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Imaggeo on Mondays: Cordillera de la Sal

Imaggeo on Mondays: Cordillera de la Sal

The photograph shows the Valle de la Luna, part of the amazing Cordillera de la Sal mountain range in northern Chile. Rising only 200 metres above the basin of the Salar de Atacama salt flat, the ridges of the Cordillera de la Sal represent a strongly folded sequence of clastic sediments and evapourites (salt can be seen in the left portion of the image), with interspersed volcanic material.

This formation evolved when the depression between the Cordillera Domeyko mountain range and the main Andean mountain ranges, filled by an ancient salt flat, was squeezed together over the last 10-15 million years, leaving behind the folded belt of hills seen today. Sand brought along from adjacent areas by the winds was caught between the ridges of the Cordillera de la Sal, accumulating to form the impressive dune shown in the foreground of the image.

Under normal conditions, the perfectly shaped Licancabur Volcano, forming the border between Chile and Argentina, would appear in the background of this sunset scene. However, the image was taken during the Invierno Boliviano (Bolivian winter), when humid air from the eastern side of the Andes travels west across the Andean Plateau, Altiplano. The air masses journey all the way to the otherwise extremely arid Atacama Desert, bringing clouds, rain and occasionally even hail.

I have been to this area three times: first for vacation, then two times for excursions with students, most recently in February this year. Interestingly, the weather was as to be expected for the Atacama Desert only one time. For the two other times, the weather was looking like this photograph, so it is hard for me to believe that the Atacama would be as arid as people always say. However, indeed, the pieces of geological and geomorphological evidence, such as the folded layers of the Cordillera de la Sal, clearly indicate its extreme aridity, prevailing for tens of millions of years!

By Martin Mergili, University of Vienna

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/.

Announcing the winners of the EGU Photo Competition 2018!

The selection committee received over 600 photos for this year’s EGU Photo Contest, covering fields across the geosciences. Participants at the 2018 General Assembly have been voting for their favourites throughout the week  of the conference and there are three clear winners. Congratulations to 2018’s fantastic photographers!

 

Foehn clouds in Patagonia,’ by Christoph Mayr (distributed via imaggeo.egu.eu). A stationary cloud formed on the lee side of Mount Fitzroy. It evolved from a lenticular cloud (Altocumulus lenticularis) and turned into a funnel-shaped cloud during sunset when the photo was taken.

 

Jebel Bayda (White Mountain),’ by Luigi Vigliotti (distributed via imaggeo.egu.eu). An aerial view of the Jebel Bayda, a white volcano created by silica-rich lava (comendite) in the Khaybar region. The flank of the volcano was shaped by rain in the region during the first half of the Holocene.

 

Remains of a former ocean floor,’ by Jana Eichel (distributed via imaggeo.egu.eu). These limestone boulders characterise the landscape of Castle Hill Basin in New Zealand’s Southern Alps. The Pacific Plate collided with the Australian Plate during the Kaikoura Orogeny 25 million years ago, giving birth not only to the Southern Alps but also lifting up thick limestone beds formed in shallow ocean water.

 

Imaggeo is the EGU’s online open access geosciences image repository. All geoscientists (and others) can submittheir 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/.

Photo Competition finalists 2018 – who will you vote for?

The selection committee received over 600 photos for this year’s EGU Photo Competition, covering fields across the geosciences. The fantastic finalist photos are below and they are being exhibited in Hall X2 (basement, Brown Level) of the Austria Center Vienna – see for yourself!

Do you have a favourite? Vote for it! There is a voting terminal (also in Hall X2), just next to the exhibit. The results will be announced on Friday 13 April during the lunch break (at 12:15).

Remains of a former ocean floor.’ Credit: Jana Eichel (distributed via imaggeo.egu.eu). These limestone boulders characterise the landscape of Castle Hill Basin in New Zealand’s Southern Alps. The Pacific Plate collided with the Australian Plate during the Kaikoura Orogeny 25 million years ago, giving birth not only to the Southern Alps but also lifting up thick limestone beds formed in shallow ocean water.

 

Foehn clouds in Patagonia.’ Credit: Christoph Mayr (distributed via imaggeo.egu.eu). A stationary cloud formed on the lee side of Mount Fitzroy. It evolved from a lenticular cloud (Altocumulus lenticularis) and turned into a funnel-shaped cloud during sunset when the photo was taken.

 

Jebel Bayda (White Mountain).’ Credit: Luigi Vigliotti (distributed via imaggeo.egu.eu). An aerial view of the Jebel Bayda, a white volcano created by silica-rich lava (comendite) in the Khaybar region. The flank of the volcano was shaped by rain in the region during the first half of the Holocene.

 

Mother-of-pearl cloud.’ Credit: Thomas Kuhn (distributed via imaggeo.egu.eu). These clouds are a special type of polar stratospheric clouds that only occur during the polar winter. The tiny ice crystals that form in these clouds must be uniform in size so that diffraction can create their shining colours.

 

Patagonian rainforest.’ Credit: Carsten W. Mueller (distributed via imaggeo.egu.eu). The magic light in the Patagonian rain forest is dominated by Southern beech (Nothofagus). The high precipitation in Southern Patagonia sustains biodiverse rainforests on peaty soils.

 

The beauty of shells.’ Credit: Rene Hoffmann (distributed via imaggeo.egu.eu). A thin section of a belemnite (Gonioteuthis, Upper Cretaceous, NW-Germany) under crossed polarizers. Belemnites are the backbone of Jurassic-Cretaceous reconstruction as they able to determine former seawater properties, such as temperature.

 

50 shades of grey.’ Credit: Paolo Paron (distributed via imaggeo.egu.eu). The dry sandy river bed of the Limpopo River. This picture was taken at the end of January, in the middle of the rainy season, and shows the devastating effects of the prolonged drought. The surrounding floodplain that is used extensively by farmers would normally be inundated.

 

Pinnacles in Nambug National Park at sunset.’ Credit: Stefan Doerr (distributed via imaggeo.egu.eu). The spectacular pinnacle karst in Western Australia. This landscape contains thousands of pinnacles up to 5 m high and 2 m wide. The pinnacles have formed in the Pleistocene Tamala Limestone, which comprises cyclic sequences of aeolian calcarenite, calcrete / microbialite and palaeosol.

 

Closer look at the deglaciation history of Lago Belgrano.’ Credit: Monika Mendelova (distributed via imaggeo.egu.eu). The Lago Belgrano valley was once occupied by a glacier, which drained part of the Patagonian Ice Sheet. The retreating glacier allowed a large palaeo-lake to form, a predecessor of modern Lago Belgrano. Spot the shoreline!

 

Poetry of water shaped formations.’ Credit: Raphael Knevels (distributed via imaggeo.egu.eu). This karst cave was discovered in 2005 and named Paradise Cave because of its exceptionally beautiful stalactites and stalagmites. The cave is located in the Phong Nha-Kẻ Bàng National Park, Vietnam.

 

The EGU General Assembly is taking place in Vienna, Austria from 8 to 13 April. Check out the full session programme on the General Assembly website and follow the Assembly’s online conversation on Twitter at #EGU18.

Imaggeo on Mondays: Iceberg viewing in Cape Spear, Newfoundland, Canada

Imaggeo on Mondays: Iceberg viewing in Cape Spear, Newfoundland, Canada

Cape Spear in Newfoundland, Canada is the easternmost location in North America and one of the few places in the world where you can contemplate icebergs from the shore. Every year, about 400 to 800 bergs journey down to this particular point. These 10,000-year-old ice giants drift along the northern shore of Newfoundland with the Labrador Current.

About 90 percent of these icebergs come from western Greenland glaciers, where they break off directly into Baffin Bay. Often these bergs remain in the bay for several years, preserved by the cold arctic waters and circulating along with local currents. Eventually, many icebergs escape through the Davis Strait, drifting down the Labrador Current and passing through Iceberg Alley to reach the Grand Banks of Newfoundland, the region of the North American continental shelf where Cape Spear is situated. This journey from Greenland to the Grand Banks usually takes between two and three years.

Cape Spear is just a few kilometres from Newfoundland’s largest city, St. John’s, and attracts many tourists during spring and early summer months to enjoy the immense icebergs. The chances of seeing them depend greatly on the temperature, wind direction, ocean currents and amount of sea ice during the winter, which protects icebergs from erosion. The icebergs have a great impact on Newfoundland’s identity and economy, bringing tourists and even giving breweries unique ice for beer and liquor production.

On the other hand, the floating ice can be a hazard to oil platforms and cargo boats. Smaller bergs can be especially hazardous since they are harder to detect with marine radar. If deep enough, the icebergs can also damage seabed structures like pipelines and cables. Thus, it is important to keep monitoring the dynamics of icebergs, especially since there will likely be a greater volume of ice breaking from the Greenland glaciers and drifting in the North Atlantic due to climate change.

By Simon Massé, PhD student, Université du Québec à Rimouski, Canada

References

Barber, D.G., Babb, D.G., Ehn, J.K., Chan,W., Matthes, L., Dalman, L. A., et al.: Increasing mobility of high Arctic Sea ice increases marine hazards off the east coast of Newfoundland, Geophysical Research Letters, 45,2370–2379, https://doi.org/10.1002/2017GL076587, 2018.

Diemand, D., Icebergs, Encyclopedia of Ocean Sciences, 3: 1255-1264,  2001.

Iceberg Finder, Icebergs Facts. Newfoundland & Labrador Tourism, 2012.

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/.