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Ocean Floor Geology Revealed

Ocean Floor Geology Revealed | Amazing Science |

Scientists from the University of Sydney’s School of Geosciences, Australia, have led the creation of the world’s first digital map of the seafloor’s geology. The composition of the seafloor, covering 70 percent of the Earth’s surface, has been mapped after the most recent map was hand drawn in the 1970s. Published in Geology, the map will help scientists better understand how our oceans have responded, and will respond, to environmental change. It also reveals the deep ocean basins to be much more complex than previously thought.

The deep ocean floor is a graveyard with much of it made up of the remains of microscopic sea creatures called phytoplankton thriving in sunlit surface waters. The composition of these remains can help decipher how oceans have responded in the past to climate change. A special group of phytoplankton called diatoms produce about a quarter of the oxygen we breathe and make a bigger contribution to fighting global warming than most plants on land. Their dead remains sink to the bottom of the ocean, locking away their carbon.

The new seafloor geology map demonstrates that diatom accumulations on the seafloor are nearly entirely independent of diatom blooms in surface waters in the Southern Ocean. This disconnect demonstrates that the researchers, amongst them co-author  Professor Dietmar Muller from the University of Sydney, understand the carbon source, but not the sink. More research is needed to better understand this relationship.

Via YEC Geo
YEC Geo's curator insight, September 12, 9:02 AM

The good news is that it's available for free digital download here:

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The magnetic mystery at the center of the Earth

The magnetic mystery at the center of the Earth | Amazing Science |
The history of the planet’s all-important magnetic field has scientists ramping up simulations and lab experiments to resolve a baffling paradox.

Earth’s depths are a hellish place. More than 5,000 kilometers belowground, the iron-rich core scorches at temperatures comparable to the sun’s surface and crushes at pressures akin to the weight of 20 blue whales balanced on a postage stamp. This extreme environment helps generate Earth’s magnetic field, the planetwide force that makes life on the surface possible. When the sun occasionally belches a blast of electrically charged particles at Earth, the magnetic field redirects the incoming bombardment. Without this magnetic defense, solar storms would fry any unsuspecting life-forms on the surface and gradually strip away Earth’s atmosphere.

For decades, scientists debated and fine-tuned their understanding of Earth’s magnetism. Heat flowing through the liquid outer core helps slosh the molten iron, generating a magnetic field, the general consensus holds. In the last few years, however, new investigations of Earth’s magnetic bodyguard have thrown a wrench into any sense of common ground. In 2012, scientists proposed that iron in the planet’s core conducts heat more readily than previously thought. That would imply less mixing in the outer core and a young Earth with only a meager magnetic field, if any at all. Yet ancient rocks reveal magnetic records of an early, powerful magnetic field protecting the planet billions of years ago.

In January, supercomputer simulations offered a possible resolution to this paradox. Simulating how electrons ricochet around iron atoms at the extremes of temperature and pressure found in Earth’s core suggested that iron’s heat conductivity could actually be low enough to allow a strong magnetic field during Earth’s youth. For a few brief weeks, researchers thought the mystery might be solved. In recent months, however, actual experiments using diamonds and lasers to re-create the intense conditions of the planet’s core raise doubts that the paradox will be resolved so easily.

In 2013, Hirose and colleagues predicted such a trend in Physics of the Earth and Planetary Interiors, suggesting that iron eventually reaches a point where the average distance an electron travels before bumping into an atom is comparable to the distance between each iron atom. At this point, with fewer remaining obstacles to bump into, the resistance to the movement of electrons will plateau even as temperatures continue to rise, they argue.

“Well, then we’re back to the paradox for now, it seems,” Smirnov said after hearing about the Hirose group’s new findings. Even with such high thermal conductivity values, the new core paradox may still be solvable, Driscoll said in May at a meeting of the American Geophysical Union and other organizations. A large enough heat flow through Earth’s interior can generate convection even when conductivity is high, he says.

Extra heat could come from the decay of radioactive elements, he proposes. In April, researchers reported in Nature that the core could contain a significant amount of radio­active uranium and thorium. Driscoll calculates that even a relatively small amount of radioactivity in the modern core would translate into a sizable boost to the ancient magnetic field. If just a small amount of radioactivity warms the core today, that would mean that billions of years ago plenty of radioactive atoms would have been around to help fuel the heat flow, he explains. “There are other knobs you can turn to get yourself out of the problem,” Driscoll says.

Via CineversityTV
Tom Latulipe's curator insight, September 9, 9:37 AM

Magnets are very cool and critical to modern life.  Amazing about how we still don't know everything about them.   

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Gold and silver found in abundance in underneath volcanoes

Gold and silver found in abundance in underneath volcanoes | Amazing Science |

Water located in deep reservoirs located in the Taupo Volcanic Zone in New Zealand is rich with gold and silver, geoscientists say. High grade deposits of precious and other types of metals are said to dissolve in magma-heated water, or hot springs, but technologies needed to extract them safely are yet to be developed.

Researchers have identified at least six deep reservoirs expected to yield high levels of gold and silver. According to a report published in the journal Geothermics this month, gold concentrations reached 20 parts per billion while silver concentrations hit 2,000 parts per billion.

Geoscientist and lead author Stuart Simmons from the University of Utah says technologies must be developed to help retrieve millions of dollars in gold and silver while also ensuring lasting production. He and his colleagues suggest a process that incorporates a two-phase pipeline.

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Scientists Explain Why Greenwich Prime Meridian Moved 102 Meters Since 1884

Scientists Explain Why Greenwich Prime Meridian Moved 102 Meters Since 1884 | Amazing Science |

The ‘Prime Meridian’ that’s been running through the Royal Observatory at Greenwich, UK, since 1884 is now located 335 feet (102 meters) east of its historic spot. Dr Ken Seidelmann from the University of Virginia and his colleagues investigated the cause of this apparent discrepancy.

In 1884, the International Meridian Conference recommended that Earth’s prime meridian “to be employed as a common zero of longitude and standard of time-reckoning throughout the globe” pass through the “center of the transit instrument at the Observatory of Greenwich.”

This instrument – named the Airy Transit Circle for its designer, British Astronomer Royal Sir George Biddell Airy – is a nineteenth-century telescopic device for measuring star positions, and could be used for determining local time. Today, tourists visiting its meridian line must walk east approximately 335 feet before their satellite-navigation receivers indicate zero longitude.

Why? Because newer technologies – primarily the superb accuracy of GPS, which uses satellites to precisely measure grid coordinates at any point on the Earth’s surface – replaced the traditional telescopic observations used to measure the Earth’s rotation.

“With the advancements in technology, the change in the prime meridian was inevitable. Perhaps a new marker should be installed in the Greenwich Park for the new prime meridian,” said Dr Seidelmann, who is a co-author of the paper published in the Journal of Geodesy.

Dr Seidelmann and co-authors concluded that a slight deflection in the natural direction of gravity at Greenwich is responsible for the offset, along with the maintenance of continuity of astronomical time. According to the team, the 335-foot offset can be attributed to the difference between two conventional methods of determining coordinates: astronomical versus geodetic, which refers to a set of reference points used to locate places on the Earth.

Their difference is known as ‘deflection of the vertical,’ and high-resolution global gravitational models confirm that the east-west component of this deflection is of the proper sign and magnitude at Greenwich to account for the entire shift. Because our planet is not perfectly round, and because different locations on Earth have different terrain features affecting gravitational pull, traditional ways to measure longitude have built-in variations, or errors, based on the specific location where measurements are taken.

The observations were based on a vertical determined from a basin of mercury and were dependent on local conditions.

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Beautiful Maps Show the World's Oceans in Motion

Beautiful Maps Show the World's Oceans in Motion | Amazing Science |
These maps from NASA show ocean currents around the world.

The world's oceans are in constant motion, and this series of maps published by the NASA/Goddard Space Flight Center Scientific Visualization Studio helps provide us with a nice illustration of this movement. The maps, which were created at various times in past years, show the many warm and cold ocean currents responsible for transporting water across long distances throughout the world's oceans.

In addition to the ocean currents, you can also see swirly features, known as ocean eddies, on the maps. An ocean eddy is formed when currents sometimes pinch off into sections, creating the circular current. Sometimes significant eddies are given names, according to NOAA.

Below we have selected a few of the maps from NASA's collection, accompanied by a brief explanation of what you are seeing.

In addition to a large-scale view of ocean circulations and eddies across the world, you can also see water temperatures in this image. The orange and red shadings in the middle of the map correspond to the warmer waters in tropics. Cooler waters depicted in green and blue are located north and south of this as you head towards the poles.

Via Bonnie Bracey Sutton, Suvi Salo, Mark E. Deschaine, PhD, Jocelyn Stoller
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New Study Suggests that Plankton Keeps Our Planet Cool

New Study Suggests that Plankton Keeps Our Planet Cool | Amazing Science |

Those microscopic organisms that float in the oceans and are known as plankton may be helping our planet against the damaging effects of climate change by keeping it cool, a new study suggests. According to the researchers who conducted the study, plankton can help with cloud formation and helps sunlight reach space, thus cooling Earth.

The new research was conducted by a team of scientists from the University of Washington in collaboration with Pacific Northwest National Laboratory. The researchers believe that the microscopic organisms that drift in the oceans can produce organic matter and airborne gases that can trigger cloud droplets. This leads to brighter clouds and more sunlight gets reflected.

The scientists wrote a paper in which they wrote about their findings and published it last week in the journal Science Advances.

According to the paper, the scientists studied the Southern Ocean region which covers latitudes between 35 degrees and 55 degrees south. By analyzing this area, the researchers said they found some pretty interesting information about the current climate conditions of our planet.

Their findings revealed that the increased brightness reflects approximately 4W of solar energy per square meter on a yearly average. Daniel McCoy, expert in atmospheric sciences, and one of the lead authors of the study, explained that the plankton blooms help the clouds which form over the Southern Ocean reflect more sunlight during the summer season. McCoy added that the plankton helps the clouds create twice as many droplets than they would normally produce if the oceans didn’t have any microscopic organisms living in them.

According to the researchers, they decided to analyze the Southern Ocean mainly because ocean live in other parts of the planet are obstructed by aerosols created by forests or heavy pollution. That’s why it would have been far more difficult for them to study and measure things in the Northern Hemisphere.

The scientists analyzed data collected by NASA’s satellites to measure the cloud droplets that form in the sky. They explained that the dimethyl sulfide created by the phytoplankton gets carried into the atmosphere at high altitudes, and then it transforms and helps produce the aerosols that move downwind. The study suggests that this happens more often in the northern part of the region they studied.

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NASA explains why 30 June 2015 will get an extra ‘leap second’

NASA explains why 30 June 2015 will get an extra ‘leap second’ | Amazing Science |
The day will officially be a bit longer than usual on Tuesday, 30 June 2015, because an extra second, or “leap” second, will be added.
“Earth’s rotation is gradually slowing down a bit, so leap seconds are a way to account for that,” said Daniel MacMillan of NASA’s Goddard Space Flight Center in Greenbelt, Maryland.

Strictly speaking, a day lasts 86,400 seconds. That is the case, according to the time standard that people use in their daily lives – Coordinated Universal Time, or UTC. UTC is “atomic time” – the duration of one second is based on extremely predictable electromagnetic transitions in atoms of caesium. These transitions are so reliable that the caesium clock is accurate to one second in 1,400,000 years.

However, the mean solar day – the average length of a day, based on how long it takes Earth to rotate – is about 86,400.002 seconds long. That’s because Earth’s rotation is gradually slowing down a bit, due to a kind of braking force caused by the gravitational tug of war between Earth, the Moon and the Sun. Scientists estimate that the mean solar day hasn’t been 86,400 seconds long since the year 1820 or so.

This difference of 2 milliseconds, or two thousandths of a second – far less than the blink of an eye – hardly seems noticeable at first. But if this small discrepancy were repeated every day for an entire year, it would add up to almost a second. In reality, that’s not quite what happens. Although Earth’s rotation is slowing down on average, the length of each individual day varies in an unpredictable way.

The length of day is influenced by many factors, mainly the atmosphere over periods less than a year. Our seasonal and daily weather variations can affect the length of day by a few milliseconds over a year. Other contributors to this variation include dynamics of the Earth’s inner core (over long time periods), variations in the atmosphere and oceans, groundwater, and ice storage (over time periods of months to decades), and oceanic and atmospheric tides. Atmospheric variations due to El Niño can cause Earth’s rotation to slow down, increasing the length of day by as much as 1 millisecond, or a thousandth of a second.

Scientists monitor how long it takes Earth to complete a full rotation using an extremely precise technique called Very Long Baseline Interferometry (VLBI). These measurements are conducted by a worldwide network of stations, with Goddard providing essential coordination of VLBI, as well as analysing and archiving the data collected.

The time standard called Universal Time 1, or UT1, is based on VLBI measurements of Earth’s rotation. UT1 isn’t as uniform as the caesium clock, so UT1 and UTC tend to drift apart. Leap seconds are added, when needed, to keep the two time standards within 0.9 seconds of each other. The decision to add leap seconds is made by a unit within the International Earth Rotation and Reference Systems Service.

Typically, a leap second is inserted either on 30 June or 31 December. Normally, the clock would move from 23:59:59 to 00:00:00 the next day. But with the leap second on 30 June, UTC will move from 23:59:59 to 23:59:60, and then to 00:00:00 on 1 July. In practice, many systems are instead turned off for one second. Previous leap seconds have created challenges for some computer systems and generated some calls to abandon them altogether. One reason is that the need to add a leap second cannot be anticipated far in advance.

“In the short term, leap seconds are not as predictable as everyone would like,” said Chopo Ma, a geophysicist at Goddard and a member of the directing board of the International Earth Rotation and Reference Systems Service. “The modelling of the Earth predicts that more and more leap seconds will be called for in the long-term, but we can’t say that one will be needed every year.”

From 1972, when leap seconds were first implemented, through 1999, leap seconds were added at a rate averaging close to one per year. Since then, leap seconds have become less frequent. This June’s leap second will be only the fourth to be added since 2000. Before 1972, adjustments were made in a different way.

Scientists don’t know exactly why fewer leap seconds have been needed lately. Sometimes, sudden geological events, such as earthquakes and volcanic eruptions, can affect Earth’s rotation in the short-term, but the big picture is more complex.

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Earth’s core contains 90 percent of Earth’s sulfur

Earth’s core contains 90 percent of Earth’s sulfur | Amazing Science |
New research shows Earth’s core contains 90% of Earth’s sulphur (equivalent to 10% mass of the Moon).

So perhaps there is some truth in the old legends of the underworld reeking of brimstone (or sulphur, as it is now called)? New research confirms that the Earth’s core does in fact contain vast amounts of sulphur, estimated to be up to 8.5 x 1018 tonnes. This is about 10 times the amount of sulphur in the rest of the Earth, based on the most recent estimates (and for comparison, around 10% of the total mass of the Moon). This is the first time that scientists have conclusive geochemical evidence for sulphur in the Earth’s core, lending weight to the theory that the Moon was formed by a planet-sized body colliding with the Earth. This work is reported in the peer-reviewed journal, Geochemical Perspectives Letters.

The Earth’s core begins 2900km beneath our feet, so it is impossible to investigate directly. However, an international group of researchers have been able to develop indirect geochemical methods to show core composition. As lead researcher Dr Paul Savage (Department of Earth Sciences, Durham University, UK) said: “Scientists have suspected that there is sulphur in the core for some time, but this is the first time we have solid geochemical evidence to support the idea.”

For a long time it has been known that the Earth’s core is too light to be made only of iron and nickel, and it had been assumed that the core contained other lighter elements, such as sulphur, silicon, oxygen and carbon. However, given the depth of the core, this has been impossible to confirm directly. Fortunately, a cataclysmic event in the distant past – when the Earth collided with a large, planet-sized body, tearing off the part which became our Moon – left a fingerprint, which has been used to confirm the core content.

The researchers believe that the impact of the collision melted the Earth’s mantle, allowing a sulphur-rich liquid to form in Earth’s mantle, the vast middle layer between the core and the crust; some was probably lost into space, but some remained and sunk into the core. The key to confirming this lay in measuring the isotope ratios of elements (isotopes are atoms of the same element with slightly different masses) in the mantle, and comparing these to certain meteorites, which are believed to be the best match to the Earth’s original composition.

Because of variability in mantle composition, it is difficult to draw firm conclusions from measuring sulphur directly, so the researchers chose to analyse copper from the Earth’s mantle and crust – copper is often bound to sulphur. “We chose copper, because it is a chalcophile element, which means it prefers to be in sulphide-rich material – so is a good element to trace the fate of sulphur on Earth,” said senior author Professor Frédéric Moynier (Institut de Physique du Globe, Paris). “Generally, where there is copper, there is sulphur; copper gives us a proxy measurement for sulphur.”

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Massive beams of selenite dwarf human explorers in Mexico’s Cave of Crystals

Massive beams of selenite dwarf human explorers in Mexico’s Cave of Crystals | Amazing Science |

Massive beams of selenite dwarf human explorers in Mexico’s Cave of Crystals, deep below the Chihuahuan Desert. Formed over millennia, these crystals are among the largest yet discovered on Earth. It's 50˚C and has a humidity of 100%, less than a couple of hundred people have been inside and it's so deadly that even with respirators and suits of ice you can only survive for 20 minutes before your body starts to fail. It’s the nearest thing to visiting another planet – it’s going deep inside our own.

Cueva de los Cristales is the incarnation of our most awesome science fiction imaginations - Jules Verne's Journey to the Centre of the Earth, Superman's Fortress of Solitude. At about the same time as humans first ventured out of Africa, these crystals began to slowly grow. For half a million years they remained protected and nurtured by a womb of hot hydrothermal fluids rich with minerals.

Undisturbed, one can only guess how big they may have eventually grown. Yet when mining began here over a hundred years ago, the water table was lowered and the cave drained. The crystals seemingly interminable development was frozen forever leaving them as relics of the deep earth. It wasn't until 2000 that miners, searching for lead, eventually penetrated the cave wall and brought it to light. Who knows what other wonders lie hidden deep inside the earth.
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NASA visualizes 13 years of cloud covers on Earth

NASA visualizes 13 years of cloud covers on Earth | Amazing Science |

Cloudy days can be a bit of a downer. But when you add them all from nearly 13 years of measurements, the bright side becomes more apparent.

NASA Earth Observatory just published a map that uses data collected between July 2002 and April 2015 to give an unparalleled view of the world’s cloudy (and sunny) spots.

One thing that’s immediately apparent is that the world is a pretty cloudy place. It’s no surprise the U.K.—renowned for its dreary weather—appears in white, indicating frequent clouds. Ditto for the Amazon rainforest, which requires copious clouds for its prodigious rain.

On the flip side, the Sahara, Atacama, Arabian and their fellow deserts (including Antarctica) are basically cloud free. Australia and the western U.S. are also light on cloud cover.

Aside from giving a sense of the globe’s overall cloudiness, the map also reveals key features of the climate system. The band of cloudiness just around the equator generally represents the Intertropical Convergence Zone, a girdle of thunderstorms around the earth that form there thanks to warm, moist air lifting off the ocean. The ITCZ, as it’s known in climatespeak, generally drifts back and forth across the equator with the seasons.

In comparison, dry air generally subsides from 15-30 degrees north and south of the equator. Not surprisingly, that’s where most of the world’s deserts are located.

Erik Saether's curator insight, May 15, 12:35 AM

Places for world solar panels

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After The Nepal Earthquake, Everest Is A Little Shorter

After The Nepal Earthquake, Everest Is A Little Shorter | Amazing Science |

The world’s tallest mountain is a little shorter after the newly-named Gorka earthquake that hit Nepal in late April, 2015.

The Nepal earthquake that hit just before noon on Saturday, April 26, 2015 officially has a name: it’s the Gorkha earthquake. The sudden slip of the tectonic plates during the earthquake literally reshaped the land. In a continent-continent collision like this one, the area closest to the fault rupture is uplifted, while the previously-buckled plate interior slaps flat, subsiding in the release of stress. The European Space Agency’s Sentinel-1A satellite tracked both uplift [blue] and subsidence [yellow], recording elevation changes of up to 1 meter, and a horizontal north-south shift of up to 2 meters.

They’ve used the same data to createinterferograms of how the region has changed in consecutive measurements before and after the earthquake. Each coloured fringe represents about 10 centimeters of displacement. Overall, Kathmandu is little taller and Mount Everest is a tiny bit shorterthan it was a month ago. Poor weather not only made things a little bit more miserable on the ground, but also limited the utility of fly-overs from NASA’s satellite network.

In related news, as part of efforts to increase access to hazard mitigation and risk reduction research, the Seismological Society of America has temporarily opened access to their collection of articles on tectonics, structure, and earthquake history of the Himalayas.

Check out more ways satellite imagery has been used in the response to the Gorkha earthquake on the American Geophysical Union’s Trembling Earth.

Lorraine Chaffer's curator insight, June 1, 1:51 AM

Australian Curriculum

The causes, impacts and responses to a geomorphological hazard (ACHGK053)

GeoWorld 8

Chapter 4: Hazards: causes, impacts and responses

(4.5 - 4.6 Earthquakes)

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Ancient megadrought entombed dodos in poisonous cocktail

Ancient megadrought entombed dodos in poisonous cocktail | Amazing Science |

Nine hundred kilometers off the east coast of Madagascar lies the tiny island paradise of Mauritius. The waters are pristine, the beaches bright white, and the average temperature hovers between 22°C and 28°C (72°F to 82°F) year-round. But conditions there may not have always been so idyllic. A new study suggests that about 4000 years ago, a prolonged drought on the island left many of the native species, such as dodo birds and giant tortoises, dead in a soup of poisonous algae and their own feces.

The die-off happened in an area known as Mare aux Songes, which once held a shallow lake that was an important source of fresh water for nonmigratory animals. Today, it’s just a grassy swamp, but beneath the surface, fossils are so common and so well preserved that the area qualifies as what scientists call a Lagerstätte, which in German means “storage space.” "What I wanted to know was, how did this drought cause this graveyard?” says Erik de Boer, a paleoecologist at the University of Amsterdam. “How did so many animals die?”

To find out, de Boer and colleagues analyzed sediment cores taken from the area. The layers in a core contain markers that can help scientists reconstruct an ecosystem’s history, such as preserved pollens and microbes. About 4200 years ago, monsoon activity declined dramatically, causing a 50-year megadrought on the island. The cores revealed that during the same time period, the ancient lake became a muddy, salty swamp. “Annually, the lake would get some fresh water in, however this drinking water turned foul during the dry season,” de Boer says.

Things got bad fairly quickly for local animals once the lake began to dry up, the team reports in the current issue of The Holocene. Sanitation appears to have become a major issue with so many animals crowding around the shrinking source of fresh water. “The animals lived around the edges, and the excrements probably got mixed up in the wetlands," de Boer says. "It’s like a big toilet.” Even worse, the researchers’ analysis shows that the feces-flooded waters encouraged the growth of single-celled algae and bacteria—diatoms and cyanobacteria—which can cause poisonous algal blooms. The circumstances combined to create what the scientists refer to as a “deadly cocktail” that they think killed many of the animals preserved as fossils at Mare aux Songes today.

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Oldest fossils turn out to be peculiarly shaped minerals

Oldest fossils turn out to be peculiarly shaped minerals | Amazing Science |

New analysis of world-famous 3.46 billion-year-old rocks by researchers from the University of Bristol, the University of Oxford and UWA (the University of Western Australia) is set to finally resolve a long running evolutionary controversy.

The new research, published this week in Proceedings of the National Academy of Sciences, shows that structures once thought to be Earth's oldest microfossils do not compare with younger fossil candidates but have, instead, the character of peculiarly shaped minerals.

In 1993, US scientist Bill Schopf described tiny carbon-rich filaments within the 3.46 billion-year-old Apex chert (fine-grained sedimentary rock) from the Pilbara region of Western Australia, which he likened to certain forms of bacteria, including cyanobacteria. These 'Apex chert microfossils' -- between 0.5 and 20 micrometres wide -- soon became enshrined in textbooks, museum displays, popular science books and online reference guides as the earliest evidence for life on Earth. In 1996, these structures were even used to test and help refute the case against 'microfossils' in the Martian meteorite ALH 84001.

Even so, their curious color and complexity gave rise to some early questions. Gravest doubts emerged in 2002, when a team led by Oxford's Professor Martin Brasier (co-author of this current study) revealed that the host rock was not part of a simple sedimentary unit but rather came from a complex, high-temperature hydrothermal vein, with evidence for multiple episodes of subsurface fluid flow over a long time. His team advanced an alternative hypothesis, stating that these curious structures were not true microfossils but pseudofossils formed by the redistribution of carbon around mineral grains during these hydrothermal events.

Although other research teams have since supported the hydrothermal context of Professor Brasier, the 'Apex microfossil' debate has remained hard to resolve because scientific instrumentation has only recently reached the level of resolution needed to map both chemical composition and morphology of these 'microfossils' at the sub-micrometre scale.

Now Dr David Wacey, a Marie Curie Fellow in Bristol's School of Earth Sciences, in collaboration with the late Professor Brasier, has come up with new high-spatial resolution data that clearly demonstrate that the 'Apex chert microfossils' comprise stacks of plate-like clay minerals arranged into branched and tapered worm-like chains. Carbon was then absorbed onto the edges of these minerals during the circulation of hydrothermal fluids, giving a false impression of carbon-rich cell-like walls.

Dr Wacey and team used transmission electron microscopy to examine ultrathin slices of 'microfossil' candidates, to build up nanoscale maps of their size, shape, mineral chemistry and distribution of carbon. Dr Wacey explains: "It soon became clear that the distribution of carbon was unlike anything seen in authentic microfossils. A false appearance of cellular compartments is given by multiple plates of clay minerals having a chemistry entirely compatible with a high temperature hydrothermal setting.

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Globally unique double crater identified in Sweden: Impact 460 million years ago

Globally unique double crater identified in Sweden: Impact 460 million years ago | Amazing Science |

Researchers at the University of Gothenburg have found traces of two enormous meteorite impacts in the Swedish county of Jämtland, a twin strike that occurred around 460 million years ago.

The researchers have discovered two craters in Jämtland. One is enormous, while the other is a tenth of the size of the first. "The two meteorite impacts occurred at the same time, 458 million years ago, and formed these two craters," says Erik Sturkell, Professor of Geophysics at the University of Gothenburg.

Erik Sturkell and his research colleagues found one of the craters 20 kilometres south of Östersund in Brunsflo. This is an enormous crater, with a diameter of 7.5 kilometers. The smaller crater is located 16 kilometers from there, and has a diameter of 700 meters.

The two meteorite impacts 458 million years ago were not the only ones to strike Earth at this time. "Around 470 million years ago, two large asteroids collided in the asteroid belt between Mars and Jupiter, and many fragments were thrown off in new orbits. Many of these crashed on Earth, such as these two in Jämtland," says Erik Sturkell.

Jämtland was under the sea at the time, with a water depth of 500 meters at the points where two meteorites simultaneously stuck. Double impacts like this are very unusual. This is the first double impact on Earth that has been conclusively proved. "Information from drilling operations demonstrates that identical sequences are present in the two craters, and the sediment above the impact sequences is of the same age. In other words, these are simultaneous impacts," says Erik Sturkell. The water was forced away during the impact, and for a hundred seconds these enormous pits were completely dry.

"The water then rushed back in, bringing with it fragments from the meteorites mixed with material that had been ejected during the explosion and with the gigantic wave that tore away parts of the sea bed," says Erik Sturkell.

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Revealed: How did our planet ever escape 'snowball Earth'?

Revealed: How did our planet ever escape 'snowball Earth'? | Amazing Science |
Glaciers once covered most of Earth's surface and reflected the sun's heat back into space.

New details of a nightmare period on Earth with surface conditions as frigid as present-day central Antarctica at the equator have been revealed thanks to the publication of a study of ancient glacier water. The research, by an international team led by Daniel Herwartz, is published in the journal Proceedings of the National Academy of Sciences and shows that even tropical regions were once covered in snow and ice.

The idea of a deep-frozen world, “snowball Earth”, has captured the imagination since first proposed in the 1990s. On several occasions in history, long before animals evolved, apparently synchronous ice sheets existed on all the continents. However, much like falling into a crevasse on a glacier, it’s easy enough to enter such an ice age, but very difficult to escape.

The snowball Earth theory came from climate modelers who found that low carbon dioxide levels could trigger the growth of ice sheets. The whole planet would become glaciated and its mean temperature drop to as low as -45°C. As ice is much more reflective than the sea, or bare land, the Earth at that point would have been bouncing nearly all of the sun’s radiation back into space. So how could the planet ever emerge from such an ice age?

Volcanoes had to be the answer. Only they could emit enough carbon dioxide into the atmosphere to overcome the effects of Earth’s cool reflective surface. But climate models still found it difficult to plausibly describe how the Earth could have shed its glaciers.

We now have the first full explanation for how the best-known snowball event, the Marinoan, finished 635 million years ago with a several hundred meter rise in sea level. The study is the result of work by an international team of scientists. The results are published in the journal Nature Geoscience.

The team of researchers found slight wobbles of the Earth’s spin axis caused differences in the heat received at different places on the planet’s surface. These changes were small, but enough over thousands of years to cause a change in the places where snow accumulated or melted, leading the glaciers to advance and retreat.

The Earth was left looking just like the McMurdo Dry Valleys in Antarctica – arid, with lots of bare ground, but also containing glaciers up to 3 km thick. Such an Earth would have been darker than previously envisaged, absorbing more of the sun’s radiation; it was easier to see how the escape from the snowball happened.

Today, to find exposed rocks that can tell us about the carbon dioxide content of the atmosphere in the Marinoan, you have to go to the Norwegian Arctic island of Svalbard. In 2009 snowball theory was vindicated after we found the telltale signal of high carbon dioxide levels in Svalbard limestone that formed during the ice age.

Immediately underneath the Marinoan deposits are some beds of rocks deposited at very regular intervals – so regular that they must have formed over thousands of years, influenced by wobbles in the Earth’s orbit. Since Svalbard was near the Equator at the time, the most likely type of wobble is caused by the Earth slowly shifting (“precessing”) its axis on cycles of approximately 20,000 years.

Researchers also found evidence of the same process in the Snowball deposits themselves. Fluctuations in ice in relation to the Earth’s orbit are a feature of our modern ice ages over the past million years, but had not been found in such an old glaciation.

For a long time the Earth was too cold for glaciers to erode and deposit sediment – the main snowball period. The sediments then show several advances and retreats of the ice. When the glaciers retreated, they left behind a patchwork of environments: shallow and deep lakes, river channels, and floodplains that appeared as arid as anything known in Earth’s history.

Carbon dioxide appears to have remained at the same high level throughout the deposition of these sediments. Since it takes millions of years for CO2 to build up in the atmosphere, this implies the sediment layers must have formed quickly – on the order of 100,000 years. All this fits with the idea of 20,000 year precession cycles.

group of climate modellers from Paris tested the theory. The rocks and the models agreed: wobbles in the Earth’s axis had caused the planet to escape its snowball phase.

So after several million years of being frozen, this icy Earth with a hot atmosphere rich in carbon dioxide had reached a Goldilocks zone – too warm to stay completely frozen, too cold to lose its ice. This transitional period lasted around 100,000 years before the glaciers fully melted and present-day Svalbard was flooded by the sea.

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Meteorite Impacts Can Create DNA Building Blocks

Meteorite Impacts Can Create DNA Building Blocks | Amazing Science |

The emergence of life's building blocks on the prebiotic Earth was the first crucial step for the origins of life. Extraterrestrial delivery of intact amino acids and nucleobases is the prevailing hypothesis for their availability on prebiotic Earth because of the difficulties associated with the production of these organics from terrestrial carbon and nitrogen sources under plausible prebiotic conditions. However, the variety and amounts of these intact organics delivered by meteorites would have been limited. Previous shock–recovery experiments have demonstrated that meteorite impact reactions could have generated organics on the prebiotic Earth.

A new study shown that meteorite impacts on ancient oceans may have created nucleobases and amino acids. Researchers from Tohoku University, National Institute for Materials Science and Hiroshima University discovered this after conducting impact experiments simulating a meteorite hitting an ancient ocean. A new study shown that meteorite impacts on ancient oceans may have created nucleobases and amino acids. Researchers from Tohoku University, National Institute for Materials Science and Hiroshima University discovered this after conducting impact experiments simulating a meteorite hitting an ancient ocean. 

Via Integrated DNA Technologies
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Earth's magnetic field is 800 million years older than previously thought

Earth's magnetic field is 800 million years older than previously thought | Amazing Science |

Earth's magnetic field is 800 million years older than previously thought, new research suggests.

A new analysis of Western Australian zircon minerals has found the engine that generates the field started not long after the planet formed. Earth's so-called "geodynamo", involving the movement of molten iron in the Earth's outer core, began 4.22 billion years ago, say researchers today in the journal Science.

"This opens a window into a period that we know almost nothing about," says co-author, Professor Francis Nimmo of the University of California, Santa Cruz"Before this study we knew that the dynamo had existed for around three and a half billion years. What this study has done is push back the age of the dynamo by another 800 million years."

Earth's magnetic field acts as a shield protecting the planet's atmosphere and water, which make life on Earth possible. Without the magnetic field Earth's atmosphere would have been eroded away by the solar wind, a stream of charged particles flowing from the Sun.

The magnetic field was particularly important in Earth's early history when solar winds were about 100 times stronger than they are now.

"The young Sun was very active, and so having a strong magnetic field early on allows you to hang on to your atmosphere," says Nimmo.

"Mars had a dynamo early on, but then that dynamo died," he says. "Part of the reason that Mars lost its atmosphere is not simply that it has less gravity, but also that it didn't have a magnetic field protecting the atmosphere from being blown away."

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Mining ancient ores for clues to early life on Earth

Mining ancient ores for clues to early life on Earth | Amazing Science |

An analysis of sulfide ore from a Canadian mine suggests microbes were active in ocean water 2.7 billion years ago.

Researchers examined sulfide ore deposits from one of the world’s richest base-metal mines—the Kidd Creek copper-zinc mine in Timmins, Ontario. The work confirms that oxygen levels were extremely low on Earth 2.7 billion years ago, but also shows that microbes were actively feeding on sulfate in the ocean and influencing seawater chemistry during that geological time period.

The research, reported by a team of Canadian and US scientists in Nature Geoscience, provides new insight into how ancient metal-ore deposits can be used to better understand the chemistry of the ancient oceans—and the early evolution of life. Sulfate is the second most abundant dissolved ion in the oceans today. It comes from the “rusting” of rocks by atmospheric oxygen, which creates sulfate through chemical reactions with pyrite, the iron sulfide material known as “fool’s gold.”

The researchers—led by PhD student John Jamieson of the University of Ottawa and Boswell Wing, an associate professor at McGill University—measured the “weight” of sulfur in samples of massive sulfide ore from the Kidd Creek mine using a highly sensitive instrument known as a mass spectrometer. The weight is determined by the different amounts of isotopes of sulfur in a sample, and the abundance of different isotopes indicates how much seawater sulfate was incorporated into the massive sulfide ore that formed at the bottom of ancient oceans.

That ancient ore is now found on the Earth’s surface, and is particularly common in the Canadian shield. The scientists found that much less sulfate was incorporated into the 2.7 billion-year-old ore at Kidd Creek than is incorporated into similar ore forming at the bottom of oceans today. From these measurements, the researchers were able to model how much sulfate must have been present in the ancient seawater.

Their conclusion: sulfate levels were about 350 times lower than in today’s ocean. Though they were extremely low, sulfate levels in the ancient ocean still supported an active global population of microbes that use sulfate to gain energy from organic carbon.

“The sulfide ore deposits that we looked at are widespread on Earth, with Canada and Quebec holding the majority of them,” says Wing. “We now have a tool for probing when and where these microbes actually came into global prominence.”

“Deep within a copper-zinc mine in northern Ontario that was once a volcanically active ancient seafloor may not be the most intuitive place one would think to look for clues into the conditions in which the earliest microbes thrived over 2.7 billion years ago,” Jamieson adds. “However, our increasing understanding of these ancient environments and our abilities to analyze samples to a very high precision has opened the door to further our understanding of the conditions under which life evolved.”

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NASA: The Global Warming "Pause" Never Actually Happened

NASA: The Global Warming "Pause" Never Actually Happened | Amazing Science |

There’s been much debate these past few years over the cause of the so-called global warming “hiatus”—a pause in the overall uptick up of Earth’s temperature due to cooling at the surface of the Pacific Ocean since the early 2000s. Did climate warming stop? Nope, we just weren’t looking deep enough.

Earth’s extra heat, you see, has spent the last 10 years sinking into the vast depths of the equatorial Pacific and Indian Oceans. That’s the conclusion of a new study, conducted by scientists at NASA’s Jet Propulsion Laboratory and published today in the journal Science. The study, which examines two decades of observational data, offers the most definitive evidence to date that Earth’s largest ocean has been massively redistributing heat since 2003. Specifically, cooling in the top 100 meter layer of the Pacific Ocean has been compensated by warming in the 100 to 300 meter layer of both the Pacific and Indian Oceans, which together cover over 40% of our planet’s surface.

The global average ocean surface temperature has been rising since 2003 by +0.001ºC per year,according to Intergovernmental Panel on Climate Change. That temperature rise is notably slower than century-timescale warming of +0.006ºC per year since 1880. For the last few years, climate scientists have been trying to understand whether the hiatus was the result of a redistribution of heat within the ocean, or less overall heat uptake at the ocean’s surface.

Over the last few years, a likely scenario has begun to emerge. Modeling studies show that the cooling of the surface of the Pacific is probably being balanced by more rapid warming in deeper parts of the Atlantic or the Pacific. What’s more, a recent paper in Nature Climate Change used observational data and models to demonstrate increased heat transport from the Pacific to the Indian Ocean over the last decade. Clearly, the pathways by which Earth’s oceans process heat seem to be changing.

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Earth's colossal crater count complete: Just 128 confirmed impact craters have been spotted on Earth’s surface

Earth's colossal crater count complete: Just 128 confirmed impact craters have been spotted on Earth’s surface | Amazing Science |

Study suggests that all craters 6 kilometers across or larger have been found. No more impact craters as big as Canada's Clearwater West and Clearwater East, which measure more than 10 kilometers across, remain to be discovered.

Mars is pocked with more than 300,000 craters, created by asteroid impacts. The moon is blanketed with millions more, too many to count. But the surface of Earth, constantly eroded by wind and rain, hides its history. Just 128 confirmed impact craters have been spotted on Earth’s surface. However, a new study suggests that this low number is not the result of lazy searching; all of the big impact craters on the planet's surface have been found, leaving none to be discovered.

“I'm definitely surprised.” says Brandon Johnson, a planetary scientist at the Massachusetts Institute of Technology in Cambridge, who was not involved in the study. “It’s the first time anyone has done this kind of thing—taking into account the effects of erosion.”

In 2014, Johnson led a similar study, which found that for craters 85 kilometers in diameter and larger, the geologic record ought to be complete. Based on the rate of impacts and the age of the crust, his team predicted eight craters this size, and there are six or seven that have been confirmed. These giant craters are deep enough to survive erosion, but they can be destroyed by plate tectonics, which splits apart, subducts, or otherwise jumbles up the crust the craters sit on—a process Johnson’s study examined.

Now, Stefan Hergarten and Thomas Kenkmann, geophysicists at the University of Freiburg in Germany, have taken the analysis further and found that the documented record is complete down to much smaller impact craters. They combined estimates of asteroid impact rates with rates of erosion, and compared the resulting theoretical crater distribution with what geologists actually see. For the 70 craters larger than 6 kilometers across, the record is complete, they say: There are no more to be found, as the researchers report in Earth and Planetary Science Letters.

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Deepest known hydrothermal vents discovered in the Pacific Ocean

Deepest known hydrothermal vents discovered in the Pacific Ocean | Amazing Science |

In spring 2015, MBARI researchers discovered a large, previously unknown field of hydrothermal vents in the Gulf of California, about 150 kilometers (100 miles) east of La Paz, Mexico. Lying more than 3,800 meters (12,500 feet) below the surface, the Pescadero Basin vents are the deepest high-temperature hydrothermal vents ever observed in or around the Pacific Ocean. They are also the only vents in the Pacific known to emit superheated fluids rich in both carbonate minerals and hydrocarbons. The vents have been colonized by dense communities of tubeworms and other animals unlike any other known vent communities in the in the eastern Pacific.

Like another vent field in the Gulf that MBARI discovered in 2012, the Pescadero Basin vents were initially identified in high-resolution sonar data collected by an autonomous underwater vehicle (AUV). MBARI’s yellow, torpedo-shaped seafloor-mapping AUV spent two days flying about 50 meters above the bottom of the Basin, using sound beams to map the depth and shape of the seafloor.

The AUV team, led by MBARI engineer David Caress, pored over the detailed bathymetric map they created from the AUV data and saw a number of mounds and spires rising up from the seafloor. Data from the AUV also showed slightly warmer water over some of the spires, which implied that they might be active hydrothermal-vent chimneys. A team of geologists led by David Clague then used a tethered underwater robot, the remotely operated vehicle (ROV) Doc Ricketts, to dive down to the seafloor, fly around the vents, and collect video and samples of rocks and hot water spewing from the chimneys.

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New technique harnesses everyday seismic waves to image Earth

New technique harnesses everyday seismic waves to image Earth | Amazing Science |

A new technique developed at Stanford University harnesses the buzz of everyday human activity to map the interior of the Earth. "We think we can use it to image the subsurface of the entire continental United States," said Stanford geophysics postdoctoral researcher Nori Nakata.

Using tiny ground tremors generated by the rumble of cars and trucks across highways, the activities within offices and homes, pedestrians crossing the street and even airplanes flying overhead, a team led by Nakata created detailed three-dimensional subsurface maps of the California port city of Long Beach.

The maps, detailed in a recent issue of the Journal of Geophysical Research, marks the first successful demonstration of an elusive Earth-imaging technique, called ambient noise body wave tomography. "It's a technique that scientists have been trying to develop for more than 15 years," said Nakata, who is the Thompson Postdoctoral Fellow at the School of Earth, Energy & Environmental Sciences.

There are two major types of seismic waves: surface waves and body waves. As their name suggests, surface waves travel along the surface of the Earth. Scientists have long been able to harness surface waves to study the upper layers of the planet's crust, and recently they have even been able to extract surface waves from the so-called ambient seismic field. Also known as ambient noise, these are very weak but continuous seismic waves that are generated by colliding ocean waves, among other things.

Body waves, in contrast, travel through the Earth, and as a result can provide much better spatial resolution of the planet's interior than surface waves. "Scientists have been performing body-wave tomography with signals from earthquakes and explosives for decades," said study coauthor Jesse Lawrence, an assistant professor of geophysics at Stanford. "But you can't control when and where an earthquake happens, and explosives are expensive and often damaging."

For this reason, geophysicists have long sought to develop a way to perform body wave tomography without relying on earthquakes or resorting to explosives. This has proven challenging, however, because body waves have lower amplitudes than surface waves, and are therefore harder to observe. "Usually you need to combine and average lots and lots of data to even see them," Lawrence said.

In the new study, the Stanford team applied a new software processing technique, called a body-wave extraction filter. Nakata developed the filter to analyze ambient noise data gathered from a network of thousands of sensors that had been installed across Long Beach to monitor existing oil reservoirs beneath the city. Using this filter, the team was able to create maps that revealed details about the subsurface of Long Beach down to a depth of more than half a mile (1.1. kilometers). The body-wave maps were comparable to, and in some cases better than, existing imaging techniques.

One map, for example, clearly revealed the Newport-Inglewood fault, an active geological fault that cuts through Long Beach. This fault also shows up in surface-wave maps, but the spatial resolution of the body-wave velocity map was much higher, and revealed new information about the velocity of seismic waves traveling through the fault's surrounding rocks, which in turn provides valuable clues about their composition and organization.

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Intense thunderclouds produce haze of antimatter photons that do not fit any known source of antiparticles

Intense thunderclouds produce haze of antimatter photons that do not fit any known source of antiparticles | Amazing Science |

When Joseph Dwyer’s aeroplane took a wrong turn into a thundercloud, the mistake paid off: the atmospheric physicist flew not only through a frightening storm but also into an unexpected — and mysterious — haze of antimatter. Although powerful storms have been known to produce positrons — the antimatter versions of electrons — the antimatter observed by Dwyer and his team cannot be explained by any known processes, they say. “This was so strange that we sat on this observation for several years,” says Dwyer, who is at the University of New Hampshire in Durham.

The flight took place six years ago, but the team is only now reporting the result (J. R. Dwyer et al. J. Plasma Phys.; in the press). “The observation is a puzzle,” says Michael Briggs, a physicist at the NASA Marshall Space Flight Center in Huntsville, Alabama, who was not involved in the report.

A key feature of antimatter is that when a particle of it makes contact with its ordinary-matter counterpart, both are instantly transformed into other particles in a process known as annihilation. This makes antimatter exceedingly rare. However, it has long been known that positrons are produced by the decay of radioactive atoms and by astrophysical phenomena, such as cosmic rays plunging into the atmosphere from outer space. In the past decade, research by Dwyer and others has shown that storms also produce positrons, as well as highly energetic photons, or γ-rays.

It was to study such atmospheric γ-rays that Dwyer, then at the Florida Institute of Technology in Melbourne, fitted a particle detector on a Gulfstream V, a type of jet plane typically used by business executives. On 21 August 2009, the pilots turned towards what looked, from its radar profile, to be the Georgia coast. “Instead, it was a line of thunderstorms — and we were flying right through it,” Dwyer says. The plane rolled violently back and forth and plunged suddenly downwards. “I really thought I was going to die.”

During those frightening minutes, the detector picked up three spikes in γ-rays at an energy of 511 kiloelectronvolts, the signature of a positron annihilating with an electron. Each γ-ray spike lasted about one-fifth of a second, Dwyer and his collaborators say, and was accompanied by some γ-rays of slightly lower energy. The team concluded that those γ-rays had lost energy as a result of travelling some distance and calculated that a short-lived cloud of positrons, 1–2 kilometres across, had surrounded the aircraft. But working out what could have produced such a cloud has proved hard. “We tried for five years to model the production of the positrons,” says Dwyer.

Electrons discharging from charged clouds accelerate to close to the speed of light, and can produce highly energetic γ-rays, which in turn can generate an electron–positron pair when they hit an atomic nucleus. But the team did not detect enough γ-rays with sufficient energy to do this.

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Hidden water below Antarctica provides hope for life on Mars

Hidden water below Antarctica provides hope for life on Mars | Amazing Science |
The McMurdo Dry Valleys form the largest ice-free region in Antarctica. They also make up the coldest and driest environments on the planet. Yet, despite these extreme conditions, the valleys' surface is home to a large diversity of microbial life. Now, new evidence suggests that a vast network of salty liquid water exists 1,000 feet below the surface — a finding that lends support to the idea that microbial life may exist beneath Antarctica's surface as well. The finding isn't just exciting for Earth ecologists, however; planetary scientists are intrigued as well. Indeed, finding salty liquid water below Antarctica provides strong support for the idea that Mars, an environment that resembles Antarctic summers, may have similar aquifers beneath its surface — aquifers that could support microscopic life.

"Before this study, we didn't know to what extent life could exist beneath the glaciers, beneath hundreds of meters of ice, beneath ice covered lakes and deep into the soil," says Ross Virginia, an ecosystem environmentalist at Dartmouth College and a co-author of the study, published in Nature Communications today. This study opens up "possibilities for better understanding the combinations of factors that might be found on other planets and bodies outside of the Earth" — including Mars.

Approximately 4.5 billion years ago, 20 percent of the Martian surface was likely covered in water. Today, Mars may still be home to small amounts of salty liquid water, which would exist on the planet's soil at night before evaporating during the daytime. Taken together, these findings are pretty exciting for those who hope to discover life on Mars — water, after all, is a requirement for life. Unfortunately, researchers have also pointed out that the Martian surface is far too cold for the survival of any known forms of life. That's why some scientists have started to wonder about what may lie beneath the Martian surface. If the extreme environment conditions found in Antarctica's subsurface contains all the elements necessary for life, it's possible that the Martian subsurface might as well.

In the study, researchers flew a helicopter more than 114 square miles over Taylor Valley— the southernmost of the three dry valleys. Below the helicopter, researchers suspended a large antenna. The technology, called SkyTem, acted as an airborne electromagnetic sensor that generated an electromagnetic field capable of penetrating through ice or into the soil in the dry valley. As the antenna surveyed the valley, the electromagnetic field reflected back information that was altered from the original signal depending on whether it encountered a brine or frozen soil or ice, Virginia explains. "So basically we're inferring the distribution of those types of materials based on what is reflected back to these helicopters flying over the surface of Antarctica."

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Two huge magma chambers sit beneath Yellowstone National Park

Two huge magma chambers sit beneath Yellowstone National Park | Amazing Science |
Underneath the bubbling geysers and hot springs of Yellowstone National Park in Wyoming sits a volcanic hot spot that has driven some of the largest eruptions on Earth. Geoscientists have now completely imaged the subterranean plumbing system and have found not just one, but two magma chambers underneath the giant volcano.

“The main new thing is we unveil a deeper and bigger magma reservoir in the lower crust,” says study author Hsin-Hua Huang, a seismologist at the University of Utah in Salt Lake City.

Scientists had already known about a plume, which brings molten rock up from deep in the mantle to a region about 60 kilometers below the surface. And they had also imaged a shallow magma chamber about 10 kilometers below the surface, containing about 10,000 cubic kilometers of molten material. But now they have found a deeper one, 4.5 times larger, that sits between 20 and 50 kilometers below the surface. “They found the missing link between the mantle plume and the shallow magma chamber,” says Peter Cervelli, a geophysicist in Anchorage, Alaska, who works at the U.S. Geological Survey’s Yellowstone Volcano Observatory.

The discovery does not, on its own, increase the chance of an eruption, which is driven by an emptying of the shallow chamber. The last major eruption was 640,000 years ago, and today the threat of earthquakes is far more likely. But the deeper chamber does mean that the shallow chamber can be replenished again and again. “Knowing that you have this additional reservoir tells you you could have a much bigger volume erupt over a relatively short time scale,” says co-author Victor Tsai, a geophysicist at the California Institute of Technology in Pasadena. The discovery, reported online today in Science, also confirms a long-suspected model for some volcanoes, in which a deep chamber of melted basalt, a dense iron- and magnesium-rich rock, feeds a shallower chamber containing a melted, lighter silicon-rich rock called a rhyolite.

The researchers used seismometers to measure the noise of earthquakes in order to take a sort of sonogram of Earth’s crust. When earthquakes pass through liquid material, seismic waves slow down. The team interprets these low-velocity regions as magma chambers (although these chambers are still mostly solid rock and contain only a small fraction of liquid melt). Distant earthquakes are useful for imaging deep structures, like the mantle plume, and local earthquakes can help to see the shallow chamber. Huang says his study is the first time that both types of data were combined so that the middle depths, and the deeper chamber, could be seen. His team used 11 seismometers from the EarthScope USArray to listen for the deep earthquakes and 69 seismometers from several local seismic networks to gather data from shallower earthquakes.
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