GeoLog

Geochemistry, Mineralogy, Petrology & Volcanology

Imaggeo on Mondays: Life on bare lava

Life on bare lava

There are plenty of hostile habitats across the globe but some flora and fauna species are resourceful enough to adapt and make extreme environments their home. From heat-loving ants of the Sahara to microbes living in the light-deprived ocean depths, through to beatles who brave the bitterly cold Alaskan winter, there are numerous examples of plants, animals and bugs who strive in environments often considered too challenging to harbour life. In today’s post, brought to you by geomorphologist Katja Laute, we feature Vinagrerilla roja, a plant species adept at making difficult terrains its home.

Vinagrerilla roja (Rumex vesicarius) / the Canary Island bladderdock is one of the most successful endemic plants for colonizing new territory in arid and volcanic areas. The photo was taken on the crater rim of the volcano Montana Bermeja (157 m asl.), located at the northernmost edge of the volcanic island La Graciosa. The island was formed by the Canary hotspot and is today part of the protected Chinijo Archipelago Natural Park which shelters endemic and highly endangered species of the Canary Islands.

The volcano Montana Bermeja is composed of red lapilli (pea to walnut-sized fragments ejected during an eruption) which seems to impede any kind of life. But as the photo shows, the bladderdock is actively growing in this apparently hostile environment. That plant life emerges from such a barren and rough volcanic environment seems almost impossible.

Only very few pioneer species succeed and manage to survive in such harsh environments with little to no soil and under an almost desertic climate. Being located on the northern side of the crater rim enables the bladderdock to capture moisture out of the reoccurring Atlantic winds. As these pioneer species grow, their dead leaves and roots will enrich the soil with organic content providing the base for a chain of ecological succession.

By Katja Laute, researcher at IUEM, Brest, France

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: the remotest place on Earth?

Imaggeo on Mondays: the remotest place on Earth?

Perhaps a bold claim, but at over 4,000 km away from Australia and 4,200 km from South Africa, Heard Island is unquestionably hard to reach.

The faraway and little know place is part of a group of volcanic islands known as HIMI (comprised of the Heard Island and McDonald Islands), located in the southwest Indian Ocean. Shrouded in persistent bad weather and surrounded by the vast ocean, Heard Island, the largest of the group, was first sighted by the merchant vessel Oriental in 1853.

Its late discovery and inaccessibility mean Heard Island is largely undisturbed by human activity (some research, surveillance, fishing and shipping take place on the island and it’s surrounding waters). It boasts a rich fauna and flora: seals, invertebrates, birds and seals call it home, as do hardy species of vegetation which grow low to the ground to avoid the fierce winds which batter the island.

Geologically speaking the islands are pretty unique too. They are the surface exposure of the second largest submarine plateau in the world, the Kerguelen Plateau. Limestones deposited some 45–50 million years ago began the process which saw the emergence of the islands from the ocean floor. Ancient volcanic activity followed, accumulating volcanic materials,  such as pillow lavas and volcanic sediments, up to 350m thick. For the last million years (or less) Heard Island has been dominated by volcanism, giving rise to the 2745m tall Big Ben and 700m tall Mt. Dixon. Eruptions and volcanic events have been observed on the island since 1947. Much of the recent volcanism in the region has centered around McDonald island, which has grown 40 km in area and 100 m in height since the 1980s.   

As the group of islands provides a remarkable setting, where geological processes and evolution (given that large populations of marine birds and mammals numbering in the millions, but low species diversity) can be observed in in real time, UNESCO declared HIMI a World Heritage Site back in 1997.

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: Tones of sand

Tones of Sand

With rocks dating as far back as the Precambrian, mountain building events, violent volcanic eruptions and being covered, on and off, by shallow seas, Death Valley’s geological history is long and complex.

Back in the Cenozoic (65 to 30 million years ago), following a turbulent period which saw the eruption of volcanoes (which in time would form the Sierra Nevada of California) and regional uplift, Death Valley was a peaceful place. There was no deposition of sediments, nor emplacement of igneous rocks. The valley was being eroded, slowly.

Fast forward a few thousand years, to the Miocene (ca. 27 million years ago) and all that changed. New volcanic eruptions drove the onset of a major extensional event, which saw basins and ranges develop into Death Valley as we know it today.

The tectonics of the region were also complex: the North American plate was riding up and over the Pacific plate, but around the same time as the extension started in the basin, the spreading centre of the Pacific plate intersected with the Fallon Plate, splitting it in half. The northern section became the Juan de Fuca plate and the San Andreas Fault was created between the remnants of the subduction zone.

The Panamint Range – a fault-block mountain range on the edge of the Mojave Desert – formed as a result of the powerful tectonic events. Initially, it rode over and piggy backed on top of The Black Mountains, before sliding towards the west.  As the mountain ranges slid apart, the valleys lost height too and started receiving sediment.

The sediment influx happens to this day, as evidenced in today’s Imaggeo on Monday’s photograph, taken by Marc Girons Lopez, a hydrologist at Uppsala University (Sweden).

“The photograph was taken from Dante’s View viewpoint terrace and shows the Death Valley on the foreground and the Panamint Range on the background,” describes Marc.

At present, a series of alluvial fans drain the Panamint Range, forming triangle-shaped deposits of gravel, sand and silt. These fans are formed through the deposition of sediments eroded from the Panamint Range during flash flood events.

Marc says that “the colour of the sand forming the alluvial fans relates to their age; the clearer the tones the younger their age.”

The salt flats in the foreground, which are covered in salt and other minerals, are the remnants of Lake Manly, a landlocked lake system which drained to no other bodies of water such as rivers or oceans. The lake was present during the Pleistocene era (2.85 million years ago) and slowly evaporated as the region progressively desertified. The evaporitic salts have been exploited in modern times.

 

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/.

The best of Imaggeo in 2016: in pictures

The best of Imaggeo in 2016: in pictures

Imaggeo, our open access image repository, is packed with beautiful images showcasing the best of the Earth, space and planetary sciences. Throughout the year we use the photographs submitted to the repository to illustrate our social media and blog posts.

For the past few years we’ve celebrated the end of the year by rounding-up some of the best Imaggeo images. But it’s no easy task to pick which of the featured images are the best! Instead, we turned the job over to you!  We compiled a Facebook album which included all the images we’ve used  as header images across our social media channels and on Imaggeo on Mondays blog post in 2016 an asked you to vote for your favourites.

Today’s blog post rounds-up the best 12 images of Imaggeo in 2016, as chosen by you, our readers.

Of course, these are only a few of the very special images we highlighted in 2016, but take a look at our image repository, Imaggeo, for many other spectacular geo-themed pictures, including the winning images of the 2016 Photo Contest. The competition will be running again this year, so if you’ve got a flare for photography or have managed to capture a unique field work moment, consider uploading your images to Imaggeo and entering the 2017 Photo Contest.

Blue Svartisen . Credit: Kay Helfricht (distributed via imaggeo.egu.eu)

When you think of a glacier the image you likely conjure up in your mind is that of bright white, icy body. So why do some glaciers, like Engabreen, a glacier in Norway, sometimes appear blue? Is it a trick of the light or some other phenomenon which causes this glacier to look so unusual?  You can learn all about it in this October post over on GeoLog.

 

‘There is never enough time to count all the stars that you want.’ . Credit: Vytas Huth (distributed via imaggeo.egu.eu). The centre of the Milky Way taken near Krakow am See, Germany. Some of the least light-polluted atmosphere of the northern german lowlands.

Among the winning images of our annual photo contest was a stunning night-sky panorama by Vytas Huth; we aren’t surprised it has been chosen as one of the most popular images of 2016 too. In this post, Vytas describes how he captured the image and how the remote location in Southern Germany is one of the few (in Europe) where it is still possible to, clearly, image the Milk Way.

 

“Above the foggy strip, this white arch was shining, covering one third of the visible sky in the direction of the ship's bow,” he explains. “It was a so-called white, or fog rainbow, which appears on the fog droplets, which are much smaller then rain droplets and cause different optic effects, which is a reason of its white colour.”

Gateway to the Arctic . Credit: Mikhail Varentsov (distributed via imaggeo.egu.eu)

“Above the foggy strip, this white arch was shining, covering one third of the visible sky in the direction of the ship’s bow,” describes Mikhail Varentsov, a climate and meteorology expert from the University of Moscow. “It was a so-called white, or fog rainbow, which appears on the fog droplets, which are much smaller then rain droplets and cause different optic effects, which is a reason of its white colour.” Mikhail captured the white rainbow while aboard the Akademik Tryoshnikov research vessel during its scientific cruise to study the effects of climate change on the Arctic.

 

History. Credit: Florian Fuchs (distributed via imaggeo.egu.eu)

The header image, History by Florian Fuchs, we used across our social media channels was popular with our Facebook followers, who chose it as one of the best of this year. The picture features La Tarta del Teide – a stratigraphic section through volcanic deposits of the Teide volcano on Tenerife, Canary Islands.

 

Find a new way . Credit: Wolfgang Fraedrich (distributed via imaggeo.egu.eu)

Lavas erupted into river waters, and as a result cooled very quickly, can give rise to fractures in volcanic rocks. They form prismatic structures which can be arranged in all kinds of patterns: horizontally (locally known as the woodpile), slightly arching (the harp) and in a radial configuration known as the rosette. The most common configuration is the ‘organ pile’ where vertical fractures form. These impressive structures are seen in the walls of the Gole dell ‘Alcantara, a system of gorges formed 8,000 years ago in the course of the river Alcantara in eastern Sicily.

 

Home Sweet Home . Credit: André Nuber (distributed via imaggeo.egu.eu)

Can you imagine camping atop some of the highest mountains in Europe and waking up to a view of snowcapped peaks, deep valleys and endless blue skies? This paints an idyllic picture; field work definitely takes Earth scientists to some of the most beautiful corners of the planet.

 

Isolated Storm . Credit: Peter Huber (distributed via imaggeo.egu.eu)

In November 2016 we featured this photograph of an isolated thunderstorm in the Weinviertel in April. The view is towards the Lower Carpathian Mountains and Bratislava about 50 kilometers from Vienna. Why do storms and isolated thunderstorms form? Find out in this post.

 

Glacial erratic rocks . Credit: Yuval Sadeh (distributed via imaggeo.egu.eu)

As glaciers move, they accumulate debris underneath their surface. As the vast frozen rivers advance, they carry the debris, which can range from pebble-sized rocks through to house-sized boulders, along with it. As the climate in the Yosemite region began to warm as the ice age came to an end, the glaciers slowly melted. Once all the ice was gone, the rocks and boulders, known as glacial erratics, were left behind.

 

Snow and ash in Iceland . Credit: Daniel Garcia Castellanos (distributed via imaggeo.egu.eu)

Icelandic snow-capped peaks are also sprinkled by a light dusting of volcanic ash in this photograph. Dive into this March 2016 post to find out the source of the ash and more detail about the striking peak.

 

Living Flows . Credit: Marc Girons Lopez (distributed via imaggeo.egu.eu)

There are handful true wildernesses left on the planet. Only a few, far flung corners, of the globe remain truly remote and unspoilt. To explore and experience untouched landscapes you might find yourself making the journey to the dunes in Sossuvlei in Namibia, or to the salty plain of the Salar Uyuni in Bolivia. But it’s not necessary to travel so far to discover an area where humans have, so far, left little mark. One of the last wilds is right here in Europe, in the northern territories of Sweden. This spectacular photograph of the Laitaure Delta is brought to you by Marc Girons Lopez, one of the winners of the 2016 edition of the EGU’s Photo Contest!

 


The power of ice. Credit: Romain Schläppy, (distributed via imaggeo.egu.eu).

The January 2016 header image across our social media was The Power of Ice, by Romain Schlappy. This vivid picture was captured from a helicopter by Romain Schläppy during a field trip in September 2011. You can learn more about this image by reading a previous imaggeo on mondays post.

 

Sea of Clouds over Uummannaq Fjord. Credit: Tun Jan Young (distributed via imaggeo.egu.eu)

The current header image, Sea of Clouds over Uummannaq Fjord by Tun Jan Young, is also a hit with our followers and the final most popular image from Imaggeo in 2016. A sudden change of pressure system caused clouds to form on the surface of the Uummannaq Fjord, Northwestern Greenland, shrouding the environment in mystery.

 

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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