The Edinburgh Geologist Magazine of the Edinburgh Geological Society Issue No 56 Autumn 2014 The Edinburgh Geologist Issue 56 Autumn 2014 Cover Illustration Borehole at West Mains Farm, Norham (scale in centimetres) showing lithologies of the Early Carboniferous Ballagan Formation, as described in the article by David Millward. BGS images are reproduced by permission of the British Geological Survey ©NERC. Published September 2014 by The Edinburgh Geological Society (Charity registered in Scotland number SC008011) www.edinburghgeolsoc.org Editors Phil Stone Bob McIntosh [email protected] [email protected] British Geological Survey Murchison House West Mains Road Edinburgh EH9 3LA ISSN 0265-7244 Price £2 net EDITORIAL Borderlands and back to the future An editorial ramble by Phil Stone There’s so much packed into this Scotland shares the stratigraphy of issue of The Edinburgh Geologist that the Carlisle Basin; in the east it’s the there is only space for a short ramble. Northumberland Trough. No surprise We go to press at the end of August, then that in David Millward’s article so by the time you receive your copy in this issue of EG, the lowermost of EG you will be either delighted Carboniferous stratigraphy of a or dismayed by the referendum critical sequence in Berwickshire was result. But not to worry, whatever the established by sinking a borehole in outcome it will not affect the geology, Northumberland. David provides a and geology has little respect for the progress update on the Tweed project, conceit of national boundaries. a multi-collaborative (yes, Scottish and English institutions) investigation Borderlands of tetrapod evolution based on some We tend to associate the Anglo- remarkable fossil discoveries in the Scottish border with the Iapetus Scottish Borders, as reported in EG 53. Suture, the large-scale result of an Early Palaeozoic act of union, but Not that long ago, the coastline the detail of cross-border outcrop is was as just as geologically irrelevant Upper Palaeozoic and Mesozoic. In the west, Cross-border geology: an anticline in the Penton Limestone (Alston Formation, Yoredale Group) viewed from Scotland but exposed in the English bank of the Liddel Water at Penton Linns. BGS image number P221694. 1 EDITORIAL as the border. Andrew Kitchener’s geological icons, Our Dynamic article on mammoth remains from Earth. Stuart Monro describes Scotland recalls a time when these the developments there in his recently-extinct beasts could walk article featuring ‘Scotland’s Time here across what is now the North Lords’ — one of which was Charles Sea. It’s a welcome follow-up to the Lyell. I was amused to read in a exhibition at the National Museum of Geoscientist magazine1, that he was Scotland earlier this year, which has regarded by the ladies as something now transferred to The Natural History of a social liability. Emma Darwin Museum, London. That might explain thought him a ‘dead weight’ and why mammoths would seem to be wrote to her sister on 2 April 1839, the current celebrity monsters. Even “Mr Lyell is enough to flatten a party, Damian Hirst has got in on the act with as he never speaks above his breath, “Gone But Not Forgotten”, a 3 metre so that everybody keeps lowering their tall, gilded Woolly Mammoth skeleton tone to his.” In the large open-plan encased in a huge glass, gold-framed offices envisaged for the Charles Lyell tank. In May the work was auctioned Centre that could well be a trait that (for Aids charities) at the Cannes Film the occupants will need to emulate. Festival — it fetched 11 million Euros. In the meantime, perhaps we can now Back to the Future move on from constitutional obsession Whatever the future holds for the and refocus on the big issues: climate British Geological Survey in Scotland, change, resource depletion and there are going to be major changes to natural hazards to name just three its presence in Edinburgh. Murchison with geological connections. Stuart House, since 1976 the BGS base on Monro touches on these, as do our Edinburgh University’s King’s Buildings book reviews. Sue Loughlin considers campus, is scheduled to close early the impact of volcanic eruptions in 2016 with the staff moving out to in Iceland; Roger Kelly looks at the Riccarton, where a new ‘Charles Lyell achievements of ‘Paraffin’ Young and Centre’ will be shared with Heriot- Scotland’s first hydrocarbons boom. Watt University … more on this as the plans are finalised. 1 Morgan, N. 2014. Guess who’s coming There are also recent changes to to dinner? Geoscientist, 24 (5), 25. report at another of Edinburgh’s 2 DRILLING THROUGH ROMER’S GAP Drilling through Romer’s Gap — The TW:eed project borehole near Berwick-upon-Tweed By David Millward On the cold sunny morning of 3rd for Tetrapod World: early evolution April 2013, heavy rock-drilling and diversification). The project equipment began to arrive at West is investigating this interval which Mains Farm, near the village of Norham, Berwick-upon-Tweed. This was the start of a two-month operation, during which a fully cored borehole was drilled to a depth of 501 m through Lower Carboniferous (Tournaisian) rocks of the Ballagan Formation (Figure 1). For members of the project team, it was a relief that, after months of planning, drilling was finally to get underway. Obtaining as complete a rock record as possible through the Ballagan Formation and into the underlying Kinnesswood Formation was a key objective for the TW:eed project (TW:eed stands Figure 1 A run of core is recovered at Norham using the Atlas Copco S-Geobor wireline system. On the trestles are a new length of drill stem (left) and a second core barrel with plastic liner fitted (right) ready to be attached. Image: D Millward©NERC 3 DRILLING THROUGH ROMER’S GAP is referred to as Romer’s Gap, the funded by the Natural Environment period when the aquatic and fish-like Research Council. The borehole work limbed vertebrates of late Devonian has been led by BGS. times emerged on land to diversify into the wide range of fully terrestrial Why drill a borehole? species seen 15 million years later in A continuous, high-resolution record Visean times. This was a step change of the lithology, sedimentology, in the evolution of life on Earth that petrology, stable isotope shaped the future of vertebrates, compositions, palynostratigraphy and and eventually the appearance of biostratigraphy is contained in the humans. cores. Such a record is not possible from outcrop. Significantly greater South-east Scotland is one of only and higher quality detail is obtainable two places in the world where from cores, though the absence of tetrapod fossils from this time interval information on the lateral extent of have been found — the other is facies is a drawback. The level of Blue Beach in Nova Scotia, Canada. detail is crucial within mudstone The Ballagan Formation comprises intervals which typically crumble to rapidly alternating beds of siltstone small fragments when exposed and and cementstone, with interbedded weathered (Figure 2). sandstone and has been interpreted as coastal alluvial plain deposits This record will enable us to interpret (Anderton 1985). the changing early Carboniferous depositional systems and climate and TW:eed builds on some remarkable to infer habitats that hosted the early fossil finds made recently in the terrestrial tetrapods. A framework Scottish Borders by the late Stan will be established for understanding Wood, and described by Nick Fraser the environmental factors that may in his article in the Spring 2013 have had an influence on why this edition of The Edinburgh Geologist. evolutionary route was taken and on The research is being undertaken the preservation of the fossils. by a consortium of organisations led by Professor Jenny Clack at In addition to establishing a the University of Cambridge, stratigraphical framework upon which and including the universities of our tetrapod localities in the region Southampton and Leicester, the can be pinned, it is hoped that we National Museums of Scotland and will be able to ‘convert’ the rock the British Geological Survey, and record data from the borehole into 4 DRILLING THROUGH ROMER’S GAP Figure 2 Comparison of profiles through Ballagan Formation paleosols, left at outcrop (pencil is 150 mm long) and right in core (core width is 102 mm). Images: D Millward (left), BGS (right), both©NERC however detailed the planning! Indeed, significant problems did arise but these were not insurmountable. time and hence begin to understand rates of tetrapod evolution. Time- Circulating the drilling mud between series analysis can be used to test the rotating drilling head and the whether the sedimentary cyclicity surface where the mud can be present through the Ballagan cleaned of cutting fragments is Formation may be related to glacio- essential to keep the drill bit moving eustatic changes in sea level resulting and the drill stem free, particularly from periodic changes in the Earth’s during coring. So, the sudden loss of orbit around the Sun. However, we drilling fluid into cavities or fractures will also need to understand where can cause serious problems and the time gaps are, for example at potentially abandonment of the unconformities and at fluvial channel borehole. bases, as well as the time locked up in the development of the thick At Norham we lost circulation paleosols present. repeatedly between 52 m and 103 m from the surface. Core recovered Problems, what problems? from one of the zones showed a There is an old saying that something steep, two centimetre-wide open will always go wrong during drilling, fracture in sandstone. This type of 5 DRILLING THROUGH ROMER’S GAP problem is usually solved by the professionalism by the team of drillers addition of materials such as mica, from Drilcorp Ltd in Co.