https://theses.gla.ac.uk/ Theses Digitisation: https://www.gla.ac.uk/myglasgow/research/enlighten/theses/digitisation/ This is a digitised version of the original print thesis. Copyright and moral rights for this work are retained by the author A copy can be downloaded for personal non-commercial research or study, without prior permission or charge This work cannot be reproduced or quoted extensively from without first obtaining permission in writing from the author The content must not be changed in any way or sold commercially in any format or medium without the formal permission of the author When referring to this work, full bibliographic details including the author, title, awarding institution and date of the thesis must be given Enlighten: Theses https://theses.gla.ac.uk/ [email protected] Neotectonics and Palaeoseismicity in North West Scotland A Thesis submitted for the degree of Doctor of Philosophy by Clark Henderson Fenton B.Sc. University of Glasgow Department of Geology & Applied Geology University of Glasgow August 1991 ProQuest Number: 11011411 All rights reserved INFORMATION TO ALL USERS The quality of this reproduction is dependent upon the quality of the copy submitted. In the unlikely event that the author did not send a com plete manuscript and there are missing pages, these will be noted. Also, if material had to be removed, a note will indicate the deletion. uest ProQuest 11011411 Published by ProQuest LLC(2018). Copyright of the Dissertation is held by the Author. All rights reserved. This work is protected against unauthorized copying under Title 17, United States C ode Microform Edition © ProQuest LLC. ProQuest LLC. 789 East Eisenhower Parkway P.O. Box 1346 Ann Arbor, Ml 48106- 1346 Declaration The material presented in this thesis summarises the results of four years of research carried out in the Department of Geology & Applied Geology, University of Glasgow and also the former Department of Applied Geology, University of Strathclyde. This study is based on my own independent research and any previously published or unpublished results of other researchers used in this thesis have been give full acknowledgement in the text. Clark Fenton. November 1991. t Abstract Detailed field investigation has revealed a number of faults that display late Quaternary movement in the formerly glaciated Highlands of North West Scotland. These include NE-orientated reverse, WNW- to NW-orientated sinistral strike-slip and N- to NNW-orientated dextral strike-slip faults. In all cases movement has occurred along pre-existing basement faults. The faults offset late Quaternary morphological features, including drainage courses, and disrupt late- and post-glacial sediments. Electron Spin Resonance was used in an attempt to accurately age-date the fault movements. Although this proved unsuccessful, this study showed the limitations of using this technique in relation to fault dating studies. Fault movement was accompanied by coseismic ground deformation as shown by the density of seismically-triggered slope failures and seismite soft sediment deformation around the fault ground ruptures. The areal distribution of these deformation features and the dimensions of the associated fault ruptures indicate elevated levels of seismic activity, with events up to Ms 7.0. This is considerably greater than the levels of seismic activity experienced at present. Faulting was associated with a period of rapid isostatic uplift during and immediately following the decay of the last glacial episode, the Main Late Devensian, c. 13,000 years BP. A short-lived glacial readvance, the Loch Lomond Stadial, lasting from c. 11,000 to 10,300 years BP, caused temporary redepression of the crust halting uplift and faulting prior the main period of fault activity post-10,300 years BP. Although the majority of fault movement occurred in the immediate post-glacial period, significant fault movement has occurred as recendy as 2,400 years BP. Faulting resulted from the sudden release of glacial loading stresses and tectonic stresses stored during ice-sheet residence. Elevated pore fluid pressure is seen to be important in the timing and sustaining of fault movement outwith the immediate post-glacial period. Such elevated pore fluid pressure also allowed the reactivation of faults that were less favourably orientated with respect to the regional stress field. This evidence for fault movement and seismic activity in the early part of the Holocene is compared with present day seismotectonic activity and used to predict the present day risk of ground rupture and damaging earthquake activity in the UK as a whole. It is proposed that present day crustal movements result from the actions of the NW European regional stress field, the effects of glacially-induced stresses now having decayed to insignificant levels. Acknowledgements Pane ii Acknowledgements This research project was funded by the Natural Environment Research Council, grant GT4/87/GS/107. NERC also provided additional funding for the extensive programme of fieldwork and the Electron Spin Resonance age-dating study. The project was initiated by Colin Davenport at the Department of Applied Geology, University of Strathclyde. His interest and enthusiasm provided direction in the early stages. The unwelcome actions of higher authority consumed the' old' Strathclyde Department in 1989. Research then moved to the new Department of Applied Geology & Geology at Glasgow University. To Iain Allison I am greatly indebted for assuming the role o f supervisor and seeing the project through to its conclusion. Many thanks are also offered to Stuart Haszeldine, unofficial supervisor extraordinaire, for his unending interest in and enthusiasm for the world of Scottish neotectonics (Not many N-S linears though!). The remainder of the Strathclyde staff: Roger Anderton, Brian Bell, Alan Hall, Jeff Harris, Mike Russell and especially George Bowes, for his help in untangling many a mess on the computer system, are all thanked for their interest, support, good humour and just making Strathclyde a great place to belong to. Within the new Department Ben Doody, Peter Haughton, Graham Jardine, Bernard Leake, 'Old Norway' and Geoff Tanner are all thanked for providing stimulating discussion and encouragement. The technical staff of both Departments made many a task much easier during the course o f this research. Their help and advice has been invaluable: Murdoch MacLeod, Dougie Turner and Jim Gallagher all kept a safe distance during mineral separations, John Gilleece and Peter 'Pigg' Wallace showed the utmost patience in making "all thae b*****d slides", Jim Kavanagh sorted many a problem with the Apple Macs, Pete Ainsworth ably piloted the Starship Enterprise (SEM!) and Kenny Roberts repaired the coring drills. Douglas MacLean deserves a special mention for the time and effort he spent transforming a large number of slides into the prints for this thesis. Roddy Morrison is thanked for providing the raw materials of post-grad, research and for managing to run the Department despite the warring factions. The Jannies': Eddie Alec and John provided good humour and anything else that could not be procured by normal means! The post-grad, fraternity of both Departments, both past and present, made my period of research a pleasure. Thanks for friendship and humour: Fawzi, Sherif, Kerr, Anne, Arshad, John (Le Cube), Russ, Pete, Scummy, Maggie, Ahmed, Ali, Lindsay, Amar, John, Wamid, Richard, Zaid, Garry, Kerim, Calum, Tim, Tom, Gordon, Rona, Orla (who wanted a mention on her own), Andy, Paul, Wobbly, Mohamed, Robbie, Morgan, Rachel, Susan and Derek. Pete Chung is especially thanked for his donkey work during the collection of samples for ESR age-dating. Outwith the Department(s) many people have helped with this project, providing data, advice, accommodation or merely an encouraging word. The staff o f the BGS Global Seismology Unit, especially Pete Marrow and Terry Turbitt, provided the data concerning instrumental seismicity in the Acknowledgements Page iii UK. Colin Ballantyne, Dougie Benn, Rob Duck, Patricia Lowe and Jill Tate of St. Andrews University taught the author about glacial geomorphology and provided much information on the Quaternary history of Scotland. Geoff Boulton (Edinburgh) and Doug Peacock (Heriot-Watt) provided stimulating discussion on all matters Quaternary. Martin Kralik (Vienna), Robert Maddock (Geoscience Ltd), David Sanderson (SURRC) and Rainer Griin (Cambridge) were all generous in their advice concerning age-dating of intrafault materials. To Rainer I am deeply indebted for his participation in the ESR age-dating study and braving the Scottish weather in October! Graham Eaton (BNF pic), Colin Ferguson (Dames & Moore), Paul Hancock (Bristol) and Graham Park (Keele) all provided information on faults both old and new. HJ. Melosh (Arizona) generously gave much information on rock avalanches from around the world. Svensk Kdrnbrdnslehantering AB, the Swedish Nuclear Fuel & Waste Management Co., generously paid for a visit to the Lansjdrv fault in Northern Sweden. Ann-Marie Hultqvist, Lars Ericsson and Roy Stanfors are thanked for their organisation and generous hospitality. Robert Lagerbdck (SGU) and Odleiv Olesen (NGU) are especially thanked for going out of their way to show me the other post-glacial faults of northern Fennoscandia. A special thank you to Robert and Anders for the memorable heli-field trip to the Pdrvie fault. John Adams and Doug Grant (Canadian Geol. Surv.), Arch Johnston