What is the Black Stone of Mecca? What is the type of Black Stone?

January 11, 2018

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What is the Black Stone of Mecca?

The Black Stone of Mecca, Al-Ḥajaru al-Aswad, “Black Stone”, or Kaaba Stone, is a Muslim relic, which according to Islamic tradition dates back to the time of Adam and Eve. It is the eastern cornerstone of the Kaaba, the ancient sacred stone building towards which Muslims pray, in the center of the Grand Mosque in Mecca, Saudi Arabia. The Stone is a dark rock, polished smooth by the hands of millions of pilgrims, that has been broken into a number of fragments cemented into a silver frame in the side of the Kaaba. Although it has often been described as a meteorite, this hypothesis is still under consideration. It is the eastern cornerstone of the Kaaba, the ancient sacred stone building towards which Muslims pray, in the center of the Grand Mosque in Mecca, Saudi Arabia.

The Stone is roughly 30 cm (12 in.) in diameter, and 1.5 meters (5 ft.) above the ground. When pilgrims circle the Kaaba as part of the Tawaf ritual of the Hajj, many of them try, if possible, to stop and kiss the Black Stone, emulating the kiss that it received from the Islamic prophet Muhammad. If they cannot reach it, they are to point to it on each of their seven circuits around the Kaaba. The Stone is broken into a number of pieces from damage which was inflicted during the Middle Ages. The pieces are held together by a silver frame, which is fastened by silver nails to the Stone.

There are various opinions as to what the Black Stone actually is. Muslims say that the Stone was found by Abraham (Ibrahim) and his son Ishmael (Ismail) when they were searching for stones with which to build the Kaaba. They recognized its worth and made it one of the building’s cornerstones.

Secular historians point to the history of stone worship, and especially meteorite worship, in pre-Islamic Arabia, and say that it is likely that the Stone is a meteorite. There is no way to test this hypothesis without removing and examining the Stone, which would not be permitted by its guardians.

Many geologists across the world have tried their best to ascertain the type and nature of the Black Stone, but couldn’t achieve the ultimate findings because of cultural and religious restrictions which didn’t allow anyone to drill the stone for scientific purpose.

The nature of the Black Stone has been much debated. It has been described variously as basalt stone, an agate, a piece of natural glass or — most popularly — a stony meteorite.

Anthony Hampton and his team of geologists from Oxford University studied the local samples collected from the emplacement of the stone and found important quantities of iridium and many shatter cones, a rare geological feature only known to form in the bedrock beneath meteorite impact craters which favored the findings of Paul Partsch who published the first comprehensive history of the Black stone in 1857.

In 1974, Robert Dietz and John McHone commented that the stone contained clearly discernible diffusion banding characteristics of agates.

They also mentioned that the color of the stone is jet black and looks polished, which is the result of constant handling by the pilgrims, and this rules out again the possibility of a chondrite which wouldn’t withstand the constant rubbing nor would it take such a high polish.

At present, the Black Stone is comprised of eight small pieces of varying sizes, the largest one being the size of a date. Six (additional) pieces are found to be in Istanbul and Turkey.

In 1294 A.H. Al-Kurdi said that there were 15 visible pieces and some of the pieces were hidden under the putty with which the stone had been repaired, and whenever any piece became loose, they were attached to the top of the stone with wax, musk and ambergris which were kneaded together.

What is the type of Black Stone? “Meteor Impact or Volcanic Lava?”

In 1980, Elsebeth Thomsen of the University of Copenhagen proposed that the Black Stone may be a glass fragment or impactite from the impact of a fragmented meteorite that fell some 6000 years ago at Wabar.

That impact site is located in Rub’al Khali Desert which lies 1,100 km east of Makkah.

At that site there are blocks of silica glass of white or yellow interior and gas-filled hollows which allow them to float in water which coincides with the property of Black Stone which floats in water and doesn’t get hot in fire.

On the contrary, a study by the United States Geological Survey have proved from Thermoluminescence (TL) dating analysis that the Wabar impact event occurred at or after 250 years from now, so surely the Black Stone wasn’t part of Wabar.

They also say that the Black Stone is probably obsidian from a common lava flow in one of the Harrats (volcanic fields) found in the western Arabian Shield.

Harrat Rahat, which lies just east of Madinah Al-Munnawarrah, erupted last around 1270 AD (anno Domini), and among other things flowed west towards Madinah and then down (northwards) the big Wadi to the east of the city where the modern airport lies.

It’s not unreasonable to think that lava at some point in western Arabia encountered water and solidified to obsidian.

There are lots of glass fragments from the Wabar impact event at the site. They are so dense, in fact, that they serve effectively as a lag-gravel and have anchored the pre-impact dune surface at the site.

Probably 99.9% of the incoming iron asteroids were converted into this glass, which is 10% iron-nickel and 90% local sand from chemical analysis.

The glass does have fragments of white impactite (instantaneously-formed quasi-sandstone from the shockwave) in it, but the surface is always extremely rugged and full of vessicles.

For this reason, the Black Stone is probably obsidian, though it could conceivably be a highly-hand-polished stony meteorite.

Nevertheless, geologists are still on their anxious seats to unveil about Al-Hajar Al-Aswad as there isn’t still any irrefutable scientific evidence.

Reference:
Wikipedia: Black Stone
Crystalinks: The Black Stone of Mecca
About Islam: Obscurity of Al-Hajar Al-Aswad
Meteoritical Society: Kaaba Stone: Not A Meteorite, Probably an AGATE

A new species of turkey-sized dinosaur is discovered from Australia

January 11, 2018

The partial skeleton of a new species of turkey-sized herbivorous dinosaur has been discovered in 113 million year old rocks in southeastern Australia. As reported in open access journal PeerJ, the fossilized tail and foot bones give new insight into the diversity of the small, bipedal herbivorous dinosaurs called ornithopods that roamed the great rift valley that once existed between Australia and Antarctica. The new dinosaur has been named Diluvicursor pickeringi, which means Pickering’s Flood-Running dinosaur.

Lower Cretaceous rocks of the deep sedimentary basins that formed within the Australian-Antarctic rift are now exposed as wave-cut rock platforms and sea-cliffs along the south coast of Victoria. The skeleton of Diluvicursor pickeringi was discovered in 2005 by volunteer prospector George Caspar, eroding from such a rock platform at a locality called Eric the Red West, near Cape Otway.

“Diluvicursor shows for the first time that there were at least two distinct body-types among closely related ornithopods in this part of Australia,” Dr Matt Herne, lead author of the new study said.

“One was lightly built with an extraordinarily long tail, while the other, Diluvicursor, was more solidly built, with a far shorter tail. Our preliminary reconstruction of the tail musculature of Diluvicursor suggests this dinosaur was a good runner, with powerful leg retracting muscles,” Dr Herne said.

“Understanding the ecology of these dinosaurs — what they ate, how they moved, where they roamed — based on the interplay between anatomy and the environment presents exciting challenges for future research.”

The species name honors the late David Pickering, who was Museums Victoria’s Collection Manager, Vertebrate Palaeontology. David contributed significantly to Australian paleontology in the lab and field, and tirelessly assisted countless students of paleontology and researchers to achieve their goals. Sadly, David passed away just over a year ago on Christmas Eve 2016.

The site of Eric the Red West has additional importance as it helps build a picture the ancient rift valley ecosystem. Fossil vertebrate remains at this site were buried in deep scours at the base of a powerful river, along with flood-transported tree stumps, logs and branches.

“The carcass of the Diluvicursor pickeringi holotype appears to have become entangled in a log-jam at the bottom of this river,” explained Dr Herne. “The sizes of some of the logs in the deposit and the abundance of wood suggest the river traversed a well-forested floodplain. The logs preserved at the site are likely to represent conifer forests of trees within families still seen in Australia today.”

“Much of the fossil vertebrate material from Eric the Red West has yet to be described, so further dinosaurs and other exciting animals from this site are now anticipated.”

Reference:
Matthew C. Herne, Alan M. Tait, Vera Weisbecker, Michael Hall, Jay P. Nair, Michael Cleeland and Steven W. Salisbury. A new small-bodied ornithopod (Dinosauria, Ornithischia) from a deep, high-energy Early Cretaceous river of the Australian–Antarctic rift system. PeerJ, 2018; DOI: 10.7717/peerj.4113

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

Steep slopes on Mars reveal structure of buried ice on Red Planet

January 11, 2018

A cross-section of underground ice is exposed at the steep slope that appears bright blue in this enhanced-color view from the HiRISE camera on NASA's Mars Reconnaissance Orbiter. — A cross-section of underground ice is exposed at the steep slope that appears bright blue in this enhanced-color view from the HiRISE camera on NASA’s Mars Reconnaissance Orbiter. The scene is about 550 yards wide. The scarp drops about 140 yards from the level ground in the upper third of the image. Credit: NASA/JPL-Caltech/UA/USGS

Researchers using NASA’s Mars Reconnaissance Orbiter (MRO) have found eight sites where thick deposits of ice beneath Mars’ surface are exposed in faces of eroding slopes.

These eight scarps, with slopes as steep as 55 degrees, reveal new information about the internal layered structure of previously detected underground ice sheets in Mars’ middle latitudes.

The ice was likely deposited as snow long ago. The deposits are exposed in cross section as relatively pure water ice, capped by a layer one to two yards (or meters) thick of ice-cemented rock and dust. They hold clues about Mars’ climate history. They also may make frozen water more accessible than previously thought to future robotic or human exploration missions.

Researchers who located and studied the scarp sites with the High Resolution Imaging Science Experiment (HiRISE) camera on MRO reported the findings today in the journal Science. The sites are in both northern and southern hemispheres of Mars, at latitudes from about 55 to 58 degrees, equivalent on Earth to Scotland or the tip of South America.

“There is shallow ground ice under roughly a third of the Martian surface, which records the recent history of Mars,” said the study’s lead author, Colin Dundas of the U.S. Geological Survey’s Astrogeology Science Center in Flagstaff, Arizona. “What we’ve seen here are cross-sections through the ice that give us a 3-D view with more detail than ever before.”

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Windows into underground ice

The scarps directly expose bright glimpses into vast underground ice previously detected with spectrometers on NASA’s Mars Odyssey (MRO) orbiter, with ground-penetrating radar instruments on MRO and on the European Space Agency’s Mars Express orbiter, and with observations of fresh impact craters that uncover subsurface ice. NASA sent the Phoenix lander to Mars in response to the Odyssey findings; in 2008, the Phoenix mission confirmed and analyzed the buried water ice at 68 degrees north latitude, about one-third of the way to the pole from the northernmost of the eight scarp sites.

The discovery reported today gives us surprising windows where we can see right into these thick underground sheets of ice,” said Shane Byrne of the University of Arizona Lunar and Planetary Laboratory, Tucson, a co-author on today’s report. “It’s like having one of those ant farms where you can see through the glass on the side to learn about what’s usually hidden beneath the ground.”

Scientists have not determined how these particular scarps initially form. However, once the buried ice becomes exposed to Mars’ atmosphere, a scarp likely grows wider and taller as it “retreats,” due to sublimation of the ice directly from solid form into water vapor. At some of them, the exposed deposit of water ice is more than 100 yards, or meter, thick. Examination of some of the scarps with MRO’s Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) confirmed that the bright material is frozen water. A check of the surface temperature using Odyssey’s Thermal Emission Imaging System (THEMIS) camera helped researchers determine they’re not seeing just thin frost covering the ground.

Researchers previously used MRO’s Shallow Radar (SHARAD) to map extensive underground water-ice sheets in middle latitudes of Mars and estimate that the top of the ice is less than about 10 yards beneath the ground surface. How much less? The radar method did not have sufficient resolution to say. The new ice-scarp studies confirm indications from fresh-crater and neutron-spectrometer observations that a layer rich in water ice begins within just one or two yards of the surface in some areas.

Astronauts’ access to Martian water

The new study not only suggests that underground water ice lies under a thin covering over wide areas, it also identifies eight sites where ice is directly accessible, at latitudes with less hostile conditions than at Mars’ polar ice caps. “Astronauts could essentially just go there with a bucket and a shovel and get all the water they need,” Byrne said.

The exposed ice has scientific value apart from its potential resource value because it preserves evidence about long-term patterns in Mars’ climate. The tilt of Mars’ axis of rotation varies much more than Earth’s, over rhythms of millions of years. Today the two planets’ tilts are about the same. When Mars tilts more, climate conditions may favor buildup of middle-latitude ice. Dundas and co-authors say that banding and color variations apparent in some of the scarps suggest layers “possibly deposited with changes in the proportion of ice and dust under varying climate conditions.”

This research benefited from coordinated use of multiple instruments on Mars orbiters, plus the longevities at Mars now exceeding 11 years for MRO and 16 years for Odyssey. Orbital observations will continue, but future missions to the surface could seek additional information.

“If you had a mission at one of these sites, sampling the layers going down the scarp, you could get a detailed climate history of Mars,” suggested MRO Deputy Project Scientist Leslie Tamppari of NASA’s Jet Propulsion Laboratory, Pasadena, California. “It’s part of the whole story of what happens to water on Mars over time: Where does it go? When does ice accumulate? When does it recede?”

The University of Arizona operates HiRISE, which was built by Ball Aerospace & Technologies Corp., Boulder, Colorado. The Johns Hopkins University Applied Physics Laboratory, Laurel, Maryland, leads MRO’s CRISM investigation. The Italian Space Agency provided MRO’s SHARAD instrument, Sapienza University of Rome leads SHARAD operations, and the Planetary Science Institute, based in Tucson, Arizona, leads U.S. involvement in SHARAD. Arizona State University, Tempe, leads the Odyssey mission’s THEMIS investigation. JPL, a division of Caltech in Pasadena, California, manages the MRO and Odyssey projects for the NASA Science Mission Directorate in Washington. Lockheed Martin Space, Denver, built both orbiters and supports their operation.

Reference:
Colin M. Dundas et al. Exposed subsurface ice sheets in the Martian mid-latitudes. Science, 2018 DOI: 10.1126/science.aao1619

Note: The above post is reprinted from materials provided by NASA/Jet Propulsion Laboratory.

Machine learning predicts new details of geothermal heat flux beneath the Greenland Ice Sheet

January 11, 2018

These are geothermal heat flux predictions for Greenland. Direct GHF measurements from the coastal rock cores, inferences from ice cores, and additional Gaussian-fit GHF data around ice core sites are used as training samples. Predictions are shown for three different values. The white dashed region roughly shows the extent of elevated heat flux and a possible trajectory of Greenland’s movement over the Icelandic plume. Credit: KU News Service

A paper appearing in Geophysical Research Letters uses machine learning to craft an improved model for understanding geothermal heat flux — heat emanating from the Earth’s interior — below the Greenland Ice Sheet. It’s a research approach new to glaciology that could lead to more accurate predictions for ice-mass loss and global sea-level rise.

Among the key findings:

Greenland has an anomalously high heat flux in a relatively large northern region spreading from the interior to the east and west.

Southern Greenland has relatively low geothermal heat flux, corresponding with the extent of the North Atlantic Craton, a stable portion of one of the oldest extant continental crusts on the planet. The research model predicts slightly elevated heat flux upstream of several fast-flowing glaciers in Greenland, including Jakobshavn Isbræ in the central-west, the fastest moving glacier on Earth.

“Heat that comes up from the interior of the Earth contributes to the amount of melt on the bottom of the ice sheet — so it’s extremely important to understand the pattern of that heat and how it’s distributed at the bottom of the ice sheet,” said Soroush Rezvanbehbahani, a doctoral student in geology at the University of Kansas who spearheaded the research. “When we walk on a slope that’s wet, we’re more likely to slip. It’s the same idea with ice — when it isn’t frozen, it’s more likely to slide into the ocean. But we don’t have an easy way to measure geothermal heat flux except for extremely expensive field campaigns that drill through the ice sheet. Instead of expensive field surveys, we try to do this through statistical methods.”

Rezvanbehbahani and his colleagues have adopted machine learning — a type of artificial intelligence using statistical techniques and computer algorithms — to predict heat flux values that would be daunting to obtain in the same detail via conventional ice cores.

Using all available geologic, tectonic and geothermal heat flux data for Greenland — along with geothermal heat flux data from around the globe — the team deployed a machine learning approach that predicts geothermal heat flux values under the ice sheet throughout Greenland based on 22 geologic variables such as bedrock topography, crustal thickness, magnetic anomalies, rock types and proximity to features like trenches, ridges, young rifts, volcanoes and hot spots.

“We have a lot of data points from around the Earth — we know in certain parts of the world the crust is a certain thickness, composed of a specific kind of rock and located a known distance from a volcano — and we take those relationships and apply them to what we know about Greenland,” said co-author Leigh Stearns, associate professor of geology at KU.

The researchers said their new predictive model is a “definite improvement” over current models of geothermal heat flux that don’t incorporate as many variables. Indeed, many numerical ice sheet models of Greenland assume that a uniform value of geothermal heat flux exists everywhere across Greenland.

“Most other models really only honor one particular data set,” Stearns said. “They look at geothermal heat flux through seismic signals or magnetic data in Greenland, but not crustal thickness or rock type or distance from a hot spot. But we know those are related to geothermal heat flux. We try to incorporate as many geologic data sets as we can rather than assuming one is the most important.”

In addition to Rezvanbehbahani and Stearns, the research team behind the new paper includes KU’s J. Doug Walker and C.J. van der Veen, as well as Amir Kadivar of McGill University. Rezvanbehbahani and Stearns also are affiliated with the Center for the Remote Sensing of Ice Sheets, headquartered at KU.

The authors found the five most important geologic features in predicting geothermal flux values are topography, distance to young rifts, distance to trench, depth of lithosphere-asthenosphere boundary (layers of the Earth’s mantle) and depth to Mohorovičić discontinuity (the boundary between the crust and the mantle in the Earth). The researchers said their geothermal heat flux map of Greenland is expected to be within about 15 percent of true values.

“The most interesting finding is the sharp contrast between the south and the north of Greenland,” said Rezvanbehbahani. “We had little information in the south, but we had three or four more cores in the northern part of the ice sheet. Based on the southern core we thought this was a localized low heat-flux region — but our model shows that a much larger part of the southern ice sheet has low heat flux. By contrast, in the northern regions, we found large areas with high geothermal heat flux. This isn’t as surprising because we have one ice core with a very high reading. But the spatial pattern and how the heat flux is distributed, that a was a new finding. That’s not just one northern location with high heat flux, but a wide region.”

The investigators said their model would be made even more accurate as more information on Greenland is compiled in the research community.

“We give the slight disclaimer that this is just another model — it’s our best statistical model — but we have not reproduced reality,” said Stearns. “In Earth science and glaciology, we’re seeing an explosion of publicly available data. Machine learning technology that synthesizes this data and helps us learn from the whole range of data sensors is becoming increasingly important. It’s exciting to be at the forefront.”

Reference:
Soroush Rezvanbehbahani, Leigh A. Stearns, Amir Kadivar, J. Doug Walker, C. J. van der Veen. Predicting the Geothermal Heat Flux in Greenland: A Machine Learning Approach. Geophysical Research Letters, 2017; DOI: 10.1002/2017GL075661

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

A close-up look at an uncommon underwater eruption

January 10, 2018

High-resolution seafloor topography of the Havre caldera mapped by the autonomous underwater vehicle (AUV) Sentry shows the new 2012 erupted lavas in red. The volcano is nearly a mile deep (1,519 meters). The top of the volcano is at 650 meters below sea level.
Credit: Rebecca Carey, University of Tasmania, Adam Soule, WHOI, ©Woods Hole Oceanographic Institution

On July 18, 2012, passengers on an airline flight over the Southwest Pacific Ocean glimpsed something unusual — a raft of floating rock known as pumice that indicated an underwater volcanic eruption had occurred on the seafloor northeast of New Zealand. The raft eventually grew to more than 150 square miles (roughly the size of Philadelphia), a sign that the eruption was unusually large.

A new paper published January 10, 2018, in the journal Science Advances describes the first up-close investigation of the largest underwater volcanic eruption of the past century. The international research team led by the University of Tasmania and the Woods Hole Oceanographic Institution (WHOI) used the autonomous underwater vehicle (AUV) Sentry and the remotely operated vehicle (ROV) Jason to explore, map, and collect erupted materials from the Havre volcano during a 2015 expedition. They found that the eruption was surprising in many ways.

“We knew it was a large-scale eruption, approximately equivalent to the biggest eruption we’ve seen on land in the 20th Century,” said Rebecca Carey, a volcanologist at University of Tasmania and Co-Chief Scientist on the expedition.

“Heading to the site, we were fully prepared to investigate a typical deep-sea explosive eruption,” added Adam Soule, WHOI associate scientist and chief scientist for the National Deep Submergence Facility. “When we looked at the detailed maps from the AUV, we saw all these bumps on the seafloor and I thought the vehicle’s sonar was acting up. It turned out that each bump was a giant block of pumice, some of them the size of a van. I had never seen anything like it on the seafloor.”

More than 70 percent of all volcanic activity on Earth occurs on the seafloor, but details of these events are largely hidden from view by seawater. Based on the size of the 2012 pumice raft, the eruption of the Havre Volcano was estimated to be the largest documented underwater silicic eruption — a particular type of eruption that produces viscous, gas-filled lava that often occurs explosively. Despite their violence, very little is known about silicic eruptions and most knowledge about them comes from ancient rock records, which lack details such as the timing, duration, source, and water depth of the events. Scientists have never been able to study a large underwater silicic eruption shortly after it occurred in order to better understand how they happen and what they produce.

Havre is part of the Kermadec Arc, a chain of volcanoes, some of which reach the surface to form the Kermadec Islands, between New Zealand and American Samoa. The volcanoes are formed by conditions at the subduction zone where one of Earth’s largest tectonic plates, the Pacific Plate, dives beneath the Australian Plate. New Zealand scientists mapped the Havre volcano, a caldera nearly three miles (4.5 kilometers) across on the seafloor northeast of the North Island of New Zealand, using shipboard sonar instruments in 2002 and again immediately after the eruption in 2012, revealing the presence of new volcanic material on the seafloor.

In 2015, scientists from the University of Tasmania, WHOI, the University of California Berkeley, the University of Otago in New Zealand, and others traveled to the region on board the research vessel Roger Revelle operated by the Scripps Institution of Oceanography. They deployed the AUV Sentry in a series of 11 dives that mapped more than 19 square miles (50 square kilometers) of seafloor. They also conducted 12 ROV Jason dives totaling 250 hours to collect samples of erupted material and to capture high-resolution imagery of the seafloor inside the crater.

The team found that the eruption history of the Havre volcano was much more complicated than they previously thought, with the most recent eruption alone consisting of lava from 14 volcanic vent sites between 900 and 1220 meters (3000 and 4000 feet) below the surface. They also discovered that, what they thought was initially an explosive eruption that would produce mainly pumice, also created ash, lava domes, and seafloor lava flows. Mapping and seafloor observations revealed that, of the material that erupted, which was nearly 1.5 times larger than the 1980 eruption of Mount St. Helens, about 75 percent floated to the surface and drifted away with winds and currents. The rest was spread across the seafloor up to several miles away.

“Ultimately we believe that none of the magma was erupted in the ways we assume an explosive eruption occurs on land,” said Soule.

Material collected using ROV Jason confirmed the diverse nature of the eruption, bringing samples of dense lava, ash, pumice, and giant pumice to the surface, including one piece measuring 5 feet (1.5 meters) in diameter that is the first of its kind ever collected and is currently on display at the National Museum of Science and Nature in Tokyo. The physical and chemical composition of these samples are helping scientists learn how the eruption proceeded, what made it act the way it did, and how the material changes over time.

This work was supported by a grant from the National Science Foundation.

Reference:
Rebecca Carey et al. The largest deep-ocean silicic volcanic eruption of the past century. Science Advances, 2018 DOI: 10.1126/sciadv.1701121

Note: The above post is reprinted from materials provided by Woods Hole Oceanographic Institution.

Giant extinct burrowing bat discovered in New Zealand

January 10, 2018

An artist's impression of a New Zealand burrowing bat, Mystacina robusta, that went extinct last century. — An artist’s impression of a New Zealand burrowing bat, Mystacina robusta, that went extinct last century. The new fossil find, Vulcanops jennyworthyae, that lived millions of years ago in New Zealand, is an ancient relative of burrowing or short-tailed bats. Credit: Gavin Mouldey.

The fossilized remains of a giant burrowing bat that lived in New Zealand millions of years ago have been found by a UNSW Sydney-led international team of scientists.

Teeth and bones of the extinct bat — which was about three times the size of an average bat today — were recovered from 19 to 16-million-year-old sediments near the town of St Bathans in Central Otago on the South Island.

The study, by researchers from Australia, New Zealand, the UK and USA, is published in the journal Scientific Reports.

Burrowing bats are only found now in New Zealand, but they once also lived in Australia. Burrowing bats are peculiar because they not only fly; they also scurry about on all fours, over the forest floor, under leaf litter and along tree branches, while foraging for both animal and plant food.

With an estimated weight of about 40 grams, the newly found fossil bat was the biggest burrowing bat yet known. It also represents the first new bat genus to be added to New Zealand’s fauna in more than 150 years

It has been named Vulcanops jennyworthyae, after team member Jenny Worthy who found the bat fossils, and after Vulcan, the mythological Roman god of fire and volcanoes, in reference to New Zealand’s tectonic nature, but also to the historic Vulcan Hotel in the mining town St Bathans.

Other research team members include scientists from UNSW Sydney, University of Salford, Flinders University, Queensland University, Canterbury Museum, Museum of New Zealand Te Papa Tongarewa, the American Museum of Natural History, and Duke University.

“Burrowing bats are more closely related to bats living in South America than to others in the southwest Pacific,” says study first author and UNSW Professor Sue Hand.

“They are related to vampire bats, ghost-faced bats, fishing and frog-eating bats, and nectar-feeding bats, and belong to a bat superfamily that once spanned the southern landmasses of Australia, New Zealand, South America and possibly Antarctica.”

Around 50 million years ago, these landmasses were connected as the last vestiges of the southern supercontinent Gondwana. Global temperatures were up to 12 degrees Celsius higher than today and Antarctica was forested and frost-free. With subsequent fragmentation of Gondwana, cooling climates and the growth of ice-sheets in Antarctica, Australasia’s burrowing bats became isolated from their South American relatives.

“New Zealand’s burrowing bats are also renowned for their extremely broad diet. They eat insects and other invertebrates such as weta and spiders, which they catch on the wing or chase by foot. And they also regularly consume fruit, flowers and nectar,” says Professor Hand, who is Director of the PANGEA Research Centre at UNSW.

“However, Vulcanops’s specialized teeth and large size suggest it had a different diet, capable of eating even more plant food as well as small vertebrates — a diet more like some of its South American cousins. We don’t see this in Australasian bats today,” she says.

Study co-author, Associate Professor Trevor Worthy of Flinders University says: “The fossils of this spectacular bat and several others in the St Bathans Fauna show that the prehistoric aviary that was New Zealand also included a surprising diversity of furry critters alongside the birds.”

Study co-author Professor Paul Scofield of Canterbury Museum says: “These bats, along with land turtles and crocodiles, show that major groups of animals have been lost from New Zealand. They show that the iconic survivors of this lost fauna — the tuataras, moas, kiwi, acanthisittid wrens, and leiopelmatid frogs — evolved in a far more complex community that hitherto thought.”

This diverse fauna lived in or around a 5600-square-km prehistoric Lake Manuherikia that once covered much of the Maniototo region of the South Island. When they lived, in the early Miocene, temperatures in New Zealand were warmer than today and semitropical to warm temperate forests and ferns edged the vast palaeolake.

Vulcanops provides new insight into the original diversity of bats in Australasia. Its lineage became extinct sometime after the early Miocene, as did a number of other lineages present in the St Bathans assemblage. These include crocodiles, terrestrial turtles, flamingo-like palaelodids, swiftlets, several pigeon, parrot and shorebird lineages and non-flying mammals. Most of these were probably warm-adapted species. After the middle Miocene, global climate change brought colder and drier conditions to New Zealand, with significant changes to vegetation and environments.

It is likely that this general cooling and drying trend drove overall loss in bat diversity in New Zealand, where just two bat species today comprise the entire native land mammal fauna. All other modern land mammals in New Zealand have been introduced by people within the last 800 years.

Reference:
Suzanne J. Hand, Robin M. D. Beck, Michael Archer, Nancy B. Simmons, Gregg F. Gunnell, R. Paul Scofield, Alan J. D. Tennyson, Vanesa L. De Pietri, Steven W. Salisbury, Trevor H. Worthy. A new, large-bodied omnivorous bat (Noctilionoidea: Mystacinidae) reveals lost morphological and ecological diversity since the Miocene in New Zealand. Scientific Reports, 2018; 8 (1) DOI: 10.1038/s41598-017-18403-w

Note: The above post is reprinted from materials provided by University of New South Wales.

Ingredients for life revealed in meteorites that fell to Earth

January 10, 2018

A blue crystal recovered from a meteorite that fell near Morocco in 1998. The scale bar represents 200 microns (millionths of a meter). Credit: Queenie Chan/The Open University, U.K.

Two wayward space rocks, which separately crashed to Earth in 1998 after circulating in our solar system’s asteroid belt for billions of years, share something else in common: the ingredients for life. They are the first meteorites found to contain both liquid water and a mix of complex organic compounds such as hydrocarbons and amino acids.

A detailed study of the chemical makeup within tiny blue and purple salt crystals sampled from these meteorites, which included results from X-ray experiments at the Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab), also found evidence for the pair’s past intermingling and likely parents. These include Ceres, a brown dwarf planet that is the largest object in the asteroid belt, and the asteroid Hebe, a major source of meteorites that fall on Earth.

The study, published Jan. 10 in the journal Science Advances, provides the first comprehensive chemical exploration of organic matter and liquid water in salt crystals found in Earth-impacting meteorites. The study treads new ground in the narrative of our solar system’s early history and asteroid geology while surfacing exciting possibilities for the existence of life elsewhere in Earth’s neighborhood.

“It’s like a fly in amber,” said David Kilcoyne, a scientist at Berkeley Lab’s Advanced Light Source (ALS), which provided X-rays that were used to scan the samples’ organic chemical components, including carbon, oxygen, and nitrogen. Kilcoyne was part of the international research team that prepared the study.

While the rich deposits of organic remnants recovered from the meteorites don’t provide any proof of life outside of Earth, Kilcoyne said the meteorites’ encapsulation of rich chemistry is analogous to the preservation of prehistoric insects in solidified sap droplets.

Queenie Chan, a planetary scientist and postdoctoral research associate at The Open University in the U.K. who was the study’s lead author, said, “This is really the first time we have found abundant organic matter also associated with liquid water that is really crucial to the origin of life and the origin of complex organic compounds in space.”

She added, “We’re looking at the organic ingredients that can lead to the origin of life,” including the amino acids needed to form proteins.

If life did exist in some form in the early solar system, the study notes that these salt crystal-containing meteorites raise the “possibility of trapping life and/or biomolecules” within their salt crystals. The crystals carried microscopic traces of water that is believed to date back to the infancy of our solar system — about 4.5 billion years ago.

Chan said the similarity of the crystals found in the meteorites — one of which smashed into the ground near a children’s basketball game in Texas in March 1998 and the other which hit near Morocco in August 1998 — suggest that their asteroid hosts may have crossed paths and mixed materials.

There are also structural clues of an impact — perhaps by a small asteroid fragment impacting a larger asteroid, Chan said.

This opens up many possibilities for how organic matter may be passed from one host to another in space, and scientists may need to rethink the processes that led to the complex suite of organic compounds on these meteorites.

“Things are not as simple as we thought they were,” Chan said.

There are also clues, based on the organic chemistry and space observations, that the crystals may have originally been seeded by ice- or water-spewing volcanic activity on Ceres, she said.

“Everything leads to the conclusion that the origin of life is really possible elsewhere,” Chan said. “There is a great range of organic compounds within these meteorites, including a very primitive type of organics that likely represent the early solar system’s organic composition.”

Chan said the two meteorites that yielded the 2-millimeter-sized salt crystals were carefully preserved at NASA’s Johnson Space Center in Texas, and the tiny crystals containing organic solids and water traces measure just a fraction of the width of a human hair. Chan meticulously collected these crystals in a dust-controlled room, splitting off tiny sample fragments with metal instruments resembling dental picks.

“What makes our analysis so special is that we combined a lot of different state-of-the-art techniques to comprehensively study the organic components of these tiny salt crystals,” Chan said.

Yoko Kebukawa, an associate professor of engineering at Yokohama National University in Japan, carried out experiments for the study at Berkeley Lab’s ALS in May 2016 with Aiko Nakato, a postdoctoral researcher at Kyoto University in Japan. Kilcoyne helped to train the researchers to use the ALS X-ray beamline and microscope.

The beamline equipped with this X-ray microscope (a scanning transmission X-ray microscope, or STXM) is used in combination with a technique known as XANES (X-ray absorption near edge structure spectroscopy) to measure the presence of specific elements with a precision of tens of nanometers (tens of billionths of a meter).

“We revealed that the organic matter was somewhat similar to that found in primitive meteorites, but contained more oxygen-bearing chemistry,” Kebukawa said. “Combined with other evidence, the results support the idea that the organic matter originated from a water-rich, or previously water-rich parent body — an ocean world in the early solar system, possibly Ceres.”

Kebukawa also used the same STXM technique to study samples at the Photon Factory, a research site in Japan. And the research team enlisted a variety of other chemical experimental techniques to explore the samples’ makeup in different ways and at different scales.

Chan noted that there are some other well-preserved crystals from the meteorites that haven’t yet been studied, and there are plans for follow-up studies to identify if any of those crystals may also contain water and complex organic molecules.

Kebukawa said she looks forward to continuing studies of these samples at the ALS and other sites: “We may find more variations in organic chemistry.”

Reference:
Queenie H. S. Chan et al. Organic matter in extraterrestrial water-bearing salt crystals. Science Advances, 2018 DOI: 10.1126/sciadv.aao3521

Note: The above post is reprinted from materials provided by DOE/Lawrence Berkeley National Laboratory.

New depth limit for deep-sea marine burrows

January 10, 2018

These are burrows on the margins of a sandstone dyke. Credit: Sarah Cobain, University of Leeds

Scientists have found fossil evidence of deep-sea marine life burrowing up to eight metres below the seabed — four times the previously observed depth for modern deep-sea life.

A team of scientists from the University of Leeds and the National Oceanography Centre examined remains of deep-sea burrows in rocky outcrops that were part of the ocean floor roughly 250 million years ago.

These outcrops are made up of sand-sheets that are widespread on modern ocean floors, suggesting that deep-sea burrowing marine life may be much more abundant than previously considered.

Study author Professor David Hodgson, from the School of Earth and Environment at Leeds, said: “Ocean ecology shows us that deep-sea burrowers have only become more prevalent and diverse through time.

“Their adaptability to new environments strengthens the idea that if their pre-historic ancestors were burrowing to these depths, then it’s likely we’d find them there today.”

The team’s findings, published today in Scientific Reports, highlights the need for new future sampling strategies to better capture the depth range of animals living in modern deep-sea sands.

Collecting intact samples from the deep-ocean floor is technologically challenging. The distance to the ocean seabed and the difficulties of extracting samples makes it problematic to determine how deeply modern animals burrow. Modern deep-sea biological studies target muds as these are simpler to sample than the shifting sands of the deep seabed.

Lead author Dr Sarah Cobain conducted this research while a PhD student at the School of Earth and Environment, she is now based at Petrotechnical Data Systems in London. She said: “These outcrops give us a snapshot of ancient deep-sea life. We know that modern marine burrowing animals are living in the same material that has been fossilised in these rocks.

“The burrowers use the networks that are already present in the deep ocean sediment below the seabed and leave behind living traces. These networks — what we call injectites after they’ve been fossilised — are caused by sand-rich water being forcibly injected into mud. They provide the animals easy pathways to burrow and find nutrients and oxygen.

“Our understanding of the process by which these injectites form allows us to not only assess how these creatures lived but also how deeply they burrowed into the sediment below the seabed.”

The branching structures that make up the trace fossils are believed to have been made by organisms that were previously thought to live mainly in the top 20 centimetres of sediment, rarely reaching further than 1.5 metres, due to the decline of oxygen and food in deeper levels of the sediment.

The team documented the creatures’ living traces — known as bioturbation — on the margins of clastic injectites from at least eight metres below the seabed.

In order to produce living traces, organisms would need to survive long enough to burrow for hours or even days. The size of the burrows suggests macro-infaunal invertebrates (tiny shrimps and worms).

Study author, Jeffrey Peakall, Professor of Process Sedimentology at Leeds, said: “This discovery gives us a window into a widespread yet barely explored environment on our planet. Little is known about modern deep seabed environments, and less about the ancient.

“These trace fossils can give us new insight into the possibility that the deepest organisms may be present in sandy sediments, rather than the clays and silts typically targeted in modern seabed investigations.”

Reference:
S. L. Cobain, D. M. Hodgson, J. Peakall, P. B. Wignall, M. R. D. Cobain. A new macrofaunal limit in the deep biosphere revealed by extreme burrow depths in ancient sediments. Scientific Reports, 2018; 8 (1) DOI: 10.1038/s41598-017-18481-w

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

Earthquakes as a driver for the deep-ocean carbon cycle

January 10, 2018

An international team led by geologist Michael Strasser has used novel methods to analyze sediment deposits in the Japan Trench in order to gain new insights into the carbon cycle.

In a paper recently published in Nature Communications, geologist Michael Strasser presented the initial findings of a month-long research expedition off the coast of Japan. The research initiative had been organised in March 2012 by MARUM – Center for Marine Environmental Sciences. Strasser, who until 2015 was Assistant Professor for Sediment Dynamics at ETH Zurich and is now a Full Professor for Sediment Geology at the University of Innsbruck, took an international team there to study dynamic sediment remobilisation processes triggered by seismic activity.

At a depth of 7,542 metres below sea level, the team took a core sample from the Japan Trench, an 800-km-long oceanic trench in the northwestern part of the Pacific Ocean. The trench, which is seismically active, was the epicentre of the Tohoku earthquake in 2011, which made headlines when it caused the nuclear meltdown at Fukushima. Such earthquakes wash enormous amounts of organic matter from the shallows down into deeper waters. The resulting sediment layers can thus be used later to glean information about the history of earthquakes and the carbon cycle in the deep ocean.

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New dating methods in the deep ocean

The current study provided the researchers with a breakthrough. They analysed the carbon-rich sediments using radiocarbon dating. This method – measuring the amount of organic carbon as well as radioactive carbon (14C) in mineralised compounds – has long been a means of determining the age of individual sediment layers. Until now, however, it has not been possible to analyse samples from deeper than 5,000 metres below the surface, because the mineralised compounds dissolve under increased water pressure.

Strasser and his team therefore had to use new methods for their analysis. One of these was what is known as the online gas radiocarbon method, developed by ETH doctoral student Rui Bao and the Biogeoscience Group at ETH Zurich. This greatly increases efficiency, since it takes just a single core sample to make more than one hundred 14C age measurements directly on the organic matter contained within the sediment.

In addition, the researchers applied the Ramped PyrOx measurement method (pyrolysis) for the first time in the dating of deep-ocean sediment layers. This was done in cooperation with the Woods Hole Oceanographic Institute (U.S.), which developed the method. The process involves burning organic matter at different temperatures. Because older organic matter contains stronger chemical bonds, it requires higher temperatures to burn. What makes this method novel is that the relative age variation of the individual temperature fractions between two samples very precisely distinguishes the age difference between sediment levels in the deep sea.

Dating earthquakes to increase forecast accuracy

Thanks to these two innovative methods, the researchers could determine the relative age of organic matter in individual sediment layers with a high degree of precision. The core sample they tested contained older organic matter in three places, as well as higher rates of carbon export to the deep ocean. These places correspond to three historically documented yet hitherto imprecisely dated seismic events in the Japan Trench: the Tohoku earthquake in 2011, an unnamed earthquake in 1454, and the Sanriku earthquake in 869.

At the moment, Strasser is working on a large-scale geological map of the origin and frequency of sediments in deep-ocean trenches. To do so, he is analysing multiple core samples taken during a follow-up expedition to the Japan Trench in 2016. “The identification and dating of tectonically triggered sediment deposits is also important for future forecasts about the likelihood of earthquakes,” Strasser says. “With our new methods, we can predict the recurrence of earthquakes with much more accuracy.”

Reference:
Rui Bao et al, Tectonically-triggered sediment and carbon export to the Hadal zone, Nature Communications (2018). DOI: 10.1038/s41467-017-02504-1

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

Between the lines: Tree rings hold clues about a river’s past

January 10, 2018

By analyzing centuries-old growth rings from trees in the Intermountain West, researchers at USU are extracting data about monthly streamflow trends from periods long before the early 1900s when recorded observations began. Credit: Matt Jensen/USU

Hydrologists are looking centuries into the past to better understand an increasingly uncertain water future.

By analyzing centuries-old growth rings from trees in the Intermountain West, researchers at Utah State University are extracting data about monthly streamflow trends from periods long before the early 1900s when recorded observations began.

Their findings were published Jan. 6 in the Journal of Hydrology and, for the first time, show that monthly streamflow data can be reconstructed from annual tree-ring chronologies — some of which date back to the 1400s.

“By linking tree rings and flow during the past 100 years when we have recorded observations, we can use trees as a tool for measuring flow long before there were gauges on the rivers,” said USU’s Dr. James Stagge, a hydrologist and civil engineer who led the research. “Our study takes this one step further and uses different tree species and locations to reconstruct monthly flow, rather than annual flow.”

Knowing monthly streamflow, the authors explain, is key to making better-informed decisions about water use and management. In Utah and around the world, populations in arid climates depend on seasonal and often inconsistent water supplies for agriculture and urban use.

“One data point per year gives a very limited picture,” said co-author Dr. David Rosenberg, an associate professor of civil and environmental engineering at USU. “Decisions about water management happen much more frequently than just once per year. Water managers have to make decisions every month, every week, sometimes every day.”

To fill in the missing monthly data, Stagge and co-authors built a model that reconstructs monthly streamflow for three rivers in Northern Utah. The reconstructions are available to the public at http://www.paleoflow.org and show monthly streamflows dating back to 1605 for the Logan River and as far back as 1400 for the Bear and Weber rivers.

The team used tree-ring chronologies from seven species selected from a range of locations and elevations. Stagge says different tree species at different elevations respond to the changing seasons at different times of the year and in slightly different ways, recording unique parts of the seasonal flow. The model overlaps the tree-ring chronologies and combines annual streamflow information and climate data to arrive at a monthly streamflow estimate.

“Now we can get down into a monthly scale and pick up seasonal patterns within the streamflow,” said Stagge. “It’s the seasonality that determines drought, how reservoirs fill, and when there are shortages. Now that we have this method, we can start looking at what major droughts over the past 600 years would mean for today’s water supply.”

Reference:
J.H. Stagge, D.E. Rosenberg, R.J. DeRose, T.M. Rittenour. Monthly paleostreamflow reconstruction from annual tree-ring chronologies. Journal of Hydrology, 2018; 557: 791 DOI: 10.1016/j.jhydrol.2017.12.057

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

Evolution of Alpine landscape recorded by sedimentary rocks

January 9, 2018

Headwaters of Alpine streams approximately 30 million years ago (left) with an Alpine plateau and a meadow countryside. The handcraft on the right side illustrates the landscape of the Alps at 25 million years before present with steep valleys where torrents originated. Credit: Philippos Garefalakis, University of Bern.

Rock avalanches and torrents started to form V-shaped valleys in the Swiss Alps approximately 25 million years ago. This landscape contrasts to the flat and hilly scenery, which characterized the Alps a few millions of years before. Geologists from the University of Bern applied digital technologies to unravel these changes in landscape evolution. They analysed 30 to 25 million-year old lithified rivers in Central Switzerland and came out with a detailed picture of how the Alps evolved within a short time interval.

The current shape of the Alps with steep V-shaped valleys and torrents have evolved during approximately five millions of years. This time span might be perceived as very long, but it is a few seconds for geologists. This was the major outcome of a study by Philippos Garefalakis and Fritz Schlunegger from the University of Bern, Switzerland, who analysed thousands of pebbles at Mount Rigi situated in Central Switzerland. This mountain, which has been considered by Goethe as the Queen of the Mountains, because of its spectacular view, consists of lithified rivers with pebbles. These rocks have been transported by the Alpine rivers in the geologic past, and they document the rise of the Alps and the related change of the landscape. The scientists found out that the Central Swiss Alps evolved from British-type of hillslopes and flats to a rugged region with torrents and deep gorges. The results of their study have recently been published by the Nature-Group in Scientific Reports.

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From a meadow countryside to the Alpine landscape

30 million years ago, the headwaters of the Alpine rivers were situated on a plateau with flat hillslopes, similar to what we currently find in Great Britain. “The leisurely streams deposited tons of pebbles, which resulted in a stack of thousands of lithified rivers, referred to as conglomerates,” explains Philippos Garefalakis, the senior author of the published article. “Accordingly, each bed represents the deposits of a river back in geologic times.” Philippos and his team analysed bed by bed and thousands of pebbles from the base to the top of Mount Rigi. The changes surprised the scientist. “The 30 million-year old deposits at the base of Mount Rigi contain pebbles that have the size of an apple, and the streams were 2-4 meters deep. On top of the mountain range, the 25 million-year old sediments expose boulders as large as a football, and torrents were less than 1 meter deep.” The Alpine streams must have gained in power, and they adapted a chaotic flow pattern.

Dramatic evolution

“The change in the Alpine landscape must have been dramatic and fast,” explains Philippos and looks toward the Alps, which are clearly visible from Bern on a sunny day like this. “Boulders as large as a football can only be entrained by strong torrents during floods.” These processes are typical in a steep landscape where rock avalanches and landslides supply large volumes of boulders and material. The Alps thus had their current shape as early as 25 million years ago. The situation, however, was different 30 million years ago. Streams were smooth and had their headwaters in a meadow countryside, which characterized the Alps at that time. “These changes occurred as the Alps started to rise and to steepen, which occurred — for geological standards — within a short time interval.”

Application of digital technologies

Engineers have disclosed quantitative relationships between the size of gravels in rivers and stream power. “We can apply the identical concepts to stream deposits of the geologic past, but we need to measure the size of thousands of pebbles,” says Philippos. This was only possible thanks to computer technologies, which allows to measure a large number of pebbles on digital photographs. This new technology has been applied for the first time to rocks and will yield new insights about our streams on Earth in the geological past.

Reference:
Philippos Garefalakis, Fritz Schlunegger. Link between concentrations of sediment flux and deep crustal processes beneath the European Alps. Scientific Reports, 2018; 8 (1) DOI: 10.1038/s41598-017-17182-8

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

Shakedown in Oklahoma: To cut the number of bigger earthquakes, inject less saltwater

January 4, 2018

Figure 2 from Pollyea et al., Annual geographic centroid locations for the years 2011-2016 (the underlying fault map is by Marsh and Holland, 2016), including volume-weighted well centroids, the 1σ radius of gyration, and M3+ earthquake centroids.
Credit: Pollyea et al. and Geology

Boulder, Colo., USA: In Oklahoma, reducing the amount of saltwater (highly brackish water produced during oil and gas recovery) pumped into the ground seems to be decreasing the number of small fluid-triggered earthquakes. But a new study shows why it wasn’t enough to ease bigger earthquakes. The study, led by Ryan M. Pollyea of Virginia Tech in Blacksburg, Virginia, was published online ahead of print in Geology this week.

Starting around 2009, saltwater disposal (SWD) volume began increasing dramatically as unconventional oil and gas production increased rapidly throughout Oklahoma. As a result, the number of magnitude 3-plus earthquakes rattling the state has jumped from about one per year before 2011 to more than 900 in 2015. “Fluids are basically lubricating existing faults,” Pollyea explains. Oklahoma is now the most seismically active state in the lower 48 United States.

Previous studies linked Oklahoma SWD wells and seismic activity in time. Instead, Pollyea and colleagues studied that correlation in space, analyzing earthquake epicenters and SWD well locations. The team focused on the Arbuckle Group, a porous geologic formation in north-central Oklahoma used extensively for saltwater disposal. The earthquakes originate in the basement rock directly below the Arbuckle, at a depth of 4 to 8 kilometers.

The correlation was clear: “When we plotted the average annual well locations and earthquake epicenters, they moved together in space,” says Pollyea. The researchers also found that SWD volume and earthquake occurrence are spatially correlated up to 125 km. That’s the distance within which there seems to be a connection between injection volume, fluid movement, and earthquake occurrence.

By separating data by year from 2011 through 2016, Pollyea and colleagues also found that the spatial correlation for smaller earthquakes weakened in 2016, when new regulations reduced pumping volumes. Yet the spatial correlation for M3.0+ earthquakes persists unabated. In fact, two particularly alarming earthquakes shook the region in September 2016 and November 2016. The first, M5.8, was the largest ever recorded in Oklahoma. The second, M5.0, rocked the area surrounding the nation’s largest oil storage facility, containing millions of barrels of oil.

Pollyea’s theory for why reduced fluid pressure has only affected small faults: “It’s like the traffic on the freeway is still moving, but the smaller arterials are cut off.” He emphasizes that so far, they can’t predict single earthquakes or even blame specific wells for specific shaking. But to reduce large fluid-triggered earthquakes, Pollyea concludes, “It appears that the way to do it is to inject less water.”

Reference:
Geospatial analysis of Oklahoma (USA) earthquakes (2011-2016): Quantifying the limits of regional-scale earthquake mitigation measures Authors: Ryan M. Pollyea (Virginia Tech; [email protected]); Neda Mohammadi; John E. Taylor; Martin C. Chapman; DOI: 10.1130/G39945.1

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

Researchers show high-performance breathing in bones

January 3, 2018

This is part of a neck vertebra of the dwarf sauropod Europasaurus with deep cavities (asterisk) that presumably housed air sacs.
Credit: (c) Modified from Lambertz et al. (2018) Biol. Lett. doi:10.1098/rsbl.2017.0514

“The respiratory organs of vertebrates exhibit a tremendous degree of diversity, but the lung-air sac system of birds is truly unique among extant species,” says Dr. Markus Lambertz from the Institute for Zoology at the University of Bonn in Germany. Air sacs are bellows-like protrusions of the lung, and their volume changes cause the air flow in the separate gas exchanger. This functional separation is crucial for the exceptional efficiency of this respiratory system, but air sacs can do more: they can invade bones, a process called “pneumatization.”

Pneumatized bones are very light, because they are filled with air instead of the more heavy marrow, which was not only important for active flight, but also for the evolution of gigantism in sauropod dinosaurs. Through the presence of the resulting pneumatic cavities, it has long been known that air sac-like structures predate the origin of birds, since they were found both in the gigantic sauropods as well as in carnivorous dinosaurs. However, when and potentially how many times air sacs did evolve was inaccessible until now.

Table of Contents

Pneumosteum: a hitherto unknown type of bony tissue as a diagnostic tool

Filippo Bertozzo was pretty surprised when he analyzed the bone structure in the course of his master’s thesis at the Steinmann-Institute for Geology, Mineralogy and Paleontology of the University of Bonn: “Bones that are in contact with air sacs exhibit a unique structure composed of very fine and densely packed fibers. After it turned out that this was true both in modern birds and extinct dinosaurs, we proposed to name this special kind of bony tissue “pneumosteum.” ”

Especially astonishing was the fact that pneumosteum was not only restricted to pneumatized bones, but was also found on the surface of conspicuous cavities present in cervical vertebrae of sauropod dinosaurs. Dr. Lambertz adds: “Such cavities had already previously been hypothesized as potential locations of air sacs, but only our microscopic analysis now provides convincing arguments for this.”

Other soft tissues, such as muscles, can leave traces in bone as well. “There are several types of fibers within bone tissue, but the pneumosteum is markedly different from them,” explains Prof. Dr. Martin Sander from the Steinmann-Institute in Bonn. This characteristic individuality of the pneumosteum thus makes it an excellent diagnostic tool for recognizing bones that were in contact with air sacs.

Access to the past and potential for future research

Given that pneumosteum was only discovered in the dinosaurian lineage now provides the opportunity to trace the evolutionary origin of air sacs. Especially the fact that pneumosteum is not restricted to pneumatized bones but was also found on bone surfaces opens up access to studying species that might have exhibited air sacs as part of their respiratory system, but lack obviously pneumatized bones.

Fossilization of air sacs is nearly impossible because their delicate structure is composed of only a few layers of cells. Professor Sander thus is convinced that the discovery of pneumosteum will lead to a greatly improved understanding of the evolution of the dinosaurian respiratory system. Dr. Lambertz concludes with: “This project once again highlights the importance of the interdisciplinary collaboration between zoologists and paleontologists for elucidating evolutionary history.”

Reference:
Markus Lambertz, Filippo Bertozzo, P. Martin Sander. Bone histological correlates for air sacs and their implications for understanding the origin of the dinosaurian respiratory system. Biology Letters, 2018; 14 (1): 20170514 DOI: 10.1098/rsbl.2017.0514

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

Which came first: Complex life or high atmospheric oxygen?

January 3, 2018

By measuring the oxidation of iron in pillow basalts from undersea volcanic eruptions, UC Berkeley scientists have more precisely dated the oxygenation of the deep ocean, inferring from that when oxygen levels in the atmosphere rose to current high levels. Credit: National Science Foundation

We and all other animals wouldn’t be here today if our planet didn’t have a lot of oxygen in its atmosphere and oceans. But how crucial were high oxygen levels to the transition from simple, single-celled life forms to the complexity we see today?

A study by University of California, Berkeley geochemists presents new evidence that high levels of oxygen were not critical to the origin of animals.

The researchers found that the transition to a world with an oxygenated deep ocean occurred between 540 and 420 million years ago. They attribute this to an increase in atmospheric O2 to levels comparable to the 21 percent oxygen in the atmosphere today.

This inferred rise comes hundreds of millions of years after the origination of animals, which occurred between 700 and 800 million years ago.

“The oxygenation of the deep ocean and our interpretation of this as the result of a rise in atmospheric O2 was a pretty late event in the context of Earth history,” said Daniel Stolper, an assistant professor of earth and planetary science at UC Berkeley. “This is significant because it provides new evidence that the origination of early animals, which required O2 for their metabolisms, may have gone on in a world with an atmosphere that had relatively low oxygen levels compared to today.”

He and postdoctoral fellow Brenhin Keller will report their findings in a paper posted online Jan. 3 in advance of publication in the journal Nature. Keller is also affiliated with the Berkeley Geochronology Center.

Oxygen has played a key role in the history of Earth, not only because of its importance for organisms that breathe oxygen, but because of its tendency to react, often violently, with other compounds to, for example, make iron rust, plants burn and natural gas explode.

Tracking the concentration of oxygen in the ocean and atmosphere over Earth’s 4.5-billion-year history, however, isn’t easy. For the first 2 billion years, most scientists believe very little oxygen was present in the atmosphere or ocean. But about 2.5-2.3 billion years ago, atmospheric oxygen levels first increased. The geologic effects of this are evident: rocks on land exposed to the atmosphere suddenly began turning red as the iron in them reacted with oxygen to form iron oxides similar to how iron metal rusts.

Earth scientists have calculated that around this time, atmospheric oxygen levels first exceeded about a hundred thousandth of today’s level (0.001 percent), but remained too low to oxygenate the deep ocean, which stayed largely anoxic.

By 400 million years ago, fossil charcoal deposits first appear, an indication that atmospheric O2 levels were high enough to support wildfires, which require about 50 to 70 percent of modern oxygen levels, and oxygenate the deep ocean. How atmospheric oxygen levels varied between 2,500 and 400 million years ago is less certain and remains a subject of debate.

“Filling in the history of atmospheric oxygen levels from about 2.5 billion to 400 million years ago has been of great interest given O2’s central role in numerous geochemical and biological processes. For example, one explanation for why animals show up when they do is because that is about when oxygen levels first approached the high atmospheric concentrations seen today,” Stolper said. “This explanation requires that the two are causally linked such that the change to near-modern atmospheric O2 levels was an environmental driver for the evolution of our oxygen-requiring predecessors.”

In contrast, some researchers think the two events are largely unrelated. Critical to helping to resolve this debate is pinpointing when atmospheric oxygen levels rose to near modern levels. But past estimates of when this oxygenation occurred range from 800 to 400 million years ago, straddling the period during which animals originated.

When did oxygen levels change for a second time?

Stolper and Keller hoped to pinpoint a key milestone in Earth’s history: when oxygen levels became high enough – about 10 to 50 percent of today’s level – to oxygenate the deep ocean. Their approach is based on looking at the oxidation state of iron in igneous rocks formed undersea (referred to as “submarine”) volcanic eruptions, which produce “pillows” and massive flows of basalt as the molten rock extrudes from ocean ridges. Critically, after eruption, seawater circulates through the rocks. Today, these circulating fluids contain oxygen and oxidize the iron in basalts. But in a world with deep-oceans devoid of O2, they expected little change in the oxidation state of iron in the basalts after eruption.

“Our idea was to study the history of the oxidation state of iron in these basalts and see if we could pinpoint when the iron began to show signs of oxidation and thus when the deep ocean first started to contain appreciable amounts of dissolved O2,” Stolper said.

To do this, they compiled more than 1,000 published measurements of the oxidation state of iron from ancient submarine basalts. They found that the basaltic iron only becomes significantly oxidized relative to magmatic values between about 540 and 420 million years ago, hundreds of millions of years after the origination of animals. They attribute this change to the rise in atmospheric O2 levels to near modern levels. This finding is consistent with some but not all histories of atmospheric and oceanic O2 concentrations.

“This work indicates that an increase in atmospheric O2 to levels sufficient to oxygenate the deep ocean and create a world similar to that seen today was not necessary for the emergence of animals,” Stolper said. “Additionally, the submarine basalt record provides a new, quantitative window into the geochemical state of the deep ocean hundreds of millions to billions of years ago.”

Reference:
A record of deep-ocean dissolved O2 from the oxidation state of iron in submarine basalts, Nature (2018). DOI:10.1038/nature25009

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

An adaptation 150 million years in the making

January 3, 2018

Just how do snapping shrimp snap? This was the question plaguing scientists who set out to uncover the mysterious mechanisms producing big biology in tiny crustaceans.

“All we’ve known until now is the endpoint of these super snapping claws,” said Rich Palmer, biological science professor at the University of Alberta and senior author on a new study on snapping shrimp claws. “What we now know is that a series of small changes in form led to these big functional changes, which essentially allow these shrimp the ability to break water, or snap.”

Through the course of two years of research investigating 114 species from 19 different shrimp families–exploration that took the scientists from the far reaches of Panama to advanced imaging facilities in Germany–the researchers discovered that this ability to break water or snap was preceded by evolution and adaptation millions of years in the making. The shrimp use the snapping for multiple reasons including communication, killing prey, territorial defense, and defending against predators.

“We realized that this spectacular ability to break water by making cavitation bubbles had to have been preceded by maybe millions of years of shrimp just shooting water. Somehow as they continue to shoot water, they got faster and faster, and they eventually broke the cavitation threshold to produce these snaps. It’s pretty extreme biology,” said Palmer.

Palmer explained that a bubble produced from the shrimp’s claw is actually a vacuum where surrounding water pressure collapses the sides of the bubble to produce a snap, something that can only happen when the water is shot so fast from the claw that it leaves before adjacent water can come in behind it. What he and his co-authors uncovered was that such extreme movements depend on both an energy-storage mechanism as well as a latching mechanism to release the stored energy quickly. Sort of similar to a bow and arrow.

“If you take an arrow and try to throw it, it doesn’t go very fast. But if you take the same amount of energy and pull back and then release, the arrow goes very quickly. Throwing just uses muscle contraction whereas storing energy and cocking releases the same amount of energy, but much more quickly.”

Palmer explained that the sum of multiple small changes in claw form–each of which is an innovation–adds up to a force so strong it breaks water by taking advantage of underwater physics, since liquids are not compressible. The end result–this remarkable ability to snap–is what is referred to as a key innovation.

“Key innovations are adaptations that permit a dramatic radiation or diversification of species, setting the stage for radiation into a wholly new kind of adaptive zone that wasn’t there before.”

Reference:
Parallel Saltational Evolution of Ultrafast Movements in Snapping Shrimp Claws. DOI: 10.1016/j.cub.2017.11.044

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

A 508 million year old sea predator with a ‘jackknife’ head

December 22, 2017

Fossil specimen of Habelia optata from the Royal Ontario Museum. This specimen spectacularly shows some of the very large jaws under the head shield. Note also the long dorsal spines on the thorax.
Credit: Photo by Jean-Bernard Caron. Copyright: Royal Ontario Museum

Paleontologists at the University of Toronto (U of T) and the Royal Ontario Museum (ROM) in Toronto have entirely revisited a tiny yet exceptionally fierce ancient sea creature called Habelia optata that has confounded scientists since it was first discovered more than a century ago.

The research by lead author Cédric Aria, recent graduate of the PhD program in the department of ecology & evolutionary biology in the Faculty of Arts & Science at U of T, and co-author Jean-Bernard Caron, senior curator of invertebrate palaeontology at the ROM and an associate professor in the departments of ecology & evolutionary biology and Earth sciences at U of T, is published today in BMC Evolutionary Biology.

Approximately 2 cm in length with a tail as long as the rest of its body, the long-extinct Habelia optata belongs to the group of invertebrate animals called arthropods, which also includes such familiar creatures as spiders, insects, lobsters and crabs. It lived during the middle Cambrian period approximately 508 million years ago and comes from the renowned Burgess Shale fossil deposit in British Columbia. Habelia optata was part of the “Cambrian explosion,” a period of rapid evolutionary change when most major animal groups first emerged in the fossil record.

Like all arthropods, Habelia optata features a segmented body with external skeleton and jointed limbs. What remained unclear for decades, however, was the main sub-group of arthropods to which Habelia belonged. Early studies had mentioned mandibulates — a hyperdiverse lineage whose members possess antennae and a pair of specialized appendages known as mandibles, usually used to grasp, squeeze and crush their food. But Habelia was later left as one of the typically unresolved arthropods of the Burgess Shale.

The new analysis by the U of T-ROM researchers suggests that Habelia optata was instead a close relative of the ancestor of all chelicerates, the other sub-group of arthropods living today, named for the presence of appendages called chelicerae in front of the mouth and used to cut food. This is mostly due to the overall anatomy of the head in Habelia, and the presence of two small chelicerae-like appendages revealed in these fossils.

“Habelia now shows in great detail the body architecture from which chelicerates emerged, which allows us to solve some long-standing questions,” said Aria, who is now a post-doctoral researcher at the Nanjing Institute of Geology and Palaeontology, in China. “We can now explain why, for instance, horseshoe crabs have a reduced pair of limbs — the chilaria — at the back of their heads. Those are relics of fully-formed appendages, as chelicerates seem to originally have had heads with no less than seven pairs of limbs.”

Aria and Caron analyzed 41 specimens in total, the majority of which are new specimens acquired by ROM-led fieldwork parties to the Burgess Shale.

The research illustrates that the well-armoured body of Habelia optata, covered in a multitude of different spines, was divided into head, thorax and post-thorax, all bearing different types of appendages. The thorax displays five pairs of walking legs, while the post-thorax houses rounded appendages likely used in respiration.

“Scorpions and the now-extinct sea scorpions are also chelicerates with bodies divided into three distinct regions,” Aria explained. “We think that these regions broadly correspond to those of Habelia. But a major difference is that scorpions and sea scorpions, like all chelicerates, literally ‘walk on their heads,’ while Habelia still had walking appendages in its thorax.”

The researchers argue that this difference in anatomy allowed Habelia to evolve an especially complex head that makes this fossil species even more peculiar compared to known chelicerates. The head of Habelia contained a series of five appendages made of a large plate with teeth for mastication, a leg-like branch with stiff bristle-like spines for grasping, and an elongate, slender branch modified as a sensory or tactile appendage.

“This complex apparatus of appendages and jaws made Habelia an exceptionally fierce predator for its size,” said Aria. “It was likely both very mobile and efficient in tearing apart its preys.”

The surprising outcome of this study, despite the evolutionary relationship of Habelia with chelicerates, is that these unusual characteristics led instead the researchers to compare the head of Habelia with that of mandibulates from a functional perspective. Thus, the peculiar sensory branches may have been used in a similar fashion as mandibulates use antennae. Also, the overlapping plate-like appendages in the middle series of five are shown to open and close parallel to the underside of the head — much as they do in mandibulates, especially those that feed on animals with hardened carapaces.

Lastly, a seventh pair of appendages at the back of the head seems to have fulfilled a function similar to that of “maxillipeds” — appendages in mandibulates that assist with the other head limbs in the processing of food. This broad correspondence in function rather than in evolutionary origin is called “convergence.”

“From an evolutionary point of view, Habelia is close to the point of divergence between chelicerates and mandibulates,” Aria said. “But its similarities with mandibulates are secondary modifications of features that were in part already chelicerate in nature. This suggests that chelicerates originated from species with a high structural variability.”

The researchers conclude from the outstanding head structure, as well as from well-developed walking legs, that Habelia optata and its relatives were active predators of the Cambrian sea floors, hunting for small shelly sea creatures, such as small trilobites — arthropods with hard, mineralized exoskeletons that were already very diverse and abundant during Cambrian times.

“This builds onto the importance of carapaces and shells for evolutionary change during the Cambrian explosion, and expands our understanding of ecosystems at this time, showing another level of predator-prey relationship and its determining impact on the rise of arthropods as we know them today,” said Caron, who was Aria’s PhD supervisor when the bulk of this research was completed.

“The appearance and spread of animals with shells are considered to be one of the defining characteristics of the Cambrian explosion, and Habelia contributes to illustrate how important this ecological factor was for the early diversification of chelicerates and arthropods in general.”

Reference:
Cédric Aria, Jean-Bernard Caron. Mandibulate convergence in an armoured Cambrian stem chelicerate. BMC Evolutionary Biology, 2017; 17 (1) DOI: 10.1186/s12862-017-1088-7

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

Modeling the effects of wastewater injection

December 20, 2017

Wastewater injected in an underground reservoir layer crossed by a fault triggers an earthquake. The earthquake rupture grows larger than the zone pressurized by water injection. Credit: Galis et al., and Thomas Willard/Caltech Graphic Resources

In work that offers insight into the magnitude of the hazards posed by earthquake faults in general, seismologists have developed a model to determine the size of an earthquake that could be triggered by the underground injection of fluids produced as a by-product of hydraulic fracturing.

Hydraulic fracturing, or “fracking,” is a petroleum-extraction procedure in which millions of gallons of water (as well as sand and chemicals) are injected deep into underground shale beds to crack the rock and release natural gas and oil. According to the United States Geological Survey, fracking itself does not typically trigger earthquakes. Instead, the increased risk for seismicity is more strongly linked with the subsequent injection of the wastewater from fracking and other oil-extraction processes into massive disposal wells that are thousands of feet underground.

Previous attempts to model the relationship between injection of wastewater and the triggering of earthquakes suggested that the maximum magnitude of the seismic activity induced in this way would be proportional to the volume of the fluids injected. However, this interpretation fails to account for the fact that earthquakes can grow beyond the area impacted by fluid pressure, says Jean Paul Ampuero, professor of seismology at Caltech and co-author of a new study on the topic that appears in the journal Science Advances on December 20.

Combining theory and computer simulations of dynamic earthquake ruptures, Ampuero and his colleagues developed a model that explains how the size of injection-induced earthquakes depends on not only the volume of fluid being injected but also the energy stored on nearby faults. The result is a model that quantifies the distance that an earthquake can propagate beyond an injection site—which in turn predicts the maximum magnitude of an induced seismic event.

“Earthquakes induced by human activities involving underground injection of fluids or gas are a growing concern, a hazard that needs to be controlled in order to develop a safer and cleaner energy future,” Ampuero says.

This induced seismicity has been the subject of significant research in recent years and is also attracting researchers who, like Ampuero, are primarily interested in unraveling the physics of natural earthquakes. “This may be the closest researchers will ever get to a large-scale controlled earthquake experiment,” Ampuero says. For the new work, Ampuero teamed up with Martin Galis, postdoctoral researcher at King Abdullah University of Science and Technology (KAUST) in Saudi Arabia.

It is important to note that the new model only predicts the maximum possible magnitude of an earthquake rather than what the earthquake magnitude will actually be, the researchers say. It defines upper limits based on the amount of pent-up energy in the earth’s crust prior to fluid injection.

The new model offers insight into natural earthquakes, creating a framework for understanding what causes earthquakes to stop shaking. Earthquakes can be triggered by the pressure and disturbance caused by fluid injection, but they may grow beyond the zone immediately impacted by the wastewater injection by tapping into tectonic energy that is already stored nearby. As is the case for induced seismicity, natural earthquakes can start in small areas of the earth’s crust where that energy is concentrated. How large they grow is determined by the amount of energy in surrounding regions.

The paper is titled “Induced seismicity provides insight into why earthquake ruptures stop.” Ampuero and Galis’s co-authors include Paul Martin Mai of KAUST and Frédéric Cappa of the Université Côte d’Azur in Nice and Institut Universitaire de France in Paris. Funding came from the National Science Foundation, KAUST, and the Agence Nationale de la Recherché in France.

This is the second study this month from Ampuero that offers new insight into earthquake science. On December 1, Ampuero and colleagues from Centre national de la recherché scientifique in Paris found that it is possible to observe disturbances in the earth’s gravitational field almost instantly after an earthquake, raising the potential for the use of these disturbances as part of an early-warning system. (These disturbances travel at the speed of light, while the fastest seismic waves of an earthquake propagate at several kilometers per second, which means that monitoring the disturbances could potentially improve existing early-warning systems by seconds or even minutes.)

Ampuero and his colleagues found that seismometers in China and South Korea picked up perturbations in the earth’s gravitational field during the 9.1 Tohoku earthquake in Japan in 2011 via signals that appeared as tiny accelerations on seismometers more than a minute before the ground beneath the seismometers started to shake.

Reference:
M. Galis el al., “Induced seismicity provides insight into why earthquake ruptures stop,” Science Advances (2017). DOI: 10.1126/sciadv.aap7528

Note: The above post is reprinted from materials provided by California Institute of Technology.

Origins of photosynthesis in plants dated to 1.25 billion years ago

December 20, 2017

The Angmaat Formation above Tremblay Sound on the Baffin Island coast. Bangiomorpha pubescens fossils occur in this roughly 500-meter thick rock formation.
Credit: Timothy Gibson

The world’s oldest algae fossils are a billion years old, according to a new analysis by earth scientists at McGill University. Based on this finding, the researchers also estimate that the basis for photosynthesis in today’s plants was set in place 1.25 billion years ago.

The study, published in the journal Geology, could resolve a long-standing mystery over the age of the fossilized algae, Bangiomorpha pubescens, which were first discovered in rocks in Arctic Canada in 1990. The microscopic organism is believed to be the oldest known direct ancestor of modern plants and animals, but its age was only poorly dated, with estimates placing it somewhere between 720 million and 1.2 billion years.

The new findings also add to recent evidence that an interval of Earth’s history often referred to as the Boring Billion may not have been so boring, after all. From 1.8 to 0.8 billion years ago, archaea, bacteria and a handful of complex organisms that have since gone extinct milled about the planet’s oceans, with little biological or environmental change to show for it. Or so it seemed. In fact, that era may have set the stage for the proliferation of more complex life forms that culminated 541 million years ago with the so-called Cambrian Explosion.

“Evidence is beginning to build to suggest that Earth’s biosphere and its environment in the latter portion of the ‘Boring Billion’ may actually have been more dynamic than previously thought,” says McGill PhD student Timothy Gibson, lead author of the new study.

Table of Contents

Pinpointing the fossils’ age

To pinpoint the fossils’ age, the researchers pitched camp in a rugged area of remote Baffin Island, where Bangiomorpha pubescens fossils have been found There,despite the occasional August blizzard and tent-collapsing winds, they collected samples of black shale from rock layers that sandwiched the rock unit containing fossils of the alga. Using the Rhenium-Osmium (or Re-Os) dating technique, applied increasingly to sedimentary rocks in recent years, they determined that the rocks are 1.047 billion years old.

“That’s 150 million years younger than commonly held estimates, and confirms that this fossil is spectacular,” says Galen Halverson, senior author of the study and an associate professor in McGill’s Department of Earth and Planetary Sciences. “This will enable scientists to make more precise assessments of the early evolution of eukaryotes,” the celled organisms that include plants and animals.

Because Bangiomorpha pubescens is nearly identical to modern red algae, scientists have previously determined that the ancient alga, like green plants, used sunlight to synthesize nutrients from carbon dioxide and water. Scientists have also established that the chloroplast, the structure in plant cells that is the site of photosynthesis, was created when a eukaryote long ago engulfed a simple bacterium that was photosynthetic. The eukaryote then managed to pass that DNA along to its descendants, including the plants and trees that produce most of the world’s biomass today.

Origins of the chloroplast

Once the researchers had gauged the fossils’ age at 1.047 billion years, they plugged that figure into a “molecular clock,” a computer model used to calculate evolutionary events based on rates of genetic mutations. Their conclusion: the chloroplast must have been incorporated into eukaryotes roughly 1.25 billion years ago.

“We expect and hope that other scientists will plug this age for Bangiomorpha pubescens into their own molecular clocks to calculate the timing of important evolutionary events and test our results,” Gibson says. “If other scientists envision a better way to calculate when the chloroplast emerged, the scientific community will eventually decide which estimate seems more reasonable and find new ways to test it.”

Reference:
Timothy M. Gibson, Patrick M. Shih, Vivien M. Cumming, Woodward W. Fischer, Peter W. Crockford, Malcolm S.W. Hodgskiss, Sarah Wörndle, Robert A. Creaser, Robert H. Rainbird, Thomas M. Skulski, Galen P. Halverson. Precise age of Bangiomorpha pubescens dates the origin of eukaryotic photosynthesis. Geology, 2017; DOI: 10.1130/G39829.1

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

New ancient dolphin species Urkudelphis chawpipacha discovered in Ecuador

December 20, 2017

Skull, Urkudelphis chawpipacha MO-1 (holotype) in right lateral view. Credit: Tanaka et al (2017)

A new dolphin species likely from the Oligocene was discovered and described in Ecuador, according to a study published December 20, 2017 in the open-access journal PLOS ONE by Yoshihiro Tanaka from the Osaka Museum of Natural History, Japan, and colleagues.

Many marine fossils described in previous research have been from long-recognized temperate regions such as South Carolina, off the coast of Oregon, Hokkaido and New Zealand. Few equatorial and polar fossils are currently known.

While in the tropical region of Santa Elena Province, Ecuador, the authors of this study found a small dolphin skull, which they identified as representing a new species, Urkudelphis chawpipacha, based on facial features. The dolphin skull had a bone crest front and center on its face, above the eye sockets. This species stands apart from other Oligocene dolphins with its shorter and wider frontal bones located near the top of the head and the parallel-sided posterior part of its jaw. The authors also conducted a phylogenetic analysis which revealed that the new species may be the ancestor of the nearly-extinct Platanistoidea, or river dolphin, and may have lived during the Oligocene era.

The fossil is one of the few fossil dolphins from the equator, and is a reminder that Oligocene cetaceans may have ranged widely in tropical waters.

Reference:
A new tropical Oligocene dolphin from Montañita/Olón, Santa Elena, Ecuador. DOI: 10.1371/journal.pone.0188380

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

Heat from below Pacific Ocean fuels Yellowstone, study finds

December 19, 2017

Recent stories in the national media are magnifying fears of a catastrophic eruption of the Yellowstone volcanic area, but scientists remain uncertain about the likelihood of such an event. To better understand the region’s subsurface geology, University of Illinois geologists have rewound and played back a portion of its geologic history, finding that Yellowstone volcanism is more far more complex and dynamic than previously thought.

“The heat needed to drive volcanism usually occurs in areas where tectonic plates meet and one slab of crust slides, or subducts, under another. However, Yellowstone and other volcanic areas of the inland western U.S. are far away from the active plate boundaries along the west coast,” said geology professor Lijun Liu who led the new research. “In these inland cases, a deep-seated heat source known as a mantle plume is suspected of driving crustal melting and surface volcanism.”

In the new study, reported in the journal Nature Geosciences, Liu and graduate students Quan Zhou and Jiashun Hu used a technique called seismic tomography to peer deep into the subsurface of the western U.S. and piece together the geologic history behind the volcanism. Using supercomputers, the team ran different tectonic scenarios to observe a range of possible geologic histories for the western U.S. over the past 20 million years. The effort yielded little support for the traditional mantle plume hypothesis.

“Our goal is to develop a model that matches up with what we see both below ground and on the surface today,” Zhou said. “We call it a hybrid geodynamic model because most of the earlier models either start with an initial condition and move forward, or start with the current conditions and move backward. Our model does both, which gives us more control over the relevant mantle processes.”

One of the many variables the team entered into their model was heat. Hot subsurface material — like that in a mantle plume — should rise vertically toward the surface, but that was not what the researchers saw in their models.

“It appears that the mantle plume under the western U.S. is sinking deeper into Earth through time, which seems counterintuitive,” Liu said. “This suggests that something closer to the surface — an oceanic slab originating from the western tectonic boundary — is interfering with the rise of the plume.”

The mantle plume hypothesis has been controversial for many years and the new findings add to the evidence for a revised tectonic scenario, the researchers said.

“A robust result from these models is that the heat source behind the extensive inland volcanism actually originated from the shallow oceanic mantle to the west of the Pacific Northwest coast,” Liu said. “This directly challenges the traditional view that most of the heat came from the plume below Yellowstone.”

“Eventually, we hope to consider the chemical data from the volcanic rocks in our model,” Zhou said. “That will help us further constrain the source of the magma because rocks from deep mantle plumes and near-surface tectonic plates could have different chemistries.”

As for likelihood of a violent demise of Yellowstone occurring anytime soon, the researchers say it is still too early to know.

“Of course, our model can’t predict specific future super-eruptions. However, looking back through 20 million years of history, we do not see anything that makes the present-day Yellowstone region particularly special — at least not enough to make us suspect that it may do something different from the past when many catastrophic eruptions have occurred,” Liu said. “More importantly, this work will give us a better understanding of some of the mysterious processes deep within Earth, which will help us better understand the consequences of plate tectonics, including the mechanism of earthquakes and volcanoes.”

Reference:
Quan Zhou, Lijun Liu, Jiashun Hu. Western US volcanism due to intruding oceanic mantle driven by ancient Farallon slabs. Nature Geoscience, 2017; DOI: 10.1038/s41561-017-0035-y

Note: The above post is reprinted from materials provided by University of Illinois at Urbana-Champaign. Original written by Lois Yoksoulian.

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