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fieldwork

Imaggeo on Mondays: Probing the Pliocene

Imaggeo on Mondays: Probing the Pliocene

The heights we go to for science…

This photograph shows a member of our team preparing to abseil down a cliff in the Charyn Canyon, in the Ili River basin of southeast Kazakhstan. The Charyn River and its tributaries, a branch of the Ili River north of the Tien Shan Mountains, have cut canyons up to 300 metres deep, carving through rocks of different geologic ages, some as old as 540 million years.

The name “Charyn” may derive from local Uighur or Turkic words for “ash tree” or “precipice” respectively, both of which are common in the area.

Charyn Canyon is presently characterized by a cold semi-arid climate, with dry summers and cold winters. However, these conditions are likely to have varied through time, becoming wetter, drier, warmer and cooler in response to major climate systems’ changing intensity and influence over the region.

Our research team investigates the past and present climate systems of the Cenozoic era, our current geological era which began 66 million years ago; the most recent 2.6 million years have been characterised by alternating ice ages and warmer so-called “interglacial” phases, and saw the evolution of humans. More specifically, we study climate systems in one of the most remote regions of Central Asia, known as the Eurasian Continental Pole of Inaccessibility. The area is a challenging place for climate research since it has no marine or ice core records, the most common calendars of ancient climate.

This region is poorly understood yet important within the global climate system, since it lies at the boundaries of the major northern hemispheric climate systems. These systems, such as the Siberian high pressure system and Asian monsoons, are likely to have shifted, expanded and contracted over time. These changes occur in response to factors like mountain uplift, and changes in the Earth’s orbital patterns and incoming solar radiation.

The aim of our study is to reconstruct climatic change over this period. By analysing various chemical and physical characteristics of the sediments, such as their age, magnetism, grain size and chemistry, we can reconstruct quantitative palaeoclimatic variability through time.

Here we focus on an 80-metre thick layer of sediment, which alternates between layers of river-transported gravels and wind-blown dust deposits, known as loess. Younger sedimentary layers have thicker dust deposits, reflecting a long-term aridification trend in the Ili Basin and, more broadly, Central Asia.

Our preliminary results from our fieldwork indicate that the canyon’s sediments represent an uninterrupted representation of the region’s climate from the Pliocene to early Pleistocene (from approximately 4.5 to 1 million years ago).

Achieving a comprehensive geological sampling of the Charyn Canyon was only possible by abseil. Our fieldwork, undertaken from May to June 2017, was a hot and dusty business, but ultimately a lot of fun. Definitely not for those with a fear of heights!

By Kathryn Fitzsimmons, Max Planck Institute for Chemistry, Germany and Giancarlo Scardia, São Paulo State University, Brazil

Last chance to enter the EGU Photo Contest 2018!

Last chance to enter the EGU Photo Contest 2018!

If you are pre-registered for the 2018 General Assembly (Vienna, 8 -13 April), you can take part in our annual photo competition! Winners receive a free registration to next year’s General Assembly! But hurry, there are only a few days left to enter!

Every year we hold a photo competition and exhibit in association with our open access image repository, Imaggeo, and our annual General Assembly. There is also a moving image competition, which features a short clip of continuous geoscience footage. Pre-registered conference participants can take part by submitting up to three original photos and/or one moving image on any broad theme related to the Earth, planetary and space sciences.

Shortlisted photos will be exhibited at the conference, together with the winning moving image, which will be selected by a panel of judges. General Assembly participants can vote for their favorite photos and the winning images will be announced on the last day of the meeting.

How to enter

You will need to register on Imaggeo to upload your image, which will also be included in the database. When you’ve uploaded it, you’ll have the option to edit the image details – here you can enter it into the EGU Photo Contest – just check the checkbox! The deadline for submissions is 15 February.

Previous winning photographs can be seen on the 20102011, 2012,  2013, 2014, 2015, 2016 and 2017 winners’ pages.

EGU 2018 will take place from 08 to 13 April 2017 in Vienna, Austria. For more information on the General Assembly, see the EGU 2018 website and follow us on Twitter (#EGU18 is the official conference hashtag) and Facebook.

Imaggeo on Mondays: Low tide at Alexandra Fjord

Imaggeo on Mondays: Low tide at Alexandra Fjord

Today’s post takes us to the far northern reaches of our planet, to a desert like nothing you’ve seen before.

This picture is a view to the north across Alexandra Fjord, on the east coast of Ellesmere Island, in the Canadian High Arctic, with Sphynx island in the middle of the fjord. The south shore of Alexandra Fjord includes a polar oasis, an area of tundra vegetation and relatively mild climatic conditions normally found hundreds of kilometres further south. The oasis is surrounded by glaciers and icefields to the south, and polar desert on mountains to the east and west. Polar deserts can also be seen on the far shore in this picture; another scientist working in this area once described to me the ease of “doing geology” from the air due to the lack of plant or developed soil cover on much of the landscape.

The tundra ecosystems of the valley produce and consume greenhouse gases carbon dioxide, methane, and nitrous oxide because of the actions of soil dwelling microorganisms. The surrounding deserts appear nearly lifeless, with only scattered plants sheltered from the harsh winds on barren, rocky ground. Nonetheless, on a per-area basis these deserts contribute nearly as much to greenhouse gas processes as the oasis ecosystems, particularly nitrous oxide.

The surface of Alexandra Fjord freezes completely each winter, to a depth sufficient to support the weight of small aircraft. Researchers visiting this area in April and May land and take off from the ice, but we arrived in late June and used the raised beach cresh that sits some 100 metres inland as our runway. As the 24-hour daylight of summer warms the land and the sea, the ice breaks up and is flushed out towards the Davis Straight to the east. Small pieces of pack ice and small icebergs frequently ground on the shore of the fjord at each low tide, creating a stark and beautiful landscape of ice, land, and water that is best viewed at a distance due to the tendency of polar bears to wander along the shoreline in search of seals and other food.

By Martin Brummell, University of Waterloo, Ontario, Canada

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 epic ‘house’ move across the ice

Imaggeo on Mondays: An epic ‘house’ move across the ice

In 2008 the NEEM Deep Ice Core Project was initiated by 14 partner countries in Northwestern Greenland (camp position 77.45°N 51.06°W) with the aim to drill from the very top of the  Greenland ice cap to its base; obtaining  ice from as far back as the last interglacial period- the Eemian – some 130,000 years old.

At the start of the 2008 field season, the NEEM camp consisted of a single heavy-duty tent, some vehicles, and a skiway. Over the summer months, the facilities could host up to 30 researchers at a time. Extra heavy duty tents were built to accommodate everyone comfortably. However to further ease the work of the many researchers who contributed to the project over several years and to create a common space, ‘the dome’ was build. Spread over three stories, the round black building included a kitchen and eating space on the ground floor, a working and relaxing area on the first floor for and a top floor for observing weather conditions before incoming flights.

After three summers of drilling through the icecap, bedrock was reached in 2010 and the Eemian ice was secured.

The 2011 season was spent on surface programs and some drilling into bedrock. Finally, in 2012 the deep ice core drilling project NEEM was terminated and camp was dismantelled.  Most of the heavy equipment was left on the NEEM site with supplies and equipment stored inside the main dome, in two garages, and on seven heavy sleds. The large dome was put on skis with the intention of moving it to the next drilling site, though exactly where was yet to be determined and  funds also needed to be secured.

In 2015, a group of 12 people, including myself, travelled back to the NEEM site. We packed down the the garages and stored them on sledges, we removed 3 years’ worth of accumulated snow (~1.5 m) from the sledges packed in 2012 and from the 45 ton main dome, and finally made the whole lot ready for moving.  Using specialist snowploughs (known as a PistenBully, sponsored by NSF ) we relocated to our new drilling site, EastGRIP at the North East Greenland Ice Stream (NEGIS).

The trip began on Monday 18th May in the afternoon. Progress was slow. By 20.30 the traverse consisting of 8 vehicles had traveled 24 km along the ice flow divide towards the south-east, towing an incredible  143 tonnes worth of equipment, not including the weight of the vehicles themselves.

After an arduous eight day traverse, on 26th May the convoy made the last 53 km of the journey and arrived at EastGRIP in the afternoon. On arrival, the team only had 3000 litres of fuel left, which would have only supported the traverse for one more day. The total route travelled was 449 km.

The focus of the work at the new ice core camp at EastGRIP is different to that of the NEEM project. While the overall aim is to also drill to the bottom of the Greenland ice sheet, this time the goal is to understand the fast flowing ice at NEGIS.

Ice streams, such as NEGIS, are responsible for draining a significant fraction of the ice from the Greenland Ice Sheet. By drilling to the bottom of the ice sheet the project hopes to gain new and fundamental information on ice stream dynamics, thereby improving the understanding of how ice streams will contribute to future sea-level change. The drilled core will also provide a new record of past climatic conditions from the northeastern part of the Greenland Ice Sheet which will be analysed at numerous laboratories worldwide. Similar to NEEM the project has many international partners and is managed by the Centre for Ice and Climate, Denmark with air support carried out by US ski-equipped Hercules aircraft managed through the US Office of Polar Programs, National Science Foundation.

By Helle Astrid Kjær, researcher at the Niels Bohr Institute,  University of Copenhagen

 

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/