Tuesday, 25 June 2013

Spot the Geologist - the start of my PhD..... by Leah Nolan

 
Leah and Peter with their supervisory team from Leicester &
BGS (from left: Melanie Leng, Peter Saycie, Mike Stephenson,
Leah Nolan, Sarah Davies and Vanessa Banks)
 Leah starts her PhD research, in Geology at Leicester University and in association with the BGS, in October. Here she describes her first field visit to the picturesque Lathkill Dale in the Peak District where famous Lower Carboniferous limestones out crop...

Spotting the geologists was an easy task as we arrived in the village of Monyash in the Peak District last Sunday. Sat outside the local cafe were three people from the British Geological Survey with their boots, hammers and compasses at the ready, looking at maps of the local area – these were my guides for the day! The point was to introduce me (and MGeol student Peter Saycie) to some of the local geology that I will be studying for the next three years. We soon set off in the sunshine down Lathkill Dale, a dry valley cut by huge rivers that would have flooded through the Dales over the Quaternary when glaciers retreated at the end of ancient glaciations. We aimed to look at Lower Carboniferous limestones, find the famous Gigantoproductid fossil bed (which I have been working on as part of my MGeol thesis over the past year), and start to think about a plan for my thesis research which is due to start in October.
 
Leah and fellow student Peter looking at brachiopods
in the fallen blocks within Ricklow Quarry in Lathkill Dale

The first stop was not far along the Dale. Here we looked for calcretes (fossil soils) on top of massive ancient limestones. I’m not convinced I saw them (!) so I have somewhere to revisit! Progressing down the Dale towards Ricklow Quarry I was really excited to see really good rock exposure. The quarry debris is littered with huge shells of a single type of brachiopod! In particular the back face of the quarry displays a huge thickness of shells, all in life position, thought to have been living in small pools around coral reefs about 350 million years ago when the Dales were at the equator. Peter will also be working on this material, and pretty quickly we were collecting shells even though this was only a “look and see” day (the shells are beautiful and we couldn’t resist it)...We moved on down the Dale, taking a short cut through tall nettles, where I wished I had worn thicker trousers...nettles are not friendly! We soon found another shell bed below the level of the reefs although the shells had been heavily recrystalised by fluids passing through the rocks.

At the end of the day we visited Butt Quarry near Worksop where we hoped to see the equivalent limestones, unfortunately the brachiopods were about 100m up the quarry face and not easily accessible! However what was interesting is that the quarry shows numerous faults and late stage fluids have brought lead ores that penetrate the limestones – these mineral rich veins must have been an added bonus when they were quarrying the limestone. Overall a good day was had by all. I left with more question about the area than when I arrived with, but that’s the point of a PhD (right!?!?).  I am excited to get stuck in and look forward to spending more time in the Dales...I have a feeling that myself and the local campsite owner are soon to become good friends. Roll on October...and another blog... 

Lathkill Dale in the Peak District which contains some
spectacular Lower Carboniferous limestones
Leah Nolan will start her PhD research at Leicester University in October 2013. She is also  sponsored by the BGS BUFI scheme. Her PhD is concerned with reconstructing palaeoenvironment of the Lower Carboniferous of the Peak District, and how this has controlled subsequent diagenesis and the development of fluid pathways through the limestones. She will be supervised by Profs Melanie Leng and Sarah Davies at Leicester and Prof Mike Stephenson and Dr Vanessa Banks from the British Geological Survey.

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