Ancient ‘megafloods’ tilted the very direction of Earth’s crust, scientists find

Image credit: NASA

Ice age flooding, recreated in models.
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Earth’s last major ice age locked up gargantuan amounts of water in vast glaciers, says Science Alert.

Once they melted, it was a spectacle to behold as tremendous floods gouged channels into the face of the planet.

The remnants of one of the largest of these ancient deluges are still visible in eastern Washington, in an area now known as the Channeled Scablands.

For a long time, geologists have been struggling to understand the dynamic properties of these floods, until a recent key insight was made.

These ancient glaciers were so large and heavy, they actually tilted Earth’s crust beneath them – when weight was released due to melting, the land would have moved too, changing the course of the megaflood.

Using modeling of ancient megafloods, researchers decided to test whether glacial isostatic adjustment (GIA) – deflections in the crust as heavy chunks of ice form and melt – would affect the routing flow and erosion in two prominent Scabland tracks.

“We used relatively simple, yet plausible, numerical experiments to test whether GIA could have had a substantial impact on flood routing and erosion for two major scabland tracts, Cheney-Palouse and Telford-Crab Creek,” write the authors of the study.

“To this end, we modeled GIA to reconstruct the topography of the Channeled Scabland at different times during the period of Ice Age flooding.”

Up until now, reconstructions of ancient megaflood routing had investigated how other variables would affect them – things like erosion and the movement of sediment, the three-dimensional mechanics of the environment, or how ice dams break, for example.

But they would also base these reconstructions on present-day topography, approximating how past landscapes may have looked.

“People have been looking at high water marks and trying to reconstruct the size of these floods, but all of the estimates are based on looking at the present-day topography,” said lead author Tamara Pico, assistant professor of Earth and planetary sciences at UC Santa Cruz.

Geologists realized that the effects melting glaciers were having on Earth’s crust were also likely playing a role in the routing and behavior of these megafloods.

“GIA caused crustal deformation in the Channeled Scabland with rates up to 10 millimeters per year, orders of magnitude above regional tectonic uplift rates and, therefore, may have influenced flood routing,” note the authors.

“The course of ancient, glacial outburst floods was likely influenced by glacial isostatic adjustment (GIA), and reconstructing these events informs our understanding of how floods shape landscapes on Earth and Mars,” they added.
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The researchers believe the deformation of Earth’s crust due to the expanding and contacting of the ice sheets would have altered the elevation of the landscape by hundreds of meters over this period.

Moving forward, the researchers want to simulate past megaflood events which incorporate the multiple factors that determine their routing.

However, understanding the important role that ice age crustal deformation plays during flood routing and erosion in these ancient megafloods is a step in the right direction.

Full article here.

Tug of sun, moon could be driving plate motions on ‘imbalanced’ Earth, suggest researchers

Credit: reference.com

Plate tectonics has always been good for a science controversy or two. This one throws some solar-planetary spice into the mix, putting a focus on the Earth-Moon barycentre.
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A study led by geophysicist Anne M. Hofmeister in Arts & Sciences at Washington University in St. Louis proposes that imbalanced forces and torques in the Earth-moon-sun system drive circulation of the whole mantle, says Phys.org.

The new analysis provides an alternative to the hypothesis that the movement of tectonic plates is related to convection currents in the Earth’s mantle.

Convection involves buoyant rise of heated fluids, which Hofmeister and her colleagues argue does not apply to solid rocks.

They argue that force, not heat, moves large objects.

Climate-friendly farming: Greenland’s melting glaciers offer an answer

Greenland drink break [image credit: leisurelylifestyle.com]

As a bonus in today’s climate obsessed times, carbon credits could come into play for farmers to sell with this discovery. Even Danish brewers can benefit. Why fear glacier melt if it makes life better?
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On a shore near Greenland’s capital Nuuk, a local scientist points to a paradox emerging as the island’s glaciers retreat: one of the most alarming consequences of global warming could deliver a way to limit its effects, says Reuters (via Yahoo News).

“It’s a kind of wonder material,” says Minik Rosing, a native Greenlander, referring to the ultra-fine silt deposited as the glaciers melt.

Known as glacial rock flour, the silt is crushed to nano-particles by the weight of the retreating ice sheet, which deposits roughly one billion tonnes of it on the world’s largest island per year.

Professor Minik Rosing and his team at the University of Copenhagen have established the nutrient-rich mud boosts agricultural output when applied to farmland and absorbs carbon dioxide from the air in the process.

Earth Tipped on Its Side 84 Million Years Ago, New Evidence Suggests

Diagram showing solid-body rotation of the Earth with respect to a stationary spin axis due to true polar wander. [Credit: Wikipedia]

The researchers say their finding ‘challenges the notion that the spin axis has been largely stable over the past 100 million years.’
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We know that true polar wander (TPW) can occasionally tilt whole planets and moons relative to their axes, but it’s not entirely clear just how often this has happened to Earth, says ScienceAlert.

Now a new study presents evidence of one such tilting event that occurred around 84 million years ago – when dinosaurs still walked the Earth.

Researchers analyzed limestone samples from Italy, dating back to the Late Cretaceous period (100.5 to 65.5 million years ago), looking for evidence of shifts in the magnetic record that would point towards an occurrence of TPW.

Bacteria fossils trapped in the rock, forming chains of the mineral magnetite, offer some of the most convincing evidence yet of true polar wander in the Late Cretaceous – and it may help settle a scientific debate that’s been going on for decades.

Iceland’s volcanic eruption the longest in half a century

A local expert comments: “There seems to be still enough magma from whatever reservoir the eruption is tapping. So it could go on for a long time.”
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It will be six months on Sunday that the volcanic eruption currently mesmerising spectators near Reykjavik first began, making it the longest Iceland has witnessed in more than 50 years, says Phys.org.

The first lava began spewing out of a fissure close to Mount Fagradalsfjall on the evening of March 19 on the Reykjanes peninsula to the southwest of Reykjavik.

And the ensuing spectacle—ranging from just a slow trickle of lava at times to more dramatic geyser-like spurts of rocks and stones at others—has become a major tourist attraction, drawing 300,000 visitors so far, according to the Iceland Tourist Board.

Iceland’s sixth volcanic eruption in 20 years is already longer than the preceding one in Holuhraun, in the centre-east of the island, which lasted from the end of August 2014 until the end of February 2015.

‘Icelandia’: Is Iceland the tip of a vast, sunken continent?

Evidence for plate divergence in Iceland [image credit: Rob Young @ Wikipedia]

There could be more to Iceland than meets the eye. A lot more, if these theorists are right.
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Academics believe they have identified a remarkable geological secret: A sunken continent hidden under Iceland and the surrounding ocean, which they have dubbed “Icelandia”, says Phys.org.

Academics believe they have identified a remarkable geological secret: A sunken continent hidden under Iceland and the surrounding ocean, which they have dubbed “Icelandia.”

An international team of geologists, led by Gillian Foulger, Emeritus Professor of Geophysics in the Department of Earth Sciences at Durham University (UK), believe the sunken continent could stretch from Greenland all the way to Europe.

It is believed to cover an area of ~600,000 km2 but when adjoining areas west of Britain are included in a “Greater Icelandia,” the entire area could be ~1,000,000 km2 in size.

If proven, it means that the giant supercontinent of Pangaea, which is thought to have broken up over 50 million years ago, has in fact not fully broken up.

The 27.5-million-year cycle of geological activity

Scientists previously proposed 26 million year cycles of mass extinctions, but this appears to correct the period. They suggest ‘cycles of activity in the Earth’s interior’ could be behind their new period, but then say: ‘However, similar cycles in the Earth’s orbit in space might also be pacing these events.’ Their study also says ‘a strong secondary signal occurs at a period 8.9 Myr’.
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Geologic activity on Earth appears to follow a 27.5-million-year cycle, giving the planet a ‘pulse,’ according to a new study published in the journal Geoscience Frontiers. Phys.org reporting.

“Many geologists believe that geological events are random over time. But our study provides statistical evidence for a common cycle, suggesting that these geologic events are correlated and not random,” said Michael Rampino, a geologist and professor in New York University’s Department of Biology, as well as the study’s lead author.

Over the past five decades, researchers have proposed cycles of major geological events—including volcanic activity and mass extinctions on land and sea—ranging from roughly 26 to 36 million years.

But early work on these correlations in the geological record was hampered by limitations in the age-dating of geologic events, which prevented scientists from conducting quantitative investigations.

Iceland: could a volcanic period be ahead?

Lava fields of the Reykjanes Peninsula [image credit: Vincent van Zeijst @ Wikipedia]

24th February: ‘Southwestern Iceland was rocked by a series of earthquakes’, reported DW.com. ‘Experts say shocks from the quake, which registered 5.7 in magnitude, sparked increased volcanic activity, triggering a number of aftershocks registering over 4.0 for hours after the initial quake hit.

“It’s an intense activity zone, we are all well aware of that but I’ve never experienced or felt so many strong earthquakes in such a short period of time. It’s unusual,” as the Icelandic Meteorological Office’s (IMO) earthquake hazards coordinator Kristin Jonsdottir told Icelandic public broadcaster RUV.’

The article below appeared five days ago.
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“If an eruption occurs, it would likely mark the beginning of such a [volcanic] period – lasting a few centuries, I believe,” states Magnús Á. Sigurgeirsson, geologist at ÍSOR Iceland GeoSurvey – a consulting and research institute in the field of geothermal sciences and utilization.

“That’s at least how it has been the past three times, and even dating further back, but we don’t have as exact data available on that,” he tells Iceland Monitor.

He is referring to the uncertainty regarding whether an eruption can be expected soon on the Reykjanes peninsula, Southwest Iceland.

Magnús assembled data on the past three volcanic periods in the area. These were 3,000-3,500 years ago, 1,900-2,400 years ago, and finally between the years 800 and 1240 AD.

His information is based on geological maps of the Reykjanes peninsula and on a comprehensive book on volcanic eruptions in Iceland called Nátt­úru­vá á Íslandi, eld­gos og jarðskjálft­ar.

Research reveals that during the latter part of Holocene – a term used to describe a period that began about 11,700 years ago – the volcanic systems on the Reykjanes peninsula have erupted every 900 to 1100 years.

Less is known about the first part of Holocene.

Each eruption period appears to have lasted about 500 years, and during that time most of the volcanic systems appear to have been active, albeit generally not simultaneously. The volcanic activity is characterized by eruptions that each last a few decades. Lava flows from volcanic fissures that can be as long as 12 km (7.5 mi).

On the Reykjanes peninsula, there are six volcanic systems, lined up side by side, pointing from southwest to northeast. Farthest west is that of Reykjanes, then those of Svartsengi, Fagradalsfjall mountain, Krýsuvík, Brennisteinsfjöll mountains and, finally, Hengill mountain.

The last volcanic period began around the year 800 in Brennisteinsfjöll mountains and in the Krýsuvík system, creating the lava fields of Hvammahraun and Hrútafellshraun.

Full article here.
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Update: Lava eruption from long-dormant Icelandic volcano (MARCH 20, 2021) — close to Fagradalsfjall mountain

Earth’s outer shell ballooned during massive growth spurt 3 billion years ago

So the Earth is, or was, a kind of giant balloon. We know seafloor spreading is still ongoing, and can affect global sea levels on historical timescales.
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Ancient fragments of Earth’s crust acted as ‘seeds’ for new crust to grow from, says LiveScience.

Around 3 billion years ago, Earth’s crust ballooned during a massive growth spurt, geoscientists have found.

At that time, just 1.5 billion years after Earth formed, the mantle — the layer of silicate rock between the crust and the outer core that was more active in the past — heated up, causing magma from that layer to ooze into fragments of older crust above it.

Those fragments acted as “seeds” for the growth of modern-day continents.

Doggerland: How did the Atlantis of the North Sea sink?

Hypothetical map of Doggerland [image credit: ancient-origins.net]

This seems semi-topical on the day Britain signs off on its new deal with the EU countries. Going back into history, but not all that far back, the river Thames flowed into the Rhine. North Sea trawlers still find bones of mammoths and other such fossils in their nets today.
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For a long time, scientists believed that a powerful tsunami destroyed Doggerland 8,200 years ago, says DW.com.

Sediment analysis now suggests that the land once connecting Great Britain with the rest of Europe had a later demise.

Around 10,000 years ago, at the end of the last ice age, the sea level in northern Europe was still about 60 meters (197 feet) below what it is today.

The British Isles and the European mainland formed a continuous landmass.

Relatively large rivers crossed this landmass, but in a different way than we know today.

Newly discovered Greenland hot rock mantle plume drives thermal activities in the Arctic

Topographic map of Greenland

We’re told ‘The North Atlantic region is awash with geothermal activity’. Any day now we should be hearing how a few extra molecules of (human-caused) CO2 make the Earth’s innards hotter than they used to be. Or maybe we won’t.
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A team of researchers understands more about the melting of the Greenland ice sheet, says SciTech Daily.

They discovered a flow of hot rocks, known as a mantle plume, rising from the core-mantle boundary beneath central Greenland that melts the ice from below.

Scientists discover volcanoes on Venus are still active

Venus

The presence of sulphur in the atmosphere hinted at this.
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A new study identified 37 recently active volcanic structures on Venus, reports Phys.org.

The study provides some of the best evidence yet that Venus is still a geologically active planet.

A research paper on the work, which was conducted by researchers at the University of Maryland and the Institute of Geophysics at ETH Zurich, Switzerland, was published in the journal Nature Geoscience on July 20, 2020.

“This is the first time we are able to point to specific structures and say ‘Look, this is not an ancient volcano but one that is active today, dormant perhaps, but not dead,'” said Laurent Montési, a professor of geology at UMD and co-author of the research paper. “This study significantly changes the view of Venus from a mostly inactive planet to one whose interior is still churning and can feed many active volcanoes.”

The tsunami that devastated ancient Britain just over 8,000 years ago: new evidence

Position of the Storegga Slide (west of Norway). The yellow numbers give the height of the tsunami wave as tsunamites recently studied by researchers [credit: Lamiot @ Wikipedia] – Mer du Nord = North Sea

The report states: ‘It is thought the tsunami, the largest to hit Northern Europe since the end of the last ice age, happened following a period of global climate change.’
We can only speculate as to the cause(s) of such climate happenings.
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Scientists have found new evidence of a massive tsunami that devastated ancient Britain in the year 6200 BC on the east coast of England, reports the Daily Mail.

The giant tsunami event, known as the Storegga Slide, was caused when an area of seabed the size of Scotland – around 30,000 square miles – under the Norwegian Sea suddenly shifted.

New geological evidence reveals three successive waves tore across an ancient land bridge connecting Britain with the rest of Europe, known as Doggerland, now submerged beneath the North Sea.

There are two faces of the Earth: study

Pacific ‘ring of fire’

Recent research has also found why changes to Earth’s magnetic field are weaker over the Pacific.
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Earth’s mantle is currently classified into two main domains, African and Pacific.

However, little is known about their formation and history, and they are commonly assumed to be chemically the same, says Tech Explorist.

In a new study by Curtin University, scientists studied chemical and isotopic “make-up” of rocks sourced from thousands of kilometers below the surface.

Mysterious lights seen: Geomagnetic Link to earthquakes?

This twitter video caught my eye last night, it was taken near Miami a few nights ago. It shows mysterious lights, confirmed from many sources and featured on national US TV channels where it’s reported answers are being demanded from the Pentagon.

UFO sighting in Miami last night‼️ 👽 pic.twitter.com/db9ONEY0Bm

— Miami WTF⚠️ (@miami_wtf) June 24, 2020

Then today my physicist friend Mike McCulloch posted a tweet about some similar phenomena which have been observed for many years in Norway.

Hundreds of towering hydrothermal chimneys discovered on seafloor off Washington

Base of “black smoker” chimney, Pacific Ocean [image credit: USGS]

How many more such discoveries could be waiting to be made? The report says ‘Geologic evidence…suggests that hydrothermal activity is part of a cycle that reshapes the seafloor over many thousands of years’.

An autonomous diving robot captured the vents in unprecedented detail, reports Live Science.

In the dark ocean depths off the coast of the Pacific Northwest, a magical fairyland of towering spires and hydrothermal chimneys sprout from the seafloor, a stunning new underwater map reveals.

These towers belch superheated liquid warmed by magma deep inside Earth.

The field of hydrothermal chimneys stretches along the ocean bottom on the Juan de Fuca Ridge to the northwest of coastal Washington state, in an area known as the Endeavor Segment.

Research reveals possibly active tectonic system on the Moon

Image credit: naturalnavigator.com

We’re told: ‘They refer to what they’ve found as ANTS, for Active Nearside Tectonic System’, which is ‘a mysterious system of tectonic features (ridges and faults) on the lunar nearside, unrelated to both lava-filled basins and other young faults that crisscross the highlands.’ Tectonic activity on one side only sounds a bit unlikely somehow, but what about tidal disturbance from Earth? We know it works the other way round: the Moon causes tides on Earth. Of course the Moon is tidally locked to Earth, hence the term ‘nearside’.
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Researchers have discovered a system of ridges spread across the nearside of the Moon topped with freshly exposed boulders, reports Phys.org.

The ridges could be evidence of active lunar tectonic processes, the researchers say, possibly the echo of a long-ago impact that nearly tore the Moon apart.

“There’s this assumption that the Moon is long dead, but we keep finding that that’s not the case,” said Peter Schultz, a professor in Brown University’s Department of Earth, Environmental and Planetary Sciences and co-author of the research, which is published in the journal Geology.

“From this paper it appears that the Moon may still be creaking and cracking—potentially in the present day—and we can see the evidence on these ridges.”

New geochemical tool reveals origin of Earth’s nitrogen: Novel analysis method may also be useful for monitoring volcanic activity

As the video reminds us: Earth’s atmosphere is mostly (78%) nitrogen. Plus about 21% oxygen at sea level, and a few minor trace gases – one or two of which some people like to fixate on.

Researchers have used a new geochemical tool to shed light on the origin of nitrogen and other volatile elements on Earth, which may also prove useful as a way to monitor the activity of volcanoes, says ScienceDaily.

Their findings were published April 16, 2020, in the journal Nature.

Nitrogen is the most abundant gas in the atmosphere, and is the primary component of the air we breathe. Nitrogen is also found in rocks, including those tucked deep within the planet’s interior.

Until now, it was difficult to distinguish between nitrogen sources coming from air and those coming from inside the Earth’s mantle when measuring gases from volcanoes.

Ear-pleasing new report confirms volcanic source of mysterious global hum

Credit: metro.co.uk

The idea is that “Every time the rock sags into the chamber, it creates a resonance and this produces this strange signal that you see far away.” Is this really ‘The Hum’?

Can you hear it? That elemental thrumming emerging just beneath the engulfing din of everyday city and suburban life? 

Well, chances are you’re not losing your mind or developing some extra-human ability akin to comic book superheroes, says SyfyWire.

Better odds are that it’s Mother Earth’s growing pains in the form of loud volcanic stirrings, as revealed in a new study published in the journal Nature Geoscience.

Forces from Earth’s spin may spark earthquakes and volcanic eruptions at Mount Etna

Mount Etna, Sicily

The article says: ‘Every 6.4 years, the axes line up and the wobble fades for a short time.’ This looks a lot like 5.4 Chandler wobbles (CW), so you would have 6.4 years minus 5.4 CW = 1 cycle, i.e. 32:27 ratio = 5 (32-27) cycles.
Much more analysis of this time period and related matters in this 2013 Talkshop post:
Ian Wilson: Solar System Timings Evolved Lunar Orbital Elements Linked to Earth’s Chandler Wobble.

New research suggests forces pulling on Earth’s surface as the planet spins may trigger earthquakes and eruptions at volcanoes, reports Phys.org.

Seismic activity and bursts of magma near Italy’s Mount Etna increased when Earth’s rotational axis was furthest from its geographic axis, according to a new study comparing changes in Earth’s rotation to activity at the well-known Italian volcano.