GEUS Bulletin no 5.pmd
GEUS Bulletin no 5.pmd GEUS Bulletin no 5.pmd
73°00′N thick succession of Middle Jurassic marine sediments, mainly sandstones, was deposited in northern Jameson Land and progressively thins distally towards the south. The proximal areas in Traill Ø acted as a bypass area for much of late Middle Jurassic time and the succession is generally thinner compared with the more distal areas in Jameson Land (Surlyk 2003). The south-easternmost part of Traill Ø constituted an eastwards-tilted fault block, in contrast to other Jurassic fault blocks in East Greenland which are tilted westwards (Donovan 1953; Carr 1998; Surlyk 2003). A detailed analysis of the Middle Jurassic succession in the Vælddal area close to the crest of the eastwardstilted block was recently undertaken by Carr (1998; Fig. 1). He demonstrated that as a result of synsedimentary movements of the Vælddal Fault during Middle Jurassic time the sedimentary evolution of the Bjørnedal area differed somewhat from that of other parts of the region. The Middle Jurassic succession in this block shows palaeocurrent directions to the east in contrast to the axial, southwards-oriented palaeocur- 32 72°45′N 72°30′N ■ ■ 72°15′N Greenland GREENLAND ■ 24°W 23°W 22°W Geographical Society Ø ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ Traill Ø Jameson Land ■ ■ ■ Vælddal Fault ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ Bjørnedal Fig. 2 Kong Oscar Fjord Vælddal ■ ■ ■ ■ 10 km ■ ■ Mountnorris Fjord N ■ ■ Palaeogene intrusives Palaeogene extrusives Cretaceous Jurassic Triassic Upper Permian Carboniferous Devonian Pre-Devonian Fault rent directions seen elsewhere. The sandstone/mudstone ratio also decreases and the succession shows proximal to distal facies changes in the same direction (Vosgerau et al. 2004, this volume). Stratigraphy GEUS Bulletin no 5.pmd 32 29-10-2004, 11:14 Fig. 1. Simplified geological map of the Traill Ø area. Location of study area (Fig. 2) is indicated. The lithostratigraphical scheme for the Jurassic of East Greenland was erected by Surlyk et al. (1973), Surlyk (1977, 1978) and Birkelund et al. (1984). The scheme is under revision and many units have been raised in rank (see Surlyk 2003, fig. 5). In the Traill Ø area, the Middle – lower Upper Jurassic succession now includes the Bristol Elv, Pelion, Fossilbjerget and Olympen Formations in ascending order (Fig. 4). The Bristol Elv Formation is probably not exposed in Bjørnedal. It is of pre-Late Bajocian but probably still Middle Jurassic age and includes fluvial pebbly sandstones and thin coaly shales (Therkelsen & Surlyk 2004, this volume). The Pelion Formation consists of shallow-marine sand-
834 N Lycett Bjerg Barrikade Gletscher Land 3 1013 Ice-covered 2 1 Bjørnedal Steenstrup Bjerg River Sea Mountnorris Fjord Brede Gletscher 2 km Fig. 2. Map of the Bjørnedal area, Traill Ø showing locations of sections and ammonite localities. 1, Locality 1 with section JTH- 15/96; 2, Locality 2 with section JTH-14/96; 3, Locality 3. Altitude of mountains in metres. stones with bivalves, belemnites, ammonites and plant fragments. The formation rests on Triassic strata or on the Bristol Elv Formation. It is overlain by, or interfingers at the top with, offshore, dark, micaceous, silty mudstones of the Fossilbjerget Formation. A regressive wedge in the top part of the Pelion Formation interrupts the overall backstepping Pelion–Fossilbjerget couplet, and belongs to the Parnas Member of the Pelion Formation (Surlyk 2003). The Fossilbjerget Formation is overlain by the lower Upper Jurassic Olympen Formation, which also consists of shallow marine sandstones themselves quite similar to the sandstones of the Pelion Formation below, making recognition of the Olympen Formation difficult. The Middle Jurassic succession in the Bjørnedal area is poorly exposed. The area described here corresponds to the ‘northern part of Bjørnedal’ of Donovan (1953). An intensive search for ammonites was made in dark, silty, micaceous mudstones exposed in small sections along the Bjørnedal river, Locality 1, and in a small section in a gully at Locality 2 (Figs 2, 5). Three ammo- nite assemblages were recovered; two ammonite species have been identified, one of them previously known from Jameson Land but hitherto undescribed. The description of the Middle Jurassic succession in Bjørnedal is based mainly on Donovan (1953), since fieldwork was focused solely on the mudstones in its middle part. The succession is subdivided into five lithological units, A–E in ascending order (Figs 4, 5). Unit A belongs to the Pelion Formation and consists of about 200 m of sandstones containing Cranocephalites, which suggests correlation with the Upper Bajocian C. pompeckji Chronozone (Fig. 3) and indetermi- Middle Jurassic Lower Callovian Bathonian Bajocian NW European/ Subboreal Province Herveyi Discus Orbis Hodsoni Morrisi Subcontractus Progracilis Tenuiplicatus Zigzag Parkinsoni Garantiana Subfurcatum Zones Humphriesianum Calloviense Koenigi * Zones identified in the Bjørnedal area GEUS Bulletin no 5.pmd 33 29-10-2004, 11:14 Boreal Province *Nordenskjoeldi (Parnas Mb, wedge of upper Pelion Fm) *Apertum (Fossilbjerget Fm) Calyx Variabile Cranocephaloide Ishmae Greenlandicus Arcticus *Pompeckji (Pelion Formation) Indistinctus Borealis Fig. 3. Scheme of standard ammonite zones in the Upper Bajocian – Lower Callovian, Middle Jurassic. Due to faunal provincialism close correlation between zones in East Greenland (right column) and the NW European/Subboreal Province (left column) is not possible. The East Greenland ammonite zonation represents a secondary standard chronostratigraphical scheme for the Boreal Province. Modified from Callomon (2003). 33
- 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 and 12: NW SE m 1000 500 0 NW SE m 1000 500
- Page 13 and 14: GEUS Bulletin no 5.pmd 13 29-10-200
- 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: Maximum Middle Jurassic transgressi
- Page 35 and 36: SW NE Lycett Bjerg Parnas Member Be
- Page 37 and 38: Cadoceras cf. nordenskjoeldi Callom
- Page 39 and 40: GEUS Bulletin no 5.pmd 39 29-10-200
- 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 81 and 82: GEUS Bulletin no 5.pmd 81 29-10-200
73°00′N<br />
thick succession of Middle Jurassic marine sediments,<br />
mainly sandstones, was deposited in <strong>no</strong>rthern Jameson<br />
Land and progressively thins distally towards the<br />
south. The proximal areas in Traill Ø acted as a bypass<br />
area for much of late Middle Jurassic time and the succession<br />
is generally thinner compared with the more<br />
distal areas in Jameson Land (Surlyk 2003).<br />
The south-easternmost part of Traill Ø constituted<br />
an eastwards-tilted fault block, in contrast to other Jurassic<br />
fault blocks in East Greenland which are tilted<br />
westwards (Do<strong>no</strong>van 1953; Carr 1998; Surlyk 2003). A<br />
detailed analysis of the Middle Jurassic succession in<br />
the Vælddal area close to the crest of the eastwardstilted<br />
block was recently undertaken by Carr (1998;<br />
Fig. 1). He demonstrated that as a result of synsedimentary<br />
movements of the Vælddal Fault during Middle<br />
Jurassic time the sedimentary evolution of the<br />
Bjørnedal area differed somewhat from that of other<br />
parts of the region. The Middle Jurassic succession in<br />
this block shows palaeocurrent directions to the east<br />
in contrast to the axial, southwards-oriented palaeocur-<br />
32<br />
72°45′N<br />
72°30′N<br />
■ ■<br />
72°15′N<br />
Greenland<br />
GREENLAND<br />
■<br />
24°W 23°W 22°W<br />
Geographical Society Ø<br />
■<br />
■<br />
■<br />
■<br />
■ ■<br />
■<br />
■<br />
■<br />
■<br />
Traill Ø<br />
Jameson<br />
Land<br />
■<br />
■ ■<br />
Vælddal<br />
Fault<br />
■<br />
■<br />
■<br />
■<br />
■<br />
■<br />
■<br />
■<br />
■<br />
■<br />
■ ■ ■<br />
■<br />
■<br />
■<br />
■<br />
■<br />
■<br />
■<br />
■<br />
Bjørnedal<br />
Fig. 2<br />
Kong Oscar Fjord<br />
Vælddal<br />
■<br />
■<br />
■<br />
■<br />
10 km<br />
■<br />
■<br />
Mount<strong>no</strong>rris Fjord<br />
N<br />
■<br />
■<br />
Palaeogene<br />
intrusives<br />
Palaeogene<br />
extrusives<br />
Cretaceous<br />
Jurassic<br />
Triassic<br />
Upper Permian<br />
Carboniferous<br />
Devonian<br />
Pre-Devonian<br />
Fault<br />
rent directions seen elsewhere. The sandstone/mudstone<br />
ratio also decreases and the succession shows<br />
proximal to distal facies changes in the same direction<br />
(Vosgerau et al. 2004, this volume).<br />
Stratigraphy<br />
<strong>GEUS</strong> <strong>Bulletin</strong> <strong>no</strong> <strong>5.pmd</strong> 32<br />
29-10-2004, 11:14<br />
Fig. 1. Simplified geological map of the<br />
Traill Ø area. Location of study area<br />
(Fig. 2) is indicated.<br />
The lithostratigraphical scheme for the Jurassic of East<br />
Greenland was erected by Surlyk et al. (1973), Surlyk<br />
(1977, 1978) and Birkelund et al. (1984). The scheme<br />
is under revision and many units have been raised in<br />
rank (see Surlyk 2003, fig. 5). In the Traill Ø area, the<br />
Middle – lower Upper Jurassic succession <strong>no</strong>w includes<br />
the Bristol Elv, Pelion, Fossilbjerget and Olympen Formations<br />
in ascending order (Fig. 4). The Bristol Elv<br />
Formation is probably <strong>no</strong>t exposed in Bjørnedal. It is<br />
of pre-Late Bajocian but probably still Middle Jurassic<br />
age and includes fluvial pebbly sandstones and thin<br />
coaly shales (Therkelsen & Surlyk 2004, this volume).<br />
The Pelion Formation consists of shallow-marine sand-
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