GeoLog

Geomorphology

Imaggeo on Mondays: A lifeline between light and shadow

Imaggeo on Mondays: A lifeline between light and shadow

The Rapaälven making its way through the Rapadalen valley in Northern Sweden. After over a week of hiking through pure wilderness I reached the summit of Skierffe together with three friends. We were just blown away by the view and completely in awe for the beautiful shape of the rivers course… little lakes in between river channels of different sizes as well as dense vegetation forming a habitat for so many animals.. all controlled by erosion and the force of the water cycle…

A few days later we learned how difficult it is to hike through terrain like this for humans but how fast and quiet a moose can move right across the valley.

The Rapaälven is the biggest river in the Sarek National Park, the Swedish part of Lapland. Four smaller rivers (Smájllajåkkå, Mikkájåkkå, Guohperjåkkå, Áhkáåkkå) form this 75km long stream that drains around 30 different glaciers and the surrounding national park.

Description by Florian Konrad, 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: how short-term storms can impact our landscapes

Imaggeo on Mondays: how short-term storms can impact our landscapes

In the Sierra de Aconquija, a mountain range in the southern Central Andes of Argentina, strong storms often come and go at a moment’s notice, but they can have a long-lasting impact on the Earth’s surface.

The thunderstorm cell featured in this photo formed in less than half an hour, giving all those nearby only a few minutes to take cover. Mitch D’Arcy, a geomorphologist and postdoctoral researcher at the University of Potsdam and the GFZ German Research Centre for Geosciences, had the opportunity to witness this storm (and snap this picture!) while carrying out field work in the area.

“It was a spectacular experience, pouring heavy rain onto a very localised part of the mountain range, but it was also a hazard because the storm was quickly moving towards us with a lot of lightning. Without any trees around, we were likely targets for lightning strikes!” said D’Arcy. Luckily, he and his colleagues were able to find shelter in their truck while the huge downpour passed over them.

These kinds of thunderstorms are short-lived, but have intense precipitation rates. In this case, the temperature dropped by 14 degrees Celsius, and the storm was accompanied by heavy hail and lightning. And while these natural hazards are transient, they can have a long-term impact on the region’s landscape. Severe storms are capable of triggering landslides and floods and can relocate large amounts of sediment and debris in a short period of time.

D’Arcy is part of an international research programme called StRATEGy (Surface processes, Tectonics and Georesources: The Andean foreland basin of Argentina), which looks into how past and present climate change makes a mark on the terrain of the Argentine Andes, among other topics.

This research is essential for understanding and predicting how human-caused climate change will alter weather patterns and impact surface processes (such as how quickly sediments are eroded and transported across landscapes), according to D’Arcy. Having a better understanding of these surface processes and their sensitivity to the climate could help scientists better inform the public about how to prepare for natural hazards, such as flooding, erosion and landslides.

D’Arcy notes that it’s also important to assess how climate and weather trends will impact the sedimentary record, since it is one of the only physical records that scientists can use to examine how the Earth’s surface has change through time.

“North-western Argentina is a fascinating place to study how climate change affects surface processes, because it has experienced pronounced and abrupt changes in hydroclimate through time,” said D’Arcy. Their research has found that even subtle changes in the region’s climate have produced large changes to the surface environment, impacting how rivers take shape and how sediments move.

For example, while the Sierra de Aconquija is a semi-arid environment today, more than 12,000 years ago it used to be much wetter as a result of global climate changes. In fact, back then the mountain range was covered in glaciers and many of the basins were filled with lakes.

“It’s really important that we understand how different landscapes function and how they react to changes in climate. When we look at places like the southern Central Andes in Argentina, we find that the landscape records interesting signatures of ancient climate changes in Earth’s past. However, one of the big questions we still don’t have a good answer to, is how important are these very intense but rare storms for shaping landscapes and creating the sedimentary record from the geological past,” said D’Arcy.

By Olivia Trani, EGU Communications Officer

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: Loch Coruisk – home of the wild Kelpie

Imaggeo on Mondays: Loch Coruisk – home of the wild Kelpie

On the south-western coast of the Isle of Skye, Scotland, lies Loch Coruisk, supposedly home of a water horse. At the southern end of this freshwater Loch, the Scavaig River discharges into a sea Loch, Loch na Cuilce. Loch Coruisk snuggles close to the center of the Cuillin Hills complex, younger than both the northern and southern formations of the Isle. At present, the neighbouring hills are dominated by Paleogene intrusive bytownite gabbros that are responsible for the jagged outline of the topography. Cuillin Hills forms the remains of an eroded magmatic chamber.

Description by Cedric Gillmann, 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: The surprising beauty of the Arctic tundra

Imaggeo on Mondays: The surprising beauty of the Arctic tundra

Close your eyes and try to imagine first thing which comes to your mind, when somebody says “Tundra”. What would you imagine?

Being a master student, I imagined cold, flat and a dead field. In fact, Tundra turn out to be completely different, at least in September 2010, when I and my colleagues were lucky to visit it.

As it is well known from textbooks no big trees grows in Tundra, however, the local mosses were full of colour and various berries.
Those hills (on the photo), called “sopkas”, build up the amazing landscape of tundra. Those hills are not originated volcanically or as debris. Those are conglomerations of stones pushed up from the ground by permafrost during melting-freezing cycle. So, each sopka should grow a little every winter, representing a magnificent power of permafrost.

Description by Alexandra Loginova, 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/.