Review of Greenland activities 1997 - Geus

More documents

Recommendations

Info

TRIASSIC JURASSIC RHAETIAN HETTANGIAN SINEMURIAN PLIENSBACHIAN TOARCIAN AALENIAN STAGE NW SB SB HORSEDAL MB SB ELIS BJERG MB DEPOSITIONAL ENVIRONMENT LEPIDOPTERISELV MB SB ? SKÆVDAL MB TREFJORD BJERG MB NATHORST FJELD MB RÆVEKLØFT FM SB HARRIS FJELD MB ASTARTEKLØFT MB ALBUEN MB SB SB SB SB SB SB SE NATHORST FJELD MB SB RÆVEKLØFT GULE HORN OSTREAELV SORTEHAT FORMATION THICKNESS (m) 185-700 300-450 Vardekløft Group Neill Klinter Group SB Offshore transition Tidal channels and subtidal shoals Pebbly shoreface Lagoon Shoreface Kap Stewart Group SB Sequence boundary Anoxic lake Delta plain, wave and storm-dominated delta front Alluvial plain Sequence boundary Fig. 3. Sequence stratigraphic scheme of Kap Stewart and Neill Klinter Groups. Slightly modified from Dam & Surlyk (1998, fig.3). 47
The Neill Klinter Group is subdivided into seven sequences, each with an overall sheet geometry and a duration of 1–2 Ma (Fig. 3; Dam & Surlyk 1995, 1998). Most sequences are characterised by near absence of well-defined parasequences, which is interpreted as reflecting a high rate of influx of sand. Continuous filling of accommodation space and erosion led to poor development of facies cyclicity and to amalgamation of parasequences. A direct correlation of systems tracts on a scale of a few tens of metres between East Greenland and the mid-Norwegian shelf seems to be possible (Dam & Surlyk 1995) and the Neill Klinter Group sequences are being used by several major oil companies as direct analogues to major Norwegian oil fields. Sequence stratigraphic analysis of the Kap Stewart Group predicts a thick shale-dominated unit of interbedded organic-rich and organic-lean units to be present in the central part of Jameson Land. High frequency lake-level fluctuations controlled the organic content of the shales and the source-prone intervals are suggested to have formed during high lake-level stand (Dam & Christiansen 1990). The low order lake-level falls caused progradation of alluvial and deltaic sediments and the model predicts thick lowstand fan deposits to be present in the buried central parts of the lacustrine basin. Thinner lowstand deltaic sandstones are associated with high frequency, lake-level falls. Sequence stratigraphic analysis of the overlying Neill Klinter Group constrains the lateral distribution and internal architecture of four major potential reservoir units. They occur in the upper Elis Bjerg Member, the Astartekløft Member, the Nathorst Fjeld, Harris Fjeld and Lepidopteriselv Members, and the Trefjord Bjerg Member (Fig. 3). Organic-rich shales with source rock potential are not associated with the reservoir units but are confined to the overlying Sortehat Formation deposited during the Aalenian – Early Bajocian sealevel rise. The dominant depositional motif of the Elis Bjerg Member is aggradational to progradational stacking of amalgamated tidal channel and subtidal shoal facies packages of the transgressive systems tract followed by the highstand systems tract. Deposition took place during conditions of high sediment influx into a flat-bottomed basin with a moderate rate of creation of new accommodation space. The highstand systems tract is characterised by the development of major tidal channel complexes, forming some of the best potential hydrocarbon reservoirs in the Neill Klinter Group. The Elis Bjerg Member is capped by offshore transition zone mudstones of the subsequent transgressive systems tract. The base of the Astartekløft Member is a major unconformity marking the incoming of subtidal shoal and tidal channel deposits corresponding to a marked seaward shift in facies. The deposits are interpreted as a thickly developed lowstand systems tract and constitute a major reservoir unit in the south-eastern part of the basin. The overlying Nathorst Fjeld and Harris Fjeld Members consist of a single coarsening-upward unit composed of offshore transition zone mudstones grading upward into shoreface sandstones. The Nathorst Fjeld Member interfingers with seaward-prograding low-angle clinoform-bedded ebb-tidal delta deposits of the Harris Fjeld Member and is referred to the transgressive systems tract. Towards the north, the deposits of the Nathorst Fjeld and Harris Fjeld Members pass into coarse-grained tidal channel and fine-grained shoreface deposits of the Lepidopteriselv Member (Fig. 3). The complex formed by the Nathorst Fjeld, Harris Fjeld and Lepidopteriselv Members is capped by offshore transition zone mudstones of the Skævdal Member. The Skævdal Member shows a slight coarsening-upward trend grading into shoreface deposits and is interpreted as highstand deposits. The Skævdal Member is truncated by a prominent basin-wide erosional unconformity draped by a lag conglomerate. The unconformity marks a basin-wide seaward shift in facies and is interpreted as a sequence boundary. It is overlain by coarse-grained tidal channel and subtidal shoal and shoreface sandstones of the Trefjord Bjerg Member, interpreted as a transgressive systems tract (Dam & Surlyk 1995, 1998). The sandstones of the Trefjord Bjerg Member are capped by offshore mudstones of the Sortehat Formation. At several localities, the sandstones of the Trefjord Member and the mudstones of the Sortehat Formation are separated by a pebble strewn drowning surface. This surface has, on the basis of field appearance, macrofossil content, organic geochemistry and the palynological assemblages been interpreted as a coalesced sequence boundary and transgressive surface (cf. Dam & Surlyk 1998). Middle–Upper Jurassic The Middle–Upper Jurassic deposits of the Jameson Land Basin have served for many years as an excellent analogue model for the petroliferous strata of the northern North Sea and mid-Norwegian shelf. The succession forms a long-term overall transgressive-regressive cycle that was initiated with maximum regression in the 48
Page 1 and 2: GEOLOGY OF GREENLAND SURVEY BULLETI
Page 3: Geology of Greenland Survey Bulleti
Page 6 and 7: Contents Bold numbers refer to the
Page 8 and 9: A review of Greenland activities, 1
Page 10 and 11: using Greenland-trained prospectors
Page 12 and 13: Canada Svartenhuk Halvø M Karrat I
Page 14 and 15: Fig. 3. Mid-Cretaceous sandstones o
Page 16 and 17: Fig. 6. View of the 300 m high part
Page 18 and 19: Dam, G., Larsen, M. & Sønderholm,
Page 20 and 21: Svartenhuk Halvø Greenland Ubekend
Page 22 and 23: 1974) and in 1978 by M.V. Dana (Bre
Page 24 and 25: offshore Marraat Killiit, where the
Page 26 and 27: these areas must therefore be treat
Page 28 and 29: Olsen, T. & Pedersen, G.K. 1991: Th
Page 30 and 31: SW 0 km 10 km 20 km 30 km 40 km 50
Page 32 and 33: Diagenesis and reservoir properties
Page 34 and 35: Fig. 3. Paragenetic sequence of dia
Page 36 and 37: Petroleum geological activities in
Page 38 and 39: Fig. 2. Incised valley in the proxi
Page 40 and 41: The thickest and most complete Jura
Page 42 and 43: 250 PALAEOZOIC 200 150 MESOZOIC 100
Page 44 and 45: Sequence stratigraphy of source and
Page 46 and 47: W PLATFORM BASIN E HST SB 2 SB 3 HS
Page 50 and 51: Cretaceous STAGES Volgian South 120
Page 52 and 53: Member, has a very low content of m
Page 54 and 55: Upper Permian Ravnefjeld Formation
Page 56 and 57: Wandel Sea Basin, eastern North Gre
Page 58 and 59: Greenland, and along the zone of la
Page 60 and 61: Fig. 3. Unconformity between faulte
Page 62 and 63: Tertiary to Recent uplift is propos
Page 64 and 65: Airborne geophysical surveys in cen
Page 66 and 67: lock is located in northern Jameson
Page 68 and 69: Carbonate-hosted Zn-Pb-Ag mineralis
Page 70 and 71: Fig. 3. New Zn-Pb-Ag occurrence, ea
Page 72 and 73: Analyses of three mineralised vein
Page 74 and 75: Karrat 97: reconnaissance mineral e
Page 76 and 77: 56° 54° 52° 0 50 km 56° 54° 52
Page 78 and 79: Mineral occurrences and exploration
Page 80 and 81: mainly defined by heavy mineral con
Page 82 and 83: Hydrothermal activity in the Upper
Page 84 and 85: A B 10 µm 10 µm C D 10 µm 10 µm
Page 86 and 87: A B Gn Cp Cp Py Sp 50 µm 100 µm G
Page 88 and 89: Christiansen, F.G., Piasecki, S., S
Page 90 and 91: Fig. 2. Common Pb diagram with mant
Page 92 and 93: Fig. 3. Sm-Nd isochron plot for dat
Page 94 and 95: Mojzsis, S.J., Arrhenius, G., McKee
Page 96 and 97: supracrustal succession is thus at
Page 98 and 99:
olite’, a unit that was traced al
Page 100 and 101:
sequence. In: Sidorenko, A.V. (ed.)
Page 102 and 103:
Fig. 1. Lithotectonic sketch map of
Page 104 and 105:
Fig. 3. Archaean basement gneisses
Page 106 and 107:
Fig. 5. Tectonic contact between Ar
Page 108 and 109:
Fig. 6. Two sets of mafic dykes fro
Page 110 and 111:
2. Emplacement ages and exhumation
Page 112 and 113:
Reassessment of the north-western b
Page 114 and 115:
Fig. 2. The basal part of the Ketil
Page 116 and 117:
▲ ▲ ▲ ▲ NNW shortening Tran
Page 118 and 119:
the dating of individual granite pl
Page 120 and 121:
North-East Greenland 1997-1998: a n
Page 122 and 123:
Fig. 2. Stauning Alper with summits
Page 124 and 125:
Fig. 4. The oldest parts of the cry
Page 126 and 127:
Fig. 6. Exposures of part of the Ym
Page 128 and 129:
Henriksen, N. 1998: Geological fiel
Page 130 and 131:
20 53° 51° 54°15' 54° 53°45' 4
Page 132 and 133:
Fig. 3. Range chart of selected pal
Page 134 and 135:
Palynostratigraphy The dinoflagella
Page 136 and 137:
epresents an overall progradation o
Page 138 and 139:
(ed.): Petroleum geology of Northwe
Page 140 and 141:
53° 51° 72° Inland Ice 72° Gree
Page 142 and 143:
from the Carlsberg Foundation, and
Page 144 and 145:
55 m 454 m a.s.l. 453 Samples Hystr
Page 146 and 147:
Seismic investigations offshore Sou
Page 148 and 149:
0.0 DLC97 Line 11 Leg 163, Site 988
Page 150 and 151:
68˚N 44˚W 42˚W 40˚W 38˚W 36˚W
Page 152 and 153:
tirelessly operating the seismic ge
Page 154 and 155:
Fig. 2. Block with ultramafic xenol
Page 156 and 157:
Late Cenozoic wood from Washington
Page 158 and 159:
Table 1. Data on wood pieces from N
Page 160 and 161:
Pingos at Nioghalvfjerdsfjorden, ea
Page 162 and 163:
A B C D E F Fig. 3. Pingos in the o
Page 164 and 165:
Late Quaternary palaeo-oceanography
Page 166 and 167:
600m waterdepth 250m 250m 250m 250m
Page 168 and 169:
flow deposits with a considerable a
Page 170 and 171:
A B Fig. 2. A: Lake G97-19 (60°04.
Page 172 and 173:
Facing page Fig. 3. Limnological me
Page 174 and 175:
7 8 5 Geology 1:500 000 10 Quaterna
Page 176 and 177:
1997/124 Investigation of the ore p
show all

Review of Greenland activities 1997 - Geus

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?