GeoLog

mountain

Imaggeo on Mondays: Sunset and moonrise at Yosemite

Imaggeo on Mondays: Sunset and moonrise at Yosemite

This side view of Half Dome at Yosemite National Park (California, USA) was taken from Washburn Point, a less frequented overlook a few hundred meters away from the popular Glacier Point outlook. The sun just on the right side behind the camera, which gave the orange tint to the back side of Half Dome. At the same time a full moon was mere minutes from bursting in the background, which resulted in the warm glow of the horizon. A few stars have already started appearing on the clear sky and a few star trails are visible.

Description by Teamrat Ghezzehei, as it first appeared on imaggeo.egu.eu.

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/.

Imaggeo on Mondays: Corno Grande, tallest peak of the Apennines

Imaggeo on Mondays: Corno Grande, tallest peak of the Apennines

In the middle of the Apennines lays the Gran Sasso d’Italia mountain chain, a picturesque collection of mountains situated in the heart of Italy.

Featured here is one of the chain’s peaks, called the Corno Grande, meaning ‘Big Horn,’ coloured with a faint reddish light of a late-winter sunset. Sitting at 2,912 metres, this summit is easily the highest mountain in the Apennines.

The areas surrounding Corno Grande is enclosed in the Gran Sasso e Monti della Laga National Park, located in the hinterland of Italy’s Abruzzo region. The park, established in 1991, encompasses 2,015 square kilometres, making it one of the largest natural reserves in Europe.

Moreover, from an ecological standpoint, the region is one of the most biologically diverse areas in Europe, with more than 2,000 plant species, many of which can only be found in the park, and many rare animals.

The landscape that surrounds Corno Grande still shows traces of glacial erosion from the Quaternary Period, which began 2.6 million years ago. The region’s smooth highlands and U-shaped valleys are engravings of the slow glacial processes that occurred on these lands. The Corno Grande is even still host to a glacier today, as you can find the Calderone glacier, Western Europe’s southernmost glacier, beneath the mountain’s peak.

Sketch of the geodynamic setting of the Gran Sasso (Credit: Cardello and Doglioni, 2015)

The Apennine Mountains were built by a paradoxical geologic process, sometimes referred to as ‘syn-orogenic extension,’ where thickened crust spreads out while, at the same time, a belt of Earth’s crust is compressed, forming a chain of mountains. In the case of the Apennines, compression took place east of the range while extension occurred to the west.

“This synchronous processes of such different motions in the convergent belts is still an issue that must be unraveled for a better understanding of the mountain ridge formation,” said Alex Righetti, a PhD student studying marine geology at the Faculty of Sciences of the University of Lisbon, in Portugal, who captured this shot.

By Olivia Trani, EGU Communications Officer and Alex Righetti, FCUL

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/.

Imaggeo on Mondays: Refuge in a cloudscape

Imaggeo on Mondays: Refuge in a cloudscape

The action of glaciers combined with the structure of the rock to form this little platform, probably once a small lake enclosed between a moraine at the mountain side and the ice in the valley.

Now it has become a green haven in the mountain landscape, a perfect place for an alp. In the Alps, stratus clouds opening up on autumn mornings often create gorgeous light display.

That day, some of the first light landed on this exact spot, while the mountain shadows still covered the valley bottom.

Description by Julien Seguinot, as it first appeared on imaggeo.egu.eu

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/.

Imaggeo on Mondays: Sneaking up from above

Imaggeo on Mondays: Sneaking up from above

Take some ice, mix in some rock, snow and maybe a little mud and the result is a rock glacier. Unlike ice glaciers (the ones we are most familiar with), rock glaciers have very little ice at the surface. Looking at today’s featured image, you’d be forgiven for thinking the Morenas Coloradas rock glacier wasn’t a glacier at all. But appearances can be misleading; as Jan Blöthe (a researcher at the University of Bonn) explains in today’s post.

The picture shows the Morenas Coloradas rock glacier, a pivotal example of actively creeping permafrost (ground that remains frozen for periods longer than two consecutive years) in the dry central Andes of Argentina. The rock glacier is located in the “Cordon del Plata” range, some 50 km east of the city of Mendoza.

The rock glacier fills the entire valley and slowly creeps downslope creating impressive lobes and tongues with steep fronts. With more than 4 km length, the Morenas Coloradas is one of the largest rock glaciers of the central Andes.

Taken from a drone, the picture looks straight up the rock glacier into the main amphitheatre-like valley formed by glacial erosion located at ~4500 m.a.s.l. From there, large amounts of loose debris are moved down the valley at speeds on the order of a few meters per year. The creeping process forms tongues of material that override each other, producing the characteristic surface with steps, ridges and furrows.

The central Andes of Argentina are semi-arid, receiving less than 500 mm of precipitation per year, mainly falling as snow during the winter. The region is famous for its wines, which are grow in the dry Andean foreland that is heavily dependent on meltwater from the mountains. How much of this meltwater is actually stored in ice-rich permafrost landforms is unknown.

As opposed to ice glaciers, rock glaciers show a delayed reaction to a changing climate, as large amounts of debris cover the ground ice, isolating it from rising air temperatures. With large areas located above the lower altitudinal limit of mountain permafrost of ~3600 m.a.s.l., the central Andes of Argentina might store significant amounts of water in the subsurface.

Using mainly near-surface geophysics, our research tries to quantify the water storage capacities in the very abundant and impressive rock glaciers of the region. The Morenas Coloradas rock glacier is of special importance in this regard, as first geophysical measurements date back to the 1980s. Since then, active layer thickness has dramatically increased in the lower parts of the rock glacier, indicating that also the ground ice of the permafrost domain of the central Andes is suffering under the currently warming climate.

A final remark: Thanks goes to the entire team of this research project, namely Christian Halla, Estefania Bottegal, Joachim Götz, Lothar Schrott, Dario Trombotto, Floreana Miesen, Lorenz Banzer, Julius Isigkeit, Henning Clemens, and Thorsten Höser.

By Jan Blöthe, University of Bonn, Germany