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Imaggeo on Mondays: Lava highway in Kanaga Island

Imaggeo on Mondays: Lava highway in Kanaga Island

On a rare sunny day, Mattia Pistone (a researcher at the Smithsonian Institution in Washington DC) was able to capture this spectacular shot of Kanaga, a stratovolcano in the remote Western Aleutians, which is usually veiled by thick cloud.

The Western Aleutians form a chain of 14 large and 55 small volcanic islands, belonging to one of the most extended volcanic archipelagos on Earth (1900 km), stretching from Alaska across the northern Pacific towards the shores of Russia.

As part of a team of researchers, Mattia spent three grueling weeks in the isolated region. Being one of the most extended volcanic arc systems on Earth, the Aleutians can shed light on one of the most fundamental questions in the Earth sciences: how do continents form?

The Earth’s landmasses are made of continental crust, which is thought to be largely andesitic in composition. That could mean it is dominated by a silicon-rich rock, of magmatic origin, which is fine grained and usually light to dark grey in colour. However, basaltic magmas derived from the Earth’s upper mantle and erupted at active volcanoes contribute to chemistry of the continental crust. The fact that continental crust bears the chemical hallmarks of both suggests that the formation of new continents must somehow be linked to motion of magma and its chemistry.

Establishing the link between magma generation, transport, emplacement, and eruption can therefore significantly improve our understanding of crust-forming processes associated with plate tectonics, and, particularly, help determining the architecture and composition of the continental crust. The Alaska-Aleutian archipelago is a natural laboratory which offers a variable range of volcanic rocks. The islands present a perfect opportunity for scientists to try and understand the origin of continents.

By collecting samples of volcanic ash erupted at Kanaga and other volcanoes of the Aleutian arc, Mattia and his colleagues are currently investigating the origin of this volcanic ash. Understanding its chemistry allow the team to get a clearer idea of the conditions that were present while the magma was forming and ascending, for example, how much water and iron were present.

The team were based on the Maritime Maid research vessel, and hoped from island to island collecting samples and taking measurements of volcanic activity as part of a large research consortium called GeoPRISMS, funded by the National Science Foundation. The field work was supported by a Bell 407 helicopter and its crew.

Today’s featured image shows an andesitic lava flow erupted in 1906. The volcanic deposits were explored during the field geological mission by Mattia and the team. Kanaga last erupted in 1994. Ash from that eruption was found in the nearby island of Adak. Even at present, there is a highly active system of fumaroles at the summit of the volcano.

If you pre-register for the 2017 General Assembly (Vienna, 22 – 28 April), you can take part in our annual photo competition! From 1 February up until 1 March, every participant pre-registered for the General Assembly can submit up three original photos and one moving image related to the Earth, planetary, and space sciences in competition for free registration to next year’s General Assembly!  These can include fantastic field photos, a stunning shot of your favourite thin section, what you’ve captured out on holiday or under the electron microscope – if it’s geoscientific, it fits the bill. Find out more about how to take part at http://imaggeo.egu.eu/photo-contest/information/.

February GeoRoundUp: the best of the Earth sciences from around the web

Comparing the TRAPPIST-1 planets

Drawing inspiration from popular stories on our social media channels, as well as  unique and quirky research news, this monthly column aims to bring you the best of the Earth and planetary sciences from around the web.

Major story

Undoubtedly the story of the month is the discovery of a star system of seven Earth-sized planets just 40 light-years away from our own. What makes the finding so exciting is that three of the planets lie in the habitable zone. All could have oceans and atmospheres, making them good candidates to search for extraterrestrial life.

The seven Earth-sized worlds orbit the ultra-cool dwarf star, TRAPPIST-1, which has been known to astronomers for some time. As the planets passed in front of TRAPPIST-1, the star’s light output dipped. Using a combination of ground and spaced based telescopes, the changes in the light output were used to detect the planets and gather information about their size, composition and orbit, explains the press release by the European Southern Observatory.

This simple GIF by New Scientist illustrates the principle of how the remarkable planets were found (while at the same time highlighting the fact there is a mind-blowing number of exoplanets scattered throughout space!).

The ultra-cool dwarf star and its planetary system has an even cooler website, which comes complete with great posters, videos, short stories, poems and graphic novels; as well as a detailed timeline of all the years of work which took place behind the scenes and culminated in the announcement made earlier this month.

Our top pick for a science poem honouring the discovery is In Search of New Life by Sam Illingworth, a lecturer at Manchester Metropolitan University.  You can also find an audio version of the poem here.

Far into space, amongst the darkest Sea

New planets sit like marbles in a row.

We turn our eyes to find out what might be

And search for patterns in their ether’s flow;

Then try to see what else might lie below.

And as we probe how life’s rich web was spun,

Do they look back towards our distant sun?

 

What you might have missed

The discovery of a previously unknown continent below New Zealand and New Caledonia dominated headlines towards the middle of the month.

Dr. Mortimer, of GNS Science and lead author of the study, argues that “being more than 1 million square kilometers in area, and bounded by well-defined geologic and geographic limits, Zealandia [the name given to the newly discovered continent] is, by our definition, large enough to be termed a continent.”

But without an official authority which designates the existence of continents, it will be for the broader scientific community to recognise Zealandia as one. And the jury is still out, as Alex Witze finds in this Nature News & Comment article:

“Claiming that Zealandia is a continent is a bit like stamp collecting,” says Peter Cawood, a geologist at Monash University in Melbourne, Australia. “So what?”

While the (potentially) new Antipodean continent dominated headlines, you might have missed the discovery of another lost continent. Deep under the waters of the Indian Ocean, sandwiched between Madagascar and India, lie the scattered pieces of an ancient, drowned, microcontient called Mauritia. The authors of the study, published earlier this month in Nature Communications, dated zircons of up to 3 billion years old from Mauritanian volcanic rocks. Considering Mauritania is much younger, the researchers argue the zircons must have come from another, already existing continent.

Meanwhile, in the southern-most reaches of our planet, a huge iceberg is set to breakaway from the Larsen C Ice Shelf, on the northeastern coast of the Antarctic Peninsula. A large crack in the ice was spotted in natural-colour satellite imagery captured by NASA back in August 2016. Int January 2017 alone, the crack grew by more than 10 km in length and now stretches 175 km over the ice.

British Antarctic Survey (BAS) scientists recently captured footage of the huge crack. The video highlights what the calving of such a large iceberg might mean for the Larsen C ice shelf, while this Nature News and Comment story highlights how far glaciology has come since similar calving events in the 90s and 00s. Scientists now have a much better understanding of what might happen in the weeks and months to come.

Five links we liked

The EGU story

After long-awaited snowfall in January, parts of the Alps are now covered with fresh powder and happy skiers. But the Swiss side of the iconic mountain range had the driest December since record-keeping began over 150 years ago, and 2016 was the third year in a row with scarce snow over the Christmas period. A study published this month in The Cryosphere, a journal of the European Geosciences Union, shows bare Alpine slopes could be a much more common sight in the future.

The new research, by scientists based at the Institute for Snow and Avalanche Research (SLF) and at the CRYOS Laboratory at the École Polytechnique Fédérale in Switzerland, shows that the Alps could lose as much as 70% of snow cover by the end of the century. However, if humans manage to keep global warming below 2°C, the snow-cover reduction would be limited to 30% by 2100.

And don’t forget! To stay abreast of all the EGU’s events and activities, from highlighting papers published in our open access journals to providing news relating to EGU’s scientific divisions and meetings, including the General Assembly, subscribe to receive our monthly newsletter.

Imaggeo on Mondays: harnessing Earth’s inner heat

Imaggeo on Mondays: harnessing Earth’s inner heat

Iceland, the land of ice and fire, is well known for its volcanicity. Most famously, it is home to Eyjafjallajökull: the volcano which caused wide spread mayhem across European airspace when it erupted in 2010.

But not all the local volcanic activity is unwelcome. High temperature geothermal areas are a byproduct of the volcanic setting and the energy released can be used to power homes and infrastructure. Indeed, geothermal power facilities currently generate 25% of the country’s total electricity production.

“I took the photograph during a three hour walk in the Krafla area, a few kilometres away from Myvatn Lake in Northern Iceland,” explains Chiara Arrighi, a PhD student at the University of Florence in Italy, who took today’s featured image while on a two week holiday on the island.

There are 20 high-temperature areas containing steam fields with underground temperatures reaching 250°C within 1,000 m depth dotted across the country. Krafla, a caldera of about 10 km in diameter, and the wider Myvatn area is one of them. The volcano has a long history of eruptions, which drives the intrusion of magma at (geologically) shallow depths which in turn heats groundwater trapped deep underground, generating the steam field. Only a few hundred meters from the shooting location a power station of 60 MW capacity exploits high- and low-pressure steam from 18 boreholes.

Fumaroles and mud pots, like the one photographed by Chiara, are the surface expression of the geothermal activity. The discoloration of the rocks in the immediate vicinity of the bubbling mire is due to the acidic nature of the water in the pool. The steam is rich in hydrogen sulphide, which oxidises to sulphur and/or sulphuric acid as it mixes with oxygen when it reaches the surface. It deposits around the vents of fumaroles and as sulphuric acid in the stagnant waters, leading to alteration of the surrounding bedrock and soil.

If you pre-register for the 2017 General Assembly (Vienna, 22 – 28 April), you can take part in our annual photo competition! From 1 February up until 1 March, every participant pre-registered for the General Assembly can submit up three original photos and one moving image related to the Earth, planetary, and space sciences in competition for free registration to next year’s General Assembly!  These can include fantastic field photos, a stunning shot of your favourite thin section, what you’ve captured out on holiday or under the electron microscope – if it’s geoscientific, it fits the bill. Find out more about how to take part at http://imaggeo.egu.eu/photo-contest/information/.

Imaggeo on Mondays: Deep in the Himalayas

Deep in the Himalayas . Credit: Yuval Sadeh (distributed via imaggeo.egu.eu).

The Himalayas: vast, formidable and home to the Earth’s highest peaks. The mountain range stretches inexorably through Indian, Bhutan, Nepal, China (Tibet) and Pakistan separating the Tibetan Plateau to the north from India’s alluvial plains to the south.

India, as we know it today, started life much further south, as an island not far off the coast of Australia. It was separated from Asia (on the Eurasian plate) by the Tethys Ocean, a vast body of water which  wrapped, almost entirely, around the supercontinent Pangea. As the supercontinent started to break up, some 200 million years ago, India began its slow (in human terms, but quite fast geologically speaking) journey north towards Asia.

Moving at speeds between 9 to 16 cm per year (for comparison, human hair grows roughly 15 cm per year), by 80 million years ago, India was located 6,400 km south of Asia. The Tethys was being slowly subducted under the Asian plate and would eventually close (disappear) all together some 30 million years later, when the Indian plate collided against Asia and the Himalayas began to uplift.

The closing and subduction of the Tethyan Ocean, followed by the collision of the two continents produced the Himalayas. The mountain range is divided into six parallel belts, each of which has distinct lithotectonic zones. They are highly complex and represent a long history of tectonic processes and deformation events.

The high peaks of Nepal and China attract a fair share of the limelight, offering thrill seeking adventurers the possibility to get close to (if not scale) the highest mountains on Earth. But lesser known areas of the Himalayas also offer a window into the geological past of the planet and breathtaking scenes for intrepid people too.

Today’s photograph features a valley deep in the Indian Himalayas, and illustrates some geological, geomorphological and other phenomena’s together with a small village that was built inside this glacier curved valley.

 

If you pre-register for the 2017 General Assembly (Vienna, 22 – 28 April), you can take part in our annual photo competition! From 1 February up until 1 March, every participant pre-registered for the General Assembly can submit up three original photos and one moving image related to the Earth, planetary, and space sciences in competition for free registration to next year’s General Assembly!  These can include fantastic field photos, a stunning shot of your favourite thin section, what you’ve captured out on holiday or under the electron microscope – if it’s geoscientific, it fits the bill. Find out more about how to take part at http://imaggeo.egu.eu/photo-contest/information/.

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