Earth’s Carbon Points To Planetary Smashup

Research by Rice University Earth scientists suggests that virtually all of Earth’s life-giving carbon could have come from a collision about 4.4 billion years ago between Earth and an embryonic planet similar to Mercury.

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In a new study this week in Nature Geoscience, Rice petrologist Rajdeep Dasgupta and colleagues offer a new answer to a long-debated geological question: How did carbon-based life develop on Earth, given that most of the planet’s carbon should have either boiled away in the planet’s earliest days or become locked in Earth’s core?

“The challenge is to explain the origin of the volatile elements like carbon that remain outside the core in the mantle portion of our planet,” said Dasgupta, who co-authored the study with lead author and Rice postdoctoral researcher Yuan Li, Rice research scientist Kyusei Tsuno and Woods Hole Oceanographic Institute colleagues Brian Monteleone and Nobumichi Shimizu.

Dasgupta’s lab specializes in recreating the high-pressure and high-temperature conditions that exist deep inside Earth and other rocky planets. His team squeezes rocks in hydraulic presses that can simulate conditions about 250 miles below Earth’s surface or at the core-mantle boundary of smaller planets like Mercury.

“Even before this paper, we had published several studies that showed that even if carbon did not vaporize into space when the planet was largely molten, it would end up in the metallic core of our planet, because the iron-rich alloys there have a strong affinity for carbon,” Dasgupta said.

Earth’s core, which is mostly iron, makes up about one-third of the planet’s mass. Earth’s silicate mantle accounts for the other two-thirds and extends more than 1,500 miles below Earth’s surface. Earth’s crust and atmosphere are so thin that they account for less than 1 percent of the planet’s mass. The mantle, atmosphere and crust constantly exchange elements, including the volatile elements needed for life.

If Earth’s initial allotment of carbon boiled away into space or got stuck in the core, where did the carbon in the mantle and biosphere come from?

“One popular idea has been that volatile elements like carbon, sulfur, nitrogen and hydrogen were added after Earth’s core finished forming,” said Li, who is now a staff scientist at Guangzhou Institute of Geochemistry, Chinese Academy of Sciences. “Any of those elements that fell to Earth in meteorites and comets more than about 100 million years after the solar system formed could have avoided the intense heat of the magma ocean that covered Earth up to that point.

“The problem with that idea is that while it can account for the abundance of many of these elements, there are no known meteorites that would produce the ratio of volatile elements in the silicate portion of our planet,” Li said.

In late 2013, Dasgupta’s team began thinking about unconventional ways to address the issue of volatiles and core composition, and they decided to conduct experiments to gauge how sulfur or silicon might alter the affinity of iron for carbon. The idea didn’t come from Earth studies, but from some of Earth’s planetary neighbors.

“We thought we definitely needed to break away from the conventional core composition of just iron and nickel and carbon,” Dasgupta recalled. “So we began exploring very sulfur-rich and silicon-rich alloys, in part because the core of Mars is thought to be sulfur-rich and the core of Mercury is thought to be relatively silicon-rich.

“It was a compositional spectrum that seemed relevant, if not for our own planet, then definitely in the scheme of all the terrestrial planetary bodies that we have in our solar system,” he said.

The experiments revealed that carbon could be excluded from the core — and relegated to the silicate mantle — if the iron alloys in the core were rich in either silicon or sulfur.

“The key data revealed how the partitioning of carbon between the metallic and silicate portions of terrestrial planets varies as a function of the variables like temperature, pressure and sulfur or silicon content,” Li said.

The team mapped out the relative concentrations of carbon that would arise under various levels of sulfur and silicon enrichment, and the researchers compared those concentrations to the known volatiles in Earth’s silicate mantle.

“One scenario that explains the carbon-to-sulfur ratio and carbon abundance is that an embryonic planet like Mercury, which had already formed a silicon-rich core, collided with and was absorbed by Earth,” Dasgupta said. “Because it’s a massive body, the dynamics could work in a way that the core of that planet would go directly to the core of our planet, and the carbon-rich mantle would mix with Earth’s mantle.

“In this paper, we focused on carbon and sulfur,” he said. “Much more work will need to be done to reconcile all of the volatile elements, but at least in terms of the carbon-sulfur abundances and the carbon-sulfur ratio, we find this scenario could explain Earth’s present carbon and sulfur budgets.”

Earth’s Mantle Appears To Have A Driving Role In Plate Tectonics

Deep down below us is a tug of war moving at less than the speed of growing fingernails. Keeping your balance is not a concern, but how the movement happens has been debated among geologists.

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New findings from under the Pacific Northwest Coast by University of Oregon and University of Washington scientists now suggest a solution to a mystery that surfaced when the theory of plate tectonics arose: Do the plates move the mantle, or does the mantle move the plates.

The separation of tectonic plates, the researchers proposed in a paper online ahead of print in the journal Nature Geoscience, is not simply dictating the flow of the gooey, lubricating molten material of the mantle. The mantle, they argue, is actually fighting back, flowing in a manner that drives a reorientation of the direction of the plates.

The new idea is based on seismic imaging of the Endeavor segment of the Juan de Fuca Plate in the Pacific Ocean off Washington and on data from previous research on similar ridges in the mid-Pacific and mid-Atlantic oceans.

“Comparing seismic measurements of the present mantle flow direction to the recent movements of tectonic plates, we find that the mantle is flowing in a direction that is ahead of recent changes in plate motion,” said UO doctoral student Brandon P. VanderBeek, the paper’s lead author. “This contradicts the traditional view that plates move the mantle.”

While the new conclusion is based on a fraction of such sites under the world’s oceans, a consistent pattern was present, VanderBeek said. At the three sites, the mantle’s flow is rotated clockwise or counterclockwise rather than in the directions of the separating plates. The mantle’s flow, the researchers concluded, may be responsible for past and possibly current changes in plate motion.

The research—funded through National Science Foundation grants to the two institutions – also explored how the supply of magma varies under mid-ocean ridge volcanoes. The researchers conducted a seismic experiment to see how seismic waves moved through the shallow mantle below the Endeavor segment.

They found that the middle of the volcanic segment, where the seafloor is shallowest and the inferred volcanic activity greatest, the underlying mantle magma reservoir is relatively small. The ends, however, are much deeper with larger volumes of mantle magma pooling below them because there are no easy routes for it to travel through the material above it.

Traditional thinking had said there would be less magma under the deep ends of such segments, known as discontinuities.

“We found the opposite,” VanderBeek said. “The biggest volumes of magma that we believe we have found are located beneath the deepest portions of the ridges, at the segment ends. Under the shallow centers, there is much less melt, about half as much, at this particular ridge that we investigated.

“Our idea is that the ultimate control on where you have magma beneath these mountain ranges is where you can and cannot take it out,” he said. “At the ends, we think, the plate rips apart much more diffusely, so you are not creating pathways for magma to move, build mountains and allow for an eruption.”

PART-II Nearby Supernovae Found to have Affected Life on Earth

The surface of the Earth was immersed in life-damaging radiation from nearby supernovae on several different occasions over the past nine million years. That is the claim of an international team of astronomers, which has created a computer model that suggests that high-energy particles from the supernovae created ionizing radiation in Earth’s atmosphere that reached ground level. This influx of radiation, the astronomers say, potentially changed the course of the Earth’s climate and the evolution of life.

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Earlier this year, two independent teams of astronomers published evidence that several supernovae had exploded some 330 light-years from Earth. Each event showered the solar system in iron-60, an overabundance of which has been found in core samples from the bottom of the Atlantic, Pacific and Indian oceans. A discovery of the same element ‘iron-60’ was found on the moon.

Iron-60 is not all that supernovae produce – they also produce cosmic rays, which are composed of high-energy electrons and atomic nuclei. Previous work by Neil Gehrels of NASA’s Goddard Space Flight Center, was found to be incorrect as he indicated that a supernova would have to explode within 25 light-years of Earth to give our planet a radiation dose strong enough to cause a major mass extinction.

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Now, a team led by Brian Thomas of Washburn University, and Adrian Melott of the University of Kansas argues that this conclusion is incorrect. The researchers looked at what would happen if a supernova exploded at a distance of 325 light-years and worked-out how its radiation would affect Earth. They found that cosmic rays accelerated towards Earth by the supernova are a different story. These have energies in the teraelectronvolt (TeV) region and are able to “pass right through the solar wind and Earth’s magnetic field and propagate much further into the atmosphere than cosmic rays normally do.”, says Melott.

When a cosmic ray strikes an air molecule, it produces a shower of secondary particles that is filled with the likes of protons, neutrons and a strong flux of muons. Ordinarily this takes place in the upper atmosphere and can be responsible for ionizing and destroying ozone in the stratosphere. However, the supernova cosmic rays are so energetic that they will pass straight through the stratosphere, lower atmosphere, and down to the surface and deep into the oceans and mantle.

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Today, muons contribute a sixth of our annual radiation dose, however, the team calculated a supernova hit would result in a 20-fold increase in the muon flux that would triple the annual radiation dose of life forms on the planet.

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IMPORTANT ARTICLE: Greater Concern of Cosmic Rays Effect to Earth Then I Realized

As you will see from the following article, it is one of many describing findings from the latest research and studies related to galactic cosmic rays. What I find to be a bit perplexing, is the amount and method of delivery from the science community regarding cosmic rays. It would appear scientific data is coming in at record pace via the incredible spacecraft such as  HERSCHEL, PLANK, CHANDRA, and WISE, and researchers are hard pressed to disseminate their findings in published papers.

***Help SoC continue its research with your supportive donation (see bottom of article)

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As related to my research on the Galaxy-Sun-Earth connection published in 2012, it appears to have hit almost every note presented, however, apparently I under estimated the foretelling possibilities galactic cosmic rays could have on Earth. There is quite a bit of data flowing out, much of which has to do with recent discoveries indicating supernovae explosions hitting Earth; and was the source of at least two ‘mass’ extinctions, and very likely the source of ‘partial’ extinctions.

New Equation:
Increase Charged Particles → Decreased Magnetic Field → Increase Outer Core Convection → Increase of Mantle Plumes → Increase in Earthquake and Volcanoes → Cools Mantle and Outer Core → Return of Outer Core Convection (Mitch Battros – July 2012)

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There is a great deal to present to you so this will be a 3 or 4 part article with this as Part-I. Below is one of the latest published findings showing the desire to, better and perhaps quickly, understand the pre and post eruptions, and most importantly, the rhythmic cycles.

STAY TUNED…………..

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Astronomers have uncovered the strongest evidence yet exhibiting an enormous X-shaped structure made of stars that lies within the central bulge of the Milky Way Galaxy. Previous computer models showing observations of other galaxies – including our own galaxy Milky Way, suggesting the X-shaped structure does exist. However, no one had observed it directly, and some astronomers argued that previous research pointed indirectly to the existence of the X, but that it could be explained in other ways.

Lead author is Melissa Ness, researcher at the Max Planck Institute for Astronomy in Heidelberg, along with Dustin Lang, research associate at the University of Toronto’s Dunlap Institute for Astronomy & Astrophysics, and co-author of the paper describing the discovery. Lang says: “Controversy about whether the X-shaped structure existed, but our paper furnishes an authoritative composition of our own Milky Way’s galactic core. The results appear in the July issue of the Astronomical Journal.

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The Milky Way Galaxy is a barred spiral galaxy; a disk-shaped collection of dust, gas and billions of stars, 100,000 light-years in diameter. It is far from a simple disk structure, being comprised of two spiral arms, a bar-shaped feature that runs through its center, and a central bulge of stars. The central bulge, like other barred galaxy’s bulges, resembles a rectangular box or peanut as viewed from within the plane of the galaxy. The X-shaped structure is an integral component of the bulge.

“The bulge is a key signature of formation of the Milky Way Galaxy,” says Ness. “If we understand the bulge we will understand the key processes which had formed and shaped our galaxy.”

“The shape of the bulge tells us about how it has formed. We see the X-shape and boxy morphology so clearly in the WISE image, demonstrating the internal formation processes have been the ones driving the bulge formation.”

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It is also evidence that our galaxy did not experience major merging events since the bulge formed. If it had, interactions with other galaxies would have disrupted its shape.

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Aftermath of the Permian – Triassic Mass Extinction

A new study of fossil fishes from Middle Triassic sediments on the shores of Lake Lugano provides new insights into the recovery of biodiversity following the great mass extinction event at the Permian-Triassic boundary 240 million years ago.

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The largest episode of mass extinction in the history of the Earth, which led to the demise of about 90% of marine organisms and a majority of terrestrial species, took place between the Late Permian and Early Triassic, around 240 million years ago. How long it took for biological communities to recover from such a catastrophic loss of biodiversity remains the subject of controversial debate among paleontologists.

A new study of fossil fishes from Middle Triassic strata on the shores of Lake Lugano throws new light on the issue. The study, undertaken by researchers led by Dr. Adriana López-Arbarello, who is a member of the GeoBiocenter at Ludwig-Maximilians-Universitaet (LMU) in Munich and the Bavarian State Collection for Paleontology and Geology, suggests that the process of recovery was well underway within a few million years. The authors, including Dr. Heinz Furrer of Zurich University and Dr. Rudolf Stockar of the Museo Cantonale di Storia Naturale in Lugano, who led the excavations at the sites, and Dr. Toni Bürgin of the Naturmuseum St. Gallen report their findings in the journal PeerJ.

The fossil fishes analyzed by López-Arbarello and her colleagues originate from Monte San Giorgio in the canton Ticino in Switzerland, which is one of the most important sources of marine fossils from the Middle Triassic in the world. The Monte San Giorgio rises to an altitude of 1000 m on the promontory that separates the southern arms of Lake Lugano in the Southern Swiss Alps. But in the Middle Triassic, it was part of a shallow basin dotted with islands fringed by lagoons, which were separated by reefs from the open sea. “The particular significance of its fossil fauna lies in the careful stratigraphic work that has accompanied the excavations here.

The positions of each of the fossil finds discovered here have been documented to the centimeter,” says Adriana López-Arbarello. On the basis of detailed anatomical studies of new material and a taxonomic re-evaluation of previously known specimens from the locality, she and her colleagues have identified a new genus of fossil neopterygians, which they name Ticinolepis. The Neopterygii include the teleost fishes, which account for more than half of all extant vertebrate species. However, the new fossil species are assigned to the second major group of neopterygians, the Holostei, of which only a handful of species survives today. The researchers assign two new fossil species to the genus Ticinolepis, namely T. longaeva and T. crassidens, which occur in different sedimentary beds within the so-called Besano Formation on Monte San Giorgio.

The two species coexisted side by side but they occupied distinct ecological niches. T. crassidens fed on mollusks and was equipped with jaws and teeth that could handle their hard calcareous shells. T. longaeva was more of a generalist, and was found in waters in which T. crassidens could not survive. The authors interpret the different distribution patterns as a reflection of changing environmental conditions following the preceding mass extinction event.

The less specialized T. longaeva was able to exploit a broader range of food items, and could thus adapt more flexibly to fluctuating conditions. On the other hand, the dietary differentiation between the two species indicates that a variety of well-established ecosystems was available in the Besano Formation at this time. “This in turn suggests that the marine biota is likely to have recovered from the great mass extinction relatively quickly,” Adriana López-Arbarello concludes.

New Study Proposes Short and Long Process of Extinction

A new study of nearly 22,000 fossils finds that ancient plankton communities began changing in important ways as much as 400,000 years before massive die-offs ensued during the first of Earth’s five great extinctions.

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The research, published July 18 in the Early Edition of the Proceedings of the National Academy of Sciences, focused on large zooplankton called graptolites. It suggests that the effects of environmental degradation can be subtle until they reach a tipping point, at which dramatic declines in population begins.

“In looking at these organisms, what we saw was a disruption of community structures – the way in which the plankton were organized in the water column. Communities came to be less complex and dominated by fewer species well before the massive extinction itself,” says co-author H. David Sheets, PhD, professor of physics at Canisius College and associate research professor in the Evolution, Ecology and Behavior graduate program at the University at Buffalo.

This turmoil, occurring in a time of ancient climate change, could hold lessons for the modern world, says co-author Charles E. Mitchell, PhD, professor of geology in the University at Buffalo College of Arts and Sciences.

The shifts took place at the end of the Ordovician Period some 450 million years ago as the planet transitioned from a warm era into a cooler one, leading eventually to glaciation and lower sea levels.

“Our research suggests that ecosystems often respond in stepwise and mostly predictable ways to changes in the physical environment – until they can’t. Then we see much larger, more abrupt, and ecologically disruptive changes,” Mitchell says. “The nature of such tipping point effects are hard to foresee and, at least in this case, they led to large and permanent changes in the composition of the oceans’ living communities.

“I think we need to be quite concerned about where our current ocean communities may be headed or we may find ourselves at the tail end of a similar event – a sixth mass extinction, living in a very different world than we would like.” The study was a partnership between Canisius, UB, St. Francis Xavier University, Dalhousie University and The Czech Academy of Sciences.

A long slide toward oblivion

In considering mass extinction, there is perhaps the temptation to think of such events as rapid and sudden: At one moment in history, various species are present, and the next they are not.

This might be the conclusion you’d draw if you examined only whether different species of graptolites were present in the fossil record in the years immediately preceding and following the Ordovician extinction.

“If you just looked at whether they were present – if they were there or not – they were there right up to the brink of the extinction,” Sheets says. “But in reality, these communities had begun declining quite a while before species started going extinct.”

The research teased out these details by using 21,946 fossil specimens from areas of Nevada in the U.S. and the Yukon in Canada that were once ancient sea beds to paint a picture of graptolite evolution.

The analysis found that as ocean circulation patterns began to shift hundreds of thousands of years before the Ordovician extinction, graptolite communities that previously included a rich array of both shallow- and deep-sea species began to lose their diversity and complexity.

Deep-water graptolites became progressively rarer in comparison to their shallow-water counterparts, which came to dominate the ocean.

“There was less variety of organisms, and the rare organisms got rarer,” Sheets says. “In the aftermath of a forest fire in the modern world, you might find that there are fewer organisms left – that the ecosystem just doesn’t have the same structure and richness as before. That’s the same pattern we see here.”

The dwindling deep-sea graptolites were species that specialized in obtaining nutrients from low-oxygen zones of the ocean. A decrease in the availability of such habitats may have sparked the creatures’ decline, Sheets and Mitchell say.

“Temperature changes drive deep ocean circulations, and we think the deep-water graptolites lost their habitats as the climate changed,” Sheets says. “As the nature of the oceans shifted, their way of life went away.”

JUST IN: Antarctic Peninsula Glacier Retreat Caused by Mantle Plumes

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A new study has found for the first time that ocean warming is the primary cause of retreat of glaciers on the western Antarctic Peninsula. The Peninsula is one of the largest current contributors to sea-level rise and this new finding will enable researchers to make better predictions of ice loss from this region.

The research, by scientists at Swansea University and British Antarctic Survey, is published in the journal Science today. The study reports that glaciers flowing to the coast on the western side of the Peninsula show a distinct spatial correlation with ocean temperature patterns. Glaciers in the south are retreating rapidly but those in the north showing little change. Some 90% of the 674 glaciers in this region have retreated since records began in the 1940s.

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Dr Alison Cook, who led the work at Swansea University, says: “Scientists know that ocean warming is affecting large glaciers elsewhere on the continent, but thought that atmospheric temperatures were the primary cause of all glacier changes on the Peninsula. We now know that is not the case.”

“The numerous glaciers on the Antarctic Peninsula give a key insight as to how environmental factors control ice behavior on a wide scale. Almost all glaciers on the western side have fractured ending in the sea. We have been able to monitor changes in their ice fronts using images as far back as the 1940s. Glaciers here are extremely diverse and yet the changes in their frontal positions showed a strong regional pattern.

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“We were keen to understand what was causing the differences, in particular why the glaciers in the north-west showed less retreat than those further South and why there was acceleration in retreat since the 1990s. The ocean temperature records have revealed the crucial link.” It appears to be regional mantle plumes along the continental shelf. The team studied ocean temperature measurements around the Peninsula stretching back several decades, alongside photography and satellite data of the 674 glaciers.

The north-south gradient of increasing glacier retreat was found to show a strong pattern with ocean temperatures, whereby water is cold in the north-west, and becomes progressively warmer at depths below 100m further south. Importantly, the warm water at mid-depths in the southerly region has been warming since as long ago as the 1990s, at the same time as the widespread acceleration in glacier retreat.

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Co-author Professor Mike Meredith at British Antarctic Survey says: “These new findings demonstrate for the first time the ocean plays a major role in controlling the stability of glaciers on the western Antarctic Peninsula.”

“Where mid-depth waters from the deep ocean intrude onto the continental shelf and spread towards the coast, they bring heat from the plumes that cause the glaciers to break up and melt. These waters have become warmer and moved to shallower depths in recent decades, causing glacier retreat to accelerate.”

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Co-author Professor Tavi Murray, who leads the Glaciology Research Group at Swansea University, says: “The glaciers on the Antarctic Peninsula are changing rapidly – almost all of the Peninsula’s glaciers have retreated since the 1940s. We have known the region is a climate warming hotspot for a while, but we could not explain what was causing the pattern of glacier change.”

“This new study shows that a warmer ocean is the key to understanding the behavior of glaciers on the Antarctic Peninsula. Currently the Peninsula makes one of the largest contributions to sea-level rise, which means understanding this link will improve predictions of sea-level rise.”

 

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