribed to Fe2 +. Fe3 + electrons generate golden-yellow colour, and when both Fe2 + and Fe3 + are present, the colour is as dark as maxixe. Light or heat decoloration of the maxix may therefore be due to the transfer of charges between Fe3 + and Fe2 +. By irradiating it with high-energy particles (gamma rays, neutrons or even X-rays), dark-blue maxix color can be produced in green, pink or yellow beryl.

Aquamarines can be discovered at the Mt. Antero peak in the Sawatch Range in central Colorado in the United States. Aquamarine was found in Wyoming, close Powder River Pass, in the Big Horn Mountains. Another U.S. place is the Sawtooth Range close Stanley, Idaho, although the minerals are within a wilderness area that prohibits collection. In Brazil, in the countries of Minas Gerais, Espírito Santo, and Bahia, and in Rio Grande do Norte, there are mines. Aquamarine is also produced by Colombia, Zambia, Madagascar, Malawi, Tanzania and Kenya mines.

The biggest Cut aquamarine gem in the world

The aquamarine Dom Pedro is the biggest cut aquamarine gem in the world. It was trimmed from a crystal with an original weight of about 100 pounds (45 kg) and a span of over 3 feet (0.91 m). The rock was mined around 1980 in Pedra Azul, Brazil’s Minas Gerais state, named after the Brazilian emperors Pedro I and Pedro II.

Bernd Munsteiner cuted the blue-green gemstone into an obelisk shape weighing 10,363 carats. The completed size is 14 inches (36 cm) high by 4 inches (10 cm) broad. Jane Mitchell and Jeffery Bland donated the gem to the Smithsonian Institution. It is located in the Janet Annenberg Hooker Hall of Geology of the National Museum of Natural History.

Dom Pedro Aquamarine

The Dom Pedro Aquamarine, the biggest single piece of cut-gem aquamarine in the globe, will be permanently displayed at the National Museum of Natural History starting Dec. 6. In the Janet Annenberg Hooker Hall of Geology, Gems and Minerals such as the Hope Diamond and the Marie Antoinette necklace, it connects an illustrious set of renowned gemstones already on display. The piece was given by Jane M. Mitchell and Jeffery S. Bland. It is an extremely rare gem due to the quality of the initial crystal and its size, magnificent blue-green colour and unique shape.

“There’s so much noteworthy about the Dom Pedro, but what excites me most is that we can maintain the tale that comes with it,” said Kirk Johnson, National Museum of Natural History’s Sant Director. “The Dom Pedro is enhanced by all the people and places in the National Gem Collection that were component of his intriguing trip from the Earth’s crust to his home here. We are thankful for their fantastic donation to Jane Mitchell and Jeffery Bland.

Mined from a Brazilian pegmatite in the early 1980s, for the first two presidents of Brazil, Dom Pedro Primeiro and his brother, Dom Pedro Segundo, the splendid aquamarine was appointed. The portion of the beryl crystal from which the obelisk-shaped gem was fashioned was 23.25 inches long and weighed almost 60 pounds before cutting. The obelisk, built by Bernd Munsteiner, a world-renowned gem artist, lies 14 inches high, measures 4 inches across the foundation and averages 10,363 carats or 4.6 pounds. These amazing sizes make the Dom Pedro recognized as the biggest aquamarine cut-and-polished gem. A model of tapering “adverse splits” facing the sea-blue obelisk’s opposite sides helps to represent the light within the gem, giving the piece startling brightness and brightness. This notable sculpture appears to be illuminated from the inside with the correct lighting.

Munsteiner is considered one of the 20th century’s greatest gem artists, the “Father of the Fantasy Cut.” In order to produce gem carvings, he mixes traditional techniques with vibrant contemporary types. Born to a family of jewel carvers, Munsteiner’s job is the expression of an art practice that has gone from generation to generation.

At the era of 14, he became a family business apprentice and subsequently became a teacher at the School of Design in Phorzheim, Germany, where he graduated as a manufacturer of precious stones and jewelry. It was at college that Munsteiner was invited to bring the traditional cameo into a fresh shape for the first time, and he has since stretched borders and questioned traditional techniques. His faceting method recognized as “Fantasy Cuts” has influenced a modernization of the development of gem art, and the Dom Pedro Aquamarine exemplifies his creative style. Munsteiner spent four months researching the crystal carefully and another six months cutting, polishing and faceting to produce this unparalleled art job.

Apart from 350,000 mineral specimens, the Dom Pedro Aquamarine joins the Smithsonian’s famous gem and mineral collection of over 10,000 gems. The Smithsonian’s collection of gems and minerals is one of its biggest.

Researchers discover oldest fossil forest in Asia

August 13, 2019

Reconstructions of lycopsid trees (Guangdedendron micrum). Left: juvenile plant. Right: adult plant. Credit: Zhenzhen Deng

The Devonian period, which was 419 million to 359 million years ago, is best known for Tiktaalik, the lobe-finned fish that is often portrayed pulling itself onto land. However, the “age of the fishes,” as the period is called, also saw evolutionary progress in plants. Researchers reporting August 8 in the journal Current Biology describe the largest example of a Devonian forest, made up of 250,000 square meters of fossilized lycopsid trees, which was recently discovered near Xinhang in China’s Anhui province. The fossil forest, which is larger than Grand Central Station, is the earliest example of a forest in Asia.

Lycopsids found in the Xinhang forest resembled palm trees, with branchless trunks and leafy crowns, and grew in a coastal environment prone to flooding. These lycopsid trees were normally less than 3.2 meters tall, but the tallest was estimated at 7.7 meters, taller than the average giraffe. Giant lycopsids would later define the Carboniferous period, which followed the Devonian, and become much of the coal that is mined today. The Xinhang forest depicts the early root systems that made their height possible. Two other Devonian fossil forests have been found: one in the United States, and one in Norway.

“The large density as well as the small size of the trees could make Xinhang forest very similar to a sugarcane field, although the plants in Xinhang forest are distributed in patches,” says Deming Wang, a professor in the School of Earth and Space Sciences at Peking University, co-first author on the paper along with Min Qin of Linyi University. “It might also be that the Xinhang lycopsid forest was much like the mangroves along the coast, since they occur in a similar environment and play comparable ecologic roles.”

The fossilized trees are visible in the walls of the Jianchuan and Yongchuan clay quarries, below and above a four-meter thick sandstone bed. Some fossils included pinecone-like structures with megaspores, and the diameters of fossilized trunks were used to estimate the trees’ heights. The authors remarked that it was difficult to mark and count all the trees without missing anything.

“Jianchuan quarry has been mined for several years and there were always some excavators working at the section. The excavations in quarries benefit our finding and research. When the excavators stop or left, we come close to the highwalls and look for exposed erect lycopsid trunks,” says Wang, who, with Qin, found the first collection of fossil trunks in the mine in 2016. “The continuous finding of new in-situ tree fossils is fantastic. As an old saying goes: the best one is always the next one.”

This work was supported by The National Natural Science Foundation of China.

Reference:
Deming Wang, Min Qin, Le Liu, Lu Liu, Yi Zhou, Yingying Zhang, Pu Huang, Jinzhuang Xue, Shihui Zhang, Meicen Meng. The Most Extensive Devonian Fossil Forest with Small Lycopsid Trees Bearing the Earliest Stigmarian Roots. Current Biology, 2019; DOI: 10.1016/j.cub.2019.06.053

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

A new timeline of Earth’s cataclysmic past

August 13, 2019

Depictions of large asteroids striking Earth, which, during parts of its early history, would have had a much thicker atmosphere than it does today. Credits: NASA with modifications by Stephen Mojzsis

Welcome to the early solar system. Just after the planets formed more than 4.5 billion years ago, our cosmic neighborhood was a chaotic place. Waves of comets, asteroids and even proto-planets streamed toward the inner solar system, with some crashing into Earth on their way.

Now, a team led by University of Colorado Boulder geologist Stephen Mojzsis has laid out a new timeline for this violent period in our planet’s history.

In a study published today, the researchers homed in on a phenomenon called “giant planet migration.” That’s the name for a stage in the evolution of the solar system in which the largest planets, for reasons that are still unclear, began to move away from the sun.

Drawing on records from asteroids and other sources, the group estimated that this solar system-altering event occurred 4.48 billion years ago — much earlier than some scientists had previously proposed.

The findings, Mojzsis said, could provide scientists with valuable clues around when life might have first emerged on Earth.

“We know that giant planet migration must have taken place in order to explain the current orbital structure of the outer solar system,” said Mojzsis, a professor in the Department of Geological Sciences. “But until this study, nobody knew when it happened.”

It’s a debate that, at least in part, comes down to moon rocks collected by Apollo astronauts — many of which seemed to be only 3.9 billion years old, hundreds of millions of years younger than the moon itself.

To explain those ages, some researchers suggested that our moon, and Earth, were slammed by a surge of comets and asteroids around that time. But not everyone agreed with the theory, Mojzsis said.

“It turns out that the part of the moon we landed on is very unusual,” he said. “It is strongly affected by one big impact, the Imbrium Basin, that is about 3.9 billion years old and affects nearly everything we sampled.”

To get around that bias, the researchers decided to compile the ages from an exhaustive database of meteorites that had crash landed on Earth.

“The surfaces of the inner planets have been extensively reworked both by impacts and indigenous events until about 4 billion years ago,” said study coauthor Ramon Brasser of the Earth-Life Science Institute in Tokyo. “The same is not true for the asteroids. Their record goes back much further.”

But those records, the team discovered, only went back to about 4.5 billion years ago.

For the researchers, that presented only one possibility: The solar system must have experienced a major bombardment just before that cut-off date. Very large impacts, Mojzsis said, can melt rocks and variably reset their radioactive ages, a bit like shaking an etch-a-sketch.

Mojzsis explained that this carnage was likely kicked off by the solar system’s giant planets, which researchers believe formed much closer together than they are today. Using computer simulations, however, his group demonstrated that those bodies started to creep toward their present locations about 4.48 billion years ago.

In the process, they scattered the debris in their wake, sending some of it hurtling toward Earth and its then-young moon.

The findings, Mojzsis added, open up a new window for when life may have evolved on Earth. Based on the team’s results, our planet may have been calm enough to support living organisms as early as 4.4 billion years ago.

Other co-authors on the study include Nigel Kelly, formerly of CU Boulder, Oleg Abramov at the Planetary Science Institute and Stephanie Werner at the University of Oslo.

Reference:
Stephen J. Mojzsis, Ramon Brasser, Nigel M. Kelly, Oleg Abramov, Stephanie C. Werner. Onset of Giant Planet Migration before 4480 Million Years Ago. The Astrophysical Journal, 2019; 881 (1): 44 DOI: 10.3847/1538-4357/ab2c03

Note: The above post is reprinted from materials provided by University of Colorado at Boulder. Original written by Daniel Strain.

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