Review of Greenland Avtivities 2001 - Geus

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Fig. 2. The new one-mast design of the automatic mass-balance stations installed in the field in May 2001; height c. 2.2 m (AMS 71). The gallows with the sonic ranger for surface height measurements can be seen to the right. Field work In late May 2001 a glaciological transect was established on Sermilik Bræ (formerly Sermitsialik Bræ) in South Greenland at the margin of the Inland Ice. The transect extends from an altitude of 270 m a.s.l. on Sermilik Bræ (glacier code 1 AI 5001, Weidick et al. 1992) up to a height of 1150 m a.s.l. on the southern dome of the Inland Ice (Fig. 1). The transect consists of two automatic mass-balance stations (AMS) placed at each end of the transect and four ablation stakes placed along the flow line. Due to the risk of loss of data in areas with high ablation rates, a new concept for the station layout has been developed to replace the former set-up of using several long stakes drilled into the ice, which often became unstable. The new AMS concept consists of one mast, supported by wires, and set on a tripod (Fig. 2). The AMS can be transported, and installed on site by two persons in about two hours. The stations measure a variety of climatic and glaciological parameters at hourly intervals. The orientation of the mast to the vertical and to magnetic north is also recorded, in order to allow for possible corrections of the parameter records. Day of year 120 150 180 210 240 270 Day of year 120 150 180 210 240 270 12 24 hour running average AMS 71 24 hour running average AMS 72 12 24 hour running average AMS 71 24 hour running average AMS 72 Temperature (°C) 8 4 Wind speed (m/s) 8 4 0 -4 30/04/2001 30/05/2001 29/06/2001 29/07/2001 28/08/2001 27/09/2001 Date 0 30/04/2001 30/05/2001 29/06/2001 29/07/2001 28/08/2001 27/09/2001 Fig. 3. Data examples from the automatic mass-balance stations for the summer season of 2001. Red: lower station. Blue: upper station. Displayed are the daily means of temperature (left) and wind speed (right) for both stations. The temperature variation ranges from –6.2 to +17.4°C for the upper and –1.1 to +12.0°C for the lower station. The maximum wind speed during the measured period was 15.8 m/s at the upper station. Date 152
Table 1. Temporal distribution of the images used for the determination of the glacier margin position Image source Image date Aerial photography CORONA satellites Landsat 2 (channel 3) Landsat 5 (channel 3) Landsat 7 (channel 3) 05.09.1953 21.07.1965 21.08.1967 09.06.1979 09.07.1979 26.08.1980 17.07.1993 14.07.1995 04.08.2000 x (1.5 m) x (~ 3 m) x (~ 3 m) x (80 m) x (80 m) x (80 m) x (80 m) x (80 m) x (30 m) Pixel resolution is given in brackets In order to measure ablation automatically over several years without having to re-drill stakes at every visit, a new system was installed at the lower AMS. This consists of a ventilated stainless steel pressure transducer connected to a 20 m fibre-reinforced PVC hose filled with alcohol. At the revisit to the site in September 2001 the new ablation system was still functioning, and the recordings from the logger are in very good agreement with data from the sonic ranger and the classically measured melting of 4.95 m in 106 days. The positions of both AMSs and stakes were remeasured by a high-precision GPS receiver on the September visit, except for stake no. 750. The analysis of the measurements shows a velocity of the upper station of 0.4 m/day, increasing downstream to 1.4 m/day at the lower station close to the glacier front. Data records for temperature and wind speed at both stations during the summer of 2001 are shown in Fig. 3. Both parameters are generally in phase for the two stations, but temperature inversions can be found on days with very low wind speed at the lower station. The data sets for the stations will be used for further analysis of melting conditions and the distribution of melting in this area. During the 2001 field season the NASA airborne ice radar and laser altimetry system was used for investigations in southern Greenland within the PARCA project. By request, one flight track was planned to cover the GEUS glaciological transect (Fig. 1). Unfortunately, the ice radar data could not provide thickness data over this track because of heavily crevassed and irregular surface conditions. However, the laser altimetry data are of very good quality, and are currently being analysed in combination with the GPS measurements and information from the satellite images. Glacier-margin detection from satellite imagery During the past 50 years the glacier Sermilik Bræ has undergone significant variations in its dimensions. Within A B N Fig. 4. Aerial views of the Sermilik Bræ region. A: Aerial photograph from 1953; B: Satellite image from Landsat 7 obtained in 2000. In the Landsat image shown in Fig. 5 Qalerallit Sermia W and Qalerallit Sermia E are also seen. 1953 2000 5 km 153
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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
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Petroleum geological activities in
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Seismic acquisition during summer 2
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Other petroleum geological work Alt
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A multidisciplinary study of the Pa
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Seismic interpretation The grid of
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Middle Eocene Lower Eocene Upper Pa
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Chalmers, J.A., Dahl, J.T., Bate, K
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95-06 ▲ ▲ 58° 95-12 95-10 56°
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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
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 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
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