GeoLog

Imaggeo

Imaggeo on Mondays: Sunset over the Labrador Sea

Ruby skies and calm waters are the backdrop for this week’s Imaggeo image – one of the ten finalist images in this year’s EGU Photo contest.

 Sunset over the Labrador Sea. Credit: Christof Pearce (distributed via  imaggeo.egu.eu)

Sunset over the Labrador Sea. Credit: Christof Pearce (distributed via imaggeo.egu.eu)

“I took the picture while on a scientific cruise in West Greenland in 2013,” explains Christof Pearce, a postdoctoral researcher at Stockholm University. “We spent most of the time inside the fjord systems around the Greenland capital, Nuuk, but this specific day we were outside on the shelf in the open Labrador Sea. The black dot on the horizon toward the right of the image is a massive iceberg floating in the distance.”

Pearce took part in a research cruise which aimed to obtain high-resolution marine sedimentary records, which would shed light on the geology and past climate of Greenland during the Holocene, the epoch which began 11,700 years ago and continues to the present day.

A total of 12 scientists and students took part in the Danish-Greenlandic-Canadian research cruise in the Godthåbsfjord complex and on the West Greenland shelf. By acquiring cores of the sediments at the bottom of the sea floor, the research team would be able to gather information such as sediment lithology, stable isotopes preserved in fossil foraminifera – sea fairing little creatures – which can yield information about past climates, amongst other data. One of the main research aims was to learn more about the rate at which the Greenland Ice Sheet melted during the Holocene and how this affected local climate conditions and the wider climate system.

“The picture was taken approximately 25 kilometres off the shore of west Greenland coast. In this region the water depth is ca. 500 meters,” describes Pearce. “At this location we deployed a so-called gravity corer and took a 6 meter long sediment core from the ocean floor. Based on radiocarbon measurements – by measuring how much carbon 14 is left in a sample, the age of the sampled units can be known – we now know that these 6 meters correspond to approximately 12000 years of sedimentation, and thus it captures a history of climate and oceanography from the last ice age all the way to present day.”

 

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/.

Studying an active volcano – in pictures

Studying an active volcano – in pictures

Santiaguito volcano in Guatemala is one of the most active volcanoes in Central America: currently erupting every 45-90 mintues, from its active lava dome Caliente, while at the same time sending a lava flow down its flanks. This makes it an ideal study object for volcanology. A group of volcanologists from the University of Liverpool, in the UK, installed a network of geophysical stations around the volcano in November 2014, (you can find out more about that trip here). They’ve since been back to Guatemala to download the data recorded by the stations and carry out some maintenance. This photo diary blog post, by Felix Von-Aulock, a postdoctoral researcher at the University of Liverpool, gives a snap shot of what it is like to carry out research on an active volcano: it’s challenging, packed full of adventure and rewarding in equal mesure!

Image credit: Felix Von-Aulock

Image credit: Felix Von Aulock

The Institute for Seismology, Volcanology, Meteorology and Hydrology (INSIVUMEH) are working hard to deliver updates on the activity of at least 3 erupting volcanoes to public, governmental bodies, and scientists. They do a really good job, despite the constant lack of funding, personel and equipment. This is our first stop on our way to Santiaguito, picking up equipment we left here last time, and catching up with Gustavo Chigna, a volcanolgist at INSIVUMEH.

Image credit: Felix Von-Aulock

Image credit: Felix Von Aulock

A few hours drive from Guatemala City, we finally see our destination, the Cerro Quemado/ Almolonga complex, with Santa Maria volcano (the tallest peak) in the background.

Image credit: Felix Von-Aulock

Image credit: Felix Von Aulock

It’s not all about the science! Guatemala is one of the biggest producers of coffee in the world and a lot of the volcanoes are surrounded by coffee plantations.

Image credit: Felix Von-Aulock

Image credit: Felix Von Aulock

While the volcanoes produce very fertile soils for the coffee to grow on, they can be very destructive. This farm at the base of Santiaguito has faced major hazards from lahars – torrents of hot or cold water, laden with rock fragments, ash and other volcaninc debris which hurtle down the flank of a volcano or valley following an eruption.

Image credit: Felix Von-Aulock

Image credit: Felix Von Aulock

The canyons fromed by the lahars cut right through the farm and the workers’ homes.

Image credit: Felix Von-Aulock

Image credit: Felix Von Aulock

Another hazard faced by the local communities is that posed by pyroclastic flows: high-density mixtures of hot, dry rock fragments and hot gases that move away from an eruptive volcaninc vent (as defined by the USGS).
Pictured above is the flow path of the pyroclastic flow of May 2014. The  flow paved the way for many Lahars which formed this canyon. The pyroclastic flow also nearly wiped out the volcano observatory and missed it only by 20m.

Image credit: Felix Von-Aulock

Image credit: Felix Von Aulock

In total we deployed 11 stations around the volcano. This trip’s main purpose was to maintain them and download the data aquired since they were installed in November 2014. We were excited to find that the first station we visited had actually been recording data until the week before we arrived. We were less excited to discover that bean plants were being planted right next to it, possibly leading to some ploughing noise in our data.

Image credit: Felix Von-Aulock

Image credit: Felix Von Aulock

Our room, three hours after our arrival. The chaos didn’t vanish, however, the smell got increasingly bad after 2 weeks of three guys sharing this room. Amongst the chaos, lots of expensive equipment and a kitten!

Image credit: Felix Von-Aulock

Image credit: Felix Von Aulock

After sorting out supplies and taking care of the stations at the base of the volcano in Quetzeltenango, we finally started our hike towards the active dome. While we (Felix Von-Aulock, pictured in the far right and Adrian Hornby, a volcanology PhD student, picture in the centre) went down towards Santiaguito Dome, Oliver, also volcanology PhD student, (pictured second from the right),  went to the top of Santa Maria to film with a thermal camera. Don Geronimo, on the far left, is a local who helped Oliver carry equipment and water to the 3700m high peak. Armando Pineda (second f. l) was our guide down the tricky path to the dome.

Image credit: Felix Von-Aulock

Image credit: Felix Von Aulock

It feels good to be finally walking after weeks of preparation and travelling, despite the packs being pretty heavy and the long day ahead of us.

Image credit: Felix Von-Aulock

Image credit: Felix Von Aulock

The first two days were hard work: a constant mix of rain and sun, heavy packs we were not quite used to yet and some extra walks made us feel sore pretty quickly.

Image credit: Felix Von-Aulock

Image credit: Felix Von Aulock

When there was rain, the sun would come out quickly thereafter and the beautiful surrounding made up for the hard work.

Image credit: Felix Von-Aulock

Image credit: Felix Von Aulock

A morning view from our campsite below the chain of domes that was formed during the last century. The riverbed below had a pretty decent river in it just the night before during a thunderstorm. We got caught by that thunderstorm, trying to move car batteries uphill, but luckily decided to turn around to the tent before the river and potential lahars would cross our route.

Image credit: Felix Von-Aulock

Image credit: Felix Von-Aulock

The valley that leads to the active dome (Agua de Caliente) is an always changing channel, washed out by the frequent lahars. Good to have an experienced guide like Armando with us.

Image credit: Felix Von-Aulock

Image credit: Felix Von Aulock

The combination of a thin layer of ash and the frequent rain made some sections a bit tricky with the heavy packs.

Image credit: Felix Von-Aulock

Image credit: Felix Von Aulock

Here we’re digging out the first station, from here on we need to wear helmets as we’re about 300m from the active dome.

Image credit: Felix Von-Aulock

Image credit: Felix Von Aulock

The stations combine measurements of the sound (infrasound), the volcano’s seismicity and the tilt of the flanks of the volcano.

Image credit: Felix Von-Aulock

Image credit: Felix Von Aulock

The volcano is erupting frequently and every hour or so, we can see an ash plume rising into the sky above our heads.

Image credit: Felix Von-Aulock

Image credit: Felix Von Aulock

An eruption of the lava dome of Santiaguito observed from our tent around 300m from the crater.

Image credit: Felix Von-Aulock

Image credit: Felix Von Aulock

We also brought along a little quadcopter to take pictures of the dome. And although it was not the main subject of our mission it proved quite successful (we didn’t crash it!) Trying to follow a tiny spot in the sky is not easy though. And I just kept thinking:

“This must be one of the best jobs in the world, flying a little helicopter over an active volcano!”

By Felix Von Aulock , Postdoctoral researcher at the University of Liverpool

We are grateful to Rüdiger Escobar-Wolf for helping us improve an earlier version of this blog post.

Do you have some stunning field work photographs that you’d like to share with the wider community? Why not upload them to the EGU’s online open access geosciences image repository, Imaggeo? 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/

Field work is an intrinsic part of the geosciences and yet the stories behind data aquisition are often left untold in scientific publlications. If you’d like to share your field work and/or lab tales, we’d love to hear from you! Part of what makes GeoLog a great read is the variety that guest posts add to our regular features, and we welcome contributions from scientists, students and professionals in the Earth, planetary and space sciences. Got an idea? If you would like to contribute to GeoLog, please send a short paragraph detailing your idea to the EGU Communications Officer, Laura Roberts  at roberts@egu.eu.

 

Imaggeo on Mondays: A voyage through scales – The Badlands National Park, South Dakota.

Imaggeo on Mondays: A voyage through scales – The Badlands National Park, South Dakota.

Layer upon layer of sand, clay and silt, cemented together over time to form the sedimentary units of the Badlands National Park in South Dakota, USA. The sediments, delivered by rivers and streams that criss-crossed the landscape, accumulated over a period of millions of years, ranging from the late Cretaceous Period (67 to 75 million years ago) throughout to the Oligocene Epoch (26 to 34 million years ago). Interbedded greyish volcanic ash layers, sandstones deposited in ancient river channels, red fossil soils (palaeosols), and black muds deposited in shallow prehistoric seas are testament to an ever changing landscape.

Fast forward to 500,000 years ago and the landscape was very different. The Cheyenne River diverted the flow of the ancient small streams and rivers down its own river bed, in a geomorphological process called capture. The destructive power of the river dominated over the deposition of sediment. The river cut through the layers of sediments and produced the stunning landscape preserved today.

“The picture was taken in 2009 as I made a road trip with my brother across the United States, from Chicago to San Francisco,” explains Iain Willis, author of today’s Imaggeo on Mondays photograph. “After a long day’s drive, we approached the edge of the Badlands in the late afternoon after turning off route 90. I took the picture of my brother after we’d taken a short walk across a couple of peaks. I didn’t think the picture would be so dramatic as it was actually pretty overcast but as I was setting up the sun was momentarily piercing through. I originally shot in colour but after seeing it in monochrome, it looked far more dramatic.”

Dramatic enough for the judges of this year’s Imaggeo Photo Competition to award Willis the prize for the image which best represented the theme of the 2015 General Assembly: A Voyage through Scales.

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: Just Passing

Imaggeo on Mondays: Just Passing

If lucky enough to visit Ilulissat Icefjord, you’d find yourself in a truly ancient landscape. From the up to 3.9 billion year old Precambrian rocks, to ice dating back to the Quaternary Ice Age (2.6 thousand years old) and archaeological remains which evidence the past settlement of this remote Greenlandic outpost, it’s no surprise this stunning location has been declared a UNESCO world heritage site.

Today’s Imaggeo on Mondays photograph was taken by Camille Clerc, at Sermermiut, an old inuit settlement at the mouth of the Ilulissat Icefjord. Located 1,000 km up the west coast of Greenland, in the Bay of Disko Bugt, 250 km inside the Arctic Circle, the icefjord is the sea mouth of Jakobshavn Glacier – one of the few glaciers on Greenland which reaches the sea. Confined either side by ancient Precambrian rocks, the icefjord forms a narrow, 3-6 km wide tidewater ice-stream, where vast amounts of meltwater and ice from the Greenland ice-sheet reach the sea.

Jakobshavn (also known as Sermeq Kujalleq) is Greenland’s fastest moving glacier. Huge chunks of ice break off the glacier front via Ilulissat Icefjord in a process known as glacier calving. Annually, over 35 km3 of ice is calved into the sea; equivalent to 10% of the production of all Greenland calf ice and more than any other glacier outside Antarctica! As a result, there is an almost constant production of icebergs, which vary in size from small lumps to bergs which can exceed 100m height. As they make their way towards the sea, the icebergs actively erode the fjord bed, slowly changing its morphology over time.

The tragic sinking of the Titanic on its maiden voyage, as a result of a collision with an iceberg on the night of the 15th April 1912, is part of modern history and was even portrayed in a Hollywood blockbuster. Could one of the mighty icebergs calved from Jakobshavn via Ilulissat Icefjord, be the culprit of the sinking of the White Star Line vessel? Pinpointing the exact location from which the glacier was calved is tricky. Most icebergs found in North Atlantic waters originate from the western coast of Greenland. They are pushed slowly towards more northerly latitudes by the West Greenland Current and then forced towards the Atlantic, hugging the coast of Canada, by the Labrador Current, eventually making their way to the Gulf Stream, along one of the world’s busiest shipping routes. The journey there is long and more often than not, the icebergs take such battering during the voyage that their original size is much diminished.

 

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/.

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