Shetland Islands Field Trip May 2014 - Summary of Results
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Shetland Islands Field Trip May 2014 - Summary of Results ENERGY AND MARINE GEOSCIENCE Report OR/15/017 BRITISH GEOLOGICAL SURVEY ENERGY and Marine Geoscience REPORT OR/15/017 Shetland Islands Field Trip May 2014 - Summary of Results The National Grid and other Ordnance Survey data © Crown Copyright and database rights 2015. Ordnance Survey Licence D.R. Tappin, D. Long, G.D.O. Carter No. 100021290. Keywords Tsunami, Shetlands, Storegga, Submarine Landslide, Climate Change. National Grid Reference SW corner 410000,1108000 Centre point 450000,119000 NE corner 472000,1222000 Map Sheet 999, 1:99 000 scale, Shetlands Front cover Tsunami deposit at Whale Firth Bibliographical reference D.R. Tappin, D. Long. G.D.O. Carter. 2015. Shetland Islands Field Trip May 2014 - Summary of Results. British Geological Survey Report, OR/15/017. 57pp. Copyright in materials derived from the British Geological Survey’s work is owned by the Natural Environment Research Council (NERC) and/or the authority that commissioned the work. You may not copy or adapt this publication without first obtaining permission. Contact the BGS Intellectual Property Rights Section, British Geological Survey, Keyworth, e-mail [email protected]. You may quote extracts of a reasonable length without prior permission, provided a full acknowledgement is given of the source of the extract. Maps and diagrams in this book use topography based on Ordnance Survey mapping. © NERC 2015. 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Natural History Museum, Cromwell Road, London SW7 5BD Tel 020 7589 4090 Fax 020 7584 8270 Tel 020 7942 5344/45 email [email protected] Columbus House, Greenmeadow Springs, Tongwynlais, Cardiff CF15 7NE Tel 029 2052 1962 Fax 029 2052 1963 Maclean Building, Crowmarsh Gifford, Wallingford OX10 8BB Tel 01491 838800 Fax 01491 692345 Geological Survey of Northern Ireland, Colby House, Stranmillis Court, Belfast BT9 5BF Tel 028 9038 8462 Fax 028 9038 8461 www.bgs.ac.uk/gsni/ Parent Body Natural Environment Research Council, Polaris House, North Star Avenue, Swindon SN2 1EU Tel 01793 411500 Fax 01793 411501 www.nerc.ac.uk Website www.bgs.ac.uk Shop online at www.geologyshop.com Final Last modified: 2015/04/01 15:10 Foreword This report presents the preliminary findings from a 13 day field excursion to the Shetland Islands between the 11th and 24th May 2014 to research tsunami sediments. The field work was a contribution to the NERC funded consortium project, ‘Will climate change in the Arctic increase the landslide-tsunami risk to the UK?’ It was part of Work Block 2 (WB2): ‘What is the timing of tsunami deposits on the UK coastline, and how is it related to the age of major Arctic slides’? The objectives of WB2 are to investigate possible tsunami deposits in Mainland Scotland and Shetland that post-date the Storegga Slide; such as those dated at ~5,500 and ~1,500 cal years BP (Bondevik et al., 2005) to constrain estimates of the frequency of tsunami events striking the coast of the UK during the Holocene. Scientists from the BGS and Dundee and Aberdeen Universities formed the research team: BGS: Mr Dave Long, Prof. Dave Tappin, Mr Gareth Carter University of Dundee: Dr Sue Dawson, Dr Fraser Milne, Ms Charlotte Gilles University of Aberdeen; Prof. Alistair Dawson Acknowledgements This report is part of a much larger project on tsunami hazard in the North Atlantic that is supported through a NERC Consortium grant led by Principal Investigator, Dr Peter Talling of the National Oceanographic Centre (NOC), Southampton whose ongoing support we wish to acknowledge together with Dr James Hunt, also of NOC, the Project Manager. The tsunami sediments work block 2 is led by Dr Sue Dawson, Dundee University who also led the 2014 fieldtrip to the Shetlands, with Post-Doctoral Research Associate (PDRA), Dr Fraser Milne, both of whom we wish to thank for their comradeship and friendship in the field and for the discussions on the science that took place on Shetland, most notably during our lively and very convivial evening dinners on Yell. Professor Alistair Dawson, of Aberdeen University shared with us his considerable knowledge of Shetland geology and geomorphology during the first part of the fieldwork and guided us to the new locations he discovered in 2013 with Dr Pedro Costa (the previous PDRA) now of the University of Lisbon. The views expressed in the report are of course those of the authors, who look forward to developing these further during the next phase of field work in 2015 and thereafter as the field observations are further developed through age dating and Laboratory analysis. Our Dundee colleagues sampled at many of the locations described in the Report and we look forward to the forthcoming results on the sediments and the new age dating that should resolve some of the problems we outline here. The authors would like to thank the Shetland islanders who allowed access to their land, particularly Mrs Jamieson, who owned the ‘Red Hoose’ and Mr Johnson for his lively conversation and access to vital coastal exposures. i Final Last modified: 2015/04/01 15:10 Contents Foreword ......................................................................................................................................... i Acknowledgements ......................................................................................................................... i Contents .......................................................................................................................................... ii Summary ....................................................................................................................................... iv 1 Introduction ............................................................................................................................ 1 1.1 Evidence for Tsunamis in the uk .................................................................................... 1 1.2 survey objectives and plan .............................................................................................. 3 2 Field surveys in 2013 .............................................................................................................. 4 3 Field Survey - May 2014 ........................................................................................................ 7 3.1 Mainland ......................................................................................................................... 7 3.2 Yell ............................................................................................................................... 12 3.3 summation, general discussion ..................................................................................... 39 3.4 conclusions ................................................................................................................... 41 Appendix 1 Field Trip Diary ................................................................................................ 43 Appendix 2 Sand Layers in Peat (Dave Long) .................................................................... 44 References .................................................................................................................................... 47 FIGURES Figure 1 Google Earth Image of mainland Scotland and northern England with locations .......................................... 1 Figure 2 Google Earth Image of Shetland with locations of coastal tsunami deposits ................................................. 2 Figure 3 Google Earth Image of Yell with locations of tsunami deposits (in red), possible deposits (yellow), no deposits (white) ..................................................................................................................................................... 4 Figure 4 Google Earth Image of Mid Yell with core and sample locations (Location Fig. 3) ...................................... 4 Figure 5 Cores from mid Yell with lithology’s and 14C dates ..................................................................................... 5 Figure 6 Google Earth Image of Whale Firth with core locations (Location Fig 3) ..................................................... 5 Figure 7 Cores from Whale Firth with lithology’s