Steve Thorpe, BGS driller and author of 'On the Bog' posts, tells all about the latest Drilling Team visit to deepest Wiltshire and their search for long lost Jurassic treasures......
There’s nothing more exciting than drilling core and finding fossils. It’s the question we get asked the most when we tell our friends and family what we’re doing. “Did you find gold/oil/fossils?” So this time when we ventured out we could say “Yes, actually we did!”. The Jurassic Oxford Clay is a dark grey laminated sequence of stiff mudstones with varying numbers and species of fossils which are relatively close to the surface in some places. This allows our shallow drilling rig the opportunity to demonstrate what we’re good at, and this week proved that this geology is ideal.
Two boreholes were drilled and the contents of the core proved the subtle variations in the lithologies of this particular part of the Oxford Clay. Of particular note were several beds of shells, mostly Dicroloma, Bositra, Meleagrinella and nuculacean bivalves, but with some interesting ammonite species too. The photo below shows a specimen of Kosmoceras that literally fell out of the drilling shoe when we brought it to the surface!
These wonderful fossils had been found previously when the railway was built around 150 years ago. But since then the location had become a mystery. In 2006 the BGS commenced a targeted drilling campaign to find the same location and succeeded. This followed with the site being the focus for an episode in the BBC Fossil Detectives series. The drilling objectives for this week were to provide some more core samples to allow further analysis of the environment and sedimentary characteristics at the time of deposition.
From a drilling point of view this was done fairly simply using our percussion drill rig, with 117mm barrel size being chosen to provide a good sample. The deeper we drilled the slower this became to the point where at 9m it was taking around 40 minutes to drill 1m of core. It also took lots of effort to pull it back out of the ground, and the deeper cores required our 20 ton pull-ram to be deployed! Heavy work indeed, but we had a great weeks drilling in a fascinating location.
Till next time, keep it greased!
Friday, 25 October 2013
Wednesday, 16 October 2013
|Me [Clive Mitchell] at Bigbury|
|Ed and Andy at Bigbury|
Monday 7th October
On a particularly grey looking day (not unusual for the East Midlands it seems), we set out for the southwest passing through north Somerset on the way (my home turf, Hi Mum!) and by mid-afternoon we had arrived at our filming base in Plymouth. So as not to waste time, and because we were keen to start filming, we headed out to the coast.
Filming location 1: Sedgewell Cove, Bigbury-on-Sea, Devon (Devonian siltstones).
Close to Burgh Island, a tidal island where Agatha Christie once holed up to write her murder mysteries. Ed and Andy made a start on the filming for the TELLUS SW project. It's overcast and drizzling but it's actually quite mild for the time of year. Surf is up with a handful of surfers braving the waves. It’s great to be by the seaside, although all I can think of during the filming is fish and chips!
(I eventually get my fish and chips at The Dolphin, Newton Ferrers).
|Richard Scrivener holding ore samples|
Filming Location 2: Hemerdon, Devon (Mineralised granite dykes intruded into Devonian slates)
We met up with ex-BGS geologist Richard Scrivener at the Miners Arms pub in the tiny Devon hamlet of Hemerdon which is just to the southwest of Dartmoor. Richard took us to a vantage point on Crownhill Down looking towards Drakeland Corner and the old mineral workings at Hemerdon Ball. This is the site of the Hemerdon tungsten deposit, one of the largest in the world, which is due to start production in 2015. Next we visited Hemerdon Ball which was previously worked for tungsten in the Second World War. Evidence of the mineralisation (90% tungsten in the form of the mineral wolframite and 10% tin in the form of the mineral cassiterite) was found in veins on the edges of the pit.
Filming Location 3: Tremough Campus, Camborne School of Mines (CSM), Penryn, Cornwall
From Hemerdon we headed west into Cornwall and to the Penryn campus (just north of Falmouth) of the Camborne School of Mines (CSM). Our first interview was with Professor Mark Smethurst (Honorary Professor of Applied Geophysics visiting from the Geological Survey of Norway) who is a Radon expert. In his opinion, the data from the radiometric survey carried out by TELLUS SW will be “worth its weight in gold” as it will significantly improve the understanding of the concentration of radon in dwellings in the southwest. In particular it should highlight local extreme exposure sites that may require special attention.
|Ed, Cally and Niell with Quadcopter|
Next we had a demonstration of an Unmanned Aerial Vehicle (UAV) by Neill Wood. The QuadCopter was equipped with a GoPro camera. We were treated to a 7 minute aerial display (the length of time Neill dares to fly the QuadCopter before its battery runs out and crash lands!) and, much to his delight, it made a perfect landing!
On the way back to way back to Plymouth we stopped off in Truro so that Ed could film Truro Cathedral. The cathedral is 80m tall, which is the height the TELLUS SW survey plane flies over open countryside (200m over populated areas).
|Ed and Tony Bennet down the mine|
Filming Location 4: Rosevale Mine, Zennor, Cornwall (tin mineralised granite)
At 8am we set off on the 2 hour drive across to the west of Cornwall. We met Tony Bennett from EGS Energy in the car park at Zennor. Tony took us up to Rosevale Mine which, along with 4 friends, is essentially run as a ‘hobby’ mine! Rosevale Mine is only accessible on request and is not generally open to the public. This is a former tin mine which originally opened in the 18th century and was worked until the First World War. There is very easy access through a drift adit into one of the mining levels. Luckily it was relatively free of water due to the recent dry weather and to the fact that it is a free draining operation not requiring an engine house to pump out water. There are not many places in Cornwall where you can truly experience what it was like to be a tin miner. Tony is the operations manager at EGS Energy which is looking to develop geothermal energy in the region. EGS is currently working at the Eden Project where it plans to drill a deep borehole into the underlying granite. Water pumped down will heat up to 180oC and the superheated steam will return through a second borehole to the surface where it will be used to generate electricity ad as a source of heating.
Next we drove across to St. Agnes Head where we met Mark Owen from Wardell Armstrong for lunch at the Driftwood Spars, Trevaunance Cove. Mark is a mining geologist with many years of experience in the industry including time as Chief Geologist at South Crofty (the last operating tin mine in the UK which closed in 1998). After lunch we walked out onto the beach from where the mining history of this part of Cornwall is all too visible with the relic of a tin mine engine house overlooking the village, the rubble of the former harbour from where tin was exported and the small tin mine adits that pockmark the cliffs.
|Ed and Mark on the beach|
Thursday 10th October
Last day in the southwest! We checked out of the hotel and headed back over the Tamar into Cornwall for the last time this trip.
Filming location 5: Minions Heritage Centre, Bodmin Moor, Cornwall (copper and tin mineralised granite)
We met Deborah Boden from the Cornish Mining World Heritage Site at Minions Heritage Centre on Bodmin Moor. In a change to the weather of the last 3 days, it was gloriously sunny but also a lot colder! The heritage centre is based in Housemans Engine House, which was built in 1881 as part of South Phoenix Mine. It was purchased and restored by Caradon District Council on behalf of the Minions area heritage project with grant aid from the Rural Development Commission in 1991. As we filmed ponies were galloping around and generally looking photogenic. Beryl Martin, key holder for the heritage centre and Minions Parish councillor, popped out to have a chat with us. The centre has a series of displays that focus on the mining history, geology and past life of the area. It was in 1836 that a rich lode of copper ore was discovered just south of the present day village of Minions. This precipitated a ‘Copper Rush’ with miners coming from all over the southwest for work creating a mining boom. The railway soon followed, which explains why Minions was actually known as ‘Cheesewring railway’ at this time. Tin and arsenic were subsequently mined.
|Housemans Engine House|
It’s a wrap! The last filming took place at vantage points looking towards Cheesewring Tor and granite quarry. We set of back to the East Midlands and I arrived home about 8.30pm. Ed still has some filming to do with the survey pane at some point (this took place the following week) and the video will be released at the end of October 2013.
Monday, 14 October 2013
|At JAEA's F-TRACE site within the exclusion|
zone where surface runoff and soil movement is
Our Prof Julia West was invited to attend a special international workshop organised by the JAEA (Japan Atomic Energy Agency) to discuss progress in remediating the contaminated areas. The experts were asked to offer their experiences and expertise which could help JAEA’s efforts. They were also taken on a trip to see first hand the damage done to the affected areas around Fukushima.
Julia is a geomicrobiologist who started her career working on radiocaesium uptake onto various geological materials. She has also advised JAEA and other organisation around the world on practical ways to communicate all things ‘radioactive’ to the uninitiated. Julia has visited Japan some 20 times but never been to Fukushima.
Here's her travel diary which gives you a personal and fascinating glimpse into Fukushima today:
An overnight 12 hour flight from Heathrow to Narita airport outside Tokyo. The long flight coupled with an 8 hour time difference turns me into a zombie and I proceed through immigration and customs in a daze. Then after 90 minutes on several different trains I make it to the hotel in Fukushima. Next task, where’s the hairdryer? Down to reception. It turns out that what I thought was the dehumidifer is the drier....
|A dosemeter placed near the hotel in Fukushima|
Meeting starts at 9am with the local press at the back of the meeting room. Formal speeches and much filming. The press then clear out and we start a full day of presentations including JAEA’s on-going remediation efforts which are hugely challenging (the clean up area extends to a radius of about 20 km inland around the reactor site - more than 600 km2). Currently, much effort is being given to remediation of the forests which cover about 70% of Fukushima prefecture. I speak on the challenges of communication and make suggestions on how the local people can be involved in the clean-up. Food for thought for JAEA. Mid-afternoon, we all watch the local news which includes a feature on the workshop. Most of the international experts (including me) are featured.
A reception for us tonight and several very eminent Japanese experts speak. It is clear that the international perspective and our advice is seen as very important to the rehabilitation of the land around Fukushima.
2nd and 3rd October
Two days of intensive discussions about radiocaesium behaviour in the environment. I present past BGS experience plus provide information on the BGS BioTran project where we have worked in JAEA on the development of biofilms to alter rock transport properties affecting contaminant flow. Biomineralisation is also discussed because both of these areas offer techniques which could be used to help prevent movement of radionuclides around the reactor site itself. Much information is being generated by JAEA and other institutes and I suggest that BGS’s long experience with archiving information and handling large datasets may help with making sure that all experiences with Fukushima remediation are fully collated and understood. At the end of the third day the international group make our recommendations which will be published on JAEA’s website.
|A temporary storage site for some of the bags|
containing contaminated vegetation and soil
Today is the day we have all been waiting for. JAEA take us by bus to their monitoring sites near Ogi-dam which is in the exclusion zone itself. As we approach the area, the villages become more deserted and the only people you see are elderly. Everywhere there are large black and blue bags neatly piled up containing contaminated vegetation and soil. Forests surround each village and you can see workers cutting back the forest and removing the soil so that a 20 m zone around each village is decontaminated. Much work is going on. As we approach the zone itself, we are kitted out with protective helmets, gloves and wellington boots. All the JAEA staff carry dosemeters and I also have one which I was given by BGS to monitor myself. We are taken into the forest to view an experimental area where water flow and Cs concentrations are measured. The forest is beautiful and the sun shines. It is hard to believe that the area is contaminated although the dose we received during our 2 hour visit was equivalent to that you would get from cosmic radiation during a transatlantic flight. We then travel to another monitoring station beside the lake itself. A monument which had been erected to commemorate the building of the dam is split and half lies some 5 m below the original site – if fell during the earthquake itself. The area is quiet apart from the sounds of water and our voices – tranquil and lovely. I feel very sad for what has happened here.
We now head off to see one of the many temporary storage sites for the bags full of contaminated material. I am amazed to see it – hundreds and hundreds of large bags all neatly stacked. The sight is staggering in size and makes us all realise the scale of what the Japanese people are doing to decontaminate the area. We are all quiet when we get on the buses to return to the hotel.
Return to Tokyo for another meeting with JAEA and then off to the hotel at Narita so I can get the flight home tomorrow. I have a mixture of feelings: great interest at what I have learned and seen during my visit; pleased that I have been able to contribute to the remediation efforts; but mostly I feel great sadness and sympathy with the Japanese people. There is a lot to do and I think BGS can really help with ongoing efforts.
Tuesday, 8 October 2013
|Herstmonceux Geodetic Observatory|
SGF/HGO makes a strong observational and computational contribution to defining the International Terrestrial Reference Frame (ITRF) at millimetre-levels of precision and accuracy, represented by the geo-centred coordinates of a variety of geodetic instrumentation at a number of observatories worldwide, including Herstmonceux. Four complementary space techniques are capable of reaching the required levels of precision and together they define the ITRF and the link to the celestial reference frame.
The first technique is Satellite laser ranging (SLR) and in 2012 Herstmonceux was awarded the status of a 'New Technology SLR Site' by the Global Geodetic Observing System (GGOS). Short pulses of visible laser light are directed at selected orbiting spacecraft carrying reflectors, and by detecting the reflections the satellite range is found from precise time-of-flight measurements. To reach millimetre precision, the times-of-flight of the laser photons have to be measured to a millionth of a millionth of a second. Using data from the global network of accurately located satellite tracking systems, precise orbits are computed for Earth observation satellites, such as CryoSat-2 and Jason-2. Critically, laser ranging to these satellites ensures that the mathematical models of their orbits are centred on the geocentre so that the satellites’ radar observations of sea level and ice-sheet altitude and thickness may be referred to a truly global reference frame.
The second, universally recognized geodetic technique is Global Navigational Satellite Systems (GNSS), including GPS (USA), GLONASS (Russian), and Galileo (European). These navigational systems, at the heart of sat navs, smart phone location services, and surveying and road building engineering techniques, need a global distribution of receivers at known locations to geo-reference the GNSS orbits and monitor the satellite clocks. One of the GNSS receivers at Herstmonceux is driven by an extremely stable Hydrogen maser clock (it loses 1 second in 30 million years) and, this, combined with its location close to the SLR, makes it a important contributor to these global services.
We have ambitions to add the third and fourth techniques to the site; a very accurate Doppler satellite-tracking beacon for the French DORIS system and, much more ambitiously, a Very Long Baseline Interferometry (VLBI) 12m radio telescope. Having a full suite of measurement techniques would place SGF/HGO on the world stage as a core station of the emerging Global Geodetic Observing System, the position service of the International Association of Geodesy.
We are also operating and researching the use of an absolute gravimeter to study local and regional site motion in conjunction with the results from GNSS and laser ranging, and have a PhD thesis in progress in collaboration with UCL and NOC Liverpool. Research into atmospheric aerosol layers is carried out in collaboration with Cambridge University, using a LiDAR system developed in-house.
|Starlette - the first satellite tracked at Herstmonceux|