Micropalaeontological evidence of brackish water conditions during deposition of the Knorringfjellet Formation, Late Triassic–Early Jurassic, Spitsbergen

Article English OPEN
Nagy, Jenö ; Berge, Sigrid H. (2008)

The Knorringfjellet Formation is a succession of mudstones and sandstones, ranging in age from Norian to Toarcian in western and west-central Spitsbergen, and contains several unconformities with associated hiatuses. Its foraminiferal succession consists almost exclusively of agglutinated taxa, shows extremely low assemblage diversities and a dominance of small-sized species. These faunal features signalize restricted environmental conditions (in contrast to those of a normal marine shelf). Comparisons with ancient and modern analogues suggest that the main restricting factor was hyposaline conditions, to a lesser extent augmented by hypoxia in near-bottom waters. These conditions were caused by high fluvial influx creating gravity stratified water masses. The depositional area was part of an extensive but shallow shelf embayment, which had an open connection to the north to the polar ocean basin. Discontinuities recognized in the foraminiferal succession indicate depositional unconformities within the formation.
  • References (24)
    24 references, page 1 of 3

    Alve A. 1995. Benthic foraminiferal distribution and recolonization of formerly anoxic environments in Drammensfjord, southern Norway. Marine Micropaleontology 25, 169-186.

    Bäckström S.A. & Nagy J. 1985. Depositional history and fauna of a Jurassic phosphorite conglomerate (the Brentskardhaugen Bed) on Spitsbergen. Norsk Polarinstitutt Skrifter 183. Oslo: Norwegian Polar Institute.

    Bjaerke T. & Dypvik H. 1977. Sedimentological and palynological studies of Upper Triassic-Lower Jurassic sediments in Sassenfjorden, Spitsbergen. Norsk Polarinstitutt Årbok 1976, 131-150.

    Buzas M.A. 1974. Vertical distribution of Ammobaculites in the Rhode River, Maryland. Journal of Foraminiferal Research 4, 144-177.

    Korcˇinskaja M.V. 1980. Rannenoriskaja fauna Arhipelaga Svalbard. (Early Norian fauna of the Svalbard Archipelago.) In D.V. Semevskij (ed.): Geologija osadocˇnogo cˇehla arhipelaga Sval'bard. (Geology of the sedimentary cover of Svalbard.) Pp. 30-43. Leningrad: Institute of Arctic Geology.

    Mørk A., Dallmann W.K., Dypvik H., Johannessen P., Larssen G.B., Nagy J., Nøttvedt A., Olaussen S., Pcˇelina T.M. & Worsley D. 1999. Mesozoic lithostratigraphy. In W.K. Dallmann (ed.): Lithostratigraphic lexicon of Svalbard. Upper Palaeozoic to Quaternary bedrock. Review and recommendations for nomenclature use. Pp. 127-214. Tromsø: Norwegian Polar Institute.

    Mørk A., Knarud R. & Worsley D. 1982. Depositional and diagenetic environments of the Triassic and Lower Jurassic of Svalbard. In A.F. Embry & H.R. Balkwill (eds.): Arctic geology and geophysics: proceedings of the Third International Symposium on Arctic Geology. Pp. 371-398. Calgary: Canadian Society of Petroleum Geologists.

    Murray J.W. 1973. Distribution and ecology of living benthic foraminiferids. London: Heinemann Education Books.

    Murray J.W. 1991. Ecology and palaeoecology of benthic foraminifera. London: Longman Scientific and Technical.

    Murray J.W. 2006. Ecology and applications of benthic foraminifera. New York: Cambridge University Press.

  • Metrics
    No metrics available
Share - Bookmark