GEUS Bulletin no 5.pmd

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The south coast of Traill Ø Upper Palaeozoic – Triassic deposits are exposed along the western part of the south coast of Traill Ø, whereas Jurassic and younger sediments are restricted to the eastern part (Fig. 1). The Jurassic succession is bounded to the west by the Månedal Fault and is cut by the Vælddal Fault situated 15 km further to the east (Figs 1, 2). The peninsula east of the Vælddal Fault is made up mainly by the Palaeogene Kap Simpson syenite complex which extends for about 30 km in a NW–SE direction parallel to the coast (Fig. 1). The coastal cliffs are high and steep, and numerous Palaeogene sills and dykes intrude the Jurassic succession. It has accordingly received very little attention. It was assigned to the Yellow and Black Series by Donovan (1953) and this was followed in the geological map of Koch & Haller (1971). The Yellow Series was very loosely defined and covered Middle and lower Upper Jurassic sandstone-dominated successions. On Traill Ø, it includes the Pelion and Olympen Formations of current usage. The Black Series includes Upper Jurassic dark grey mudstones and black shales corresponding in part to the Bernbjerg Formation (Surlyk 1977b). Successively younger Jurassic strata are exposed from west to east along the coast east of the Vælddal Fault (Fig. 2). The succession includes Lower Bajocian sandstones and mudstones of the Bristol Elv Formation, Upper Bajocian – Lower Callovian sandstones of the Pelion Formation, Callovian mudstones of the Fossilbjerget Formation, intercalated with sandstones of the Parnas Member (top member of the Pelion Formation), overlain by Lower–Middle Oxfordian mudstones and sandstones of the Olympen Formation, and Upper Oxfordian – Kimmeridgian dark grey and black mudstones of the Bernbjerg Formation (Fig. 3). The exposures along the coastal cliffs vary in quality. From a stratigraphic point of view they are generally good, whereas sedimentary structures commonly are obliterated by the effects of the Palaeogene sills and dykes. For this study, five sedimentological sections were measured along the coast allowing construction of a W–E dip section (Fig. 3). The sections are correlated by lateral tracing of major sedimentary packages and drowning surfaces in the field and on a high-quality photo-mosaic, and by ammonite dating of a number of levels. The succession dips about 13° to the east except in the easternmost section where it dips 9° towards the north, but in this area dip-directions reflect disturbances by the immediately adjacent syenite complex (Fig. 1). 12 The oldest strata are exposed to the west immediately east of the Vælddal Fault where Jurassic strata rest directly on Triassic redbeds of the Fleming Fjord Formation (Stauber 1942). The base of the Middle Jurassic sandstones is not exposed further east, but fluvial to marginal marine sandstones and mudstones of the Bristol Elv Formation (Price & Whitham 1997; Stemmerik et al. 1997; Therkelsen & Surlyk 2004, this volume) occur below marine Upper Bajocian sandstones of the Pelion Formation in two sections. Three of the measured sections (Fig. 3, sections 1–3) reach up into black mudstones of the Upper Oxfordian – Kimmeridgian Bernbjerg Formation. Stratigraphic development GEUS Bulletin no 5.pmd 12 29-10-2004, 11:14 The basal part of the Jurassic succession consists of channelised, trough cross-bedded pebbly sandstones interbedded with dark grey laminated shales occasionally with thin sandstone ripples. Crude fining-upwards trends can be recognised, and rootlet beds are common. Palaeocurrents are mainly towards the south-west (Fig. 3). The interbedded shales contain abundant leaves and scattered tree trunks. Both facies contain scattered trace fossils of marine affinity. The sandstones are interpreted as having been deposited in coastal rivers and the shales were formed by drowning of the fluvial system either due to delta switching and abandonment or to base-level rise. The trace fossils suggest some marine influence and deposition of the shales probably took place under estuarine conditions or in interdistributary bays. A succession of fluvial deposits at the base of the Jurassic succession of Traill Ø was recognised independently by Facing page: Fig. 3. NW–SE-oriented dip-parallel correlation panel of the Bjørnedal Block, based on five measured sections along the south coast of Traill Ø (for location, see Fig. 1B). Note the eastwards, down-dip decrease in sandstone–mudstone ratio and increase in the thickness of mudstone packages. The key motif is a coarsening-upwards parasequence composed of offshore mudstones, overlain by offshore transition zone heteroliths followed by shoreface sandstones. The parasequences stack into parasequence sets, numbered PS1–8 from below. The succession belongs from below to the dominantly fluvial Bristol Elv Formation, the marine sandstone-dominated Pelion Formation, the mudstone-dominated Fossilbjerget Formation, the Olympen Formation of interbedded marine sandstones and mudstones, and the dark, deeper marine mudstone-dominated Bernbjerg Formation. P., Pelion.
GEUS Bulletin no 5.pmd 13 29-10-2004, 11:14 13 Bristol Elv Fm Pelion Fm Olympen Fm Bernbjerg Fm Fossilbj. Fm Parnas Mb (P. Fm) Fossilbj. Bjørnedal (Section 1) Mud FMC Sand C. nordenskjoeldi C. apertum C. pompeckji 100 m Vælddal (Section 2) Mud FMC Sand Mud FMC Sand A. serratum PS8 PS7 PS6 C. apertum C. apertum PS5 PS4 PS3 PS2 PS1 E. Steenstrup Dal (Section 3) ? Mud FMC Sand A. cymodoce E. Steenstrup Dal (Section 4) Mud FMC Sand 8 km 10 km 2 km 19 km Lithology Fossils and symbols Mudstone Hummocky crossstratification Belemnite Siltstone Trough cross-bedding Ammonite Sandstone Single trough cross-beds Bivalve Pebbles Planar cross-bedding Roots Concretions Plant fragments Structures Trace fossils Coalified wood Massive Diplocraterion habichi Palaeocurrent direction Wavy bedding Curvolithos multiplex PS1–8 Parasequence set Plane bedding Ophiomorpha nodosa Lithostratigraphic boundary Plane lamination Degree of bioturbation Parasequence set boundary C. pompeckji C. pompeckji Forårsdal (Section 5) ? Mud FMC Sand A. cranocephaloide A. ishmae
Page 1 and 2: GEOLOGICAL SURVEY OF DENMARK AND GR
Page 3 and 4: GEUS Bulletin no 5.pmd 3 29-10-2004
Page 5 and 6: Contents Preface . . . . . . . . .
Page 7 and 8: (Alsen & Surlyk 2004, this volume).
Page 9 and 10: Jurassic syn-rift sedimentation on
Page 11: NW SE m 1000 500 0 NW SE m 1000 500
Page 15 and 16: grained than the lower parasequence
Page 17 and 18: the Pelion Formation. The mudstone-
Page 19 and 20: The fluviatile Bristol Elv Formatio
Page 21 and 22: Name. After the river Bristol Elv i
Page 23 and 24: edded, and display both sheet-like
Page 25 and 26: N S Fig. 5. Coarse-grained sandston
Page 27 and 28: Fig. 7. Lacustrine deposits from th
Page 29 and 30: deposition of peat and coal. Journa
Page 31 and 32: Maximum Middle Jurassic transgressi
Page 33 and 34: 834 N Lycett Bjerg Barrikade Gletsc
Page 35 and 36: SW NE Lycett Bjerg Parnas Member Be
Page 37 and 38: Cadoceras cf. nordenskjoeldi Callom
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 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
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and mudstone drapes reflects varyin
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with the presence of a minor angula
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the north-east and south-west, resp
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elly mass-flow deposits. In: Koster
Page 73 and 74:
Jurassic dinoflagellate cyst strati
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74°00'N ■■ ■■ ■■ 73°5
Page 77 and 78:
Bernbjerg Formation Payer Dal Forma
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Depositional environment. The prese
Page 81 and 82:
GEUS Bulletin no 5.pmd 81 29-10-200
Page 83 and 84:
Page 85 and 86:
Metres 30 20 10 Hold with Hope, Loc
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Correlations The Pelion Formation o
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Jurassic dinoflagellate cysts from
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Fig. 2. Sedimentological log of the
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LITHOSTRATIGRAPHY BIOSTRATIGRAPHY F
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ALPHABETICAL SPECIES LIST 41 Adnato
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References Alsgaard, P.C., Felt, V.
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Jurassic dinoflagellate cyst strati
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parties from the Geological Survey
Page 103 and 104:
may indicate a hiatus in the sedime
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Metre 50 25 0 Store Koldewey Ravn P
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Fig. 6. Schematic stratigraphical c
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Chronozone) to the earliest Kimmeri
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The Upper Jurassic succession is co
Page 113 and 114:
Page 115 and 116:
185 Greenland from Archaean to Quat
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GEUS Bulletin no 5.pmd

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