Hostname: page-component-78c5997874-mlc7c Total loading time: 0 Render date: 2024-11-03T05:23:11.809Z Has data issue: false hasContentIssue false

Depositional environments within Middle Jurassic oyster-dominated lagoons: an integrated litho-, bio- and palynofacies study of the Duntulm Formation (Great Estuarine Group, Inner Hebrides)

Published online by Cambridge University Press:  03 November 2011

Julian E. Andrews
Affiliation:
School of Environmental Sciences, University of East Anglia, Norwich, NR47TJ, U.K.
William Walton
Affiliation:
Stratigraphic Laboratory, B.P. Development Ltd., Farburn Industrial Estate, Dyce, Aberdeen, AB2 OPB, U.K.

Abstract

The Duntulm Formation of the Bathonian (Middle Jurassic) Great Estuarine Group represents a marine-brackish lagoonal complex which was transgressively established on the drowned delta of the underlying Valtos Sandstone Formation. Duntulm Formation sediments accumulated in adjacent basins, the Sea of the Hebrides-and Inner Hebrides-basins. Litho-, bio-, and palynofacies analysis of these rocks show that the most distinctive lithologies, monotypic shell banks of the oyster Praeexogyra hebridica (Lithofacies 1), accumulated under variable, but distinctly marine conditions. Argillaceous carbonate muds (Lithofacies 2), probably accumulated in the lee of the oyster banks under variably marine-freshwater conditions, while the supralittoral lagoon shores were fringed by algal marshes (Lithofacies 3). The palynology of Lithofacies 3 shows that some marshes accumulated close to the lagoon (dominated by marine dinocysts), while others formed further inland (dominated by terrestrial pollen and spores). In the N of the Sea of the Hebrides Basin, small deltas continued to prograde into the lagoons (Lithofacies 4), and toward the end of Duntulm Formation times, muds and sands colonised by freshwater molluscs (Unio and Neomiodon), the planktonic alga Botryococcus, and dominated by terrestrial pollen and spores (Lithofacies 5), accumulated in this area, representing a basin-wide change from marine to freshwater conditions. The structural high which divided the basins exerted a strong control on lithofacies evolution, effectively preventing any material coarser than silt grade entering the Inner Hebrides Basin. Thickness variation in the Formation is similarly structurally/facies linked, with thick sequences accumulating where sandstones (Lithofacies 4) predominate, and thin sequences occurring close to the structural high.

Type
Research Article
Copyright
Copyright © Royal Society of Edinburgh 1990

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. V. & Wallace, P. 1970. The distribution and significance of trace fossils in the uppermost Jurassic rocks of the Boulonnais, Northern France. In Crimes T. P. & Harper J. C. (eds) Trace Fossils, 1–18. Geological Journal Special Issue No. 3. Liverpool: Seel House Press.Google Scholar
Aigner, T. 1985. Storm Depositional Systems (Lecture notes in Earth Sciences, 3). Berlin: Springer.Google Scholar
Anderson, F. W. 1948. Algal beds in the Great Estuarine Series of Skye. R PHYS SOC 23, 123141.Google Scholar
Anderson, F. W. & Dunham, K. C. 1966. The Geology of Northern Skye. MEM GEOL SURV SCOTLAND.Google Scholar
Anderton, R., Bridges, P. H., Leeder, M. R. & Sellwood, B. W. 1979. A Dynamic Stratigraphy of the British Isles. London: Allen and Unwin.Google Scholar
Andrews, J. E. 1984. Aspects of Sedimentary Facies and Diagenesis in Limestone-Shale Formations of the (Middle Jurassic) Great Estuarine Group, Inner Hebrides. Unpublished Ph.D. Thesis, University of Leicester.Google Scholar
Andrews, J. E. 1985. The sedimentary facies of a late Bathonian regressive episode: the Kilmaluag and Skudiburgh Formations of the Great Estuarine Group, Inner Hebrides, Scotland. J GEOL SOC LONDON 142, 11191137.CrossRefGoogle Scholar
Andrews, J. E. 1986a. Microfacies and geochemistry of Middle Jurassic algal limestones from Scotland. SEDIMENTOLOGY 33, 499520.CrossRefGoogle Scholar
Andrews, J. E. 1986b. Tube-like microproblematica as environmental and stratigraphic indicators in British Jurassic lagoonal deposits. PALAIOS 1, 8586.CrossRefGoogle Scholar
Andrews, J. E. 1987. Jurassic clay-mineral assemblages and their post depositional alteration: upper Great Estuarine Group, Scotland. GEOL MAG 124, 261271.CrossRefGoogle Scholar
Binns, P. E., McQuillan, R., Fannin, N. G. T., Kenolty, N. & Ardus, D. A. 1975. Structure and stratigraphy of sedimentary basins in the Sea of the Hebrides and the Minches. In Woodland, A. W. (ed.) Petroleum and the Continental Shelf of North West Europe. 1. Geology, 93102. Barking, Essex: Applied Science Publishers.Google Scholar
Bradshaw, M. J. 1978. A Facies Analysis of the Bathonian of Eastern England. Unpublished D. Phil. Thesis, University of Oxford.Google Scholar
Bradshaw, M. J. & Penney, S. R. 1982. A cored Jurassic sequence from north Lincolnshire, England: stratigraphy, facies analysis and regional context. GEOL MAG 119, 113228.CrossRefGoogle Scholar
Bromley, R. G. 1970. Borings as trace fossils and Enthobia cretacea Portlock, as an example. In Crimes, T. P. & Harper, J. C. (eds) Trace Fossils, 4990. Geological Journal Special Issue No. 3. Liverpool: Seel House Press.Google Scholar
Brown, P. R. 1963. Algal limestones and associated sediments in the basal Purbeck of Dorset. GEOL MAG 100, 565573.CrossRefGoogle Scholar
Brown, S. 1984. Chapter 6: Jurassic. In Glennie, K. W. (ed.) Introduction to the Petroleum Geology of the North Sea, 103131. Oxford: Blackwell Scientific Publications.Google Scholar
Elliott, T. 1986. Chapter 6-Deltas. In Reading, H. G. (ed.) Sedimentary Environments and Facies, 2nd edn, 113–54. Oxford: Blackwell Scientific Publications.Google Scholar
El-Shahat, A. & West, I. M. 1983. Early and late lithification of aragonite bivalve beds in the Purbeck Formation (Upper Jurassic-Lower Cretaceous) of southern England. SEDIMENT GEOL 35, 1541.CrossRefGoogle Scholar
Ensom, P. C. 1984. Vertical packing of oyster shells in the Cinder Bed of Warbarrow Tout. PROC DORSET NAT HIST ARCH SOC 105, 167168.Google Scholar
Fürsich, F. T. 1975. Trace fossils as environmental indicators in the Corallian of England and Normandy. LETHAIA 8, 151172.CrossRefGoogle Scholar
Goodman, D. K. 1979. Dinoflagellate ‘Communities’ from the Lower Eocene Nanjemoy Formation of Maryland, USA. PALYNOLOGY 3, 169190.CrossRefGoogle Scholar
Greensmith, J. T. & Tucker, E. V. 1968. Imbricate structure in Essex offshore shell banks. NATURE 220, 11151116.CrossRefGoogle Scholar
Grinnell, R. S. Jn. 1974. Vertical orientation of shells on some Florida oyster reefs. J SEDIMENT PETROL 44, 116122.Google Scholar
Hardie, L. A. 1977. Sedimentation on the Modern Carbonate Tidal Flats of Northwest Andros Island, Bahamas, John Hopkins University Studies in Geology 22. Baltimore: John Hopkins University Press.Google Scholar
Hardie, L. A. & Garrett, P. 1977. General environmental setting. In Hardie, L. A. (ed.) Sedimentation on the Modern Carbonate Tidal Flats of Northwest Andros Island, Bahamas, 12-49, John Hopkins University Studies in Geology 22. Baltimore: University Press.Google Scholar
Harper, C. W. 1984. Improved method of facies sequence analysis. In Walker, R. G. (ed.) Facies Models, 2nd edn., 1113. St. John's, Newfoundland: Geological Association of Canada.Google Scholar
Harris, J. P. 1984. Environments of Deposition of Middle Jurassic Sandstones in the Great Estuarine Group, N.W. Scotland. Unpublished Ph.D. Thesis, University of Leicester.Google Scholar
Harris, J. P. & Hudson, J. D. 1980. Lithostratigraphy of the Great Estuarine Group (Middle Jurassic), Inner Hebrides. SCOTT J GEOL 16, 231250.CrossRefGoogle Scholar
Hudson, J. D. 1962. The stratigraphy of the Great Estuarine Series (Middle Jurassic) of the Inner Hebrides. TRANS EDINBURGH GEOL SOC 19, 139165.CrossRefGoogle Scholar
Hudson, J. D. 1963a. The recognition of salinity-controlled mollusc assemblages in the Great Estuarine Series (Middle Jurassic) of the Inner Hebrides. PALAEONTOLOGY 6, 318326.Google Scholar
Hudson, J. D. 1963b. The ecology and stratigraphical distribution of the invertebrate fauna of the Great Estuarine Series. PALAEONTOLOGY 6, 327348.Google Scholar
Hudson, J. D. 1964. The petrology of the sandstones of the Great Estuarine Series, and the Jurassic palaeogeography of Scotland. PROC GEOL ASSOC 75, 499527.CrossRefGoogle Scholar
Hudson, J. D. 1970. Algal limestones with pseudomorphs after gypsum from the Middle Jurassic of Scotland. LETHAIA 3, 1140.CrossRefGoogle Scholar
Hudson, J. D. 1980. Aspects of brackish-water facies and faunas from the Jurassic of north-west Scotland. PROC GEOL ASSOC 91, 99105.CrossRefGoogle Scholar
Hudson, J. D. 1983. Mesozoic sedimentation and sedimentary rocks in the Inner Hebrides. PROC R SOC EDINBURGH 83B, 4763.Google Scholar
Hudson, J. D. & Harris, J. P. 1979. Sedimentology of the Great Estuarine Group (Middle Jurassic) of north-west Scotland. Symposium sur la Sédimentation de Jurassique W. Européen, Paris, 910May, 1977. Paris: Association des Sédimentologists Français.Google Scholar
Hudson, J. D. & Morton, N. 1969. International field symposium on the British Jurassic, Excursion No. 4, Guide for Western Scotland. Keele: Keele University.Google Scholar
Hudson, J. D. & Palmer, T. J. 1976. A euryhaline oyster from the Middle Jurassic and the origin of true oysters. PALAEONTOLOGY 19, 7993.Google Scholar
Hurst, A. R. 1981. Mid-Jurassic stratigraphy and facies at Brora, Sutherland. SCOTT J GEOL 17, 169177.CrossRefGoogle Scholar
Leeder, M. R. & Nami, M. 1979. Sedimentary models for the non-marine Scalby Formation (Middle Jurassic) and evidence for late Bajocian/Bathonian uplift of the Yorkshire Basin. PROC YORKSHIRE GEOL SOC 42, 461482.CrossRefGoogle Scholar
Logan, B. W., Rezak, R. & Ginsburg, R. N. 1964. Classification and environmental significance of algal stromatolites. J GEOL 72, 6883.CrossRefGoogle Scholar
Miller, H. 1858. The Cruise of the Betsey. Edinburgh.Google Scholar
Millon, J. A. 1987. The Jurassic evolution of the Celtic Sea Basins. In Brooks, J. & Glennie, K. (eds) Petroleum Geology of North West Europe, 599610. London: Graham and Trotman.Google Scholar
Monty, C. L. V. 1976. The origin and development of cryptalgal fabrics. In Walter, M. R. (ed.) Stromatolites, Developments in Sedimentology 20, 193249. Amsterdam: Elsevier.Google Scholar
Monty, C. L. V. & Hardie, L. A. 1976. The geological significance of the freshwater blue green algal calcareous marsh. In Walter, M. R. (ed.) Stromatolites, Developments in Sedimentology 20, 447477. Amsterdam: Elsevier.Google Scholar
Morter, A. A. 1984. Purbeck-Wealden Beds mollusca and their relationship to ostracod biostratigraphy, stratigraphical correlation and palaeoecology in the Weald and adjacent areas. PROC GEOL ASSOC 95, 217234.CrossRefGoogle Scholar
Morton, N. 1983. Palaeocurrents and palaeo-environment of part of the Bearreraig Sandstone (Middle Jurassic) of Skye and Raasay, Inner Hebrides. SCOTT J GEOL 19, 8795.CrossRefGoogle Scholar
Morton, N. 1987. Jurassic subsidence history in the Hebrides, N.W. Scotland. MAR PET GEOL 4, 226242.CrossRefGoogle Scholar
Palmer, T. J. 1979. The Hampen Marly and White Limestone Formations: Florida-type carbonate lagoons in the Jurassic of central England. PALAEONTOLOGY 22, 189228.Google Scholar
Penn, I. E. & Evans, C. D. R. 1976. The Middle Jurassic (mainly Bathonian) of Cardigan Bay and its palaeogeographical significance. REP INST GEOL SCI 76/6.Google Scholar
Raaf, J. F. M. De, Boersma, J. R. & Gelder, A. Van 1977. Wave-generated structures and sequences from a shallow marine succession, Lower Carboniferous, County Cork, Ireland. SEDIMENTOLOGY 24, 451483.CrossRefGoogle Scholar
Reineck, H. E. & Singh, I. B. 1980. Depositional Sedimentary Environments, 2nd edn. Berlin: Springer.CrossRefGoogle Scholar
Seilacher, A. 1967. Bathymetry of trace fossils. MAR GEOL 5, 413428.CrossRefGoogle Scholar
Staff, G. M., Stanton, R. J., Powell, E. N. & Cummins, H. 1986. Time-averaging, taphonomy, and their impact on palaeocommunity reconstruction: death assemblages in Texas bays. GEOL SOC AM BULL 97, 428443.2.0.CO;2>CrossRefGoogle Scholar
Steel, R. J. 1977. Triassic rift basins of northwest Scotland-their configuration, infilling and development. MNNSS/7. In Finstad, K. G. & Selley, R. C.Proceedings: Mesozoic NORTHERN North Sea Symposium, Oslo 1977, 118. Norsk Petroleumforening.Google Scholar
Tan, F. C. & Hudson, J. D. 1974. Isotopic studies of the palaeoecology and diagenesis of the Great Estuarine Series (Jurassic) of Scotland. SCOTT J GEOL 10, 91128.CrossRefGoogle Scholar
Torrens, H. S. 1980. Bathonian correlation chart. In Cope, J. C. W., Duff, K. L., Parsons, C. F., Torrens, H. S., Wimbledon, W. A. & Wright, J. K.A Correlation of Jurassic Rocks in the British Isles. Part 2: Middle and Upper Jurassic, 2145. GEOL SOC LONDON SPEC REP 15.Google Scholar
Walker, R. G. 1979. Facies and facies models. General introduction. In Walker, R. G. (ed.) Facies Models, 17. St. John's, Newfoundland: Geological Association of Canada.Google Scholar
Wall, D. 1965. Microplankton, pollen and spores from the Lower Jurassic in Britain. MICROPALAEONTOLOGY 11, 151190.CrossRefGoogle Scholar
Wall, D., Dale, B., Lohmann, G. P. & Smith, W. K. 1977. The environmental and climatic distribution of dinoflagellate cysts in modern marine sediments from regions in the North and South Atlantic Oceans and adjacent seas. MAR MICROPALAEONTOL 2, 121200.CrossRefGoogle Scholar
Wedd, C. B. 1910, Chapter X: Jurassic, In Peach, B. N., Horne, J., Woodward, H. B., Clough, M. A., Harker, A. & Wedd, C. D.The Geology of Glenelg, Lochalsh and south-east part of Skye, 93131. MEM GEOL SURV SCOTLAND 71.Google Scholar