Archives par mot-clé : Volcanism

WORLDWIDE VOLCANIC UPTICK — MULTIPLE ERUPTIONS TO 45,000+ FT (13.7+ KM) — DIRECT COOLING EFFECT

by Cap Allon, May 1, 2020 in Electroverse


These past few days have seen a violent worldwide volcanic uptick, sending us all further signs that the next Grand Solar Minimum is dawning.

HIMAWARI-8 (a Japanese weather satellite) recorded two HIGH-LEVEL eruptions on May 16, both occurring in Indonesia.

The first took place at Ibu –a relatively new volcano with only 3 notable eruptions; in 1911, 1998, and 2008– and was confirmed by the Volcanic Ash Advisory Center (VAAC) Darwin which warned of an ash plume rising to an estimated 45,000 ft (13.7 km).

The second high-level eruption took place just a few hours later at Semeru –a very active volcano with an eruptive history peppered with VEI 2s and 3s; the first coming in 1818, the most recent in 2014– and as with Ibu’s, Semeru’s eruption was picked up by both HIMAWARI-8 and the VAAC Darwin, with the latter confirming the generation of “a dark ash plume which reached an altitude of 46,000 ft (14 km).”

In addition, and as recently reported by VolcanoDiscovery.com, active lava flows remain active on the Semeru’s southeast flank, currently about 4,921 ft (1.5 km) long (as of the morning of May 18).

https://principia-scientific.org/do-cosmic-rays-trigger-earthquakes-volcanic-eruptions/https://www.researchgate.net/publication/234022172_Explosive_volcanic_eruptions_triggered_by_cosmic_rays_Volcano_as_a_bubble_chamber

Scientists “Discover” Largest Shield Volcano on Earth

by D. Middleton, May 15, 2020 in WUWT


And it’s not Mauna Loa…

UH researchers reveal largest and hottest shield volcano on Earth
Posted on May 13, 2020 by Marcie Grabowski

In a recently published study, researchers from the University of Hawai‘i at Mānoa School of Ocean and Earth Science and Technology revealed the largest and hottest shield volcano on Earth. A team of volcanologists and ocean explorers used several lines of evidence to determine Pūhāhonu, a volcano within the Papahānaumokuākea Marine National Monument, now holds this distinction.

Geoscientists and the public have long thought Mauna Loa, a culturally-significant and active shield volcano on the Big Island of Hawai‘i, was the largest volcano in the world. However, after surveying the ocean floor along the mostly submarine Hawaiian leeward volcano chain, chemically analyzing rocks in the UH Mānoa rock collection, and modeling the results of these studies, the research team came to a new conclusion. Pūhāhonu, meaning ‘turtle rising for breath’ in Hawaiian, is nearly twice as big as Mauna Loa.

“It has been proposed that hotspots that produce volcano chains like Hawai‘i undergo progressive cooling over 1-2 million years and then die,” said Michael Garcia, lead author of the study and retired professor of Earth Sciences at SOEST. “However, we have learned from this study that hotspots can undergo pulses of melt production. A small pulse created the Midway cluster of now extinct volcanoes and another, much bigger one created Pūhāhonu. This will rewrite the textbooks on how mantle plumes work.”

[…]

University of Hawai‘i at Mānoa School of Ocean and Earth Science and Technology

Did heavy rains trigger the eruption of the most dangerous U.S. volcano? Scientists are skeptical

by  RP Ortega, April 22, 2020 in ScienceAAAS


In May 2018, Hawaii’s Kilauea volcano let loose its largest eruption in 200 years, spewing plumes of ash high into the air, and covering hundreds of homes in lava. The eruption terrified local residents, but it gave scientists a once-in-a-lifetime opportunity to study the volcano’s explosive behavior. Now, a new study claims that extreme rainfall boosted underground pressures and was the “dominant factor” in triggering the eruption.

It’s not the first time rainfall has been linked to volcanic activity, says Jenni Barclay, a volcanologist at the University of East Anglia who was not involved in the new work. Previous research suggests storms passing over Mount St. Helens may have played a role in explosive activity between 1989 and 1991. And intense rains fell shortly before and during the activity of Montserrat’s Soufrière Hills volcano from 2001 to 2003. Rain may have also triggered eruptions of Réunion’s Piton de la Fournaise volcano. Still, Barclay believes rain is, at best, a contributing factor to volcanic eruptions and not the main driver. “It’s a series of coincident events that have led to the triggering of this larger episode,” she says.

Researchers on the new study used satellite data from NASA and Japan’s space agency to estimate rainfall during the first months of 2018, before the start of the eruption. More than 2.25 meters of rain fell on the volcano in the first months of 2018, the researchers found. They created a model to show how the accumulated rainfall could seep into the pore spaces in rocks deep underground, boosting pressures that eventually caused fissures in the volcano’s flank to open up and release magma. When they looked at records of previous Kilauea eruptions going back to 1790, they found that 35—more than half—started during the nearly 6-month rainy season.

Magma Flood Linked To Sudden Ancient Global Warming Event

by H. Lee, April 1, 2020 in ClimateChangeDispatch


A study has cemented the link between an intense global warming episode 56 million years ago and volcanism in the North Atlantic, with implications for modern climate change.

Roughly 60 million years ago, circulation changes deep within our planet generated a hot current of rock — the Iceland plume — causing it to rise from the heart of Earth’s mantle.

 

The Giant’s Causeway in Northern Ireland is a geologic feature consisting of thousands of interlocking basalt columns that formed from volcanic eruptions 60 million years ago.

The Wrong Kind Of Carbon

Although a great deal of North Atlantic volcanism happened close in time to the PETM, scientists were initially skeptical that it could have driven the warming.

Sedimentary layers that formed at the time had the wrong kind of carbon — they were rich in the isotope carbon-12, indicating an organic carbon source rather than a volcanic one.

The leading theory was that fluctuations in Earth’s orbit around the sun melted a type of frozen methane just beneath the seabed called methane clathrates.

Yet scientists found scant evidence that enough clathrates existed in the pre-PETM world, or that they could have melted fast enough to drive the warming.

A possible missing link between the North Atlantic Igneous Province and organic carbon was spotted in 2004 in seismic scans through the seabed off the coast of Norway.

Continuer la lecture de Magma Flood Linked To Sudden Ancient Global Warming Event

A chunk of Yellowstone the size of Chicago has been pulsing. Why?

by R.G. Andrews, March 19, 2020 in NationalGeographic


An injection of magma under Norris Geyser Basin may be why the region is five inches higher today than it was 20 years ago.

In northwestern Wyoming, in the center of Yellowstone National Park, a bubbling caldera is the scar of a 640,000-year-old, gargantuan volcanic eruption. The 3,472-square-mile park encompassing the caldera is filled with geologic wonderlands of sprouting geysers and effervescing pools, all ultimately driven by magma and superheated fluids churning in the rock below the surface.

One of these areas, Norris Geyser Basin to the northwest of the caldera, contains more than 500 hydrothermal features. These tempestuous geysers and pools often change from day to day, but a much larger transformation has been taking place as well: For more than two decades, an area larger than Chicago centered near the basin has been inflating and deflating by several inches in erratic bursts. In a hyperactive volcanic region like Yellowstone, the exact causes of any specific movement are difficult to pin down. But a recent study in the Journal of Geophysical Research: Solid Earth may help explain why this pocket of land has been breathing in and out.

“In all likelihood, Norris has been a center of deformation for a very long time,” says Daniel Dzurisin, a research geologist at the U.S. Geological Survey’s Cascades Volcano Observatory and one of the co-authors of the new research.

Norris Geyser Basin, Yellowstone National Park, Wyoming.
PHOTOGRAPH BY MARC MORITSCH, NAT GEO IMAGE COLLECTION

Thwaites Glacier: Why Did The BBC Fail To Mention The Volcanoes Underneath?

by D. Whitehouse, January 29, 2020 in GWPF


Scientists have known for years that subglacial volcanoes and other geothermal “hotspots” are contributing to the melting of the Thwaites Glacier. Why did the BBC fail to mention these facts in its recent report?

 

The International Thwaites Glacier Collaboration is performing some magnificent science, conducting the most ambitious fieldwork ever undertaken at the tip of what is one of the most significant glaciers on Earth. Its melting already contributes 4% of global sea level rise and there are fears that it could become unstable and contribute many metres to global sea level.

The reason for its vulnerability lies in its geology. While most of the glacier is on ground and making its way into the West Antarctic seas, Thwaites lip floats on water allowing warm water to weaken and melt it from beneath. Being one of the most difficult places in the world to reach the scientific collaboration planned for years to transport many tonnes of equipment to the glaciers front. Two weeks ago they announced they had carried out the first warm water borehole through the ice at the point where it lifts off the land and starts to be suspended by the ocean. Image courtesy British Antarctic Survey.

Big volcanic bump unlike anything seen before found on the moon

by R.G. Andrews, December 13, 2019 in NationalGeography


Scientists scouring the lunar surface for clues to past impact rates found a bonus feature that has geologists “thoroughly confused.”

Sometime after the solar system formed 4.6 billion years ago, a projectile slammed into Earth’s youthful moon and formed the 620-mile-wide basin known as the Crisium basin. No one knows exactly when this impact happened, but for decades scientists have been trying to solve the puzzle as part of a larger debate over whether the moon and, by proxy, Earth endured a period of frenzied meteor bombardment in their early histories.

Now, scientists scouring the region say they’ve spotted a crater within the basin that appears to contain pristine impact melt, a type of volcanic rock that can act like a definitive geologic clock. If future astronauts or a robot could obtain a sample and tease out its age, that may help reveal what was happening on Earth during the primordial period when life first emerged on our planet.

And, as an added bonus, the discovery comes with an intriguing mystery: The basin also holds a geologic blister the size of Washington, D.C., that’s unlike anything else seen in the solar system. As the team reports in an upcoming paper in the Journal of Geophysical Research: Planets, this volcanic lump appears to have been inflated and cracked by peculiar underground magmatic activity that the researchers can’t currently explain.

“I’m thoroughly confused by it,” says Clive Neal, an expert in lunar geology at the University of Notre Dame who was not involved with the new research.

 

Volcanism Altering Bering Sea Eco-Systems, Not Climate Change

by James  E. Kamis, July 8, 2019 in ClimateChangeDispatch


Volcanism, primarily ocean floor in nature, is the most feasible and plausible cause of recent alterations to the Bering Sea physical and biological systems, not climate change.

Since 2014, multiple changes to the Bering Sea’s physical and biological systems such as a rise in seawater temperature, sea ice melting, alteration of commercial fish migration patterns and the very sudden die-off of certain sea bird species have made front-page news.

Many scientists have been quick to attribute these supposedly ‘unnatural’ events to human-induced atmospheric warming or climate change without mentioning or giving due consideration to emissions from active volcanic features that circumvent the entire Bering Sea and populate its seafloor.

This immediate jump to a climate change cause and event effect relationship is especially difficult to understand knowing that frequently during the last five years we have been informed of yet another eruption from a Bering Sea area volcano located in either Russia, Alaska, or on the Bering seafloor.

So, let’s take a moment to review Bering Sea volcanic activity and its likely effect on the area’s physical and biological systems.

Multiple NASA Studies Confirm Bedrock Heat Flow Behind Melting Polar Ice, Not Global Warming

by James E. Kamis, August 7, 2018 in ClimateChangeDispatch

In what amounts to dissension from National Aeronautics and Space Administration (NASA) climate change policy, a series of just-released studies by working-level scientists prove that geological and not atmospheric forces are responsible for melting of Earth’s polar ice sheets.

 

NASA Greenland Study August 1, 2018

The results of this research study illustrated in Figure 2 confirm the very high geothermal bedrock heat-flow from Greenland’s massive subglacial Mantle Plume, which was originally documented in four previous research studies (see herehere, here, and here).

A geothermal heat-flow cause for the melting of Greenland’s ice sheet has been the focus of numerous Climate Change Dispatch articles (see here, here, here, and here).

 

 

Ship spies largest underwater eruption ever

by Roland Pease, May 21, 2019 in Science


Last week, Marc Chaussidon, director of the Institute of Geophysics in Paris (IPGP), looked at seafloor maps from a recently concluded mission and saw a new mountain. Rising from the Indian Ocean floor between Africa and Madagascar was a giant edifice 800 meters high and 5 kilometers across. In previous maps, there had been nothing. “This thing was built from zero in 6 months!” Chaussidon says.

His team, along with scientists from the French national research agency CNRS and other institutes, had witnessed the birth of a mysterious submarine volcano, the largest such underwater event ever witnessed. “We have never seen anything like this,” says IPGP’s Nathalie Feuillet, leader of an expedition to the site by the research vessel Marion Dufresne, which released its initial results last week.

The quarter-million people living on the French island of Mayotte in the Comoros archipelago knew for months that something was happening. From the middle of last year they felt small earthquakes almost daily, says Laure Fallou, a sociologist with the European-Mediterranean Seismological Centre in Bruyères-le-Châtel, France. People “needed information,” she says. “They were getting very stressed, and were losing sleep.”

New evidence suggests volcanoes caused biggest mass extinction ever

by University of Cincinnati, April 15, 2019 in ScienceDaily from Nature


Mercury found in ancient rock around the world supports theory that eruptions caused ‘Great Dying’ 252 million years ago.

Researchers say mercury buried in ancient rock provides the strongest evidence yet that volcanoes caused the biggest mass extinction in the history of the Earth.

The extinction 252 million years ago was so dramatic and widespread that scientists call it “the Great Dying.” The catastrophe killed off more than 95 percent of life on Earth over the course of hundreds of thousands of years.

Paleontologists with the University of Cincinnati and the China University of Geosciences said they found a spike in mercury in the geologic record at nearly a dozen sites around the world, which provides persuasive evidence that volcanic eruptions were to blame for this global cataclysm.

The study was published this month in the journal Nature Communications.

The eruptions ignited vast deposits of coal, releasing mercury vapor high into the atmosphere. Eventually, it rained down into the marine sediment around the planet, creating an elemental signature of a catastrophe that would herald the age of dinosaurs.

“Volcanic activities, including emissions of volcanic gases and combustion of organic matter, released abundant mercury to the surface of the Earth,” said lead author Jun Shen, an associate professor at the China University of Geosciences.

Our Planet Is Beautiful But Far From Fragile

by W.E. William, March 7, 2019 in ClimateChangeDispatch


Rep. Alexandria Ocasio-Cortez claims that “the world is going to end in 12 years if we don’t address climate change.”

The people at the Intergovernmental Panel on Climate Change agree, saying that to avoid some of the most devastating impacts of climate change, the world must slash carbon emissions by 45 percent by 2030 and completely decarbonize by 2050.

Such dire warnings are not new. In 1970, Harvard University biology professor George Wald, a Nobel laureate, predicted, “Civilization will end within 15 or 30 years unless immediate action is taken against problems facing mankind.”

Also in 1970, Paul Ehrlich, a Stanford University biologist, predicted in an article for The Progressive, “The death rate will increase until at least 100-200 million people per year will be starving to death during the next ten years.”

The year before, he had warned, “If I were a gambler, I would take even money that England will not exist in the year 2000.”

Geological ‘Hotspot’ Melting Pine Island And Thwaites Glaciers, Not Global Warming

by J.E. Kamis, February 25, 2019 in ClimateChangeDispatch


SUMMARY

Research study after research study has now proven beyond any doubt that the 350,000-square-mile subglacial Marie Byrd Mantle Plume and its associated geological features that are emitting massive amounts of ice melting heat and heated fluid onto the base of the Pine Island Glacier and Thwaites Glaciers.

Failure of the media to include in their numerous articles this telling scientific evidence which substantiates the significant and likely dominant role of this subglacial geologically induced heat flow in melting of West Antarctic glaciers is difficult to reconcile with proper scientific methodology.

A methodology which states that new and relevant data should be used to review old supposedly 100% settled theories.

Most of these research studies have been released one by one during the last three years which has led to minimizing their collective importance.  Numerous previous Climate Change Dispatch articles written by this author beginning in 2014 have inexplicably been ignored by mainstream media outlets.

It’s time for the media to inform the public that by tying all this information together that a clear picture emerges concerning the significant impact of Antarctic subglacial geologically induced heat flow.

Do volcanoes or an asteroid deserve blame for dinosaur extinction?

by Univ. of California – Berkeley, February 21, 2019 in ScienceDaily


Based on new data published today in the journal Science, it seems increasingly likely that an asteroid or comet impact 66 million years ago reignited massive volcanic eruptions in India, half a world away from the impact site in the Caribbean Sea.

But it leaves unclear to what degree the two catastrophes contributed to the near-simultaneous mass extinction that killed off the dinosaurs and many other forms of life.

The research sheds light on huge lava flows that have erupted periodically over Earth’s history, and how they have affected the atmosphere and altered the course of life on the planet.

New Explanation For Missing Global Warming? Scientists Claim Extratropical Volcanoes Underestimated!

by P. Gosselin , February 19, 2019 in NoTricksZone


Readers should note that among climate modelers volcanoes and atmospheric aerosols have been a favorite way of fudging climate models to explain away inconvenient cooling periods that weren’t supposed to happen in a system that is supposed to be dominated by trace gas CO2.

Extratropical volcanoes influence climate more than assumed

Study shows surprisingly strong cooling after volcanic eruptions in mid and high latitudes

Novel hypothesis goes underground to predict future of Greenland ice sheet

by Penn State, February 2,  2019 in ScienceDaily


Paleoclimatic records indicate that most of Greenland was ice-free within the last 1.1 million years even though temperatures then were not much warmer than conditions today. To explain this, the researchers point to there being more heat beneath the ice sheet in the past than today.

Data show that when the Iceland hot spot — the heat source that feeds volcanoes on Iceland — passed under north-central Greenland 80 to 35 million years ago, it left molten rock deep underground but did not break through the upper mantle and crust to form volcanoes as it had in the west and east. The Earth’s climate then was too warm for Greenland to have an ice sheet, but once it cooled the ice sheet formed, growing and shrinking successive with ice ages.

Volcano In Scotland May Have Caused Prehistoric Global Warming prehistoric volcanic eruption

by S. Beech, January 25, 2019 in ClimateChangeDispatch


A massive volcanic eruption in Scotland on the same scale as the infamous Krakatoa blast may have contributed to prehistoric global warming.

Scientists say that global temperatures spiked around 56 million years ago.

And a new study suggests that a major explosive eruption from the Red Hills on the Isle of Skye may have been a contributing factor to the massive climate disturbance.

Large explosive volcanic eruptions can have lasting effects on climate and have been held responsible for severe climate effects in Earth’s history.

One such event occurred around 56 million years ago when global temperatures increased by up to 8 degrees Celcius (46 degrees Fahrenheit.)

The event has been named the Paleocene-Eocene Thermal Maximum (PETM).

 

Volcanoes fed by ‘mush’ reservoirs rather than molten magma chambers

by Imperial College London, December 4, 2018 in ScienceDaily


Volcanoes are not fed by molten magma formed in large chambers finds a new study, overturning classic ideas about volcanic eruptions.

Instead, the study suggests that volcanoes are fed by so-called ‘mush reservoirs’ — areas of mostly solid crystals with magma in the small spaces between the crystals.

Our understanding of volcanic processes, including those leading to the largest eruptions, has been based on magma being stored in liquid-filled ‘magma’ chambers — large, underground caves full of liquid magma. However, these have never been observed.

The new study, by researchers at Imperial College London and the University of Bristol and published today in Nature, suggests the fundamental assumption of a magma chamber needs a re-think.

Volcanoes and glaciers combine as powerful methane producers

by Lancaster University, November 20, 2018 in ScienceDaily


The Lancaster university-led research, which is featured in Scientific Reports, is the first published field study to show methane release from glaciers on this scale.

“This is a huge amount of methane lost from the glacial meltwater stream into the atmosphere,” said Dr Peter Wynn, a glacial biogeochemist from the Lancaster Environment Centre and corresponding author of the study. “It greatly exceeds average methane loss from non-glacial rivers to the atmosphere reported in the scientific literature. It rivals some of the world’s most methane-producing wetlands; and represents more than twenty times the known methane emissions of all Europe’s other volcanoes put together.”

Discovery Of Massive Volcanic CO2 Emissions Puts Damper On Global Warming Theory

by J.E. Kamis, November 6, 2018 in ClimateChangeDispatch


Recent research shows that the volume of volcanic CO2 currently being emitted into Earth’s atmosphere is far greater than previously calculated, challenging the validity of the man-made global warming theory.

he cornerstone principle of the global warming theory, anthropogenic global warming (AGW), is built on the premise that significant increases of modern era human-induced CO2 emissions have acted to unnaturally warm Earth’s atmosphere.

A warmed atmosphere that directly, or in some cases indirectly fuels anomalous environmental disasters such as ocean warming, alteration of ocean chemistry, polar ice sheet melting, global sea level rise, coral bleaching and most importantly dramatic changes in climate.

There are numerous major problems with the AGW principle.

Identification of Volcanic vs. Man-made CO2

USGS issues first USA Volcano Threat Assessment in over a decade

by Anthony Watts, October 24, 2018 in WUWT


18 volcanoes in the USA are classified as “very high threat”, many are in the Pacific Northwest.

Here the .pdf (USGS, 2018)

The United States has 161 young, active volcanoes within its borders. Since 1980, there have been 120 eruptions and 52 episodes of notable volcanic unrest at 44 U.S. volcanoes.

The U.S. Geological Survey systematically assesses U.S. volcanoes considered to be active or potentially active, and publishes a volcanic threat assessment that ranks the volcanoes based on 24 hazard and exposure factors. Last published in 2005, this 2018 update considers (1) field and laboratory research that adds or removes volcanoes from the list of potentially active volcanoes, and (2) updates the hazard and exposure factors used to produce a relative threat ranking of volcanoes.

Addressing on Abrupt Global Warming, Warming Trend Slowdown and Related Features in Recent Decades

by Indriani Roy, September28,  2018 in FrontiersinEarthScience


  • College of Engineering, Mathematics and Physical Sciences, University of Exeter, Exeter, United Kingdom

The puzzle of recent global warming trend slowdown has captured enough attention, though the underlying cause is still unexplained. This study addresses that area segregating the role of natural factors (the sun and volcano) to that from CO2 led linear anthropogenic contributions. It separates out a period 1976–1996 that covers two full solar cycles, where two explosive volcanos erupted during active phases of strong solar cycles. The similar period also matched the duration of abrupt global warming. It identifies that dominance of Central Pacific (CP) ENSO and associated water vapor feedback during that period play an important role. The possible mechanism could be initiated via a preferential alignment of NAO phase, generated by explosive volcanos. Inciting extratropical Rossby wave to influence the Aleutian Low, it has a modulating effect on CP ENSO. Disruption of Indian Summer Monsoon and ENSO during the abrupt warming period and a subsequent recovery thereafter can also be explained from that angle. Interestingly, CMIP5 model ensemble, and also individual models, fails to comply with such observation. It also explores possible areas where models miss important contributions due to natural drivers.

Iceland’s monster volcano charging up for eruption

by Anthony Watts, September 20, 2018 in WUWT


The Katla volcano, hidden beneath the ice cap of Mýrdalsjökull glacier in Iceland, has historically erupted violently once every 40-80 years.  In-as-much as it’s last such eruption took place one hundred years ago, in 1918, Katla’s next eruption is long overdue.

An eruption in Katla would dwarf the 2010 Eyjafjallajökull eruption, scientists have warned.

A new study by Icelandic and British geologists showed that Katla is emitting enormous quantities of CO2 – at least 20 kilotons of CO2 every day. Only two volcanoes worldwide are known to emit more CO2, Evgenia Ilyinskaya a volcanologist with the University of Leeds told the Icelandic National Broadcasting Service RÚV.

N ICE CAULDRON IN MÝRDALSJÖKULL Geothermal activity in the volcano’s caldera melts the glacier, creating cauldrons in the ice. Photo/Fréttablaðið

Napoleon at Waterloo versus the volcano – Napoleon lost

by Anthony Watts, August 23, 2018 in WUWT


Napoleon’s defeat at Waterloo caused in part by Indonesian volcanic eruption

Electrically charged volcanic ash short-circuited Earth’s atmosphere in 1815, causing global poor weather and Napoleon’s defeat, says new research.

Historians know that rainy and muddy conditions helped the Allied army defeat the French Emperor Napoleon Bonaparte at the Battle of Waterloo. The June 1815 event changed the course of European history.

Two months prior, a volcano named Mount Tambora erupted on the Indonesian island of Sumbawa, killing 100,000 people and plunging the Earth into a ‘year without a summer’ in 1816.

Now, Dr Matthew Genge from Imperial College London has discovered that electrified volcanic ash from eruptions can ‘short-circuit’ the electrical current of the ionosphere – the upper level of the atmosphere that is responsible for cloud formation.

The findings, published today in Geology, could confirm the suggested link between the eruption and Napoleon’s defeat.

A new volcanic province: an inventory of subglacial volcanoes in West Antarctica

by M. Van Wyk De Vries et al., August 16, 2018 in Geol.Soc.London


Abstract: The West Antarctic Ice Sheet overlies the West Antarctic Rift System about which, due to the comprehensive ice cover, we have only limited and sporadic knowledge of volcanic activity and its extent. Improving our understanding of subglacial volcanic activity across the province is important both for helping to constrain how volcanism and rifting may have influenced ice-sheet growth and decay over previous glacial cycles, and in light of concerns over whether enhanced geo- thermal heat fluxes and subglacial melting may contribute to instability of the West Antarctic Ice Sheet. Here, we use ice-sheet bed-elevation data to locate individual conical edifices protruding upwards into the ice across West Antarctica, and we propose that these edifices represent subglacial volcanoes. We used aeromagnetic, aerogravity, satellite imagery and databases of confirmed volca- noes to support this interpretation. The overall result presented here constitutes a first inventory of West Antarctica’s subglacial volcanism. We identified 138 volcanoes, 91 of which have not previously been identified, and which are widely distributed throughout the deep basins of West Antartica, but are especially concentrated and orientated along the >3000 km central axis of the West Antarctic Rift System.