GEUS Bulletin no 5.pmd

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m 25 20 15 10 5 0 92 Mud Sand 351548 351547 351546 351545 351544 351543 351542 351541 351540 351539 Fig. 3. Sedimentological log of the Bernbjerg Formation at Agnetesøelven (Locality 3) showing the positions of analysed samples. For legend, see Fig. 2. seams interbedded with black carbonaceous shales and light-coloured sandstones of the Muslingebjerg Formation (Clemmensen & Surlyk 1976). No marine fossils have been recorded from the formation but the high sulphur content of the coals and shales suggests a marine depositional environment (Petersen et al. 1998). The Jurassic succession at Kulhus extends up the western flank of Søndre Muslingebjerg where the stratigraphically highest strata contain Upper Oxfordian ammonites referable to the Amoeboceras glosense and/ or A. serratum Zones (Ravn 1911; Sykes & Surlyk 1976). Coals and shales of the Muslingebjerg Formation have been prepared palynologically without finding any microscopic marine fossils. At Kulhus, the first dinoflagellate cysts appear in the basal mudstone bed of the overlying Payer Dal Formation, immediately above the highest coal seam, at the same level as the earliest marine faunas. Restricted assemblages of sporomorphs from the underlying coals indicate an overall Jurassic age. Agnetesøelven (Localities 2 and 3) GEUS Bulletin no 5.pmd 92 29-10-2004, 11:14 Fine-grained sandstone, with abundant marine fossils, is exposed at Locality 2 and referred to the Payer Dal Formation (Figs 1, 2). Shell beds of Pecten spp., oysters, other bivalves and serpulids occur throughout the succession and are commonly concentrated in scour fills. Belemnites are present, but no ammonites were recovered during the short visit. Woody material and small logs are also common. The sandstone is intensely bioturbated and many sedimentary structures are obliterated although cross-bedding or lamination is recognisable in most beds. Planolites ispp. is common at certain horizons. The shale succession exposed at Locality 3 is referred to the Bernbjerg Formation. It consists of laminated, dark mudstones alternating with lenticular-bedded, fine-grained, grey sandstones (Fig. 3). Ammonites and bivalves are abundant in a concretionary bed low in the section and belemnites and bivalves occur scattered higher in the succession. The concretionary beds are washed out from the lowermost succession and lie at the foot of the cliff. They contain accretions of ammonites in several stacked laminae together with abundant Buchia sp. Abundant male and female individuals occur together in the ammonite assemblages (J.H.
LITHOSTRATIGRAPHY BIOSTRATIGRAPHY FORMATION AMMONITE ZONE Bernbjerg Payer Dal Callomon, personal communication 1999). The assemblage is equivalent to ammonite Fauna 15 from Milne Land in the lower Rasenia cymodoce Zone, Lower Kimmeridgian (Fig. 4; Birkelund & Callomon 1985; J.H. Callomon, personal communication 1999). Lower Kimmeridgian ammonites have been reported previously from sandstones at the locality of Nanok in southern Hochstetter Forland (Frebold 1932). Ammonites of the lowermost Kimmeridgian Rasenia cymodoce and Aulacostephanoides mutabilis Zones, have been collected from mudstones of the Bernbjerg Formation in Hochstetter Forland (Frebold 1932; Surlyk 1978). Stratigraphy A. mutabilis R. cymodoce Basal Payer Dal Formation (Locality 1) Dinoflagellate cysts. An unusual and relatively poor assemblage of dinoflagellate cysts was recorded immediately above the lithological transition from the barren Muslingeelv Formation to the fossiliferous Payer Dal Formation (Fig. 5). Limbicysta bjaerkei, Pilosidinium fensomei and Pareodinia halosa dominate the assemblage, in association with Gonyaulacysta jurassica, Nannoceratopsis sp., Occisucysta sp., Pareodinia sp., Solisphaeridium sp., Tubotuberella cf. dangeardii and Tubotuberella cf. egemenii. Single specimens of Atopodinium haromense, Mendicodinium groenlandicum and Rhynchodiniopsis cladophora were recorded. Age. Stratigraphically diagnostic species are few in AGE BASED ON DINOFLAGELLATE CYSTS Early Kimmeridgian CHRONOZONES A. mutabilis R. cymodoce A. glosense – A. serratum Late Oxfordian A. glosense – A. serratum Late Callovian P. athleta Muslingebjerg No marine fossils (Callovian?) pre-P. athleta Fig. 4. Summary of the Jurassic stratigraphy of Hochstetter Forland. GEUS Bulletin no 5.pmd 93 29-10-2004, 11:14 CHRONOSTRATIGRAPHY this assemblage. In East Greenland, Limbicysta bjaerkei has not been recorded stratigraphically higher than the basal Boreal Middle Jurassic in the Cranocephalites borealis Chronozone in Jameson Land (Milner & Piasecki 1996). However, a stratigraphical range of Middle Callovian and possibly into lowermost Upper Callovian has been reported from both the Subboreal and Arctic regions (Smelror 1987, 1993). In Jameson Land, M. groenlandicum appears no lower than the Kosmoceras jason Chronozone (mid-Callovian) and distinct Rhynchodiniopsis cladophora and Tubotuberella dangeardii appear in the basal Upper Callovian in the Peltoceras athleta Chronozone (Milner & Piasecki 1996). In conclusion, the sparse data indicate an age equivalent to the earliest Late Callovian, P. athleta Chronozone (Fig. 4). An Early Callovian age previously indicated for this unit (Petersen et al. 1998) was based on a sample that was subsequently found to be from another section and locality. Depositional environment. The dinoflagellate cyst assemblage is dominated by three species (Fig. 5). Limbicysta bjaerkei is possibly an acritarch because no clear archaeopyle has been documented. The assemblage differs markedly from normal marine assemblages described from time equivalent strata in Milne Land (Piasecki 1996). Bailey & Hogg (1995) reported abundant L. bjaerkei in otherwise non-marine assemblages. This may indicate that the associated, frequent species, Pilosidinium fensomei and Pareodinia halosa, may have had similar environmental preferences. The abundance of L. bjaerkei – together with the restricted 93
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GEOLOGICAL SURVEY OF DENMARK AND GR
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GEUS Bulletin no 5.pmd 3 29-10-2004
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Contents Preface . . . . . . . . .
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(Alsen & Surlyk 2004, this volume).
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Jurassic syn-rift sedimentation on
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NW SE m 1000 500 0 NW SE m 1000 500
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grained than the lower parasequence
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the Pelion Formation. The mudstone-
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The fluviatile Bristol Elv Formatio
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Name. After the river Bristol Elv i
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edded, and display both sheet-like
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N S Fig. 5. Coarse-grained sandston
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Fig. 7. Lacustrine deposits from th
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deposition of peat and coal. Journa
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Maximum Middle Jurassic transgressi
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834 N Lycett Bjerg Barrikade Gletsc
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SW NE Lycett Bjerg Parnas Member Be
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Cadoceras cf. nordenskjoeldi Callom
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Page 41 and 42: 4 C B 1 2 GEUS Bulletin no 5.pmd 41
Page 43 and 44: Fig. 1. Sketch-map of the Jameson L
Page 45 and 46: Table 1. Measurement of dimensions
Page 47 and 48: GEUS Bulletin no 5.pmd 47 29-10-200
Page 49 and 50: 1 2 GEUS Bulletin no 5.pmd 49 29-10
Page 51 and 52: A new Middle-Upper Jurassic success
Page 53 and 54: 74º00'N ■■ ■■ ■■ 73º5
Page 55 and 56: System Ma 159.4 154.1 164.4 169.2 1
Page 57 and 58: Sedimentary structures Biota Struct
Page 59 and 60: wards units is biogenic carbonate d
Page 61 and 62: Fig. 7. Log panel giving a broadly
Page 63 and 64: SPM LU to medium-grained and consis
Page 65 and 66: and mudstone drapes reflects varyin
Page 67 and 68: with the presence of a minor angula
Page 69 and 70: the north-east and south-west, resp
Page 71 and 72: elly mass-flow deposits. In: Koster
Page 73 and 74: Jurassic dinoflagellate cyst strati
Page 75 and 76: 74°00'N ■■ ■■ ■■ 73°5
Page 77 and 78: Bernbjerg Formation Payer Dal Forma
Page 79 and 80: Depositional environment. The prese
Page 85 and 86: Metres 30 20 10 Hold with Hope, Loc
Page 87 and 88: Correlations The Pelion Formation o
Page 89 and 90: Jurassic dinoflagellate cysts from
Page 91: Fig. 2. Sedimentological log of the
Page 95 and 96: ALPHABETICAL SPECIES LIST 41 Adnato
Page 97 and 98: References Alsgaard, P.C., Felt, V.
Page 99 and 100: Jurassic dinoflagellate cyst strati
Page 101 and 102: parties from the Geological Survey
Page 103 and 104: may indicate a hiatus in the sedime
Page 105 and 106: Metre 50 25 0 Store Koldewey Ravn P
Page 107 and 108: Fig. 6. Schematic stratigraphical c
Page 109 and 110: Chronozone) to the earliest Kimmeri
Page 111 and 112: The Upper Jurassic succession is co
Page 115 and 116: 185 Greenland from Archaean to Quat
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