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Imaggeo on Mondays: Living flows

Imaggeo on Mondays: Living flows

There are handful true wildernesses left on the planet. Only a few, far flung corners, of the globe remain truly remote and unspoilt. To explore and experience untouched landscapes you might find yourself making the journey to the dunes in Sossuvlei in Namibia, or to the salty plain of the Salar Uyuni in Bolivia. But it’s not necessary to travel so far to discover an area where humans have, so far, left little mark. One of the last wilds is right here in Europe, in the northern territories of Sweden. Today’s spectacular photograph of the Laitaure delta is brought to you by Marc Girons Lopez, one of the winners of the 2016 edition of the EGU’s Photo Contest!

The photograph shows a part of the Laitaure delta, at the entrance of Sarek National Park (Northern Sweden). Sarek is one of the oldest national parks in Europe and it is often considered to be one of the last wild areas in Europe. The Sami people, however, have traditionally used these lands.

This delta is formed by the Rapa River when it flows into Lake Laitaure. The Rapa River springs from the Sarektjåkkå glacier and is fed by over thirty glaciers. The specific flow of the Rapa River — the ratio between its flow and the area of its catchment — is the highest in Sweden. The magnitude of the flow has strong seasonal fluctuations which are reflected in the sediment transport, which can be as high as 10,000 tons per day during the summer. This heavy sediment load gives the river its characteristics greyish colour. The different colours in the backwater zones may be produced by dissolved organic matter from decomposing vegetation.

The delta in this area is flanked by  patches of montane forests along the river banks in an area otherwise covered by marshes. Regarding the fauna, according to Wikipedia the Eurasian teal, the Eurasian wigeon, the greater scaup, the red-breasted merganser, the sedge warbler and the common reed bunting are common in the Laitaure delta.

By Marc Girons Lopez, researcher at the Centre for Natural Disaster Science, Uppsala University

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/.

 

Going deeper underground – why do we want to know how rocks behave?

Going deeper underground – why do we want to know how rocks behave?

Imagine you find yourself standing atop a wooden box in the middle of your home town, on a rainy weekend day, with the sole aim of talking to passersby about your research work. It can be a rather daunting prospect! How do you decide what the take-home message of your work is: which single nugget of information do you want members of the public to take away after having spoken to you? Even more important still, how are you going to grab their attention in the first place? After all, they’ll be going about their business and not expecting to see you there, on top of your box, least of all talk to you about your work! But if you fancy the challenge, then read on, as Stephanie Zihms, the ECS Representative of the Earth Magnetism and Rock Physics Division, describes her experience doing just that!

Now in its 6th year Soapbox Science is spreading and I was selected to take part in the 1st Edinburgh event on July 24th on The Mound. The weather was typically Scottish but it didn’t seem to bother the crowds and it definitely did not dampen the enthusiasm of the 12 speakers.

I have done a range of different outreach events but I was particularly drawn to Soapbox Science because it specifically promotes female scientists and their work. It was great to meet the other scientists and to see the range of soapbox “performances” as well as the variety of props utilised to showcase each research topic.

Photo taken at the Soapbox Science event courtesy of Sarah Caldwell (smcneem)

Photo taken at the Soapbox Science event courtesy of Sarah Caldwell (smcneem)

The scary thing for this type of event is that you don’t know who might stop, listen & ask questions since we were standing on The Mound in Edinburgh – this also means that your  material has to be accessible and engaging to a wide audience.

Here is what I did to explain my research in geomechanics: Going deeper underground – why do we want to know how rocks behave?

I opted for a big PVC banner showing different heights & depths. With help from the audience I added a picture to each line to show what it represented. I used this banner to set the scene for the type of work I do. I’m a researcher in geomechanics – I want to understand why rocks deform the way they do and what part or component of the rock controls the deformation. The rocks I work with are related to a very deep oil field that lies under 2km of ocean and 5km of rocks. It would take me ~1 hour to run this. At this depth the pressure squeezing the rocks is very high – each square meter of rock experiences the pressure of 16 African elephants per km of depth. So at 5km depths that is 80 African Elephants per square meter.

Under these high pressures the slightest change in conditions e.g. through oil production affects the rocks and changes the distribution of this pressure onto the rocks. I want to understand how different rocks respond to these changes. I do this by collecting rock samples that are easy to get to e.g. from quarries. But they have to be similar to the ones found in the oil field of interest – we call this an analogue (or think of it as a sibling).

Rock sample before it is placed into the Hoek Cell. Image Credit: Stephanie Zihms

Rock sample before it is placed into the Hoek Cell. Image Credit: Stephanie Zihms

In the lab at Heriot-Watt University I have an apparatus that lets me deform rocks under different conditions. The sample, usually a core sample (seeimage above) gets placed into a rubber sleeve before being placed into a stainless steel cell called a Hoek Cell. The space between the rubber sleeve and stainless stell cell is filled with oil that can be pressurised. That way the rock samples can be placed under different pressures that mimic the conditions at different depths. After this initial pressurisation the rock is squeezed in a press until it deforms. When the readings pass a peak value it indicates that the rock sample can’t withstand the squeeze pressure any longer and the test is stopped.

Unfortunatley we can’t see what happens to the rock during the squeezing process but we measure the sample before and after testing – we can also take a x-ray images of the entire sample. We do this with the sample before it is deformed and then again afterwards. This technique lets us see inside the rock – similar to having a x-ray in hospital to see if a bone is broken or not.

Using special computer software we can then look at different parts of the rock’s inside – I am particularly interested in the fractures that formed during the deformation and I’m working on ways to relate these observed features to the rock type, grain size and pore shape.

Why is this important? As I mentioned above I look at rocks related to an oil field – and the response of the rocks to oil production could hinder or help extraction. Oil companies are very interested in predicting the rock response to ensure it does not have a negative impact on oil production.

3D reconstruction of the rock sample using the x-ray images. Image Credit: Stephanie Zihms

3D reconstruction of the rock sample using the x-ray images. Image Credit: Stephanie Zihms

Additionally this research is also relevant to other areas: for example geothermal energy. One method of generating geothermal energy is by pumping water into a rock that is hotter than the surface to increase the water temperature. When this water then reaches the surface it can be used to generate electricity. Adding water into the rock also changes the pressure conditions. Another field is Carbon Capture & Storage – If we want to store CO2 securely and long-term into the subsurface e.g. in a disused gas field – understanding how rocks respond to changes in conditions firstly by removal of gas & secondly by filling the rocks with CO2 is important.

By Stephanie Zihms, Postdoctoral researcher and ECS Representative of the Earth Magnetism and Rock Physics Division.

This post was published under the original title:Going deeper underground – My Soapbox Science Edinburgh contribution, on Stephanie Zihms’ personal blog.

Imaggeo on Mondays: Glacier de la Pilatte

Imaggeo on Mondays: Glacier de la Pilatte

The relentless retreat of glaciers, globally, is widely studied and reported. The causes for the loss of these precious landforms are complex and the dynamics which govern them difficult to unravel. So are the consequences and impacts of reduced glacial extent atop the world’s high peaks, as Alexis Merlaud, explains in this week’s edition of Imaggeo on Mondays.

This picture was taken on 20 August 2009 at the Pilatte Hutt (44.87° N, 6.33° E,  2572 m.a.s.l.), located in the massif des Ecrins in the French Alps. It shows the Pilatte Glacier, which  was recently described as being 2.64km2 wide and 2.6 km long.

As most of the glaciers in the world, the Pilatte Glacier has been retreating over the last decades as can be seen from the two pictures in figure 1, taken respectively in 1921 and 2003, and from quantitative measurements since the 19th century. The glacier has lost 1.8 km since the end of the Little Ice Age (1850).

Figure 1: Retreat of the Pilatte Glacier over the last decades (pictures adapted from Bonet et al, 2005, time series from Reynaud and Vincent, 2000).

Figure 1: Retreat of the Pilatte Glacier over the last decades (pictures adapted from Bonet et al, 2005, time series from Reynaud and Vincent, 2000).

Two climatic variables affect glacier extents in opposite directions: the amount of winter precipitations (which accumulates snow converting to ice on the glacier) and the summer temperatures (which determines the melting altitude and thus the glacier ablation area – the zone where ice is lost from the glacier, commonly via melting).

The initial retreat of the Alpine glaciers in the 19th century can’t be explained by summer temperatures which remained stable until the 20th century. It has thus been explained by a reduction in snowfall . On the other hand, a recent study suggests that industrial black carbon could have triggered the end of the little ice age in Europe, by reducing the glaciers’albedo. But the globally observed glacier retreat from the 20th century is attributed to the increasing summer temperatures.

Figure 2: Global mean temperature series (Oerlemans, 2005, supporting online material)

Figure 2: Global mean temperature series (Oerlemans, 2005, supporting online material)

Understanding the relationship between glacier dynamics and climate enables to use glacier extents  as proxies to reconstruct global temperature time series, as was done by Oerlemans (2005). Using 169 glacier across the globe, this study provided independent evidences on the timing and magnitude of the warming, that are useful to corroborate other time series obtained through other proxies (such as tree rings) or by direct temperature measurements (see Figure. 2), all showing a temperature increase by around 0.5K across the 20th century.

Glaciers continued to retreat in the 20th century, at an accelerating rate. In the 2015 foreword of the Bulletin of the World Glacier Monitoring Service, its director Michael Zemp writes: “The record ice loss of  the 20thcentury, observed in 1998, was exceeded in 2003, 2006, 2011, 2013, and probably again in 2014 (based on the ‘reference’ glacier sample)”. Using climate models, it appears now possible to distinguish an increasing anthropogenic signature in this phenomenon.

Figure 3: Average glacier retreat worldwide from 1980 in mm of water equivalent (mm.w.e), a unit representing the average thickness of a glacier (WGMS website)

Figure 3: Average glacier retreat worldwide from 1980 in mm of water equivalent (mm.w.e), a unit representing the average thickness of a glacier (WGMS website)

One of the many problems caused by glaciers depletion is the impact on water supplies: glaciers are huge reservoirs of fresh water and their vanishings affect drinking water stock and irrigation for the neighboring population. In the Alps, the idea of replacing the glaciers by dams is already studied. This solution would probably be more difficult to implement in other parts of the world, such as in nothern Pakistan, an area covered with over 5000 glaciers, whose melting is already problematic, causing in particular severe floods.

 

By Alexis Merlaud, Belgian Institute for Space Aeronomy, Brussels, Belgium

References

Bonet, R., Arnaud, F., Bodin, X., Bouche, M., Boulangeat, I., Bourdeau, P., … Thuiller, W. (2015). Indicators of climate: Ecrins National Park participates in long-term monitoring to help determine the effects of climate change. Eco.mont (Journal on Protected Mountain Areas Research), 8(1), 44–52. http://doi.org/10.1553/eco.mont-8-1s44

Ravanel, L., Dubois, L., Fabre, S., Duvillard, P.-A., & Deline, P. (2015). The destabilization of the Pilatte hut (2577 m a.s.l. – Ecrins massif, France), a paraglacial process? EGU General Assembly 2015, Held 12-17 April, 2015 in Vienna, Austria.  id.8720, 17.

Reynaud, L., Vincent, C., & Vincent, C. (2000). Relevés de fluctuations sur quelques glaciers des Alpes Françaises. La Houille Blanche, (5), 79–86. http://doi.org/10.1051/lhb/2000052

Pointer, T. H., Flanner, M. G., Kaser, G., Marzeion, B., VanCuren, R. A., & Abdalati, W. (2013). End of the Little Ice Age in the Alps forced by industrial black carbon. Proceedings of the National Academy of Sciences of the United States of America, 110(38), 15216–21. http://doi.org/10.1073/pnas.1302570110

Vincent, C., Le Meur, E., Six, D., & Funk, M. (2005). Solving the paradox of the end of the Little Ice Age in the Alps. Geophysical Research Letters, 32(9), L09706. http://doi.org/10.1029/2005GL022552

Oerlemans, J. (2005). Extracting a climate signal from 169 glacier records. Science (New York, N.Y.), 308(5722), 675–7. http://doi.org/10.1126/science.1107046

Farinotti, D., Pistocchi, A., Huss, M., al, A. A. et, Barnett T P, A. J. C. and L. D. P., Bavay M, L. M. J. T. and L. H., … Zemp M, H. W. H. M. and P. F. (2016). From dwindling ice to headwater lakes: could dams replace glaciers in the European Alps? Environmental Research Letters, 11(5), 054022. http://doi.org/10.1088/1748-9326/11/5/054022

Marzeion, B., Cogley, J. G., Richter, K., Parkes, D., Gregory, J. M., White, N. J., … Adams, W. (2014). Glaciers. Attribution of global glacier mass loss to anthropogenic and natural causes. Science (New York, N.Y.), 345(6199), 919–21. http://doi.org/10.1126/science.1254702

WGMS (2008): Global Glacier Changes: facts and figures. Zemp, M., Roer, I., Kääb, A., Hoelzle, M., Paul, F. and Haeberli, W. (eds.), UNEP, World Glacier Monitoring Service, Zurich, Switzerland: 88 pp

 

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/

Who do you think most deserves the title of the Mother of Geology?

Who do you think most deserves the title of the Mother of Geology?

Much ink is spilled hailing the work of the early fathers of geology – and rightly so! James Hutton is the mind behind the theory of uniformitarianism, which underpins almost every aspect of geology and argues that processes operating at present operated in the same manner over geological time, while Sir Charles Lyell furthered the idea of geological time. William Smith, the coal miner and canal builder, who produced the first geological map certainly makes the cut as a key figure in the history of geological sciences, as does Alfred Wegner, whose initially contested theory of continental drift forms the basis of how we understand the Earth today.

Equally deserving of attention, but often overlooked, are the women who have made ground-breaking advances to the understanding of the Earth. But who the title of Mother of Geology should go to is up for debate, and we want your help to settle it!

In the style of our network blogger, Matt Herod, we’ve prepared a poll for you to cast your votes! We’ve picked five leading ladies of the geoscience to feature here, but they should only serve as inspiration. There are many others who have contributed significantly to advancing the study of the planet, so please add their names and why you think they are deserving of the title of Mother of Geology, in the comment section below.

We found it particularly hard to find more about women in geology in non-English speaking country, so if you know of women in France, Germany, Spain, etc. who made important contributions to the field, please let us know!

Mary Anning (1799–1847)

Credited to 'Mr. Grey' in Crispin Tickell's book 'Mary Anning of Lyme Regis' (1996).

Mary Anning. Credited to ‘Mr. Grey’ in Crispin Tickell’s book ‘Mary Anning of Lyme Regis’ (1996).

Hailing from the coastal town of Lyme Regis in the UK, Mary was born to Richard Anning, a carpenter with an interest in fossil collecting. On the family’s doorstep were the fossil-rich cliffs of the Jurassic coast. The chalky rocks provided a life-line to Mary, her brother and mother, when her father died eleven years after Mary was born. Upon his death, Richard left the family with significant debt, so Mary and her brother turned to fossil-collecting and selling to make a living.

Mary had a keen eye for anatomy and was an expert fossil collector. She and her brother are responsible for the discovery of the first Ichthyosaurs specimen, as well as the first plesiosaur.

When Mary started making her fossil discoveries in the early 1800s, geology was a burgeoning science. Her discoveries contributed to a better understanding of the evolution of life and palaeontology.

Mary’s influence is even more noteworthy given that she was living at a time when science was very much a man’s profession. Although the fossils Mary discovered where exhibited and discussed at the Geological Society of London, she wasn’t allowed to become a member of the recently formed union and she wasn’t always given full credit for her scientific discoveries.

Charlotte Murchinson (1788–1869)

Roderick and Charlotte Murchinson made a formidable team. A true champion of science, and geology in particular, Charlotte, ignited and fuelled her husband’s pursuit of a career in science after resigning his post as an Army officer.

Roderick Murchinson’s seminal work on establishing the first geologic sequence of Early Paleozoic strata would have not arisen had it not been for his wife’s encouragement. With Roderick, Charlotte travelled the length and breadth of Britain and Europe (along with notable friend Sir Charles Lylle), collecting fossils (one of the couple’s trips took them to Lyme Regis where they met and worked with Mary Anning, who later became a trusted friend) and studying the geology of the old continent.  Roderick’s first paper, presented at the Geological Society in 1825 is thought to have been co-written by Charlotte.

Not only was Charlotte a champion for the sciences, but she was a believer in gender equality. When Charles Lylle refused women to take part in his lectures at Kings Collage London, at her insistence he changed his views.

Florence Bascom (1862–1945)

By Camera Craft Studios, Minneapolis - Creator/Photographer: Camera Craft Studios, Minneapolis Medium: Black and white photographic print. Persistent Repository: Smithsonian Institution Archives Collection: Science Service Records, 1902-1965 (Record Unit 7091)

By Camera Craft Studios, Minneapolis – Creator/Photographer: Camera Craft Studios, Minneapolis. Persistent Repository: Smithsonian Institution Archives Collection: Science Service Records, 1902-1965 (Record Unit 7091)

Talk about a life of firsts: Florence Bascom, an expert in crystallography, mineralogy, and petrography, was the first woman hired by the U.S Geological Survey (back in 1896); she was the first woman to be elected to the Geological Society of America (GSA) Council (in 1924) and was the GSA’s first woman officer (she served as vice-president in 1930).

Florence’s PhD thesis (she undertook her studies at Johns Hopkins University, where she had to sit behind a screen during lectures so the male student’s wouldn’t know she was there!), was ground-breaking because she identified, for the first time, that rocks previously thought to be sediments were, in fact, metamorphosed lavas. She made important contributions to the understanding of the geology of the Appalachian Mountains and mapped swathes of the U.S.

Perhaps influenced by her experience as a woman in a male dominated world, she lectured actively and went to set-up the geology department at Bryn Mawr College, the first college where women could pursue PhDs, and which became an important 20th century training centre for female geologist.

Inge Lehmann (1888-1993)

There are few things that scream notoriety as when a coveted Google Doodle is made in your honour. It’s hardly surprising that Google made such a tribute to Inge Lehmann, on the 127th Anniversary of her birth, on 13th May 2015.

The Google Doodle celebrating Inge Lehmann's 127th birthday.

The Google Doodle celebrating Inge Lehmann’s 127th birthday.

A Danish seismologist born in 1888, Inge experienced her first earthquake as a teenager. She studied maths, physics and chemistry at Oslo and Cambridge Universities and went on to become an assistant to geodesist Niels Erik Nørlund. While installing seismological observatories across Denmark and Greenland, Inge became increasingly interested in seismology, which she largely taught herself. The data she collected allowed her to study how seismic waves travel through the Earth. Inge postulated that the Earth’s core wasn’t a single molten layer, as previously thought, but that an inner core, with properties different to the outer core, exists.

But as a talented scientist, Inge’s contribution to the geosciences doesn’t end there. Her second major discovery came in the late 1950s and is named after her: the Lehmann Discontinuity is a region in the Earth’s mantle at ca. 220 km where seismic waves travelling through the planet speed up abruptly.

Marie Tharp (1920-2006)

That the sea-floor of the Atlantic Ocean is traversed, from north to south by a spreading ridge is a well-established notion. That tectonic plates pull apart and come together along boundaries across the globe, as first suggested by Alfred Wegner, underpins our current understanding of the Earth. But prior to the 1960s and 1970s Wegner’s theory of continental drift was hotly debated and viewed with scepticism.

Bruce Heezen and Marie Tharp with the 1977 World Ocean’s Map. Credit: Marie Tharp maps, distributed via Flickr.

Bruce Heezen and Marie Tharp with the 1977 World Ocean’s Map. Credit: Marie Tharp maps, distributed via Flickr.

In the wake of the Second World War, in 1952, in the then under resourced department of Columbia University, Marie Tharp, a young scientist originally from Ypsilanti (Michigan), poured over soundings of the Atlantic Ocean. Her task was to map the depth of the ocean.

By 1977, Marie and her boss, geophysicist Bruce Heezen, had carefully mapped the topography of the ocean floor, revealing features, such as the until then unknown, Mid-Atlantic ridge, which would confirm, without a doubt, that the planet is covered by a thin (on a global scale) skin of crust which floats atop the Earth’s molten mantle.

Their map would go on to pave the way for future scientists who now knew the ocean floors weren’t vast pools of mud. Despite beginning her career at Columbia as a secretary to Bruce, Marie’s role in producing the beautiful world ocean’s map propelled her into the oceanography history books.

Over to you! Who do you think the title of the Mother of Geology should go to? We ran a twitter poll last week, asking this very question, and the title, undisputedly, went to Mary Anning. Do you agree?

By Laura Roberts, EGU Communications Officer

 

All references to produce this post are linked to directly from the text.

 

EGU, the European Geosciences Union, is Europe’s premier geosciences union, dedicated to the pursuit of excellence in the Earth, planetary, and space sciences for the benefit of humanity, worldwide. It is a non-profit international union of scientists with over 12,500 members from all over the world. Its annual General Assembly is the largest and most prominent European geosciences event, attracting over 11,000 scientists from all over the world.

 

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