Hostname: page-component-cd9895bd7-dzt6s Total loading time: 0 Render date: 2024-12-26T16:20:34.736Z Has data issue: false hasContentIssue false
  • English
  • Français

Combined sea-level and climate controls on limestone formation, hiatuses and ammonite preservation in the Blue Lias Formation, South Britain (uppermost Triassic – Lower Jurassic)

Published online by Cambridge University Press:  30 January 2017

GRAHAM P. WEEDON ,
HUGH C. JENKYNS  and
KEVIN N. PAGE
GRAHAM P. WEEDON*
Affiliation:
Met Office, Maclean Building, Benson Lane, Crowmarsh Gifford, Wallingford, Oxfordshire, OX10 8BB, UK
HUGH C. JENKYNS
Affiliation:
Department of Earth Sciences, University of Oxford, South Parks Road, Oxford, OX1 3AN, UK
KEVIN N. PAGE
Affiliation:
School of Geography, Earth and Environmental Sciences, Plymouth University, Drakes Circus, Plymouth, PL4 8AA, UK
*
†Author for correspondence: [email protected]
Get access Rights & Permissions [Opens in a new window]

Abstract

Lithostratigraphic and magnetic-susceptibility logs for four sections in the Blue Lias Formation are combined with a re-assessment of the ammonite biostratigraphy. A Shaw plot correlating the West Somerset coast with the Devon/Dorset coast at Lyme Regis, based on 63 common biohorizon picks, together with field evidence, demonstrate that intra-formational hiatuses are common. Compared to laminated shale deposition, the climate associated with light marl is interpreted as both drier and stormier. Storm-related non-deposition favoured initiation of limestone formation near the sediment–water interface. Areas and time intervals with reduced water depths had lower net accumulation rates and developed a greater proportion of limestone. Many homogeneous limestone beds have no ammonites preserved, whereas others contain abundant fossils. Non-deposition encouraged shallow sub-sea-floor cementation which, if occurring after aragonite dissolution, generated limestones lacking ammonites. Abundant ammonite preservation in limestones required both rapid burial by light marl during storms as well as later storm-related non-deposition and near-surface carbonate cementation that occurred prior to aragonite dissolution. The limestones are dominated by a mixture of early framework-supporting cement that minimized compaction of fossils, plus a later micrograde cement infill. At Lyme Regis, the relatively low net accumulation rate ensured that final cementation of the limestones took place at relatively shallow burial depths. On the West Somerset coast, however, much higher accumulation rates led to deeper burial before final limestone cementation. Consequently, the oxygen-isotope ratios of the limestones on the West Somerset coast, recording precipitation of the later diagenetic calcite at higher temperatures, are lower than those at Lyme Regis.

Keywords

sedimentary cyclessea levelclimatic cyclesBlue Lias Formationdiagenesishiatuses
Type
Original Article
Information
Geological Magazine , Volume 155 , Issue 5 , July 2018 , pp. 1117 - 1149
Copyright
Copyright © Cambridge University Press 2017 

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Ager, D. 1986. A reinterpretation of the basal ‘Littoral Lias’ of the Vale of Glamorgan. Proceedings of the Geologists’ Association 97, 29–35.Google Scholar
Allison, P. A., Hesselbo, S. P. & Brett, C. A. 2008. Methane seeps on an Early Jurassic seafloor. Palaeogeography, Palaeoclimatology, Palaeoecology 270, 230–8.CrossRefGoogle Scholar
Ambrose, K. 2001. The lithostratigraphy of the Blue Lias Formation (Late Rhaetian–Early Sinemurian) in the southern part of the English Midlands. Proceedings of the Geologists’ Association 112, 97–110.Google Scholar
Arzani, N. 2004. Diagenetic evolution of mudstones: black shales to laminated limestones, an example from the Lower Jurassic of SW Britain. Journal of Sciences Islamic Republic of Iran 15, 257–67.Google Scholar
Arzani, N. 2006. Primary versus diagenetic bedding in the limestone-marl/shale alternations of the epeiric seas, an example from the Lower Lias (Early Jurassic) of SW Britain. Carbonates and Evaporites 21, 94–109.CrossRefGoogle Scholar
Barras, C. G. & Twitchett, R. J. 2007. Response of the marine infauna to Triassic–Jurassic environmental change: ichnological data from southern England. Palaeogeography, Palaeoclimatology, Palaeoecology 244, 223–41.CrossRefGoogle Scholar
Bixler, W. G., Elmore, R. D. & Engel, M. H. 1998. The origin of magnetization and geochemical alteration in a fault zone, Kilve, England. Geological Journal 33, 89–105.Google Scholar
Bleil, S. & Petersen, N. 1987. Magnetic properties of natural minerals. In Physical Properties of Rocks, Volume 1, Subvolume B (ed. Angenheister, G.), pp. 308–65. Berlin: Springer.Google Scholar
Bloos, G. & Page, K. N. 2000a. The basal Jurassic ammonite succession in the North-West European Province – review and new results. In Advances in Jurassic Research 2000. Proceedings of the Fifth International Symposium on the Jurassic System (eds Hall, R. L. & Smith, P.), pp. 27–40. GeoResearch Forum 6, Trans Tech Publications.Google Scholar
Bloos, G. & Page, K. N. 2000 b. The proposed GSSP for the base of the Sinemurian Stage near East Quantoxhead/West Somerset (SW England) – the ammonite sequence. In Advances in Jurassic Research 2000. Proceedings of the Fifth International Symposium on the Jurassic System (eds Hall, R. L. & Smith, P. L.), pp. 13–26. GeoResearch Forum 6, Trans Tech Publications.Google Scholar
Bloos, G. & Page, K. N. 2002. The Global Stratotype Section and Point for base of the Sinemurian Stage (lower Jurassic). Episodes 25, 22–8.Google Scholar
Bonis, N. A., Ruhl, M. & Kürschner, W. M. 2010. Milankovitch-scale palynological turnover across the Triassic–Jurassic transition at St. Audrie's Bay, SW UK. Journal of the Geological Society, London 167, 877–88.CrossRefGoogle Scholar
Bottrell, S. & Raiswell, R. 1989. Primary versus diagenetic origin of Blue Lias rhythms (Dorset, UK): evidence from sulphur geochemistry. Terra Nova 1, 457–56.CrossRefGoogle Scholar
Bown, P.R. 1987. Taxonomy, evolution, and biostratigraphy of late Triassic–early Jurassic calcareous nannofossils. Special Papers in Palaeontology 38, 1–118.Google Scholar
Bown, P. R. & Cooper, M. K. E. 1998. Jurassic. In Calcareous Nannofossil Biostratigraphy (ed. Bown, P. R.), pp. 34–85. British Micropalaeontological Society Publications Series. New York: Springer Science+Business Media.Google Scholar
Bromley, R. G. & Ekdale, A. A. 1984. Chondrites: a trace fossil indicator of anoxia in sediments. Science 224, 872–4.Google Scholar
Bukri, P. M., Dent Glasser, L. S. & Smith, D. N. 1982. Surface coatings on ancient coccoliths. Nature 297, 145–7.Google Scholar
Callomon, J. 1985. Biostratigraphy, chronostratigraphy and all that – again! In International Symposium on Jurassic Stratigraphy, Erlangen 1984 (eds Michelsen, O., , O. & Zeiss, A. A.), pp. 611–24. Geological Survey of Denmark, Copenhagen 3.Google Scholar
Callomon, J. 1995. Time from fossils: S.S. Buckman and Jurassic high-resolution geochronology. Milestones in Geology (ed. Le Bas, M. L.), pp. 127–50. Geological Society of London, Memoirs no. 16.Google Scholar
Campos, J. G. & Hallam, A. 1979. Diagenesis of English Lower Jurassic limestones as inferred from oxygen and carbon isotope analysis. Earth and Planetary Science Letters 45, 23–31.CrossRefGoogle Scholar
Clémence, M-E., Bartolini, A., Gardin, S., Paris, G., Beaumont, V. & Page, K. N. 2010. Early Hettangian benthic-planktonic coupling at Doniford (SW England). Palaeoenvironmental implications from the aftermath of the end-Triassic crisis. Palaeogeography, Palaeoclimatology, Paleoecology 295, 102–15.Google Scholar
Clements, R. G. & Members of the Field Studies in Local Geology Class. 1975. The Geology of the Long Itchington Quarry (Rugby Portland Cement Co. Ltd., Southam Works). Percival Guildhall, Rugby and Department of Geology, University of Leicester, 30 pp.Google Scholar
Clements, R. G. & Members of the Field Studies in Local Geology Class, Percival Guildhouse, Rugby. 1977. The Geology of the Parkfield Quarry, Rugby (Rugby Portland Cement Co. Ltd., Rugby Works, Rugby, Warwickshire). Department of Geology, University of Leicester, 54 pp.Google Scholar
Collinson, D. W. 1983. Methods in Rock Magnetism and Palaeomagnetism: Techniques and Instrumentation. London: Chapman and Hall, 503 pp.Google Scholar
Cornford, C. 2003. Triassic palaeopressure and Liassic mud volcanoes near Kilve, west Somerset. Geoscience in South-West England 10, 430–4.Google Scholar
Curtis, C. D., Cope, J. C. W., Plant, D. & Macquaker, J. H. S. 2000. ‘Instantaneous’ sedimentation, early microbial sediment strengthening and a lengthy record of chemical diagenesis preserved in Lower Jurassic ammonitiferous concretions from Dorset. Journal of the Geological Society, London 157, 165–77.CrossRefGoogle Scholar
Day, E. C. H. 1865. On the Lower Lias of Lyme Regis. Geological Magazine 2, 518–9.Google Scholar
Deconinck, J.-F., Hesselbo, S. P., Debuisser, N., Averbuch, O., Baudin, F. & Bessa, J. 2003. Environmental controls on clay mineralogy of an Early Jurassic mudrock (Blue Lias Formation, southern England). International Journal of Earth Sciences 92, 255–66.Google Scholar
Donovan, D. T. 1956. The zonal stratigraphy of the Blue Lias around Keynsham, Somerset. Proceedings of the Geologists’ Association 66, 182–212.CrossRefGoogle Scholar
Donovan, D. T., Horton, A. & Ivimey-Cook, H. C. 1979. The transgression of the Lower Lias over the northern flank of the London Platform. Journal of the Geological Society, London 136, 165–73.Google Scholar
Donovan, D. T. & Kellaway, G. A. 1984. Geology of the Bristol District; the Lower Jurassic Rocks. Memoir for 1:63360 Bristol Geological Special Sheet. London: HMSO, 69 pp.Google Scholar
Fleet, A. J., Clayton, C. J., Jenkyns, H. C. & Parkinson, D. N. 1987. Liassic source rock deposition in Western Europe. In Petroleum Geology of North-West Europe, 1 (eds Brooks, J. & Glennie, K.), pp. 59–70. London: Graham & Trotman.Google Scholar
Fletcher, C. J. N. 1988. Tidal erosion, solution cavities and exhalative mineralization associated with the Jurassic unconformity at Ogmore, South Glamorgan. Proceedings of the Geologists’ Association 99, 1–14.CrossRefGoogle Scholar
Gallois, R. W. & Paul, C. R. C. 2009. Lateral variations in the topmost part of the Blue Lias and basal Charmouth Mudstone Formations (Lower Jurassic) on the Devon and Dorset Coast. Geoscience in South-West England 12, 125–33.Google Scholar
Gluyas, J. G. 1984. Early carbonate diagenesis within Phanerozoic shales and sandstones of the NW European shelf. Clay Minerals 19, 309–21.Google Scholar
Hall, A. & Kennedy, W. J. 1967. Aragonite in fossils. Philosophical Transactions of the Royal Society, London B168, 377–412.Google Scholar
Hallam, A. 1960. A sedimentary and faunal study of the Blue Lias of Dorset and Glamorgan. Philosophical Transactions of the Royal Society, London B243, 1–44.Google Scholar
Hallam, A. 1964. Origin of limestone-shale rhythms in the Blue Lias of England: a composite theory. Journal of Geology 72, 157–69.Google Scholar
Hallam, A. 1981. A revised sea-level curve for the early Jurassic. Journal of the Geological Society, London 138, 735–43.CrossRefGoogle Scholar
Hallam, A. 1986. Origin of minor limestone-shale cycles: climatically induced or diagenetic? Geology 14, 609–12.Google Scholar
Hallam, A. 1987. Reply to Weedon, 1987 Comment on: ‘Origin of limestone-shale cycles: climatically induced or diagenetic?’ Geology 15, 93–4.Google Scholar
Hallam, A. 1997. Estimates of the amount and rate of sea-level change across the Rhaetian–Hettangian and Pliensbachian–Toarcian boundaries (latest Triassic to early Jurassic). Journal of the Geological Society, London 154, 773–9.Google Scholar
Hallam, A. & Bradshaw, M. J. 1979. Bituminous shales and oolitic ironstones as indicators of transgression and regression. Journal of the Geological Society, London 136, 157–64.CrossRefGoogle Scholar
Hamilton, G. B. 1982. Triassic and Jurassic calcareous nannofossils. In A Stratigraphical Index of Calcareous Nannofossils (ed. Lord, A. R.), pp. 17–39. British Micropalaeontological Society Series. Chichester: Ellis Horwood.Google Scholar
Hanzo, M., Lathuilière, B., Alméras, Y., Dagallier, G., Guérin-Franiatte, S., Guillocheau, F., Huault, V., Nori, L. & Rauscher, R. 2000. Paléoenvironnements dans le Calcaire à gryphées du Lias de Lorraine, de la carrière de Xeuilley au Bassin parisien. Eclogae Geologicae Helvetiae 93, 183–206.Google Scholar
Hays, J. D., Imbrie, J. & Shackleton, N. J. 1976. Variations in the Earth's orbit: pacemaker of the ice ages. Science 194, 1121–32.Google Scholar
Hesselbo, S. P. 2008. Sequence stratigraphy and inferred relative sea-level change from the onshore British Jurassic. Proceedings of the Geologists’ Association 119, 19–34.CrossRefGoogle Scholar
Hesselbo, S. P. & Jenkyns, H. C. 1995. A comparison of the Hettangian to Bajocian successions of Dorset and Yorkshire. In Field Geology of the British Jurassic (ed. Taylor, P. D.), pp. 105–50. London: The Geological Society.Google Scholar
Hesselbo, S. P. & Jenkyns, H. C. 1998. British Lower Jurassic sequence stratigraphy. In Mesozoic and Cenozoic Sequence Stratigraphy of European Basins (eds Hardenbol, J., Thierry, J., Farley, M. B., Jacquin, T., de Graciansky, P.-C. & Vail, P.), pp. 562–81. Society of Sedimentary Geology (SEPM) Special Publication no. 60.Google Scholar
Hesselbo, S. P., Robinson, S. A. & Surlyk, F. 2004. Sea-level change and facies development across potential Triassic–Jurassic boundary horizons, SW Britain. Journal of the Geological Society, London 161, 365–79.Google Scholar
Hillebrandt, A. V. & Krystyn, L. 2009. On the oldest Jurassic ammonites of Europe (Northern Calcareous Alps, Austria) and their global significance. Neues Jahrbuch für Geologie und Paläontologie, Abhandlungen 253, 163–95.Google Scholar
Hillebrandt, A. V., Krystyn, L. & Kuerschner, W. M. 2007. A candidate GSSP for the base of the Jurassic in the Northern Calcareous Alps (Kuhjoch section, Karwendel Mountains, Tyrol, Austria). International Sub-Commission on Jurassic Stratigraphy Newsletter 34, 2–20.Google Scholar
Hodges, P. 1986. The Lower Lias (Lower Jurassic) of the Bridgend area, South Wales. Proceedings of the Geologists’ Association 97, 237–42.CrossRefGoogle Scholar
Hodges, P. 1994. The base of the Jurassic System: new data on the first appearance of Psiloceras planorbis in southwest Britain. Geological Magazine 131, 841–44.CrossRefGoogle Scholar
Hounslow, M. W. 1985. Magnetic fabric arising from paramagnetic phyllosilicate minerals in mudrocks. Journal of the Geological Society, London 142, 995–1106.Google Scholar
Hounslow, M. W., Posen, P. E. & Warrington, G. 2004. Magnetostratigraphy and biostratigraphy of the Upper Triassic and lowermost Jurassic succession, St. Audrie's Bay, UK. Palaeogeography, Palaeoclimatology, Palaeoecology 213, 331–58.Google Scholar
House, M. R. 1985. A new approach to an absolute time scale from measurements of orbital cycles and sedimentary microrhythms. Nature 313, 17–22.Google Scholar
House, M. R. 1986. Are Jurassic microrhythms due to orbital forcing? Proceedings of the Ussher Society 6, 299–311.Google Scholar
Hudson, J. D. & Martill, D. M. 1991. The Lower Oxford Clay: production and preservation of organic matter in the Callovian (Jurassic) of central England. In Modern and Ancient Continental Shelf Anoxia (eds Tyson, R. V. & Pearson, T. H.), pp. 363–79. Geological Society of London, Special Publication no. 58.Google Scholar
Jenkyns, H. C., Jones, C. E., Gröcke, D. R., Hesselbo, S. P. & Parkinson, D. N. 2002. Chemostratigraphy of the Jurassic System: applications, limitations and implications for palaeoceanography. Journal of the Geological Society, London 159, 351–78.CrossRefGoogle Scholar
Jenkyns, H. C. & Senior, J. R. 1991. Geological evidence for intra-Jurassic faulting in the Wessex Basin and its margins. Journal of the Geological Society, London 148, 245–60.Google Scholar
Johnson, M. E. & McKerrow, W. S. 1995. The Sutton Stone: an early Jurassic rocky shoreline deposit in South Wales. Palaeontology 38, 529–41.Google Scholar
Kent, P. E. 1936. The formation of hydraulic limestones of the Lower Lias. Geological Magazine 73, 476–8.Google Scholar
Kent, P. E. 1937. The Lower Lias of South Nottinghamshire. Proceedings of the Geologist's Association 48, 163–74.Google Scholar
Korte, C., Hesselbo, S. P., Jenkyns, H. C., Rickaby, R. E. & Spotl, C. 2009. Palaeoenvironmental significance of carbon- and oxygen-isotope stratigraphy of marine Triassic–Jurassic boundary sections in SW Britain. Journal of the Geological Society, London 166, 432–45.CrossRefGoogle Scholar
Lang, W. D. 1924. The Blue Lias of the Devon and Dorset Coasts. Proceedings of the Geologists’ Association 35, 169–84.Google Scholar
Lees, J. A., Bown, P. R. & Young, J. R. 2006. Photic zone palaeoenvironments of the Kimmeridge Clay Formation (Upper Jurassic, UK) suggested by calcareous nannoplankton palaeoecology. Palaeogeography, Palaeoclimatology, Palaeoecology 235, 110–34.Google Scholar
Marshall, J. D. 1982. Isotopic composition of displacive fibrous calcite veins: reversals in pore-water composition trends during burial diagenesis. Journal of Sedimentary Petrology 52, 615–30.Google Scholar
Milner, A. C. & Walsh, S. 2010. Reptiles. In Fossils from the Lower Lias of the Dorset Coast (eds Lord, A. R. & Davis, P. G.), pp. 372–94. London: Palaeontological Association.Google Scholar
Moghadam, H. V. & Paul, C. R. C. 2000. Trace fossils of the Jurassic, Blue Lias, Lyme Regis, Southern England. Ichnos 7, 283–306.Google Scholar
O'Brien, L. J., Braddy, S. J. & Radley, J. D. 2009. A new arthropod resting trace and associated suite of trace fossils from the Lower Jurassic of Warwickshire, England. Palaeontology 52, 1099–112.CrossRefGoogle Scholar
Odin, G. S. & Matter, A. 1981. De glauconiarum origine. Sedimentology 28, 611–41.Google Scholar
Ogg, J. G. & Hinnov, L. A. 2012. Jurassic. In The Geologic Time Scale 2012 (eds Gradstein, F. M., Ogg, J. G., Schmitz, M. & Ogg, G.), pp. 731–91. Amsterdam: Elsevier.Google Scholar
Old, R. A., Sumbler, M. G. & Ambrose, K. 1987. Geology of the Country around Warwick. Memoir of the British Geological Survey Sheet 84 (England and Wales).Google Scholar
Page, K. N. 1992. The sequence of ammonite-correlated horizons in the British Sinemurian (Lower Jurassic). Newsletters on Stratigraphy 27, 129–56.Google Scholar
Page, K. N. 1995. East Quantoxhead, Somerset, England: a potential Global Stratigraphic Section and Point (GSSP) for the base of the Sinemurian Stage (Lower Jurassic). Proceedings of the Ussher Society 9, 446–50.Google Scholar
Page, K. N. 2002. A review of the ammonite faunas and standard zonation of the Hettangian and Lower Sinemurian succession (Lower Jurassic) of the East Devon Coast (South West England). Geoscience in South-West England 10, 293–303.Google Scholar
Page, K. N. 2003. The Lower Jurassic of Europe – its subdivision and correlation. In The Jurassic of Denmark and Adjacent Areas (eds Ineson, J., & Surlyk, F.), pp. 23–59. Geological Survey of Denmark and Greenland, Bulletin 1.Google Scholar
Page, K. N. 2005. The Hettangian ammonite faunas of the west Somerset Coast (South West England) and their significance for the correlation of the candidate GSSP (Global Stratotype and Point) for the base of the Jurassic System at St. Audries Bay. In Còlloque l'Hettangien à Hettange de la Science au Patrimoine, pp. 15–19. Université Henri Poincarré.Google Scholar
Page, K. N. 2010a. High resolution ammonite stratigraphy of the Charmouth Mudstone Formation (Lower Jurassic: Sinemurian–Lower Pliensbachian) in south-west England, UK. Volumina Jurassica 7, 19–29.Google Scholar
Page, K. N. 2010b. Stratigraphical framework. In Fossils from the Lower Lias of the Dorset Coast (eds Lord, A. R. & Davis, P. G.), pp. 33–53. Palaeontological Association Field Guides to Fossils 13.Google Scholar
Page, K. N. 2010c. Ammonites. In Fossils from the Lower Lias of the Dorset Coast (eds Lord, A. R. & Davis, P. G.), pp. 169–261. Palaeontological Association Field Guides to Fossils 13.Google Scholar
Page, K. N. In press. From Oppel to Callomon (and beyond!): building a high resolution ammonite-based biochronology for the Jurassic System. Lethaia.Google Scholar
Page, K. N. & Bloos, G. 1995. The base of the Jurassic System in West Somerset, South-West England – new observations on the succession of ammonite faunas of the lowermost Hettangian Stage. Geoscience in South-West England 9, 231–35.Google Scholar
Page, K. N., Bloos, G., Bessa, J. L., Fitzpatrick, M., Hart, M. B., Hesselbo, S., Hylyon, M., Morris, A. & Randall, D. E. 2000. East Quantoxhead, Somerset: a candidate Global Stratotype Section and Point for the base of the Sinemurian Stage (Lower Jurassic). In Advances in Jurassic Research 2000, Proceedings of the Fifth International Symposium on the Jurassic System (eds Hall, R. L. & Smith, P. L.), pp. 163–72. GeoResearch Forum 6, Trans Tech Publications.Google Scholar
Palmer, C. P. 1972. The Lower Lias (Lower Jurassic) between Watchet and Lilstock in North Somerset (United Kingdom). Newsletters on Stratigraphy 2, 1–30.Google Scholar
Paul, C. R. C., Allison, P.A. & Brett, C. E. 2008. The occurrence and preservation of ammonites in the Blue Lias Formation (lower Jurassic) of Devon and Dorset, England and their palaeoecological, sedimentological and diagenetic significance. Palaeogeography, Palaeoclimatology, Palaeoecology 270, 258–72.Google Scholar
Paris, G., Beaumont, V., Bartolini, A., Clémence, M.-E. & Gardin, S. 2010. Nitrogen isotope record of a perturbed paleoecosystem in the aftermath of the end-Triassic crisis, Doniford section, SW England. Geochemistry, Geophysics, Geosystems 11, Q08021, doi: 10.1029/2010GC003161.Google Scholar
Pearson, S. J., Marshall, J. E. A. & Kemp, A. E. S. 2004. The White Stone Band of the Kimmeridge Clay Formation, an integrated high-resolution approach to understanding environmental change. Journal of the Geological Society, London 161, 675–83.Google Scholar
Price, G. D., Vowles-Sheridan, N. & Anderson, M. W. 2008. Lower Jurassic mud volcanoes and methane, Kilve, Somerset, UK. Proceedings of the Geologists’ Association 119, 193–201.Google Scholar
Radley, J. D. 2008. Seafloor erosion and sea-level: Early Jurassic Blue Lias Formation of central England. Palaeogeography, Palaeoclimatology, Palaeoecology 270, 287–94.Google Scholar
Raiswell, R. 1988. Chemical model for the origin of minor limestone-shale cycles by anaerobic methane oxidation. Geology 16, 641–44.Google Scholar
Raiswell, R. & Fisher, Q. J. 2000. Mudrock-hosted carbonate concretions: a review of growth mechanisms and their influence on chemical and isotopic composition. Journal of the Geological Society, London 157, 239–51.Google Scholar
Richardson, L. 1905. The Rhaetic and contiguous deposits of Glamorganshire. Quarterly Journal of the Geological Society, London 61, 385–424.Google Scholar
Richardson, W. A. 1923. Petrology of the Shales-with-‘Beef’. Quarterly Journal of the Geological Society, London 79, 88–98.Google Scholar
Ruhl, M., Deenen, M. H. L., Abels, H. A., Bonis, N. R., Krijgsman, W. & Kürschner, W. M. 2010. Astronomical constraints on the duration of the early Jurassic Hettangian stage and recovery rates following the end-Triassic mass extinction (St. Audrie's Bay/East Quantoxhead, UK). Earth and Planetary Science Letters 296, 262–76.Google Scholar
Ruhl, M., Hesselbo, S. P., Hinnov, L., Jenkyns, H. C., Xu, W., Riding, J. B., Storm, M., Minisini, D., Ullmann, C. V. & Leng, M. J. 2016. Astronomical constraints on the duration of the Early Jurassic Pliensbachian Stage and global climatic fluctuations. Earth and Planetary Science Letters 455, 149–65.Google Scholar
Seilacher, A. 2007. Trace Fossil Analysis. Berlin: Springer, 226 pp.Google Scholar
Sellwood, B. W. 1970. The relation of trace fossils to small-scale sedimentary cycles in the British Lias. In Trace Fossils (eds Crimes, T. R. & Harper, J. C.), pp. 489–504. Geological Journal Special Issue 3.Google Scholar
Sellwood, B. W. & Jenkyns, H. C. 1975. Basins and swells and the evolution of an epeiric sea (Pliensbachian–Bajocian of Great Britain). Journal of the Geological Society, London 131, 373–88.Google Scholar
Sheppard, H. T. 2006. Sequence architecture of ancient rocky shorelines and their response to sea-level change: an Early Jurassic example from South Wales, UK. Journal of the Geological Society, London 163, 595–606.CrossRefGoogle Scholar
Sheppard, H. T., Houghton, R. D. & Swan, A. R. H. 2006. Bedding and pseudo-bedding in the Early Jurassic of Glamorgan: deposition and diagenesis of the Blue Lias in South Wales. Proceedings of the Geologists’ Association 117, 249–64.Google Scholar
Shukri, N. M. 1942. Rhythmic bedding in the Lower Lias of England. Faculty of Science Fouad I University Cairo Bulletin 24, 66–73.Google Scholar
Simms, M. J. 2004. British Lower Jurassic Stratigraphy: an Introduction. In British Lower Jurassic Stratigraphy (eds Simms, M. J., Chidlaw, N., Morton, N. & Page, K. N.), pp. 3–51. Geological Conservation Review Series 30.Google Scholar
Simms, M. J., Little, C. T. S. & Rosen, B. R. 2002. Corals not serpulids: mineralized colonial fossils in the Lower Jurassic marginal facies of South Wales. Proceedings of the Geologists’ Association 113, 31–6.Google Scholar
Smith, D. G. 1989. Stratigraphic correlation of presumed Milankovitch cycles in the Blue Lias (Hettangian to earliest Sinemurian), England. Terra Nova 1, 457–60.Google Scholar
Smith, A. G., Smith, D. G. & Funnell, B. M. 1994. Atlas of Mesozoic and Cenozoic Coastlines. Cambridge: Cambridge University Press, 99 pp.Google Scholar
Trueman, A. E. 1920. The Liassic rocks of the Cardiff District. Proceedings of the Geologists’ Association 31, 93–107.Google Scholar
Trueman, A. E. 1922. The Liassic rocks of Glamorgan. Proceedings of the Geologists’ Association 33, 245–84.Google Scholar
Trueman, A. E. 1930. The Lower Lias (Bucklandi Zone) of Nash Point, Glamorgan. Proceedings of the Geologists’ Association 61, 149–59.Google Scholar
Van Buchem, F. S. P., McCave, I. N. & Weedon, G. P. 1994. Orbitally induced small-scale cyclicity in a siliciclastic epicontinental setting (Lower Lias, Yorkshire, UK). In Orbital Forcing and Cyclic Sequences (eds de Boer, P.L. & Smith, D.G.), pp. 345–66. International Association of Sedimentologists Special Publication 19.Google Scholar
van de Schootbrugge, B., Tremolada, F., Rosenthal, Y., Bailey, T. R., Feist-Burkhardt, S., Brinkhuis, H., Pross, J., Kent, D. V. & Falkowski, P. G. 2007. End-Triassic calcification crisis and blooms of organic-walled ‘disaster species’. Palaeogeography, Palaeoclimatology, Palaeoecology 244, 126–41.Google Scholar
Warrington, G. & Ivimey-Cook, H. C. 1995. The Late Triassic and Early Jurassic of coastal sections in west Somerset and South and Mid-Glamorgan. In Field Geology of the British Jurassic (ed Taylor, P. D.), pp. 9–30. London: The Geological Society.Google Scholar
Waterhouse, H. K. 1999a. Orbital forcing of palynofacies in the Jurassic of France and the United Kingdom. Geology 27, 511–14.Google Scholar
Waterhouse, H. K. 1999b. Regular terrestrially derived palynofacies cycles in irregular marine sedimentary cycles, Lower Lias, Dorset, UK. Journal of the Geological Society, London 156, 1113–24.Google Scholar
Waters, R. A. & Lawrence, D. J. D. 1987. Geology of the South Wales Coalfield, Part III, the Country around Cardiff. Memoir for the 1:50000 Geological Sheet 263 (England and Wales). London: HMSO.Google Scholar
Weedon, G. P. 1985. Palaeoclimatic information from ancient pelagic and hemipelagic cyclic sediments. Terra Cognita 5, 110.Google Scholar
Weedon, G. P. 1986. Hemipelagic shelf sedimentation and climatic cycles: the basal Jurassic (Blue Lias) of South Britain. Earth and Planetary Science Letters 76, 321–35.CrossRefGoogle Scholar
Weedon, G. P. 1987a. Palaeoclimatic significance of open-marine cyclic sequences. D. Phil. Thesis, University of Oxford, Oxford, UK. Published thesis. Two volumes available at: https://ora.ox.ac.uk/objects/uuid:aa009e6b-d429-4340-b3c5-30f5227f0148.Google Scholar
Weedon, G. P. 1987b. Comment on: ‘Origin of limestone-shale cycles: climatically induced or diagenetic?’ by Hallam, A., 1986. Geology 15, 92–4.Google Scholar
Weedon, G. P. & Jenkyns, H. C. 1999. Cyclostratigraphy and the Early Jurassic time scale: data from the Belemnite Marls, Dorset, southern England. Geological Society of America Bulletin 111, 1823–40.2.3.CO;2>CrossRefGoogle Scholar
Weedon, G. P., Jenkyns, H. C., Coe, A. L. & Hesselbo, S. P. 1999. Astronomical calibration of the Jurassic time-scale from cyclostratigraphy in British mudrock formations. Philosophical Transactions of the Royal Society, London 357, 1787–813.Google Scholar
Whittaker, A. & Green, G. W. 1983. Geology of the Country around Weston-super-Mare. Memoir for the 1:50000 Geological Sheet 279, new series with parts of sheets 263 and 295. London: HMSO.Google Scholar
Whittaker, A., Holliday, D. W. & Penn, I. E. 1985. Geophysical Logs in British Stratigraphy. Geological Society Special Report 18. London: The Geological Society, 74 pp.Google Scholar
Wignall, P. B. 2001. Sedimentology of the Triassic-Jurassic boundary beds in Pinhay Bay (Devon, SW England). Proceedings of the Geologists’ Association 112, 349–60.CrossRefGoogle Scholar
Williams, R. B. G. 1984. Introduction to Statistics for Geographers and Earth Scientists. London: MacMillan, 349 pp.Google Scholar
Wilson, D., Davies, J. R., Fletcher, C. J. N. & Smith, M. 1990. Geology of the South Wales Coalfield, Part VI, the Country around Bridgend. Memoir for the 1:50000 geological sheets 261 and 262 (England and Wales). London: HMSO.Google Scholar
Wobber, F. J. 1963. A directional structure from the Lower Jurassic of Great Britain. Journal of Sedimentary Petrology 34, 692–3.Google Scholar
Wobber, F. J. 1965. Sedimentology of the Lias (Lower Jurassic) of South Wales. Journal of Sedimentary Petrology 35, 683–703.Google Scholar
Wobber, F. J. 1966. A study of the depositional area of the Glamorgan Lias. Proceedings of the Geologists’ Association 77, 127–37.Google Scholar
Wright, V. P., Cherns, L. & Hodges, P. 2003. Missing molluscs: field testing taphonomic loss in the Mesozoic through large-scale aragonite dissolution. Geology 31, 211–4.Google Scholar
Young, J. R. & Bown, P. R. 1991. An ontogenetic sequence of coccoliths from the Late Jurassic Kimmeridge Clay of England. Palaeontology 4, 843–50.Google Scholar