Review of Greenland Avtivities 2001 - Geus

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A multidisciplinary study of the Palaeogene succession offshore southern West Greenland Finn Dalhoff, James A. Chalmers, Henrik Nøhr-Hansen, Jan A. Rasmussen, Emma Sheldon and Ulrik Gregersen A project with the aim of amalgamating an interpretation of reflection seismic data from offshore southern West Greenland with a new interpretation of well data was finalised at the Geological Survey of Denmark and Greenland (GEUS) in 2001 (Chalmers et al. 2001b). As part of this study, seismic and depositional sequences between major regional unconformities of Danian and mid-Eocene age were delineated and dated. New palaeoenvironmental and sedimentological interpretations using dinoflagellate cyst, microfossil and nannoplankton stratigraphies and palaeoenvironmental interpretations from the five exploration wells drilled offshore West Greenland in the 1970s have been combined with a revised interpretation of lithology and correlated with the aid of seismic stratigraphy. The Qulleq-1 well drilled in 2000 was relinquished late in the project period (Christiansen et al. 2002, this volume), and it has therefore only been possible to incorporate biostratigraphic information from this well into the project. The results show that the region offshore southern West Greenland (Fig. 1) was subject to major uplift and erosion during the Danian, when uppermost Cretaceous sediments were removed. Sedimentation resumed in the late Danian, and was coeval with major volcanism in central West Greenland and the start of sea-floor spreading in the Labrador Sea. Upper Paleocene sediments were deposited in a predominantly extensional tectonic environment. The extensional stresses continued in most areas during the Early Eocene, but in the northern and north-western part of the region, a transtensional system developed along a major strike-slip fault system that transferred sea-floor spreading movements between the Labrador Sea and Baffin Bay. A stratigraphic framework for the basins offshore southern West Greenland has been erected based on knowledge from the six drilled exploration wells and the onshore exposures of sediments and volcanic rocks in the Nuussuaq Basin and at Cape Dyer, Canada (Rolle 1985; Nøhr-Hansen 1998; Nøhr-Hansen et al. 2000; Chalmers et al. 2001b; Christiansen et al. 2001). Furthermore, seismic sequence studies have been carried out in the southern West Greenland basins (Chalmers et al. 1993, 1995, 2001a; Chalmers & Pulvertaft 2001) and these have been compared with the drilled successions offshore Labrador (Balkwill 1987). Of the five wells drilled in the 1970s, three penetrated only Cenozoic sediments before terminating in Paleocene basalts (Hellefisk-1, Nukik-2) or Precambrian basement (Nukik-1). The Kangâmiut-1 well drilled through an Eocene and younger, sand-dominated succession, then Lower Eocene and Paleocene mudstones, below which the well penetrated a coarse arkosic sand interleaved with mudstone before terminating in Precambrian basement. Only one well from the 1970s (Ikermiut-1) drilled a significant section of pre-Cenozoic sediments, sampling an 850 m mudstone section of Santonian–?Campanian age (unpublished data, H. Nøhr-Hansen 2002) before drilling was stopped. However, the well drilled in 2000 (Qulleq-1), also penetrated thick Campanian mudstones below a Neogene and a thin Palaeogene succession, and terminated in sandstones of Santonian age (Nøhr- Hansen et al. 2000; Christiansen et al. 2001; Pegrum et al. 2001). The sediments forming the subject of this study lie above a major, regional unconformity of Danian age. The package is bounded above by an unconformity that can be traced over the whole of the southern West Greenland basin (Fig. 1; Chalmers et al. 2001a), here referred to as the mid-Eocene unconformity. The sediments immediately above the mid-Eocene unconformity are of middle to late Lutetian age (Nøhr-Hansen 1998, 2001), which coincides with the time at which seafloor spreading slowed abruptly in the Labrador Sea (magnetochrons 20–21; Roest & Srivastava 1989; Chalmers & Pulvertaft 2001). The package of sediments forming the subject of this report was thus deposited during active sea-floor spreading in the Labrador Sea between magnetochrons 27n and 20r. 90 Geology of Greenland Survey Bulletin 191, 90–96 (2002) © GEUS, 2002
500 58° 57° 56° 55° 54° 68° Eroded at ‘B a se Hellefisk-1 A 53° Limits of horizon due to either erosion or onlap 1500 Depths in metres below sea level 1000 Quaternary’ Mound 67° Davis Strait High/ Ikermiut Fault Zone 1500 Ikermiut-1 SB A' Syn-rift wedge Amplitudes indicating turbidites on prograding wedge Fan complexes of late Cretaceous age 1500 2000 Kangâmiut-1 NB Seismic grid Nuussuaq Basin 66° SB Sisimiut Basin 2500 Nukik-2 2500 Nukik-1 Greenland 1500 65° Maniitsoq High NB 1000 1500 2000 1500 64° 63° 1500 Hecla High 100 km Qulleq-1 Fig. 1. Locality map showing the extent of the investigated region and the positions of the wells and the seismic lines used to interpret the seismic sequences in this study. The contours show the depths in metres below sea level to the mid-Eocene unconformity. The described Paleocene to mid-Eocene seismic sequences lie under this unconformity, and their distribution shows the maximum extent of the Paleocene to mid-Eocene succession. The map also indicates the distribution of seismic facies representing possible hydrocarbon reservoirs. Seismic line A–A’ is shown in Fig. 2. 91
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GEOLOGY OF GREENLAND SURVEY BULLETI
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Geology of Greenland Survey Bulleti
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Contents Numbers of articles corres
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■ ■ ■ ■ ■ ■ ■ ■ ■
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Canada Pituffik O 1 Thule Air Base
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Publications A complete list of geo
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Canada Greenland Greenland Inland I
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northern Nagssugtoqidian orogen (SN
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western to the north-eastern corner
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group consists of conjugate sets of
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y pure shear. Coincidence of the or
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The Precambrian supracrustal rocks
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68°25′ 52° 68°25′ BIF 0 3 km
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Fig. 4. Dolomitic marble in the sou
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Bugt (Fig. 1; Henderson 1969). The
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Keto, L. 1962: Aerial prospecting b
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▲ ▲ ▲ ▲ ▲ ▲ ▲ ▲ ▲
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increases towards the south. We obs
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Kalsbeek, F. & Taylor, P.N. 1999: R
Page 42 and 43: Canada Nuussuaq 0 50 km PROTEROZOIC
Page 44 and 45: deposit. Descriptions of the differ
Page 46 and 47: Pegmatites The gneisses throughout
Page 48 and 49: tacts with quartzo-feldspathic coun
Page 50 and 51: Geological correlation of magnetic
Page 52 and 53: Fig. 2. The hand-held magnetic susc
Page 54 and 55: Susceptibility distribution (%) Sus
Page 56 and 57: have a reducing effect, which hinde
Page 58 and 59: ancy between the susceptibility val
Page 60 and 61: 67° Sisimiut • 53° 52° 51° 50
Page 62 and 63: Table 1. Range of Nb concentrations
Page 64 and 65: chemical composition - may indicate
Page 66 and 67: Concentration/C1 chondrite 100.00 1
Page 68 and 69: Menzies, M.A. & Hawkesworth, C.J. (
Page 70 and 71: 72°30´ Aeromag 2001 50 km Upernav
Page 72 and 73: 56° 54° 52° 72° 72° nT 71°30
Page 74 and 75: Conclusions The aeromagnetic survey
Page 76 and 77: 53° 51° Inland Ice Greenland 72°
Page 78 and 79: On the south coast of Nuussuaq, wes
Page 80 and 81: Fig. 5. Blocks and boulders in the
Page 82 and 83: 2000 SW NE 1500 Surface trace 1985
Page 84 and 85: 1979). Along other sections of the
Page 86 and 87: Petroleum geological activities in
Page 88 and 89: Seismic acquisition during summer 2
Page 90 and 91: Other petroleum geological work Alt
Page 94 and 95: Seismic interpretation The grid of
Page 96 and 97: Middle Eocene Lower Eocene Upper Pa
Page 98 and 99: Chalmers, J.A., Dahl, J.T., Bate, K
Page 100 and 101: 95-06 ▲ ▲ 58° 95-12 95-10 56°
Page 102 and 103: 70° 71° 60° 2000 2000 2400 400 1
Page 104 and 105: Storey, M., Duncan, R.A., Pedersen,
Page 106 and 107: 24° 100 km 30° 27° 21 ° Jameson
Page 108 and 109: Oligocene Krabbedalen Fm Eocene Bop
Page 110 and 111: grading. Bivalve shell material is
Page 112 and 113: References Birkenmajer, K. 1972: Re
Page 114 and 115: B A 72° Palaeogene basalts Gl 50 k
Page 116 and 117: a b c d e f g h 20 µm i j k l Fig.
Page 118 and 119: offshore South-East Greenland, onsh
Page 120 and 121: ▲ Albert Heim Bjerge Wordie Gletc
Page 122 and 123: T D A CW NS placed the lowermost c.
Page 124 and 125: is abundant and highly diverse, and
Page 126 and 127: The Heimbjerge Formation comprises
Page 128 and 129: Late Permian carbonate concretions
Page 130 and 131: m 25 20 15 B3 L2 B2 Fig. 3. Simplif
Page 132 and 133: (2001), who pointed out the restric
Page 134 and 135: Piasecki, S. 1984: Preliminary paly
Page 136 and 137: 66° 68° • • • • • • 7
Page 138 and 139: absent at Tikeraussaq where a postu
Page 140 and 141: 72° 70° 68° 66° Sample locality
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Table 2. Summary of selected elemen
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Concluding remarks Observations dur
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Lake-catchment interactions with cl
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lakes. As in earlier reports (e.g.
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Discussion Global climate models pr
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Glaciological investigations on ice
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Fig. 2. The new one-mast design of
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A B N 20 km 1993 1995 Fig. 5. Satel
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Krabill, W., Frederick, E., Manizad
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2001/47: Calibration of stream sedi
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Hanghøj, K., Kelemen, P., Bernstei
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Danmarks og Grønlands Geologiske U
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GEOLOGY OF GREENLAND SURVEY BULLETI
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