Archive for the ‘Geology’ Category

Hebridean islands of Scotland


So it is believed at least. Researchers say a more detailed underwater survey is needed.

Evidence for the ancient, 1.2 billion years old, meteorite strike, was first discovered in 2008 near Ullapool, NW Scotland by scientists from Oxford and Aberdeen Universities.

The thickness and extent of the debris deposit they found suggested the impact crater—made by a meteorite estimated at 1km wide—was close to the coast, but its precise location remained a mystery.

In a paper published today in Journal of the Geological Society, a team led by Dr. Ken Amor from the Department of Earth Sciences at Oxford University, show how they have identified the crater location 15-20km west of a remote part of the Scottish coastline.

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1989 Loma Prieta earthquake damage [image credit: H.G. Wilshire, U.S. Geological Survey]


Smaller quakes seem to have taken over, for the time being at least. The Loma Prieta earthquake of 1989 in Northern California had a magnitude of 6.9 but was not considered to be ‘major’, despite some deaths and billions of dollars worth of damage.

There have been no major ground rupturing earthquakes along California’s three highest slip rate faults in the past 100 years, reports ScienceDaily.

A new study concludes that this current ‘hiatus’ has no precedent in the past 1000 years.

U.S. Geological Survey researchers Glenn Biasi and Kate Scharer analyzed long paleoseismic records from the San Andreas, San Jacinto and Hayward Faults for the past 1000 years, to determine how likely it might be to have a 100-year gap in earthquakes across the three faults.

They found that the gap was very unlikely — along the lines of a 0.3% chance of occurring, given the seismic record of the past 1000 years.

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National flag of South Korea

Is this the end for ‘enhanced’ geothermal technology? Note this quake was 1,000 times stronger than the next one of similar causes.

The nation’s energy ministry expressed ‘deep regret’, and said it would dismantle the experimental plant, as Nature News reports.

A South Korean government panel has concluded that a magnitude-5.4 earthquake that struck the city of Pohang on 15 November 2017 was probably caused by an experimental geothermal power plant.

The panel was convened under presidential orders and released its findings on 20 March.

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The ability to recognize patterns in Earth’s behaviour by sifting through masses of geological data could be programmed into machines.

Scientists seeking to understand Earth’s inner clockwork have deployed armies of sensors listening for signs of slips, rumbles, exhales and other disturbances emanating from the planet’s deepest faults to its tallest volcanoes.

“We measure the motion of the ground continuously, typically collecting 100 samples per second at hundreds to thousands of instruments,” said Stanford geophysicist Gregory Beroza. “It’s just a huge flux of data.”

Yet scientists’ ability to extract meaning from this information has not kept pace, reports Phys.org.

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Location of Mayotte, in the Indian Ocean off the coast of Southeast Africa


Epic. Why are ‘schools of dead fish appearing in the water?’

Last November, a huge seismic event that shook the planet left experts wondering about its possible source, says ScienceAlert.

Researchers now think they know what might have caused it: an offshore volcanic event unlike any other in recorded history.

If the hypothesis is right, and there has been a massive movement of magma underneath the sea floor, that has implications for nearby Mayotte and the neighbouring Comoros islands off the coast of Africa.

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Glacier in Patagonia


The latest Ice Ages theory rolls off the production line. This one relies on ‘pulling enough carbon dioxide out of the atmosphere’, so we can see how they’re thinking. A possible problem there is that historical data from ice cores usually show carbon dioxide changes following temperature changes by a few hundred years, which seems to contradict the findings here. It’s the old chicken and egg conundrum – effects can’t precede causes. An important part of the carbon cycle is ocean outgassing of CO2 (response to warming) and absorption (response to cooling).

Over the last 540 million years, the Earth has weathered three major ice ages—periods during which global temperatures plummeted, producing extensive ice sheets and glaciers that have stretched beyond the polar caps.

Now scientists at MIT, the University of California at Santa Barbara, and the University of California at Berkeley have identified the likely trigger for these ice ages, reports Phys.org.

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Arctic region


At last – something that can’t be blamed on Brexit! Just joking of course, and wandering poles can be a serious matter for navigators.

Erratic motion of north magnetic pole forces experts to update model that aids global navigation.
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Something strange is going on at the top of the world, a Nature article says.

Earth’s north magnetic pole has been skittering away from Canada and towards Siberia, driven by liquid iron sloshing within the planet’s core.

The magnetic pole is moving so quickly that it has forced the world’s geomagnetism experts into a rare move.

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Ross Ice Shelf, Antarctica


The latest research comes up with a new addition to the list of possible ice age mechanisms.

Earth’s latest ice age may have been caused by changes deep inside the planet, reports ScienceDaily.

Based on evidence from the Pacific Ocean, including the position of the Hawaiian Islands, Rice University geophysicists have determined Earth shifted relative to its spin axis within the past 12 million years, which caused Greenland to move far enough toward the north pole to kick off the ice age that began about 3.2 million years ago.

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Topographic map of Greenland


Something creating a 19-mile wide dent in the Earth’s surface would clearly have been a major strike. If confirmed it would be the most northerly impact crater on Earth.

What looks to be a large impact crater has been identified beneath the Greenland ice sheet, reports BBC News.

The 31km-wide depression came to light when scientists examined radar images of the island’s bedrock.

Investigations suggest the feature was probably dug out by a 1.5km-wide iron asteroid sometime between about 12,000 and three million years ago.

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Even today, more than eighty percent of our ocean is unmapped, unobserved, and unexplored. How many more hidden volcanoes may remain to be discovered?

The find offers a glimpse into a previously unknown marine ecosystem — and spotlights just how little we know about the seafloor, says Euronews.

While mapping the seafloor some 250 miles off the coast of the Australian island of Tasmania, scientists recently discovered what’s being called a “volcanic lost world” deep underwater.

The chain of volcanic seamounts — huge undersea mountains that loom as tall as 9,800 feet, or more than six times taller than the Empire State Building — offer a glimpse into a previously unknown ocean ecosystem.

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The research includes an animation which explains ‘how three ancient land masses collided to form the British Isles’.

Scientists have for centuries believed that England, Wales and Scotland were created by the merger of Avalonia and Laurentia more than 400 million years ago, says EurekAlert.

However, geologists based at the University of Plymouth now believe that a third land mass – Armorica – was also involved in the process.

The findings are published in Nature Communications and follow an extensive study of mineral properties at exposed rock features across Devon and Cornwall.

They reveal a clear boundary running across the two counties, with areas north of it sharing their geological roots with the rest of England and Wales but everything south being geologically linked to France and mainland Europe.

Among other things, scientists believe the research explains the abundance of tin and tungsten in the far South West of England – metals also found in Brittany and other areas of mainland Europe, but not so evident in the rest of the UK.

The research’s lead author, Lecturer in Igneous Petrology Dr Arjan Dijkstra, said: “This is a completely new way of thinking about how Britain was formed. It has always been presumed that the border of Avalonia and Armorica was beneath what would seem to be the natural boundary of the English Channel. But our findings suggest that although there is no physical line on the surface, there is a clear geological boundary which separates Cornwall and south Devon from the rest of the UK.”

Continued here.


A new tweak to tidal theory is proposed. The research team hopes that ‘understanding continental configurations and tidal strengths will impact the development of climate models’.

Daily tides are driven primarily by Earth’s rotation and the gravitational force of the moon on oceans, says Earth magazine.

However, in a new study in Geophysical Research Letters, researchers suggest that tidal magnitudes are also influenced, on longer timescales, by the size and shape of the ocean basins, and are therefore driven by plate tectonics.

Plate tectonics gives rise to the formation of supercontinents — massive aggregations of continental lithosphere — which form and break apart in cycles that last about 400 million to 500 million years. With the breakup of the last supercontinent, Pangea, about 180 million years ago, and the projected formation of a new supercontinent, known as Aurica, in about 200 million years, Earth is currently in the middle of a supercontinent cycle.

Because the size and shape of ocean basins impact ocean circulation and tides, researchers led by Mattias Green, a physical oceanographer at Bangor University in England, hypothesized that tides may be linked to the supercontinent cycle in a so-called supertidal cycle.

Current tides, particularly those in the North Atlantic, are very large, Green’s team noted because of tidal resonance, which occurs when ocean basins and continental shelves reinforce and amplify the natural oscillation of tides as they sweep back and forth across oceans. “So the tides are larger at present because the continents are configured the way they are.”

To model Earth’s future oceanic tides, the researchers used predictions of continental configurations for the next 250 million years, through when Aurica is predicted to form. Ocean basin size was the main factor considered in the modeling, but the team also accounted for the moon’s gravitational pull on the oceans, Earth’s axial tilt, and simplified ocean bathymetries for future plate tectonic reconstructions.

Simplification of these fine details does affect the team’s modeling, notes David Waltham, a mathematical geologist at the Royal Holloway University of London, who was not involved in the study. But the simplifications used likely do not change the overall results, he adds.

Green and his colleagues reported that global tides are likely to increase over the next 50 million years “due to an enhanced tide in the North Atlantic and Pacific at 25 million years, followed by a very large Pacific tide at 50 million years.”

Continued here.

USnatgasBloomberg:

World energy ministers representing about two thirds of the global population tussled over how the world can achieve a cleaner energy future. The compromise answer: Natural gas, at least for now.

A consensus statement from G20 energy ministers meeting in Argentina cited the potential of natural gas “to expand significantly over the coming decades.” Meanwhile, the group said that nations that “opt to enhance their renewable energy strategies” should boost investment and financing within that arena.

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Arizona, USA


Amazing what can be gleaned from a 1,700 feet long rock core.
H/T Ian Wilson

Every 405,000 years, gravitational tugs from Jupiter and Venus slightly elongate Earth’s orbit, an amazingly consistent pattern that has influenced our planet’s climate for at least 215 million years and allows scientists to more precisely date geological events like the spread of dinosaurs, according to a Rutgers-led study.

The findings are published online today in the Proceedings of the National Academy of Sciences, reports ScienceDaily.

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The planet Mercury, as imaged by the MESSENGER spacecraft [Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington]


More theoretical speculations about Mercury’s origins, arising from what is now believed to be evidence of historical volcanic activity.

Mercury is the closest planet to the sun, but far from being a dull cinder of a world, it has instead turned out to be a real eye opener for geologists, says Phys.org.

Among the revelations by NASA’s MESSENGER probe, which first flew past Mercury in 2008 and orbited it between 2011 and 2015, is the discovery of a hundred or so bright red spots scattered across the globe. Now they are at last being named.

Although they appear more yellow-orange than red on the accompanying colour-enhanced images, they are the reddest features on Mercury, a planet that looks dull and grey on unenhanced images.

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Is there evidence of a cause and effect connection between geological forces and El Niño generation? A look at one theory.

The Next Grand Minimum

El Niño and La Niña weather patterns have a significant impact on California climate. This illustration shows the drought impacts.

west-with-out-water-page-54

Long-term La Niña periods have been associated with long-term droughts in the southwest lasting 200, 90 and 55 years. More specifically severe droughts from AD1021 to 1051, AD1130 to 1180, AD1240 to 1265, AD1360 to 1365.

I often wondered what was the controlling mechanism that generated long-term La Niña conditions with few La Niño conditions. Plate Climatology Theory may be one possible answer, the generation of La Niña events by undersea volcanic activity.

I found this article on Plate Climatology most interesting.

eruptive-warm-burstGeologically induced “Eruptive” warm burst that helps generate 2014-2015 El Nino.

All El Ninos originate at the same fixed “Point Source” located east of Papua New Guinea and the Solomon Islands. Fixed point sources are typical of geological features, and not typical of ever moving atmospheric or ocean…

View original post 364 more words

Earth’s atmosphere [image credit: BBC]


“These results are going to require rewriting the textbooks,” according to the research program director.

Not all of the nitrogen on the planet comes from the atmosphere, according to a UC Davis study in the journal Science. Up to a quarter comes from Earth’s bedrock. 

The discovery could greatly improve climate change projections, says Eurekalert. 

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Cobalt boom turns life upside down in DR Congo

Posted: March 2, 2018 by oldbrew in Geology
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Cobalt mining in DR Congo [image credit: BBC]


If two thirds of the world’s cobalt comes from this one country, then given the projected numbers of electric vehicles – and other electronic devices – needing it in the years ahead, the question must be: is this sustainable? Recent rapid price rises suggest scarcity of supply in relation to demand. China moved in there in a big way about ten years ago.

In early 2014, according to local folklore, a man digging a septic tank or a well in his garden in Kasulo came across rocks with a distinctive grey-green sheen: cobalt.

From then on—rather like the find at Sutter’s Mill in 1848 that sparked the California Gold Rush—life for local people was never quite the same again, says Phys.org.

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What’s in a place name?


Anglo-Saxon England was unusually warm and stormy. Place names coined then could hold clues to how the weather will get wetter and wilder as the climate changes, says Sott.net. Assuming the weather does do that, of course. The author asks: “Is it a surprise that places with watery names are more prone to flooding?”

It’s blowy on the B4380 to Buildwas, writes Richard Webb in the New Scientist. A keen wind whipping across the floodplain from Shrewsbury flaps a misarranged saddle bag strap against my back wheel.

As I cross the river Severn at Atcham, and bend right down the back road past Wroxeter, a black cloud delivers the first dribbles of rain.

England’s place names are a treasure trove of hidden history – if only we could find the key.

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Goldman Sachs, the merchant bank, calls cobalt ‘the new gasoline’ but there are no signs of new wealth in the DRC, where the children haul the rocks brought up from tunnels dug by hand.

Adult miners dig up to 600ft below the surface using basic tools, without protective clothing or modern machinery. Sometimes the children are sent down into the narrow makeshift chambers where there is constant danger of collapse.

Cobalt is such a health hazard that it has a respiratory disease named after it – cobalt lung, a form of pneumonia which causes coughing and leads to permanent incapacity and even death.

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