Review of Greenland Avtivities 2001 - Geus

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1979). Along other sections of the north-facing coasts the slides that occur are slow earth slides or rock glaciers. Areas with a high risk of landslides accompanied by tsunamis are found on the south coast of Nuussuaq between Paatuut and Nuusap Qaqqarsua (Fig. 2). Here, the very steep slopes and the active erosion of the thick pile of hyaloclastite breccias generate thick, steep, high-lying debris fans, which are unstable and may easily slide. Studies of aerial photographs show that at least 17 major landslides have occurred in the high-risk section prior to 1985, but only three of these slides are known to have reached the sea. In addition three landslides occurred at Paatuut between 1988 and 2000. Four of the twenty landslides generated within the last 3000 years reached the sea, and the minimum frequency of tsunamis is thus 1–2 per 1000 years. However, two of the four slides occurred within the last 50 years (1952 and 2000), and it may be that some older landslides have not been recognised due to fluvial reworking. The historical record indicates that catastrophic landslides are not common. The town Qullissat was founded in 1924 and, apart from the slide in 1952 which caused some material damage and the loss of one life, the town has not been damaged by tsunamis in 76 years. In the coastal cliff at Asuk, the tsunami in 2000 disturbed graves several hundred years old. Although the graves were already somewhat damaged by ground creep or perhaps previous tsunamis, it is obvious that a tsunami like the one in 2000 is a rare event. Prediction of future slides is not possible. However, it is certain that the lithologies and the morphology of the south coast of Nuussuaq from Paatuut and westwards will continue to generate landslides in the future. Conclusions The landslide at Paatuut on 21 November 2000 is interpreted as a rock avalanche initiated by a rock fall (Fig. 8). The fall was probably initiated by thawing and freezing in fractures at altitudes of 1000–1400 m a.s.l. The landslide removed 90 million m 3 of scree and volcanic rocks which were transported to the coastal area with an average velocity of about 140 km/h. It built a lobe comprising c. 60 million m 3 , and c. 30 million m 3 continued seawards in a submarine slide which initiated a tsunami and caused heavy damage in the coastal areas of the Vaigat strait. The slide deposited clast-supported conglomerates from modified grain flows, and matrix-supported conglomerates from debris flows. Despite the high risk of landslides on the south coast of Nuussuaq the frequency of catastrophic landslides and tsunamis is not high. The seismic records make the Paatuut 2000 landslide one of the best-documented events of its type. Acknowledgements This project was funded by the Bureau of Minerals and Petroleum, Government of Greenland. Arktisk Station, Qeqertarsuaq, is thanked for use of their research vessel Porsild and for support during the field work. References Dam, G. & Nøhr-Hansen, H. 2001: Mantle plumes and sequence stratigraphy: Late Maastrichtian – Early Paleocene of West Greenland. Bulletin of the Geological Society of Denmark 48, 189–207. Dam, G. & Sønderholm, M. 1998: Sedimentological evolution of a fault-controlled Early Paleocene incised valley system, Nuussuaq Basin, West Greenland. In: Shanley, K.W. & McCabe, P.J. (eds): Relative role of eustasy, climate and tectonism in continental rocks. Society of Economic Paleontologists and Mineralogists Special Publication 59, 109–121. Henderson, G. 1969: Oil and gas prospects in the Cretaceous– Tertiary basin of West Greenland. Rapport Grønlands Geologiske Undersøgelse 22, 63 pp. Keefer, D.K. 1999: Earthquake-induced landslides and their effects on alluvial fans. Journal of Sedimentary Research 69, 84–104. Koch, B.E. 1959: Contribution to the stratigraphy of the nonmarine Tertiary deposits on the south coast of Nûgssuaq Peninsula, Northwest Greenland. Bulletin Grønlands Geologiske Undersøgelse 22, 100 pp. (also Meddelelser om Grønland 162(1)). Long, A.J., Roberts, D.H. & Wright, R. 1999: Isolation basin stratigraphy and Holocene relative sea-level change on Arveprinsen Ejland, Disko Bugt, West Greenland. Journal of Quaternary Science 14(4), 323–345. Marcussen, C., Chalmers, J.A., Andersen, H.L., Rasmussen, R. & Dahl-Jensen, T. 2001: Acquisition of high-resolution multichannel seismic data in the offshore part of the Nuussuaq Basin, central West Greenland. Geology of Greenland Survey Bulletin 189, 34–40. Pedersen, A.K., Larsen, L.M. & Dueholm, K.S. 1993: Geological section along the south coast of Nuussuaq, central West Greenland, 1:20000, coloured sheet. Copenhagen: Geological Survey of Greenland. Pedersen, G.K. & Pulvertaft, T.C.R. 1992: The nonmarine Cretaceous of the West Greenland basin, onshore West Greenland. Cretaceous Research 13, 263–272. Pedersen, S.A.S., Foged, N. & Frederiksen, J. 1989: Extent and economic significance of landslides in Denmark, Faroe Islands and Greenland. In: Brabb, E.E. & Harrod, B.L. (eds): Landslides, extent and economic significance, 153–156. Rotterdam: Balkema. 82
Pedersen, S.A.S., Dahl-Jensen, T., Jepsen, H., Larsen, L.M., Pedersen, G.K., Nielsen, T., Pedersen, A.K. & Weng, W. 2001: Fjeldskred ved Paatuut. Danmarks og Grønlands Geologiske Undersøgelse Rapport 2001/99, 47 pp. Pulvertaft, T.C.R. 1979: Stenfald og fjeldskred ved Niakornat, Umanak Kommune, Vest-Grønland. Rapport til Umanak Kommune, 12 pp. Unpublished report, Grønlands Geologiske Undersøgelse, København (in archives of Geological Survey of Denmark and Greenland, Copenhagen, Denmark). Rosenkrantz, A. 1967: Bjørnefælden ved Nûgssuaq og nordboernes Eysunes i geologisk belysning. Tidsskriftet Grønland 12, 377–384. Charlottenlund, Danmark: Det grønlandske Selskab. Steenstrup, K.J.V. 1900: Beretning om en Undersøgelsesrejse til Øen Disko i Sommeren 1898. Meddelelser om Grønland 24(3), 249–306. Authors’ addresses S.A.S.P., L.M.L., T.D.-J., H.F.J., T.N., F.v.P.-H. & W.W., Geological Survey of Denmark and Greenland, Øster Voldgade 10, DK-1350 Copenhagen K, Denmark. E-mail: sasp@geus.dk G.K.P., Geological Institute, University of Copenhagen, Øster Voldgade 10, DK-1350 Copenhagen K, Denmark. A.K.P., Geological Museum, University of Copenhagen, Øster Voldgade 5–7, DK-1350 Copenhagen K, Denmark. 83
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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
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 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 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
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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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