GEOCHEMISTRY AND PETROGRAPHY OF A LOWER CARBONIFEROUS, LACUSTRINE, HOT SPRING DEPOSIT: EAST KIRKTON, BATHGATE, SCOTLAND. A thesis submitted for the degree of Doctor of Philosophy. bvj Rona Ann Richardson McGill. BSc. Edinburgh University. Department of Geology and Applied Geology. University of Glasgow. January 1994. ProQuest Number: 13818562 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 13818562 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 ACKNOWLEDGEMENTS This research project was funded by NERC, and was a CASE studentship with the National Museums of Scotland; jointly supervised by Dr W.D.I Rolfe (of the NMS) and Dr A.J. Hall of the Department of Geology and Applied Geology, at the University of Glasgow. It is unlikely that this thesis would ever have been completed without the help of Dr Allan Hall and Dr Tony Fallick, from SURRC, for pointing me in the right directions and plenty of good advice. I am also grateful to Dr Iain Rolfe for his guidance, and for contacts through the East Kirk ton Project; it was helpful to be part of a large scale, multidisciplinary project. Other academic staff, from Glasgow Geology department, that have been actively involved in this project include Dr B. Bell, Dr C. J. Braithwaite, Dr G. Bowes, Dr J.J. Doody, Dr J. Harris, Prof. M. J. Russell, and Prof. D. K. Smythe; Dr A. Boyce and Dr G. Jenkin, from SURRC; I would like to thank them for all their help, and Gordon Walkden for making my work more controversial. The technical assistance that I have received whilst pursuing this project, has been exceptional. Staff at the Chambers Street Museum, Edinburgh prepared thin sections and were very helpful and co-operative with information about the quarry, and access to museum samples; particularly Colin Chaplin, Bob Reekie, Bill Baird and Bobbie Paton. Technicians at the University of Glasgow were also brilliant: Dugald and Murdoch, with XRD analyses (and general moral advice); Dougie for the time he put into the photographs for the thesis and numerous presentations; Roddy and Eddie, lots of help; Jim Gallagher for the geochemistry techniques; Peter Ainsworth with SEM analyses; Alan and Erchie for thin sections, and cut rocks; John, Jimmy and Alec the jannies, for being cheerful and helpful; Jeanette, Mary and Irene in the office. Thanks, also to all the SURRC staff, in Block C: Terry, Alison, wee Julie, Elspeth, Gary and Chris; and to Fred, the glass blower, and Julian Jocelyn for references and his interest in the project. For my friends in the Geology Department; especially Gaz and John for sharing a flat with me for the last year; Carolyn, Mark, Joe, Allison, Susan, Mehmet, Huseyin, Veysel, Helen, Dave D, Campbell, Chris, Richard, Tim, Lynda, John, Simon, Orla, Fish, Morgan, Clark, Peter, Maggie, Janey and her Feldspars. Friends outside of geology; Davy, Jane, Anne, Kirst and Stef, Jean Bell, Marnie, Sandra, Jennifer, Ann and Gordon. Family: especially Mum, Dad, Aunt Ann, Uncle Bill and Dusty. Also to all the people who helped me in the month I spent in New Zealand, especially at the DSIR in Taupo, and Rotorua; Moira Johnstone, Norma & Geoff, and Mr & Mrs Thane, for digs. Lower Carboniferous palaeolatitude being dose to the equator. 834S analyses were made for pyrite samples, collected from a wide variety of lithological assodations at East Kirkton. A large range of results was obtained, +8 to -34 %o with no strong mode, which is consistent with the potential variety of sulphur sources available within a lacustrine environment. The lowest values were obtained for pyrite associated with fossil wood, and for these samples bacterial involvement in sulphate reduction is inferred. Values of +6 to -2 %o are observed for pyrite extracted from chert samples, and this may possibly reflect a direct magmatic/hydrothermal source for the sulphur. It is thought that the East Kirkton results are not consistent with sulphur originating from dosed-system marine sulphate reduction Whole rock analyses, by XRD and XRF, were obtained for thirty-one samples, collected from the five main lithological groups of the East Kirkton succession: Group I are stromatiform carbonate samples; Group II are shales and tuffs; Group El are carbonate-rich tuff samples; Group IV are shaley laminites; and Group V are carbonate-rich laminites. The results of these analyses show that the majority of elements which are found in East Kirkton samples (major and trace elements), are derived from the contemporary volcanic activity in the Bathgate Hills. SiC>2 and CaO are anomalously enriched in the East Kirkton Ethologies, relative to the Bathgate basalts (Smedley, 1986, for basalt analyses). It is thought that a second source from which both elements could be derived, are the Tyninghame or Gullane Formations, carbonate-rich sediments which occur at depth, beneath the East Kirkton Limestone. It is proposed that the elements were remobilised from these sediments via hydrothermal fluids, associated with the volcanic activity. Silica could be precipitated by the mixing of cooler lake waters with these fluids, but the CaO, forming calcite, could have been precipitated via biogenic mediation. Group II samples have the highest concentrations of trace elements. These shales contain clay minerals, on which trace elements may be adsorbed; or trace elements may become concentrated in slowly deposited sediment. Sr values are high in all East Kirkton samples, and it is thought that the Sr- enriched basalts are a likely source. The highest values were obtained for samples containing biogenic carbonate features, like spherules. It would appear that biogenic precipitation mechanisms may also increase concentrations of Sr. CONTENTS THESIS DECLARATION. ACKNOWLEDGEMENTS. ABSTRACT. CHAPTER 1 - INTRODUCTION. Page 1 .1 Background. 1 1 . 2 Aims. 2 1.3 Background Geology. 2 1.4 Description of the East Kirkton Limestone. 3 1.5 Rationale of the project. 4 1 . 6 On the origin and sources of silica in lacustrine deposits. 4 1.6.1 Magadiite precursor to chert. 5 1 .6 . 2 Chertifcation associated with biogenic and volcanogenic silica. 7 1.7 Format of the Thesis. 8 1 . 8 Bibliography. 9 1.9 Figure Captions. 1 2 CHAPTER 2 - PETROGRAPHY AND GEOCHEMISTRY OF A LOWER CARBONIFEROUS, LACUSTRINE, HOT-SPRING DEPO! EAST KIRKTON, BATHGATE, SCOTLAND. 2 . 0 Abstract 18 2 . 1 Introduction. 19 2.1.1 General Background. 19 2.1.2 Palaeoenvironm ent. 2 0 2 . 2 Petrography. 2 1 2.2.1 General Features. 2 1 2.2.2 Silica Textures. 2 1 2.2.3 Spherulites. 2 2 2.3 Stable Isotope Analyses. 23 2.4 Interpretation of Isotope Results. 24 2.5 Conclusions. 25 2 . 6 Acknowledgements. 26 2.7 Bibliography. 27 2 . 8 Figure Captions. 28 Figures. 29 Page CHAPTER 3 - THE EAST KIRKTON PALAEOENVIRONMENT: STABLE ISOTOPE EVIDENCE FROM SILICATES AND SULPHIDES. 3.0 Abstract. 33 3.1 Introduction. 34 3.2 Petrography. 35 3.2.1 Primary Silica. 35 3.2.2 Altered and Secondary Silica. 36 3.2.3 Pyrite. 37 3.3 Analytical Procedures. 38 3.3.1 Silica: sample collection and preparation. 38 3.3.2 Pyrite: sample collection and preparation. 38 3.3.3 Oxygen extraction for 5lsO analyses. 39 3.3.4 Hydrogen extraction for 5D analyses. 39 3.3.5 Sulphur extraction for 534S analyses. 39 3.4 Results. 40 3.4.1 Silica. 40 3.4.2 Pyrite. 40 3.5 Discussion. 41 3.5.1 Oxygen isotopic analyses and their implications for formation temperature. 41 3.5.2 Hydrogen isotope analyses and their implications for formation fluids. 43 3.5.3 Sulphur isotope analyses. 44 3.6 Conclusions. 46 3.7 Acknowledgements. 46 3.8 Bibliography. 47 3.9 Figure Captions. 50 Figures. 53 Tables. 63 CHAPTER 4 - THE INFLUENCE OF VOLCANIC MATERIAL ON THE EAST KIRKTON GEOCHEMICAL SIGNATURE. 4.0 Abstract. 67 4.1 Introduction. 6 8 4.2 Sample collection and petrographic groupings. 6 8 4.3 Analytical Procedures. 69 4.3.1 X-Ray Diffraction. 69 4.3.2 X-Ray Fluorescence. 69 4.3.2.1 Major Element Analyses. 69 4.3.2.2 Minor Element Analyses. 70 Page 4.4 Summaries of geochemical characteristics for each group. 71 4.4.1 Group I: Stromatiform Carbonate Samples. 71 4.4.2 Group II: Black Shales and Tuff Samples. 72 4.4.3 Group II: Carbonate-rich Tuff Samples. 74 4.4.4 Group IV: Shaley Laminite Samples. 75 4.4.5 Group V: Carbonate-rich Laminites. 76 4.5 Interpretation. 78 4.5.1 Correlations between AI 2 O 3 and other 79 major elements. 4.5.1.1 AI2 O3 plotted against Ti 0 2 (and P 2 O5 ). 79 4.5.1 . 2 AI2 O 3 plotted against K 2 O (and Na 2 0 ). 80 4.5.1.3 AI2 O3 plotted against SiCb. 81 4.5.1.4 AI2 O3 plotted against CaO & LOI 82 (and MnO). 4.5.1.5 AI2 O 3 plotted against MgO & Festal- 83 4.5.2 Other major element correlations (not including AI 2 O 3 ). 84 4.5.2.1 MgO plotted against Fe (total). 84 4.5.2.2 MnO plotted against CaO (& LOI).