Tài liệu The Kimmeridgian ammonite faunas of Milne Land, central East Greenland by Tove Birkelund and John H.

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    The Kimmeridgian ammonite faunas of Milne Land, central East Greenland
    by Tove Birkelund and John H. Callornon

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    CONTENTS
    Introduction 5
    Lithostratigraphy . 6
    Ammonitezonation . 11
    Systematic description of ammonites 12
    Family Cardioceratidae Siemiradzki. 1891 12
    Genus Amoeboceras Hyatt. 1912 . 12
    SubgenusAmoebitesBuckman. 1925 12
    Amoeboceras (Amoebites) bayi sp . nov 13
    Amoeboceras (Amoebites) sp. aff . A.(A.) schulginae Mesezhnikov, 1967 . 18
    Amoeboceras (Amoebites) cf . A . (A.) ernesti (Fischer, 1913) 18
    Amoeboceras (Amoebites) subkitchini Spath, 1935 19
    Amoeboceras (Amoebites) cf . A . (A.) beaugrandi (Sauvage, 1871) . 23
    Amoeboceras (Amoebites) elegans Spath. 1935 24
    Subgenus Euprionocerm Spath. 1935 26
    Amoeboceras (Euprionoceras) kochi Spath. 1935 . 26
    Subgenus Hoplocardioceras Spath. 1935 . 28
    Amoeboceras (Hoplocardioceras) decipiens Spath. 1935 28
    Family Aulacostephanidae Spath. 1924 29
    Genus Pictonia Bayle. 1878 29
    Pictonia sp. nov . A aff . P. normandiana Tornquist 30
    Pictonia? sp . indet . B . 32
    Genus Rasenia Salfeld, 1913 . 33
    Rasenia inconstans Spath, 1935 . 33
    Rasenia cymodoce (dlOrbigny. 1850) 35
    Rasenia evoluta Spath. 1935 36
    Rasenia borealis Spath. 1935 . 38
    Genus ?Pachypictonia Schneid. 1940 40
    ?Pachypictonia sp . nov . C . 40
    Genus Aulacostephanoides Schindewolf. 1925 42
    Aulacostephanoides mutabilk (Sowerby. 1823) 42
    Genus Aulacostephanus Tornquist. 1896 . 44
    Aulacostephanus eudoxur (d'orbigny. 1850) 44
    Aulacostephanus sp. cf . or aff . A u. kirghisemis (d'orbigny, 1845) 45
    Family Oppeliidae Douville. 1890 . 46
    Genus Streblites Hyatt. 1946? 46
    Streblites? cf . S . taimyrenris Mesezhnikov. 1976 . 46
    Appendix 48
    Acknowledgements . 53
    References . 54

    INTRODUCTION
    The Upper Jurassic deposits of Milne Land lie in a key area for Jurassic Boreal
    ammonite stratigraphy. Early collections brought back to Copenhagen by Rosenkrantz
    (1929) and Aldinger (1935) were described in two classical monographs by
    Spath (1935, 1936), and all these works continue to form the basis for subsequent
    stratigraphical and palaeontological revisions. Since then extensive field work and
    collecting have yielded important new material and much more detailed stratigraphical
    information (Callomon, 1961; Hikansson et al., 1971; Birkelund et al.,
    1978a; Higgins & Hikansson, 1980; Birkelund, Callomon & Fiirsich, 1984). The
    biostratigraphy of the ammonites in particular has revealed a rich succession that
    can be used to provide close chronostratigraphic control. Some 48 ammonite faunas
    range from Boreal Upper Bathonian (Middle Jurassic) resting on crystalline
    basement to Valanginian (Lower Cretaceous). Of these, faunas 1-19 were summarized
    previously (Callomon & Birkelund, 1980), and the descriptions of the ammonites
    given there and in Sykes & Callomon (1979) leave little to add up to and including
    the Upper Oxfordian , faunas 1-13. Faunas 24-48, covering Lower Volgian,
    Middle Volgian and Lower Valanginian, were also described previously (Callomon
    & Birkelund, 1982).
    In the present work we describe the succession through the Kimmeridgian, used
    in the international sense (Lower Kimmeridgian sensu anglico). This covers faunas
    14-23 (table 1). The choice is largely one of convenience, for the faunas in this
    range coincide roughly with the material treated in Spath's first monograph (1935),
    are bounded by a sharp fauna1 change at the top, and consist of a closely circumscribed
    group of forms belonging almost wholly to only two families, the Cardioceratidae
    and Aulacostephanidae.
    The area from which the material came is shown on the map (fig. 1). It was collected
    bed by bed in about half of the total of some 50 or so recorded sections, the
    detailed descriptions of which are deposited together with the collections in the Geological
    Museum of the University of Copenhagen.
     

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