Wednesday, 31 October 2012

Searching for the origins of Life on Land by Tim Kearsey

How our ancestors (4 limbed vertebrates) came out of the swamps and adapted to life on land some 360 million years ago is still poorly understood, despite what adverts for Irish Stout may suggest! We don’t know how lungs, ears and other adaptations for land evolved (it appears legs evolved in the water).The main reason for this is there is a gap in the fossil record covering this critical interval in our evolution, known as Romer’s Gap.

Over the last two weeks I have been doing the first bit of fieldwork as part of a large 4-year project with scientists from the Universes of Cambridge, Leicester, Southampton, and the National Museum of Scotland on a set of unique locations in the Scottish Borders which are yielding fossils which could fill in this gap.  Some tantalising glimpses have already been found but in the next 4 years we hope to shine a torch on this pivotal stage in the evolution of life.

My job over the last two weeks was, with Carys Bennett from Leicester University (see her blog at www.tetrapodworld.com), to measure and describe the sedimentary rocks in which the fossils were found.

Dr. Sarah Davies, Dr. Carys Bennet and Prof. John Marshall Sampling at sunset – a must on tidal sections.

Hang on - I thought you were looking for fossil! Why do you need to look at the rocks as well??

Yes, the fossils are being looked at (by the team from Cambridge University) but to understand the evolution of these animals the context has to be understood too.
What I was doing is very similar to what an archaeologist does; a ancient piece of jewellery may be interesting on its own, but only by understanding the buildings and layers that it was found in can you work out how old it was and what it can say about the type of people who may have owned it.
The same is true of sedimentology;   by understanding the sediments we can firstly work out fundamental things like which fossil is older than another. This will then allow us to track the evolutionary changes as these creatures adapted to life on land. Secondly, through reading the rocks we can understand the environment in which these vertebrates were living, and how it changed through time.  This may help to explain why they came on to land rather than just how.

Fossilised roots (the black lines in the white sandstone) – key to building up a picture of the environment the fossils lived in

So what were you doing?

To start off with I have been sedimentary logging. A sedimentary log is an illustrative representation of the sedimentary rocks in the sequence you are studying. It is in effect a column that is drawn from oldest rocks at the bottom to youngest at the top, with the rock units stacked on top of each other in sequence (see Cary’s blog for more details www.tetrapodworld.com). Also we have been sampling for a range for fossil plant spores (palynology) and to understand how the rocks formed better using a range of microscopic and chemical techniques which will help us understand the environment the rocks were formed in.


Me (left with a dGPS) and Sarah Finney collecting specimens (courtesy of Rob Clack)

This is only the first stage in a large programme of investigations. In 2013 we will be drilling a 500 metre borehole as well as doing many more fossil excavations to hopefully finally understand how, and why, our ancestors came on to land some 360 million years ago – Watch this space for more updates.

Tuesday, 23 October 2012

Comment on the L'Aquila verdict by Dr Roger Musson

BGS has received a number of requests for interviews following the announcement that six Italian scientists and one government official have been charged with manslaughter following the L’Aquila earthquake in 2009 in Italy.
The geological community is concerned after yesterday's verdict, that outcome of the L' Aquila trial will inevitably compromise the relationship between scientists concerned with natural hazards, and the public and state.
The background to this is that in the spring of 2009, a series of small but highly perceptible earthquakes were being felt in the central Italian city of L' Aquila and the nearby villages. As there was much public concern about whether these earthquakes were building up  to something worse, a meeting was called at which six scientists and one government official from in the civil protection agency were summoned to give advice. The six scientists were people at the top of the engineering seismology community in Italy, people of the highest international standing.
There were two possibilities to deliberate. Firstly, it sometimes happens that a large earthquake is preceded by a series of smaller ones. The term for these events is foreshocks. Secondly, it sometimes happens that a series of intense small earthquakes occur and die away again without any large event. Seismologists call this a swarm. There is no measurable property that distinguishes a foreshock from a common small earthquake. The panel noted two things, based on historical experience. Firstly, swarms are not uncommon in Italy. Second, large earthquakes in Italy usually do not have foreshocks. Hence, on the balance of probabilities, the L' Aquila events were more likely to be a swarm and would die away without any large event.
They were careful to add that L' Aquila is in a well-known area of high seismic hazard, and it was always possible that a strong earthquake could strike at any moment.
The offical from the Dept of Civil Protection, who was not a seismologist, gave a TV interview, in which he stated that the small earthquakes were acting as a safety valve by releasing energy; consequently a large earthquake was now unlikely; therefore residents could relax and have a nice glass of wine.
There is no basis for such a statement, and this is why: the energy involved in a 6.3 magnitude earthquake like the one that struck L' Aquila a few days after the scientists met,  is about 50,000 times more than any of the small earthquakes. Therefore the sequence that had been felt up to that date had barely skimmed off the slightest fraction of the energy available.
The statements made in the TV interview were taken by many inhabitants of L’ Aquila as a sign that they had nothing more to fear, an assumption that proved incorrect when the earthquake struck a few days later.
The verdict of this trial is not about the science of predicting earthquakes, but about the communication of risk to the general public. 

Roger Musson

Thursday, 18 October 2012

Hospital Appointment for Fossil Fish

Scottish Pavement Fish Project
To date, twenty remains of fossil fish and plants from the Devonian Caithness flagstones lining the streets of Edinburgh have been found. With more areas within Edinburgh to explore (the Edinburgh International Climbing Arena at Ratho) we don’t doubt that more will be found. And that is just in Edinburgh! Caithness flagstones have been used in the pavements of Glasgow, Aberdeen, Dundee, London, Paris and even Beunos Aires! See the last project post for more details of the project and pictures of our Edinburgh finds.
 It’s been a busy fortnight for The Scottish Pavement Fish Project. Myself [Dr Tom Challands (Geovertical)] and Jeff Liston (National Museum of Scotland) visited the Scottish Parliament on Tuesday 2nd October  to discuss the rescue and conservation of two fine fossil fish specimens lying in the flagstones right on the doorstep of the parliament building.

Scottish Parliament building

Jerry Headley, Group Head of Facilities Management, Events and Exhibitions and Visitor Services at the Scottish Parliament, took us around the parliament building to look for further fish specimens in the Caithness flagstones that line the floors and interior courtyards. Fortunately for the parliament, and possibly for us, no more were found and it looks likely that the two slabs will be lifted when building work on a new security hall extension to the front of the parliament begins in the coming month. Once the specimens have been prepared and studied they are likely to go on display inside the Scottish Parliament.  Many thanks to the police officers on duty outside the parliament for initiating this meeting!!



National Museum of Scotland
Pantak Industrial X-ray machine



The following day saw one of the specimens being taken to the National Museum of Scotland (NMS) for X-raying. X-raying is an extremely useful technique to use before preparation begins on the specimen because it allows you to view where fossil is hidden beneath the surface of the rock and therefore get a detailed picture of how much preparation is needed. This way the correct tools can be chosen rather than having to experiment directly on the specimen itself. Analytical conservator Lore Troalen very kindly spent the day testing and experimenting with various voltages, current strengths and filters to obtain images that revealed not only the internal structure of the fossils but of the rock itself. The X-ray facility at the NMS is unique for its size and the density of material that the x-rays can penetrate. Most conventional medical x-ray machines will only emit relatively low-powered x-rays as living tissue is easily penetrated by x-rays and also there is a significant risk to health from exposure to high-powered x-rays (radiation burns). Despite being thirty years old the NMS Pantak Industrial X-ray machine is one of a kind in Scotland and an invaluable resource for archaeological, palaeontological and industrial analysis. Sadly, it may be decommissioned soon and are no plans to reinstate the machinery. If this was to happen it would mean a valuable research resource is lost to science in Scotland.

Flagstone being CT-scanned at the
Royal Hospital for Sick Children











A week later one of the fish extracted from East Market Street and another large specimen found in Spittal Quarry, Caithness, were taken to the Royal Hospital for Sick Children in Edinburgh for CT-scanning. CT-scanning allows us to view inside the rock and fossil prior to preparation similar to standard x-raying but it also allows us to build a 3D computer model of the fossil. This fantastic opportunity for the project came to be through the BGS Open Day at Murchison House held back in September. Thank you very much to radiologist Jen Matrundola for suggesting we scan the pavement fish and also to radiographer Dr Michael Jackson for assisting in the scanning and 3D reconstructions. The information from these scans will hopefully allow us to view the underside of the fish which has to remain in the rock because the fossil is so fragile. Results of the scans will be posted as soon as all the data processing has been completed.

The next stage of the Scottish Pavement Fish Project is to secure funding for the preparation of the fossils. Because the specimens are so delicate and intricate, preparing the fossils using micro-drills and micro-sand blasters takes a great amount of time. We are currently looking for funding to pay a preparator for this job which could take up to six months to prepare all the specimens. In the mean time there are plenty of pavements around Scotland to search for more interesting finds in as well as another trip up to the quarries in Caithness where the paving slabs originate from. Spittal Quarry are currently excavating the horizon that yields the fossil fish so we intend to pay another visit to see if they match the fish we find in the paving slabs of Edinburgh.
Keep watching for more updates, photos and the exciting CT scan results!!
Tom
Dr Tom Challands
Geovertical
@geovertical  
facebook.com/geovertical

info@geovertical.co.uk

Wednesday, 10 October 2012

The Frozen Deep & Roger Moore’s eyebrows by Andy Farrant

Caves aren’t just holes in the ground. They are also valuable geological archives. The type of cave, its shape, length, morphology, along with the sediments and stalagmites they contain, all provide information on past climates, hydrology and landscape evolution. Moreover, these archives are preserved intact for millennia, protected from surface weathering, erosion and bioturbation. Cave sediments and stalagmites can also be dated, thus enabling these archives to be set in their rightful chronological context. So, when the BBC asked me to film a piece for ‘The One Show’ on the geology of a recent discovery in a cave in Cheddar Gorge, it was too good an opportunity to pass up.

Preparing to go down the cave. Left to right: Nick Chipchase (digger), Andrew Atkinson (cave surveyor), Miranda Krestovnikoff (BBC presenter), myself, Dr Pete Glanvill (digger), Martin Grass (digger). Photograph by Alison Moody

Reservoir Hole is a cave in the side of Cheddar Gorge, discovered back in the late 1950’s by a local geologist, Dr William Stanton. A few years ago, a group of Mendip cavers (most of whom are retired with an average age of over 60!) began digging at various points in the cave. I visited the cave on a tourist trip last year with one of the diggers, Martin Grass. They had looked at one site in the cave where a good draft was blowing out through some boulders. Dissolutional flow markings on the wall known as scallops indicated that large volumes of water had flowed down this choked passage. I suggested, based on the geological evidence, that this particular site would be well worth excavating to try and find new passage. So I was delighted when Martin Grass rang me up in early September to announce that the dig had ‘gone’ and they had found a continuation of the cave. It is always very gratifying when a prophecy comes true!

In the Frozen Deep with Miranda and Martin, admiring the formations whilst being filmed. Photograph by Alison Moody
It transpired that not only had they found some new passage, but also one of the largest, most impressive chambers in the UK, which they named ‘The Frozen Deep’. Moreover, the chamber is superbly decorated with some fantastic white stalagmites, stalactites and columns. So, a few days later, I found myself down the cave helping to survey some of the passages and to take a look at the chamber. Being only the fifth person to explore this new find was awesome. More people had been to the moon, yet we were only 20 miles from Bristol, and only a few kilometres from where I grew up. The find made quite a splash in the local news.

Filming in the Frozen Deep, with Miranda and Martin sitting with myself behind. Photo by Nick Chipchase

Then the BBC got involved, wanting to feature the discovery on ‘The One Show’. So, in early October, a team of very experienced cavers, along with the BBC presenter Miranda Krestovnikoff assembled in Cheddar Gorge, along with a mountain of tackle bags containing cameras, ropes, lights and batteries all of which had be carried underground. The script was that Martin and I would escort Miranda down the cave, with Martin explaining how they discovered the cave, whilst I, as a BGS geologist, would provide some of the background information about why the cave was so big and how the stalagmites grew.

Filming in the Frozen Deep, with Miranda and Martin sitting with myself behind discussing the cave on camera. Photo by Nick Chipchase

The chamber had also been scanned with a 3D Laser Scanner, loaned by Leica Geosystems the previous week by Kevin Dixon with help from the digging team (another 12 hour trip). Miranda had the results on an Ipad, along with a similar scan of Gaping Gill in Yorkshire, Britain’s biggest known chamber. The results were revealed to us whilst we were being filmed, and it turns out that The Frozen Deep, with a floor area of 2981 m2, was now the largest chamber in the country, some 252 m2 larger than Gaping Gill.

A muddy Miranda with one of the film lights. No BBC make up team here… Photo by Nick Chipchase
Nine muddy hours, and a lot of hard graft later - cameras and batteries are heavy, we exited the cave with over an hour of footage. However, on watching ‘The One Show’ the following evening, I think we were all pretty gutted that our piece had been cut to less than 2 minutes, Apparently ‘due to studio time constraints’ they had to cut a minute or two of the Frozen Deep film, which meant all the interviews I gave ending up on the cutting room floor.
 
Scalloping at the top of The Frozen Deep. The large dissolutional hollows (up to 30 cm across) indicate slow water flow in a phreatic environment, whilst the smaller 1-2 cm diameter scallops superimposed on top indicate much faster water flow (1-2 m/s) into the cave, away from the camera. Photo Andy Farrant

The moral of the story is that media companies are not there to promote your science, no matter how good it is, but to deliver light entertainment, often with very tight schedules. In this instance, Roger Moore’s eyebrows were deemed to be of far more public interest that night than the geology behind the UK’s largest and most spectacular cave. However, it was still worth going, as with the filming lights it was possible to see far more of the spectacular chamber. Perhaps more importantly, it allowed me to examine the scalloping on the passage walls which showed that there has been at least two phases of water flow through the approach passage, and to identify former water-table levels. This, along with evidence from other nearby caves, enables us to piece together the history of cave formation and base-level lowering in the Cheddar catchment. Coupled with dating of cave sediments and stalagmites, this will enable us to quantify rates of cave formation and valley incision over the last million years.

Andy Farrant - links to his full staff profile at bgs.ac.uk