Review of Greenland Avtivities 2001 - Geus

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ancy between the susceptibility values obtained in the field and those indicated by modelling will also have to be investigated further. The ground magnetic profile carried out during the field season illustrates well the significant difference in resolution of the geological details that are possible from different survey types, at the same time confirming the correlation of geology and airborne anomalies. The investigations will continue in the 2002 field season, when ground geophysical surveys will be undertaken in connection with lineament studies and the study of a mineralised horizon in amphibolite at the fjord Inuarullikkat (Stendal et al. 2002, this volume). The database of the magnetic susceptibility of rocks will be supplemented with new measurements and with laboratory determinations of petrophysical properties when these become available. Acknowledgements Jette Blomsterberg and Aaju Simonsen (both Bureau of Minerals and Petroleum, Government of Greenland) are thanked for their contributions to the field work. The project is part of a Ph.D. study by B.M.N. at the University of Aarhus and is funded by GEUS and the Danish Research Agency. The Geological Institute of the University of Copenhagen is thanked for lending us the magnetic gradiometer. References Blakely, R.J. & Connard, G.G. 1989: Crustal studies using magnetic data. In: Mooney, W.D. (ed.): Geophysical framework of the continental United States. Geological Society of America Memoir 172, 45–60. Card, K.D. & Poulsen, K.H. 1998: Geology and mineral deposits of the Superior Province of the Canadian Shield. In: Lucas, S. (ed.): Geology of the Precambrian Superior and Grenville Provinces and Precambrian fossils in North America. Geology of Canada 7, 13–194. Ottawa: Geological Survey of Canada (also The geology of North America C-1, Geological Society of America). Clark, D.A. 1997: Magnetic petrophysics and magnetic petrology: aids to geological interpretation of magnetic surveys. AGSO Journal of Australian Geology and Geophysics 17(2), 83–103. Clark, D.A. & Emerson, D.W. 1991: Notes on rock magnetization characteristics in applied geophysical studies. Exploration Geophysics 22, 547–555. Connelly, J.N. & Mengel, F.C. 2000: Evolution of Archaean components in the Paleoproterozoic Nagssugtoqidian orogen, West Greenland. Geological Society of America Bulletin 112(5), 747–763. Henkel, H. 1991: Petrophysical properties (density and magnetization) of rocks from the northern part of the Baltic Shield. Tectonophysics 192, 1–19. Marker, M., Mengel, F.[C.] & van Gool, J.[A.M.] 1995: Evolution of the Palaeoproterozoic Nagssugtoqidian orogen: DLC investigations in West Greenland. Rapport Grønlands Geologiske Undersøgelse 165, 100–105. Rasmussen, T.M. & van Gool, J.[A.M.] 2000: Aeromagnetic survey in southern West Greenland: project Aeromag 1999. Geology of Greenland Survey Bulletin 186, 73–77. Shive, P.N., Blackely, R.J., Frost, B.R. & Fountain, D.M. 1992: Magnetic properties of the lower continental crust. In: Kay, R.W. (ed.): Continental crust. Developments in geotectonics 23, 145–177. Stendal, H., Blomsterberg, J., Jensen, S.M., Lind, M., Madsen, H.B., Nielsen, B.M., Thorning, L. & Østergaard, C. 2002: The mineral resource potential of the Nordre Strømfjord – Qasigiannguit region, southern and central West Greenland. Geology of Greenland Survey Bulletin 191, 39–47 (this volume). Telford, W.M., Geldart, L.P. & Sheriff, R.E. 1998: Applied geophysics, 2nd edition, 770 pp. Cambridge: Cambridge University Press. Thorning, L. 1986: A decade of geophysical surveying in - Greenland. Rapport Grønlands Geologiske Undersøgelse 128, 123–133. van Gool, J.[A.M.], Marker, M., Mengel, F.[C.] & field party1996: The Palaeoproterozoic Nagssugtoqidian orogen in West Greenland: current status of work by the Danish Lithosphere Centre. Bulletin Grønlands Geologiske Undersøgelse 172, 88–94. van Gool, J.A.M. et al. 2002: Precambrian geology of the northern Nagssugtoqidian orogen, West Greenland: mapping in the Kangaatsiaq area. Geology of Greenland Survey Bulletin 191, 13–23 (this volume). Authors’ address Geological Survey of Denmark and Greenland, Øster Voldgade 10, DK-1350 Copenhagen K, Denmark. E-mail: bmn@geus.dk 56
Kimberlites and other ultramafic alkaline rocks in the Sisimiut–Kangerlussuaq region, southern West Greenland Sven Monrad Jensen, Henriette Hansen, Karsten Secher,Agnete Steenfelt, Frands Schjøth and Thorkild M. Rasmussen The alkaline province of southern West Greenland includes swarms of dykes described as kimberlites and lamproites (Larsen 1991), and these rock types are widely distributed in the Sisimiut–Sarfartoq–Kangerlussuaq region (Figs 1, 2). Kimberlites and lamproites are potential carriers of diamond, and since the description of the Sarfartoq carbonatite complex and the kimberlitic dykes related to this complex (Larsen 1980; Secher & Larsen 1980), the Sisimiut–Sarfartoq–Kangerlussuaq region has seen several campaigns of commercial diamond exploration. The latest and most persistent stage of exploration began in the mid-1990s and has continued to date, with varying intensity. Numerous reports of diamond-favourable indicator minerals from till sampling, finds of kimberlitic dykes, and recovery of actual diamonds from kimberlitic rocks have emerged since 1995 (Olsen et al. 1999). A drilling programme in late 2001 confirmed the unusually great length and width of a magnetic kimberlitic dyke (Ferguson 2001). The alkaline ultramafic dykes within the Sisimiut– Kangerlussuaq and Sarfartoq regions intrude the border zone between the Archaean craton and the Palaeoproterozoic Nagssugtoqidian orogen (van Gool et al. 2002, this volume). This border is defined as the southern boundary of Palaeoproterozoic reworking of the Archaean basement gneisses. The reworking has affected the Palaeoproterozoic Kangâmiut dolerite dykes, which Nordre Strømfjord Nordre Isortoq Greenland Ikertooq steep belt 67° Sisimiut Ikertooq 67° Inland Ice 66° Itilleq Kangaamiut Søndre fjord Strø m Sukkertoppen Iskappe Palaeoproterozoic Syntectonic granite suite Arfersiorfik quartz diorite Sisimiut charnockite Kangâmiut dyke swarm Archaean Archaean gneiss (s.l.) Early Archaean gneiss Fig. 1. Geological map of the region with the project area (Fig. 2) outlined in a red frame. Modified from Mengel et al. (1998). 50 km 54° Maniitsoq 52° Undifferentiated Supracrustal rocks Mafic dykes Thrust High strain zone Geology of Greenland Survey Bulletin 191, 57–66 (2002) © GEUS, 2002 57
Page 1:
GEOLOGY OF GREENLAND SURVEY BULLETI
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Geology of Greenland Survey Bulleti
Page 7 and 8: Contents Numbers of articles corres
Page 9: ■ ■ ■ ■ ■ ■ ■ ■ ■
Page 12 and 13: Canada Pituffik O 1 Thule Air Base
Page 14 and 15: Publications A complete list of geo
Page 16 and 17: Canada Greenland Greenland Inland I
Page 18 and 19: northern Nagssugtoqidian orogen (SN
Page 20 and 21: western to the north-eastern corner
Page 22 and 23: group consists of conjugate sets of
Page 24 and 25: y pure shear. Coincidence of the or
Page 26 and 27: The Precambrian supracrustal rocks
Page 28 and 29: 68°25′ 52° 68°25′ BIF 0 3 km
Page 30 and 31: Fig. 4. Dolomitic marble in the sou
Page 32 and 33: Bugt (Fig. 1; Henderson 1969). The
Page 34 and 35: Keto, L. 1962: Aerial prospecting b
Page 36 and 37: ▲ ▲ ▲ ▲ ▲ ▲ ▲ ▲ ▲
Page 38 and 39: increases towards the south. We obs
Page 40 and 41: 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 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 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
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66° 68° • • • • • • 7
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absent at Tikeraussaq where a postu
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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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