Wednesday, 25 June 2014

Hexacopter flight over tetrapod site

Last week Tim Kearsey, along with BGS colleagues Ed Haslem and Pete Hobbs were at our main field site in the Scottish Borders flying a hexakopter survey over the rocks exposed in the foreshore. A hexakopter is a type of model helicopter with six rotor blades. This keeps it very steady in the air and means we can use it to do aerial photography from a low height, rather than an aircraft.  The hexakopter has a normal digital camera under it which takes a photo every second. It also has an onboard GPS which records the position of each photograph. These photos can then be combined in a computer using programs that use both the GPS position and the features in the photos (in a similar way that software that allows you to build several photos into a panorama does). This creates a single image with is also scaled so we can measure feature on it.
The Hexakopter in action over the sandstone beds
The reason we are  doing this survey is because the rock there are all up on end, that is to say have been rotated through 90 degrees  since the time they were formed. This gives us a unique 500m by 200m view of the river systems and floodplain in which the tetrapods lived. However, unlike a cliff, it is impossible to stand back and get a broad picture view.

Ed Haslam and Tim Kearsey using a dGPS to plot control points to aid combination of the photos
The images collected by the hexakopter will help us to understand the large scale shapes of the sandstones and the units in between. This will help us to answer questions like ‘what were the rivers like where the tetrapods lived?’; ‘were there lakes?’; ‘how close were we to the sea at the time the tetrapods lived?’
Until next time
Tim Kearsey

Saturday, 21 June 2014

Ostracod hunting

Last week I was hunting for fossils, this week it was microfossils! I was visiting the fossil collections at the British Geological Survey in Edinburgh. During the week I studied the material from the Norham West Mains core for ostracods. What are ostracods? They are small arthropod crustaceans, about 1mm in length, which live in just about any aquatic environment. Their carapace is preserved in the rock record, and different features of the carapace indicate their species. They lived at the same time as tetrapods, alongside fish, molluscs and other aquatic life. 
Me with the trolley of samples containing ostracods

I am studying them because different ostracod species live in different salinity conditions, so this can tell us what the environment was like. Freshwater and marine ostracods are quite different. I saw many different species in the hundreds of samples I examined last week, a promising start. The next step will be to examine the specimens under a Scanning Electron Microscope, to confirm their species.

It was great to re-visit this field after studying ostracods for my PhD, I am a big fan of ostracods! They are remarkably resilient animals, surviving in aquifers, on leaves out of water, in hypersaline conditions and they can even survive being eaten by fish! Find out more about ostracods: 10 amazing facts about ostracods 
A living freshwater ostracod Eucypris virens, you can see some of the appendages emerging from its shell (the carapace). Image copyright Carys Bennett

Until next time


Tuesday, 17 June 2014

Fossil hunting!

The team examining fossil material: Janet Sherwin, Carys Bennett, Tim Smithson and James Mawson
Last week I was joined by undergraduate James Mawson from the University of Leicester. James was volunteering with me to gain experience in palaeontology and we spent the week hunting for fossils! James helped me continue the time-consuming (but rewarding!) job of splitting apart some of the hundreds of rock samples I have collected from the Ballagan Formation. Each sample was split along the bedding planes, and freshly exposed surfaces examined under a binocular microscope. 

Throughout the week we found a lot of fish material such as scales, teeth and bone fragments. Specimens of actinopterygians and rhizodonts were the most common, with rare lungfish fragments. We also found many ostracods that were preserved in 3D and from which we could identify the species present. This is very useful in terms of understanding the ancient environment, and it was exciting after seeing quite a lot of flattened carapaces or poorly preserved specimens in other samples. James is interested in arthropods, and although these are very rare, we did find numerous scorpion cuticle fragments.

On Thursday we had a visit from TW:eed Project member Tim Smithson, who came to help the Leicester team identify some of the vertebrate material we have found. It was fantastic to have an expert with us for the day, and we all learnt a lot about fish palaeobiology. Great work Team TW:eed!

Until next time