Thursday, 29 May 2014

Random variables and poetry... by Murray Lark

Murray Lark is back from his annual visit to The Isaac Newton Institute for Mathematical Sciences (INI) and invites you to explore with him some random variables and mathematical poetry...

The INI is a sort of large hadron collider for mathematical sciences, you put mathematicians into it and see what happens when they bump into each other.  The results of collisions are captured on blackboards.  These are on every available bit of wall-space in the INI building, there is even one in the gents!  When I first saw it I assumed that the architect was engaged in a bit of micky-taking.  Be that as it may, it had clearly been put to use.  INI programmes may address abstract branches of pure mathematics, but they also tackle applications where new maths may be needed.  Next year, for example, there is to be a four-month programme on the causes and consequences of melt in the Earth's mantle. 

Unassuming on the outside but inspirational on the inside,
it must be The Isaac Newton Institute for Mathematical Sciences
The INI is funded by five of the UK research councils as a centre of excellence in mathematics.  The institute maintains a network of correspondents at universities and institutes around the UK to keep it in touch with the wider scientific world in which maths is developed and applied.  I am the correspondent for BGS, which means that once a year I get to visit the INI in Cambridge  to hear about its work and to give feedback.

At this year's meeting for correspondents we had an opportunity to discuss the INI's role, and that of maths more generally, with representatives from four of the UK research councils including  NERC, BGS's parent body.  The discussions were informative and encouraging, the importance of maths is clearly appreciated, but did any of the day's activities have any bearing on what I do day to day as Environmental Statistican at BGS?  The answer is yes, but from an unexpected quarter. 

Professor John Barrow (author of "Pi in the sky" and numerous other popular books on mathematics) gave a lecture to show that "Mathematics is Everywhere".  Of the examples he gave to illustrate his point it was, perhaps surprisingly, the mathematical analysis of poetry which connected with my own interests from earth sciences.

A little over 100 years ago the Russian mathematician, A.A. Markov, presented a quantitative analysis of Alexander Pushkin's verse novel  Eugene Onegin.  More recently Brian Hayes repeated the analysis on an English translation, and took it further.  Consider any letter of the alphabet, "a" for example.  When one analyses the text of Pushkin's poem one finds a number of letters that follow "a";  "s", for example, in "was".  One may compute for each of the 26 letters the probability that it succeeds "a".  These are called the "transition probabilities".  The transition probability for "b" as the successor to "a" can be written as P(b|a).   If one computed all the transition probabilities for all the successors to all letters one could then generate "random  Pushkin" by using these first-order transition probabilities to generate random sequences of letters, first-order because we generate a letter by examining its solitary predecessor.  So, for example,  when generating  a letter we examine its predecessor, if that is "a" we then select a new letter at random, with the probability that it is "b" equal to P(b|a), the probability that it is "c" equal to P(c|a), and so on.  An example of first order random Pushkin, generated by Hayes, went "Theg sheso pa lyikly ut."  That may be a true realization of first-order Pushkin rules, but it does not look very convincing.


Hayes computed higher order transition probabilities.  For example, the third-order transition probabilities would give us the probability of each possible successor to groups of three predecessor letters.  The successors of  "fro", for example,  include "n" as in "front", and "m" as in "from".  The complete set of rules assigns transition probabilities to all groups of three letters that occur in the original text, values that we denote by P(n|fro), for example.  Once again, these can be used to generate random Pushkin.  An example of third-order random Pushkin, again from Hayes, goes "At oness, and no fall makestic to us".  It's still gibberish, but it is beginning to resemble English.  Push on to fifth-order transition rules and we have "Farewell.  Evgeny loved one, honoured fate by calmly, not yet seeking".  It won't win prizes, but it is recognizably English, and with something of the flavour of the translation of Pushkin on which it was statistically "conditioned".

So what does this have to do with the geology? 

In the methods of spatial analysis commonly used for earth sciences data we usually work with the statistics of pairs of observations.  That is to say, we represent the variability of a quantity by a mathematical model of the correlations between all pairs of observations.  This is similar to the first-order transition probabilities of random Pushkin, which gives a probability for one letter, given the immediate predecessor.  This works for many tasks much of the time, but not for characterizing all the spatial properties of structured variables such as properties of sedimentary rocks with complex depositional history.  In these circumstances the pairwise correlations alone does not capture, for example, the extent to which  those parts of a rock through which water can flow most rapidly are connected to each other.  That connectivity is very important if we are to predict liquid or gas flows through rock.  This is directly comparable to the way in which the first-order transition probabilities fail to capture  features which would make the random Pushkin recognizable as poetry in English.

One active area of research at BGS is in a field called multiple point geostatistics.  One can think of this as directly analogous with the task of generating probability rules of sufficient order to generate random Pushkin which looks like the real thing.  Our motivation is to be able to capture those features of data sets which control how fluids  flow  through a rock, or how contaminants might disperse in soil.

An example of recent research in this area at BGS is this study on random geometrical models for patterns of soil variation generated by ice wedges that formed in tundra conditions during the last ice age. 
 
http://nora.nerc.ac.uk/503392/  Full text will be freely downloadable after 21st July.

Murray

Tuesday, 13 May 2014

Diamond Light... by Daniel Parkes

from left to right: Jeremy Rushton, myself [Daniel Parkes] and
Tony Milodowski at the Diamond Light Source, Didcot
Following on from the interest in Barry's post about the amazing Diamond facility and the search for carbon here's team member Daniel Parkes to tell us more about the trip...

In late April I was one of a team of four staff from Mineralogy and Petrology to travel down to the Diamond Light Source near Harwell, Oxfordshire. Diamond is the UK’s national syncatron facility; the main building is a huge half-kilometre wide circular structure. The shape is governed by the central ring, which consists of a tube encased in electro-magnets and is used to accelerate electrons to colossal speeds; the electrons at diamond are travelling fast enough to circumnavigate the globe 7.5 times a second. At certain points around the ring different electro-magnets bend the electrons causing them to lose energy in the form of X-rays and long-wavelength light. The generated X-rays and light are directed away from the main ring and down what are known as ‘beam lines’. Each beamline has a unique application and the generated x-rays are used for a wide range of applications ranging from the 3d-imaging of fossil interiors to the study of vaccines and viruses. Our aim was to use the X-rays to investigate and tomographically image the organic matter distribution in soils, in order to better understand the factors controlling microbial mineralisation in relation to the turnover of soil organic matter and global climate change.

In order to image the samples the soils had to be specially prepared by Jo Wragg and Gemma Purser at the BGS. Gemma carried out gas chromatography (GC) on the samples in order to pick four soils with high microbial mineralisation rates (high CO2 production) and four with low microbial mineralisation rates (low CO2 production) Jo Wragg then doped the samples with osmium, osmium was used as it readily binds to organic matter and is considerably denser than the soil, so it was hoped it would give a good contrast images (as x-ray absorption is a function of density) of the organic matter distribution when scanned with the x-rays.

Working hard
Arriving at Diamond on Tuesday night there was a chance for a built of team building in the form of a Nepalise curry and a few character building (for Tony and Jeremy) games of pool. The next day, while the beamline staff set up the experiment, which included calibrating the machine and finding the Osmiun ‘edge’ (the energy at which osmium begins to absorb x-rays), we had a fairy intensive safety course which due to the serious consequences of being trapped in the experimental area or ‘hutch’ when the x-ray beam is switched on, included learning how to carry out a thorough search of the experimental area.

Long hours!
The plan was to carry out the 24 hr (the syncatron is constantly running as it is in such high demand and takes a lot of energy to start up) scanning of the samples in pairs, each working on 12 hr shifts, me and Tony settled down for the first night shift with the initial help and guidance of our dedicated beam line scientist Christina. Unfortunately we ran into a number of contrast related problems with the imaging software that meant it was difficult to correctly align our samples in the beamline, these continued into the following day and were eventually sorted when a fried £10,000 mirror in one of the recording cameras was replaced in classic ‘bodging’ style with a piece of reflective silicon. This allowed us on Thursday night to run all of our samples in one long effort; unfortunately the images that were produced were very blurry due to another mirror being knocked out of alignment when installing the piece of silicon. This meant that on Saturday night after some re-calibration work by the beamline scientist we had to re-run all our samples, thankfully this time we managed to capture an excellent set of data.

Barry Rawlins remained at Diamond for an extra day in order to process the images and is planning to carry out further statistical work in order to investigate the relationship between the amount of microbial mineralisation and the physical isolation of SOM, which will hopefully play a part in the better refinement of models relating to soil structure and organic matter turnover.

Personally the trip was a great opportunity to be involved in a project that allowed me to visit and learn about a fantastic science facility and also be involved in some new research that will hopefully for the basis of some high impact science for BGS. Overall a great experience and if anyone has the opportunity I would thoroughly recommend a trip to Diamond.

By Daniel Parkes

Monday, 12 May 2014

COGER Meeting 2014... by Charles Gowing

Each year around Easter, environmental radiochemists and radioecologists from all over the UK congregate for the meeting of the Co-Ordinating Group on Environmental Radioactivity (COGER). Our Dr Charles Gowing tells us more about this years happenings...
 
This year’s event was hosted in uncharacteristically sunny and spring-like conditions at the University of Lancaster. Combining formal lectures with a convivial poster session and relaxed evening social events provides a welcome opportunity to network with like-minded colleagues and students from universities the length and breadth of the UK and as far afield as Ireland and France.

The COGER meeting is a relatively informal conference providing an ideal platform for research students to experience the joys of presenting their research as well as more experienced researchers covering the more global topics such as the long term impacts of the reactor accidents at Fukushima and Chernobyl. 50-60 delegates were treated to topics as diverse as Naturally Occurring Radioactive Material in industry, radionuclides in sediment transport and 14CH4 migration in soil to genotoxic uptake in mussels and radionuclide uptake in plants. A particular highlight this year was a showcasing of the projects funded under NERC’s “The NERC Radioactivity And The Environment (RATE) Programme”, the secretariat for which is located in BGS Keyworth.
 

Gamma Spectrometry in the BGS Inorganic
Geochemistry Laboratories
I found the range of presentations at this conference appealed across a broad reach of environmental science; my particular interest was sparked by a study of transport and accumulation of nuclides from Sellafield and Parys Mountain into estuarine sediments. The conference was an ideal platform for my presentation on “Dating the Anthropocene: Pb-210 geochronology of river and estuarine sediments from the River Thames”, outlining the work carried out at BGS using gamma spectrometry and mathematical models to interpret the natural radioactivity in a complex river system. It is always rewarding to present to a receptive audience who show an interest in my work and to discuss the potential for using Pb-210 chronology in other estuarine and lake settings.

Next year the COGER meeting is being hosted at the BGS in Keyworth, with accommodation at the University of Nottingham – enhancing the developing links within The Centre for Environmental Geochemistry.

by Dr Charles Gowing (secretary of COGER and a researcher in The Centre for Environmental Geochemistry at the British Geological Survey)

White Ribbons and Morris Dancing on the Jurassic Coast – by Keith Westhead

In April, a BGS scientific team ventured forth to the spectacular Jurassic Coast in Dorset, famous for the geology, habitats, heritage and tourism which combine to make it a UNESCO World Heritage Site. Here Keith Westhead tells us more about their blustery adventures and shows us some amazing field photos and 3D videos...

Panorama of Stair Hole, with the famous ‘Lulworth Crumple’ on the left (pic: Keith Westhead)

Our task was to use the Dorset coast as a test bed for filling the ‘White Ribbon’, as the often-poorly surveyed and studied ‘gap’ between onshore and offshore geology has become known (and after which our own BGS inshore research vessel is named). This work is part of a strategy across BGS to improve both offshore and coastal geological surveying and modelling and relates to the wider Marine Environmental Mapping Programme (MAREMAP). As a reflection of the multi-disciplinary nature of this work, the team included people from across the BGS scientific programmes - Marine Geology (Keith Westhead), Environmental Modelling (Mark Barron), Engineering Geology (Pete Hobbs and Matt Kirkham) and Climate & Landscape Change (Martin Hurst).

BGS and Channel Coastal Observatory scanning teams
discussing tactics (left to right: Matt Kirkham, BGS,
Andrew Colenutt & Sally Hawkins, CCO) (pic: Keith Westhead)
We met in the field with experts from the Channel Coastal Observatory (CCO) and the World Heritage Jurassic Coast team to discuss integrated research and surveying techniques. We are also working with the University of Southampton on extending the work further offshore. On this fieldtrip, teams from both the BGS and CCO carried out co-ordinated high resolution, ground-based laserscans of the geologically famous Lulworth Cove and Stair Hole localities, and also of the large landslide complexes near Lyme Regis. The two surveys at Lulworth and Stair Hole will be combined to produce a collaborative MAREMAP output. As well as being of interest scientifically, these laser surveys will also be valuable for public communication in an area of great geological interest.


Active landsliding in Lias rocks at Crow’s Nest above Lyme Regis; the BGS and CCO have carried out repeated laserscans of this landscape.

Before we headed into the field, we carried out a phase of ‘virtual fieldwork’ back at BGS, using the host of high-quality digital observational data that already exists in this area – one of the reasons for picking the Jurassic Coast as a White Ribbon test-bed. This includes aerial LiDAR (Light Detection And Ranging), aerial photography and bathymetry (Multibeam Echo Sounder, MBES) data for much of the Dorset coastline and offshore area, collected as part of the Dorset Integrated Seabed Survey (DORIS), a collaboration between the Dorset Wildlife Trust, The Maritime and Coastguard Agency, Channel Coastal Observatory, National Oceanographic Centre and the Royal Navy and others. As the aerial LiDAR surveys were carried out (deliberately) at low-tide, and the bathymetry surveys at high-tide, they actually overlap and enable us to produce a seamless elevation surface across the coastline, perfect for geological and geomorphological studies.

This virtual fieldwork was made possible by using together the BGS-Virtalis GeoVisionary and BGS System for Integrated Geoscience Mapping (BGS▪SIGMAv2012) software packages, which enable us to fly around and map on the elevation surfaces, as well as to analyse them in three-dimensions.

video
 
Flying along the seamless elevation surface across the coastline from Weymouth to Lulworth Cove, showing the full form of the coastal White Ribbon but ‘bald’ of geology. This surface was produced in GeoVisionary using data from DORIS (DORset Integrated Seabed survey), a collaborative project involving Dorset Wildlife Trust, The Maritime and Coastguard Agency, Channel Coastal Observatory and the Royal Navy, with major funding from Viridor Credits Environmental Company.  Other partners include Natural England, Dorset Strategic Partnership, the National Oceanography Centre and University of Southampton. (vid: GeoVisionary)


Using BGS▪SIGMAmobile and paper maps to study
landslides above Lyme Regis; left to right: Keith Westhead,
BGS, Richard Edmonds, geologist for the  Jurassic Coast
World Heritage Site and Mark Barron, BGS) (pic: Peter Hobbs)
The use of digital surveying techniques doesn’t stay in the lab, as we can now take much of this digital information into the field using the field version of the BGS digital mapping software - BGS▪SIGMAmobile. One of the aims of this field trip was to collect ground-truthing lines using this method, in order to confirm the virtual surveying. We found this integrated lab-and-field surveying approach to be very useful in improving our maps in steep coastal areas, where accuracy is important, for example, for later cliff instability modelling or coastal erosion studies. It can be a strange feeling, however, to actually visit an area after spending a lot of time flying around it digitally back in the office!
 

BGS’s Mark Barron inspecting Blue Lias Formation limestones
exposed at low-tide on the wave-cut platform in Chippel
Bay, west of Lyme Regis.  These limestones form seabed
features which can be traced for kilometres offshore
using bathymetric surveys. (pic: Keith Westhead)


Of course, you can’t spend time surveying at the coast without venturing out onto wave-cut platforms. We were lucky with the tides (and the weather!) and were able to collect information from platforms in the key bedrock marker sequences along the Dorset coast – the Penarth, Corallian, Purbeck Limestone and Portland Limestone groups, for instance. These ‘harder’ groups of rocks form extensive erosional platforms which can be mapped for many kilometres offshore using the detailed bathymetric data. The morphology of these platforms records a long history of relative sea-level fluctuations along the southern coast of the UK, which is one of our developing research threads. In between these limestone and sandstone-dominated bedrock formations, the softer mudstone-dominated sequences, such as, in the Lias Group or Oxford Clay and Kimmeridge Clay formations, form extensive landslide complexes or low-lying bays.  By surveying these variations, we are aiming to produce an accurate, seamless geological map from onshore, through the cliff-sections, across the wave-cut platforms and into the offshore, which gives the true geological picture of the White Ribbon. We hope this will support a much better environmental understanding of the coast, including how both natural processes and human activities may interact with and affect it.

Initial results of the work include this seamless geological bedrock map of the Purbeck coastline from Lulworth to Worbarrow Bay. The mapping is being extended along the whole Jurassic Coast and up to 20km offshsore. (pic: Keith Westhead, GeoVisionary screenshot)

BGS and CCO colleagues standing on a wind-swept Chesil
Beach at West Bay, Weymouth, discussing the effects of
the winter storms on the beach. The crestline of the beach
has been moved back metres in a single year (left to right: Mark
Barron & Martin Hurst, BGS, Stuart McVey and Andrew
Colenutt, CCO). (pic: Keith Westhead)

We were also able to discuss with CCO colleagues the effects on the coastline of the severe winter 2013-14 storms. One of the key aims of the network of Strategic Regional Coastal Monitoring Programmes (for which the CCO are the data management centre) is to identify and monitor natural coastal hazards, such as landslides, rock falls and coastal response to storm conditions to inform flood and coastal erosion risk management, raise awareness of hazards and inform shoreline management and planning to protect life, properties and coastal communities. Understanding how to depict these aspects of applied coastal science in our geological maps and models is an important part of our White Ribbon investigations.

 

Morris Dancers at the Elm Tree in Langton Herring,
part of our evening’s post-work entertainment.
(pic: Keith Westhead)
So, all-in-all, this was a highly useful fieldtrip, with many new scientific ideas generated on how to ‘fill the White Ribbon’, which will support our efforts to improve geological surveying, modelling and research in the complex coastal zone. So look forward to more blogs from the ‘White Ribbon Team’ on our future results!


‘Fill the White Ribbon’ sounds quite like the name of a Morris dance (but isn’t). Coincidentally, after working extremely hard in the evening to write up our work, the team were able to enjoy, and even participate in, a spot of Morris dancing…but we’ll spare you the video of that!

 




The search for soil carbon... by Barry Rawlins

Last week a team of BGS scientists spent 5 days in one of the worlds most advanced scientific facilities firing light, 10 billion times brighter than the sun, at soil samples! Barry Rawlins explains more about their hunt for organic carbon and why it's so important for the future…

At the UK's synchrotron 'Diamond Light Source' in Harwell we're trying to find where the organic carbon is locked away inside soil aggregates. If we know this we can understand whether the structure of the soil might influence whether it is available for bacteria to feed on. If the carbon is freely available then the organic matter becomes an active source of CO2, and may change with changing climate scenarios.  If the organic matter is locked deep inside the aggregates then it might not be available to bacteria. So different soil types could potentially be sources or sinks of CO2.  It's all about understanding the processes within the carbon cycle.
 
Here's a video explaining exactly what we got up to with our soil aggregates (aka clumps of soil held together by clay and organic matter including bacteria etc) at Diamond:
 

 
We used a chemical (osmium) to stain the organic matter. It is possible using the beamline at Diamond to locate where this osmium and organic matter is in 3 dimensions by scanning the sample at different energy levels using X-ray computed tomography (on the I12 beamline). 
As many visitors find when they visit the beamline, it took us some time to set up our experiment and because the scientists there had recently installed some new optics it took a while to get this working.  Once we were up and running the procedure was really effective.   We worked through the night to capture our data – changing samples at 4am is something I have never experienced before!  We now have nearly 10 terra-bytes of data to process so our results will take some time to generate. 
We did make a short video about the experiments which you can see above, and a short visualization showing where the carbon is in the aggregate (coloured gold) below. The Diamond Light Source is an incredible facility and I am really pleased to have had the opportunity to work there. I hope we'll be writing another blog when we know more from our results.
video
 
By Barry Rawlins, the Team Leader for Sustainable Soils at the BGS

Friday, 9 May 2014

Uncertainty in Vienna... #EGU2014 by Murray Lark

In a previous post Murray Lark discussed some recent work by BGS and the Geological Survey of Ireland on how to communicate uncertain information derived from geochemical surveys. Murray's post got wide attention from colleagues and those in the community so we thought we'd catch up with Murray after his session at EGU2014 and see how it all went:


Good discussions around the poster displays
The EGU meeting was a collaborative enterprise with colleagues from BGS (Fiona McEvoy), Rothamsted Research (Dr Alice Milne) and Wageningen University (Dr Gerard Heuvelink). It brought together statisticians and mathematicians along with earth scientists from a range of disciplines, and a psychologist, Dr Adam Harris, from University College London, who is particularly interested in how uncertain information is perceived. 

To give you a flavour of proceedings here are some questions that came up. Whilst there are no easy answers I've picked out some points from our exciting and lively discussions (facilitated by a great mix of people and interests):


Q1. How do non-specialists interpret the fixed verbal expressions ("likely", "very unlikely","about as likely as not") that the Intergovernmental Panel on Climate Change (IPCC) uses to convey uncertain information to policy makers and the public?  Are the translated expressions interpreted in the same way in different countries?

A1. There is a tendency for non-specialists to interpret the verbal expressions "regressively", that is, large or small probabilities tend to be interpreted closer to "50:50".  That really matters.  For example, when the IPCC recently stated that "It is very likely that there is a substantial anthropogenic contribution to the global mean sea level rise since the 1970sthis means that the probability is over 90% (which is roughly the same as the probability of getting more than one "Head" in ten tosses of a fair coin).  Clearly it matters that voters and politicians clearly understand the strength of the evidence.

Q2. Geological mappers know that the lines they draw on maps are not completely certain, and they take that into account when they interpret maps.  Can we reproduce the expert mapper's understanding of uncertainty to explain the reliability of geological boundaries to data users?

A2. Yes, by using methods of "expert elicitation" groups of geological mappers can sit down and come up (usually) with a consensus  on how to represent their interpretation of uncertainty.  Some soil surveyors at the meeting were keen to join in.

Q3. What kind of statistical plots work best at explaining uncertain information about greenhouse gas emissions to policy makers and industry representatives — and does it depend on how good they were at maths?

A3. Not surprisingly the best way to present uncertain information depends on the kind of question you are asking, and which method you prefer does depend on how good you are at maths.  The take-home message is "know your target audience", but the research identified more specific guidelines too.

Q4. We can use powerful statistical methods to map properties of rocks or soils from data, and the more measurements we make the better the map will be.  Can we show the relationship between numbers of measurements and the uncertainty of the map in a way that will help a non-specialist decide how much money it is worth spending on data collection?

A4. A method to express the reliability of maps of properties on a simple intuitive scale from zero to one has been developed at BGS.  You can read the details here

Please get engaged and leave any questions or thoughts in the comments box below, if you were at the meeting in Vienna what did you think, can you add any more to the Q&A's?

by Murray Lark


For "I know" seems to describe a state of affairs which guarantees what is known, guarantees it as a fact. One always forgets the expression "I thought I knew". Ludwig Wittgenstein "On Certainty" translated by D. Paul and G.E.M. Anscombe.  One morning on the way to the congress I called in on the house that Wittgenstein built for his sister Margaret.

Wednesday, 7 May 2014

The mass exodus of geoscientists to Vienna... by Prof Melanie Leng

Every year around this time a European Geosciences Union (EGU) is held in Vienna, Austria. The weeklong conference brings together geoscientists from all over the world to discuss their latest findings in earth, planetary and space sciences. Melanie Leng attended EGU for the first time this year and here tells us about her experience.

The EGU is a hugely popular destination for geoscientists across the world to get together, discuss and present their latest findings, hold multinational workshops, attend town hall meetings & receive training – all within 5 (long) days. The first problem is the sheer volume of activities and events. For example the presentations alone are divided into 25 disciplines each with dedicated presentations (15 minute talking slots) and poster sessions each day. There are plenaries, award ceremonies, keynote lectures, division meetings, editorial board meetings and short courses (for the truly exhausted there is even a geological cinema)… It is, I admit, a little overwhelming (especially for my first attendance) but all accessible by a Personal Programme app available on all good smart phones!
For me it was a great conference once I got organised with my essential programme including time and place of my talk on carbon stored in Greenland lakes. I was able to meet with international collaborators, hold workshops and brainstorm some of our ongoing projects. For example we were able to put together a working group of researchers interested in the climate history of the South Georgia Island (sub Antarctic) which was attended by people from the UK, Germany, Norway and Sweden – some of whom we had never met before, despite being interested in the same research. Through this core group we think we can bring everyone together and make our individual efforts collaborative at the International scale, an outcome that will surely speed our science impact.

Overall there were 28 BGS staff at EGU, everything from the science of soils, landslides, carbon capture and storage, environmental change, geochronology and archaeology. The meeting was so big (12,000 delegates) I didn’t get to see much of anyone as we were all in on different sessions. Hopefully everyone had a useful week and look out for our research papers to come later this year.
By Prof Melanie Leng is a Science Director in Geochemistry at the British Geological Survey and University of Nottingham.

More info on EGU, and their twitter @EuroGeosciences

Spring into Iceland... by Erica Dewell


Virkisjökull and its sandur
Todays update from Iceland comes from intrepid guest blogger Erica Dewell, an MSc student at the University of Dundee...

Hello from the latest field campaign at the BGS's glacier observatory at Virkisjökull in southeast Iceland. We’re a diverse group here this trip, with people hailing from BGS, University of Dundee, Wallingford Hydrosolutions, and Helsinki University & Technical Research Centre of Finland VTT. Our home here is wonderfully situated below a waterfall and between two glaciers: Svinafellsjökull, and Virkisjökull. For all the Game of Thrones nerds reading, you might be excited to know that Svinafellsjökull happens to be where the scenes North of the Wall were filmed!
 
Svinafellsjökull, aka North of the Wall
The activities have been as diverse as the group, with sediment sampling, stream flow gauging, ablation stake measuring, and piezometer data downloads all happening on our first working day. Since then, we’ve continued to do more of the same, with the addition of dye tracing tests on Fallajökull and Virkisjökull, groundwater and surface water chemistry sampling, and the collection of microbiological samples from groundwater, springs, the river, the lake, snow, and ice. In general the activities here are related to the holistic study of the catchment system, specifically as it relates to a rapidly melting glacier. The microbiological component was new this trip: it is to assess the changes in microbial communities, mainly through molecular biology based on DNA.
 

Groundwater chemistry sampling
Half of the group had never been to Iceland before this trip, and are completely charmed by the waterfalls, volcanic rocks and the gorgeous, albeit odd, landscape. Iceland provides quite a stark contrast of scenery in a very short distance, with the flat, barren sandur just in front of the steep iced slopes of Virkisjökull and its surrounding mountains. Most feel as though we’re on a trip to the Moon or Mars, but love this weird world we landed in.

The Virkisjökull glacier is particularly impressive, and is one of the many places in Iceland where the power of nature is so evident. Looking like a mix of Mordor and the North Pole, Virkisjökull provides great views when eating lunch. It’s a really ice-olated place (sorry), and is very quiet besides the sounds of meltwater flowing into moulins and the occasional creak of an imminent icefall. Despite the dangers of snow-covered crevasses, we were quite safe and well prepared with Verity’s clever system of roping up the group of three that head to the glacier. Impressively, when one of the three simulated falling down a crevasse (by running hard in the opposite direction), the other two barely felt the impact, as the rope holds and absorbs the weight of the fallen ice-climber. Fortunately, this has not been tested with a real crevasse yet. The team was also introduced to the system of crocheting the rope together after use, so that it doesn’t tangle, and is easy to unravel (not to mention, really fun to do). Despite the sore feet that come with climbing glaciers, the views and fun are definitely worth it.


Testing the Ropes



Crocheting Safety Ropes





Dye Tracing Tests in a Moulin

The glacial river, Virkisá, has been gauged on several occasions throughout the trip, and has produced its fair share of challenges each time, the most memorable of which include unintentionally fishing for rocks with the tape measure (and having to cut the tape as a result), having the current flowing so strong it carried pieces of the flow gauging equipment away with it and having a shorter member of the team state “I can’t feel the bottom!!” while “trolling” beneath the bridge.

In the other extreme of the terrain, the sandur, other members of the team were busy digging pits to collect sediment samples. The samples have to be dried before they are sorted, so that has resulted in baking a lot of dirt …
 
Yum – rock cakes!
Fortunately, the array of cuisine has been quite the contrary - we’ve had lots of delicious meals. It did feel like we were moving into the extreme and remote wilderness of Iceland after we carried two overflowing grocery trollies worth of food into the house with us. Other than the fact that we will soon be out of bread, we’ve done pretty well in our portioning! The trip will likely be remembered as a blur of chocolate raisins, glacier views, caramel wafers, volcanic sediment inhalation, mid-afternoon sardines, second lunch, sour cream and onion crisps, which were all enjoyed in the varied astonishing surroundings… Oh, and the fieldwork!

by Erica Dewell, MSc student at the University of Dundee

Friday, 2 May 2014

Tales from the Underground... by Andy Farrant

 
Looking up into the roof of Deer Cave,
home to 3 million bats
Deep beneath the jungles of Borneo are some of the worlds most spectacular cave systems and right now our intrepid geologist and caver Dr Andrew Farrant is exploring and surveying deeper than ever before...
  
It is dark when I wake up. Pitch dark. Above I can hear hundreds of swiftlets chattering in the dark, finding their way through this, one of the biggest cave systems in the world. Turning my light on, tell-tale glints of light down the passage mark the location of Huntsman spiders lying in wait for an unsuspecting cave-cricket, their eyes reflecting my light. Rising above is the huge void of Hyperspace, a massive chamber over 100 m across lying hidden beneath the tropical rainforests of the Gunung Mulu National Park in Sarawak. Today, we are heading out to daylight after a 3 day camp in Clearwater Cave. At around 200 km long, it is one of the top ten longest caves in the World.


Returning to daylight. At the entrance after 3 days
underground. L-R: Carl Clark, Tony Radmell, Professor
Peter Smart, Dr Andy Farrant (photo Fran White)

It has been 23 years since I last trod this spot, when I was a young postgraduate student at the University of Bristol, and today my former PhD supervisor (Professor Peter Smart) is in our team. Yesterday we had pushed a passage which led into 1.6 km of new cave, eventually emerging at a fine entrance high above the Melinau Paku valley, surveying as we went. Ancient gravels, long abandoned by the formative stream and now perched 300 m above the Clearwater River littered the passage floor, sometimes capped by stalagmites. The gravel composition, imbrication and cross bedding combined with dissolutional flow markings on the passage walls yield clues to the direction of water flow and the discharge of this ancient river. It is these stalagmites and sediments that provide the key to the age of these caves.



Weathered remnants of volcanic ash deposits; here
they once filled this passage, but have been subsequently
washed out, leaving remnants on the cave roof
Stalagmites can be dated by Uranium series dating and hence give a minimum age for the passage. Relict sediments in high level passages such as the one we had just found preserve evidence of palaeomagnetic reversals, the last occurring around 780,000 years ago. The data suggests that the highest caves are probably 2-3 million years old. Combining the Uranium series and palaeomagnetic chronology with observations of sediment and cave geomorphology enables a record of landscape evolution to be constructed in an area where all the surface evidence has long been destroyed. Elsewhere in Clearwater Cave, deposits of waxy white clay are remnants of volcanic ash deposits washed down into the cave (photo right). These bear witness to massive volcanic eruptions that periodically blanketed this part of Borneo with thick deposits of ash over the past few million years.

 
Looking out of the Secret Garden entrance to Deer Cave;
the immense size of the passage (nowhere less than 100m
high) can be gleaned by the rainforest trees in the entrance
This time, the research is focussed on investigating the swiftlet and bat guano upon which the rich cave ecosystem depends ['bottom' photo for those with strong stomachs- ed]. Faecal sterols within these deposits have the potential to act as geochemical markers, whilst the acidity generated by guano decay alters the limestone and contributes to cave enlargement. A key site for this study is Deer Cave. Over 3 million bats live in the roof of this huge void, which at over 100 m high and wide is the biggest passage in the World. Yet the guano piles are less than a metre deep, highlighting a rapid recycling rate by the myriad of insects that live in this twilight zone.

Back at the base camp at the National Park HQ, other members of the expedition return with tales of yet more kilometres of huge passage discovered; all providing additional clues about the tectonic, climatic and landscape evolution of this part of Southeast Asia.


Thanks to Andy Eavis and members of the Mulu Caves 2014 expedition, to the Gunung Mulu National Park and the Sarawak Forest Department.


More details can be found at http://www.mulucaves.org/
Andy Farrant


The guano from 3 million bats hosts a diverse ecosystem within Deer Cave, including cockroaches, spiders, centipedes, crabs and cave crickets