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Imaggeo on Mondays: Colourful hydrovolcanism

Imaggeo on Mondays:  Colourful hydrovolcanism

Like in a beautiful painting, layers of colour adorn the flanks of this volcano. In this week’s Imaggeo on Monday’s post, Stephanie Flude describes how these colourful layers came to be and gives an insight into why she became a geologist. What inspired you? Share your reasons for becoming a geoscientist with us in the comment section or via twitter using the hashtag #WhyGeo!

“Why do you want to study rocks??! They are just dull and grey and boring”. That is a comment I hear remarkably often when I tell people I’m a geologist. For me, the locality of this photograph is a reminder that they could not be more wrong. The rocks of the cliff are a mixture of shades of black red and orange. The sand on the beach appears black, but look closely and you find thousands of brilliant green olivine crystals. The lagoon between the beach and the cliff is also a vibrant green due to algae.

This photo shows a cliff exposing the inner stratigraphy of the El Golfo tuff cone, on Lanzarote. I first visited this location whilst on holiday in 2010 as part of a guided tour of the western part of the island. When the tour guide found out I was a geologist he offered to tell me all of the “scientific details” of the local geology and enthusiastically described how a large whirlpool was generated in the centre of cone during El Golfo’s eruption and it eroded away part of the cone(!) I smiled and nodded politely. Thankfully, since that visit, scientific work describing and interpreting the stratigraphy of the tuff cone has been published by Pedrazzi et al (2013), so it is now possible for me to more fully appreciate the geological history of this location.

Hydrovolcanism, where heat from magma can cause water to flash to steam, expanding rapidly, driving gas-rich, explosive, phreatic or phreatomagmatic eruptions, can result in many different types of volcanic eruption and associated deposits. Hydrovolcanism is not always explosive – pillow lavas form by chilling of effusive basalt lava beneath water. But adding water to a volcanic eruption can result in very violent explosions – in the 1883 eruption of Krakatoa, early eruptive activity caused sea water to flow into the magma chamber, culminating in the massive explosion that Krakatoa is so famous for. Less dramatic, but equally relevant for the modern world, hydrovolcanism is one of the reasons the 2010 eruption of Eyjafjallajökull was so disruptive to air travel; part of the eruption took place beneath a glacier, and mixing of the lava with glacial meltwater increased the violence of the eruption, sending the eruption column higher and producing finer grained material that stays in the atmosphere for longer.

El Golfo is a basaltic tuff cone that formed on the west coast of Lanzarote, next to the Timanfaya National Park, as part of a NEE-SWW oriented volcanic chain. The edifice was formed by a series of explosions driven by magma interacting with water. The dune structures visible in the lower part of the cliff in this photo are indicative of pyroclastic surge deposits that are common in hydrovolcanism. The orange / red colour shows areas of the cone that have been altered to palagonite by the still-hot basaltic glass reacting with water. Pedrazzi et al suggested that the water and steam driving the hydrovolcanism became trapped within the pyroclastic deposits and was the source of water for the palagonitization. They used the distribution of palagonite to infer that the entire cone was deposited quickly – fast enough that the upper strata were deposited before the steam had time to escape from the lower strata.

So, not quite a whirlpool in the middle of a volcano, but exciting nonetheless.

By Stephanie Flude, School of Geosciences, The University of Edinburgh

References

Pedrazzi, D., Marti, J., and Geyer, A. : Stratigraphy, sedimentology and eruptive mechanisms in the tuff cone of El Golfo (Lanzarote, Canary Islands), Bulletin of Volcanology, 75, 740, DOI: 10.1007/s00445-013-0740-3, 2013.

Imaggeo is the EGU’s online open access geosciences image repository. All geoscientists (and others) can submit their photographs and videos to this repository and, since it is open access, these images can be used for free by scientists for their presentations or publications, by educators and the general public, and some images can even be used freely for commercial purposes. Photographers also retain full rights of use, as Imaggeo images are licensed and distributed by the EGU under a Creative Commons licence. Submit your photos at http://imaggeo.egu.eu/upload/.

Drinkable rocks!

Drinkable rocks!

When water is scarce, you’ve gotta save it, or come up with an ingenious way to get more. Some Spanish shrubs do just that, quenching their thirst with water from rocks. Sara Mynott explains where they source it…

Often, in areas where water is sparse, plants use a suite of techniques to harness what limited resources are available in their environment, from hairs that trap moisture in the air to deep roots that tap into water sources deep underground. Some, though, use a rather unusual strategy.

While presenting at the EGU General Assembly last week, Sara Palacio showed that some Spanish shrubs can get water from straight from minerals in the soil. Gypsum is a mineral containing 20% water and in parts of northern Spain the soil’s gypsum content can be as high as 85%, providing ample water for the plants – if they can get to it.

Quite how they do this remains a bit of a mystery. Many plants use fungi to help them meet their nutrient needs, so the plants could have a partner to help them snatch up the extra water. Alternatively, they could alter the soil’s pH or even utilise molecules that aid water uptake. This is something that only additional research can answer, says Palacio.

These shrubs, also known as rock rose, have exceedingly shallow roots – some 20 centimetres long – meaning that they can only stretch into the parched topsoil during periods of drought. What’s more, they don’t appear to have any clear means of gathering water from their surroundings, at least at first sight. Intrigued, Palacio set out to find what made these shrubs so special.

Rock rose (aka Helianthamum squamatum). Credit: Wikimedia Commons User Ghislain118.

Rock rose (aka Helianthamum squamatum). Credit: Wikimedia Commons User Ghislain118.

By comparing the stable isotope signatures of water in the soil, the minerals, and the plant’s plumbing system, Palacio and her colleagues were able to work out how these shrubs sated their thirst. The isotope signatures of the water contained in the minerals and of the plant’s water were a match!

During  a wet spring, the shrubs use both free water in the soil and water they’ve obtained from gypsum crystals, but in summer the minerals can meet up to 90% of the plant’s water needs, helping them make it through a summer drought.

By Sara Mynott, PhD Student, University of Exeter

 

References

 

Palacio, S., Azorín, J., Montserrat-Martí, G. and Ferrio, J. P.: Drinkable rocks: plants can use crystallization water from gypsum. Geophysical Research Abstracts Vol. 17, EGU2015-9011-1, 2015

 

Palacio, S., Azorín, J., Montserrat-Martí, G. and Ferrio, J. P.: The crystallization water of gypsum rocks is a relevant water source for plants. Nature Communications, 5, 2014

Announcing the winners of the EGU Photo Contest 2015!

Announcing the winners of the EGU Photo Contest 2015!

The selection committee received over 200 photos for this year’s EGU Photo Contest, covering fields across the geosciences. Participants have been voting for their favourites throughout the week  and there are three clear winners. Congratulations to  – 2015’s fantastic photographers!

The late Holocene fever,. Credit: Christian Massari (distributed via imaggeo.egu.eu)

The late Holocene fever. Credit: Christian Massari (distributed via imaggeo.egu.eu)

Heiturpottur. Credit: Morgan Jones (distributed via imaggeo.egu.eu)

Heiturpottur. Credit: Morgan Jones (distributed via imaggeo.egu.eu)

 

You don't form in the wet sand by Nicasio T. Jiménez-Morilo (distributed via imaggeo.egu.eu).

You don’t form in the wet sand by Nicasio T. Jiménez-Morilo (distributed via imaggeo.egu.eu).

On the occasion of the International Year of Soils, the judges also awarded an honourable mention to the best image in the Soil System Sciences category submitted to the EGU Photo Contest. The chosen image was ‘You don’t form in the wet sand’ by Nicasio T. Jiménez-Morilo. .

In addition, this year, to celebrate the theme of the EGU 2015 General Assembly, A voyage through scales, the photo that best captured the theme of the conference was selected by the judges. The winner is the stunning ‘Badlands National Park’, by Iain Willis! Congratulations! Scroll to the top of this post to view Iain’s image.

Imaggeo is the EGU’s online open access geosciences image repository. All geoscientists (and others) can submit their photographs and videos to this repository and, since it is open access, these images can be used for free by scientists for their presentations or publications, by educators and the general public, and some images can even be used freely for commercial purposes. Photographers also retain full rights of use, as Imaggeo images are licensed and distributed by the EGU under a Creative Commons licence. Submit your photos at http://imaggeo.egu.eu/upload/.

Science Policy Fellowship at the EGU – open for applications!

Do you have an interest in science policy and the geosciences? Then this fellowship might be just right for you!

EGU fellowships offer early career researchers the opportunity to gain experience in science management and communication in a large scientific union through a targeted assignment at the EGU Executive Office in Munich, Germany. Fellows are strategically deployed to develop new initiatives and capabilities for long-term use by the EGU. Fellowships last one year and are subject to a probation period of six months.

In 2015, we intend to appoint a fellow to develop the Union’s science policy programme, which is aimed at building bridges between geoscientists and European policymakers, engaging the EGU membership with public policy, and informing decision makers about the Earth, planetary and space sciences. The fellow will be tasked with mapping out policy opportunities for the EGU, setting up a pairing scheme between EGU researchers and members of the European Parliament, writing information briefings, and developing training and networking events for scientists to engage with policy making.

We are looking for a good team player with excellent interpersonal, organisational, and communication skills to fill this role. The successful applicant will have a masters or PhD in the Earth, space or planetary sciences, experience in science policy, flexibility to travel (as the fellowship involves short stays in Brussels), and an expert command of English.

The deadline for application is 24 March 2015. Further details about the position and how to apply can be found here.

Feel free to contact Dr Bárbara Ferreira, the Media and Communications Manager, at media@egu.eu or on +49-89-2180-6703 if you have any questions about the position.

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