Review of Greenland Avtivities 2001 - Geus

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66° 68° • • • • • • 70° 72° I n L a n d g l e f i e l d Kap Alexander McCormick Fjord Kangerlussuaq Inglefield Bredning Northumberland Ø Siorapaluk Red Cliffs Inland Ice P Sonntag Bugt n d r u d h o e L a Morris Jesup Gletscher Robertson Fjord Hubbard Gletscher Qaanaaq Tikeraussaq Josephine Peary Ø Qeqertat Kangerlussuaq Smithson Bjerge Bowdoin Scarlet Heart Gletscher Permanent ice Surficial deposits Main fault QUATERNARY Prudhoe Land supracrustal complex Undifferentiated gneiss complex incl. Etah Group of Inglefield Land 78° Smithson Bjerge magmatic association Thule mixed-gneiss complex MESOPROTEROZOIC ARCHAEAN PALAEO- PROTEROZOIC THULE BASIN Dundas Group Baffin Bay Group Nares Strait Group Smith Sound Group PRECAMBRIAN SHIELD •N BI BB EI CH P MB Greenland Fjord 77°30′ Academy Bugt Kap Trautwine Olrik Fjord 'Hill 620' 'Mount Gyrfalco' 0 40 km Fig. 1. Geological map of the Qaanaaq region with place names used in the text; project limits of Qaanaaq 2001 are shown by red dashed lines. Basic sills, that in some areas of the Dundas Group form large outcrops, are not shown. Only faults affecting disposition of groups of the Thule Supergroup are depicted. Black dots are settlements; red dots other localities. Inset map: BB, Baffin Bay; BI, Baffin Island; CH, Clarence Head; EL, Ellesmere Island; MB, Melville Bugt; N, Nanisivik; P, Pituffik (Thule Air Base). Red frame, location of Qaanaaq region. Compiled from Dawes (1991) and Dawes et al. (2000) with modifications from Qaanaaq 2001. 134
Precambrian shield Thule mixed-gneiss complex. This is an Archaean complex of highly deformed amphibolite- to granulitefacies gneisses of variable lithology and derivation, with genetically related granitic rocks. The 2001 work confirmed the intricate association of paragneisses and orthogneisses and it is clear that some intermixed packages can only be unravelled by future detailed mapping. Of note are widespread light coloured garnetbearing quartzitic layers interleaved with gneisses. At the head of Olrik Fjord, these rock associations contain a rusty unit of banded iron-formation (BIF), e.g. north-east of ‘Mount Gyrfalco’ (see later under Mineralisation). Several amphibolite bodies were found to grade into ultramafic rocks and new occurrences of ultramafic bodies were discovered, the largest being a boudin (c. 500 x 150 m) within orthogneiss at the head of Academy Bugt. Prudhoe Land supracrustal complex. These supracrustal rocks, of supposed Palaeoproterozoic age, comprise a thick succession of pelitic, semi-pelitic and quartzitic rocks with some mafic units (amphibolite and pyribolite). The supracrustal complex has conspicuous rusty weathering, and is considered to be a cover sequence to the Thule mixed-gneiss complex (Fig. 3). Both units are interleaved by large-scale isoclinal folds. New outcrops of supracrustal rocks were noted around Bowdoin Fjord and in Robertson Fjord, and units of marble, not hitherto known in the succession, were discovered at Bowdoin Fjord and Morris Jesup Gletscher. This strengthens our view that the supracrustal rocks are a correlative of the Etah Group of Inglefield land in which marble units are common. Fig. 2. The basic logistics of Qaanaaq 2001 with typical weather: M/S Kissavik and rubber dinghies with overcast, low cloud and rain. View is across Olrik Fjord in late August. Thule Basin The Thule Supergroup is a thick, multicoloured, mainly shallow water sedimentary succession with one main interval of volcanic rocks. Basic sills are common at several levels. Five groups are recognised (Dawes 1997), all but one of which (Narssârssuk Group) crop out in the Qaanaaq region (Fig. 1). The Smith Sound Group, present north of Sonntag Bugt, represents the northern basin margin equivalent of the Nares Strait Group and the overlying Baffin Bay Group. Access to inland exposures in 2001 resulted in some adjustments to group/formation distribution on existing maps. One revision concerns the distribution of the Nares Strait Group with its volcanic component of hypabyssal, effusive and pyroclastic rocks and associated red beds – the Cape Combermere Formation (Dawes 1997). Breccias of the formation have proved to be mineralised. The Nares Strait Group was deemed Fig. 3. Basement–cover relationship. Rusty-weathering pelitic and quartzitic rocks with amphibolites of the Palaeoproterozoic Prudhoe Land supracrustal complex overlying darker gneisses of the Archaean Thule mixedgneiss complex. The pelitic schists, rich in graphite and pyrite, generate several Landsat anomalies. North side of Inglefield Bredning, west of Josephine Peary Ø, with main summit 770 m above sea level. 135
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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
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Canada Nuussuaq 0 50 km PROTEROZOIC
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deposit. Descriptions of the differ
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Pegmatites The gneisses throughout
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tacts with quartzo-feldspathic coun
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Geological correlation of magnetic
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Fig. 2. The hand-held magnetic susc
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Susceptibility distribution (%) Sus
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have a reducing effect, which hinde
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ancy between the susceptibility val
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67° Sisimiut • 53° 52° 51° 50
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Table 1. Range of Nb concentrations
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chemical composition - may indicate
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Concentration/C1 chondrite 100.00 1
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Menzies, M.A. & Hawkesworth, C.J. (
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72°30´ Aeromag 2001 50 km Upernav
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56° 54° 52° 72° 72° nT 71°30
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Conclusions The aeromagnetic survey
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53° 51° Inland Ice Greenland 72°
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On the south coast of Nuussuaq, wes
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Fig. 5. Blocks and boulders in the
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2000 SW NE 1500 Surface trace 1985
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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 92 and 93: A multidisciplinary study of the Pa
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 138 and 139: absent at Tikeraussaq where a postu
Page 140 and 141: 72° 70° 68° 66° Sample locality
Page 142 and 143: Table 2. Summary of selected elemen
Page 144 and 145: Concluding remarks Observations dur
Page 146 and 147: Lake-catchment interactions with cl
Page 148 and 149: lakes. As in earlier reports (e.g.
Page 150 and 151: Discussion Global climate models pr
Page 152 and 153: Glaciological investigations on ice
Page 154 and 155: Fig. 2. The new one-mast design of
Page 156 and 157: A B N 20 km 1993 1995 Fig. 5. Satel
Page 158 and 159: Krabill, W., Frederick, E., Manizad
Page 160 and 161: 2001/47: Calibration of stream sedi
Page 162 and 163: Hanghøj, K., Kelemen, P., Bernstei
Page 165 and 166: Danmarks og Grønlands Geologiske U
Page 167: GEOLOGY OF GREENLAND SURVEY BULLETI
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