GeoLog

Imaggeo

Imaggeo on Mondays: A walk at the glacier

Imaggeo on Mondays: A walk at the glacier

In 2012 I had the opportunity to help lead a teaching excursion to the Norwegian archipelago Svalbard. On this trip, geography students from the Ruhr-University of Bochum in Germany had the chance to learn more about the nature of this fascinating island.

In addition to Svalbard’s climatology and the wildlife, the region’s glaciology and geomorphology were the main topics we focused on. For example, we walked to the glacier ice, measured the glacier drainage flow and assigned various glacial debris accumulations (also known as moraines) to their genesis. Furthermore, PhD students from the local university showed us field experiments on how the region’s permafrost melts and wet soils slide downhill (also known as solifluction). We could see the giant glacier tongues with ice fronts at the sea level on a boat trip to the old coal mining town of Longyearbyen. The debris cover and the incredibly large medial moraine (debris that collects when two glaciers merge together) of the pictured glacier particularly impressed us.

We were astonished when the two polar bears came into sight after a short moment. Of course, we had secretly hoped to see polar bears on this excursion, but when it actually happened, not only the glaciers and the whole landscape seemed bigger, but also the wild nature of Svalbard got much more impressive. For me, my colleague André and my students this experience will be unforgettable.

By A. Martina Grudzielanek, Ruhr-University of Bochum, Germany

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: An expedition to better understand Antarctic soils

Imaggeo on Mondays: An expedition to better understand Antarctic soils

A dramatic evening sky puts the frame to a photo taken during the Brazilian Antarctic expedition to James Ross Island in 2016. Brazilian palaeontologists and soil scientists together with German soil scientists spent over 40 days on the island to search for fossils and sample soils at various locations of the northern part of the island.

The island was named after Sir James Clark Ross who led the British expedition in 1842, which first charted locations at the eastern part of the island. James Ross Island is part of Graham Land, the northern portion of the Antarctic Peninsula, separated from South America by the stormy Drake sea passage.

Map of the Antarctic Peninsula featuring the James Ross Archipelago (Credit: The Scientific Committee on Antarctic Research, Antarctic Digital Database Map Viewer)

This photo was taken in the northern Ulu Peninsula, which is the northernmost part of the relatively large James Ross Island and the largest ice-free area in the Antarctic Peninsula region. The island’s characteristic appearance is formed by Late Neogene volcanic rocks (3-7 million years old) over fossil rich Late Cretaceous sandstones (66-120 million years old).

In the photo we are looking from a higher marine terrace at the Santa Martha Cove, the ‘home’ to the 2016 Brazilian Antarctic expedition, towards the steep cliffs of Lachman Crags, a characteristic mesa formed by Late Neogene lava flows. The Lachman Crags mesa, the Spanish word for tablelands, dominates the landscape of the northern part of the Ulu Peninsula. Above the cliffs visible in the photo, a glacier covered plateau stretches to the Northwest.

The marine terrace on which the tent is standing is comprised of a flat area that has been ice-free for approximately 6000 years and thus makes for a great model system to study soil development after glacial retreat. The ground is composed of a mixture of volcanic rocks and Cretaceous sandstones rich in all sorts of fossils, from fossilised wood to shark teeth, ammonites and reptile bones.

The strong winds that can start in Antarctica from one moment to the other and the very low precipitation led to the characteristic desert pavement, with stones sorted in a flat arrangement on top of the fine textured, deeply weathered permafrost soils. Although these soils host a surprisingly high number of microorganisms, most terrestrial life is restricted to wetter areas surrounding fresh water lakes and melt water streams. Thus lakes and snow meltwater-fed areas make for higher primary production of algae and mosses, fostering biodiversity and soil development by organic matter input.

As there are no larger bird rookeries on James Ross Island the only way sea-derived nutrients reach the Ulu Peninsula is by a rather grim feature:  dead seal carcasses that lie distributed across the lowlands (< 150 m asl) of the Ulu Peninsula. Carcasses fertilise the soils in their direct vicinity while slowly decomposing over decades, thus feeding small patches of lichens and mosses within the barren cold arid desert. The region is thus an illustration of the harsh Antarctic environment where even Weddell seals, animals that are well adapted for the living in dense pack ice during the polar night, die when losing track on land on the way to the water.

By Carsten Müller, Technical University of Munich Chair of Soil Science, Germany

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 colourful sinkhole clusters at Ghor Al-Haditha

Imaggeo on Mondays: The colourful sinkhole clusters at Ghor Al-Haditha

Sinkholes that form on the Dead Sea shore at Ghor Al-Haditha, Jordan, often occur in clusters, with many holes packed into a small area. However the visual appearance of neighbouring sinkholes can vary significantly. Mineral precipitation in the foremost sinkhole in this picture, which has no fresh water supply, gives it a garish pink-orange colouration. The larger hole behind has a groundwater-derived supply of fresher (blue) water which allows it to harbour life: ground-nesting birds and frog spawn are both prevalent in the marshy area surrounding the holes. It is slightly paradoxical that such a destructive force can also be an oasis for life in an otherwise barren wilderness.

Description by Rob Watson, 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 polje between sky and Earth

Imaggeo on Mondays: The polje between sky and Earth

Poljes are one of the most impressive features existing in karst landscapes. These large flat closed depressions are prone to regular flooding that can form temporary lakes on their surface. Planinsko Polje [in Slovenia] is surely the most famous example of polje existing. The highest floods can reach up to 8 metres above the gauging station and last for more than two months. The lake is then more than 10km squared large, which strongly modify the daily life of the inhabitants living in the polje surroundings.

Description by Cyril Mayaud, 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/.