Review of Greenland Avtivities 2001 - Geus

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Discussion Global climate models predict considerable future change in the Arctic, although response will not be uniform. This variability is clear from a synthesis of longterm monitoring data, which shows that around Søndre Strømfjord temperature has declined in the period 1970–2000 (Serreze et al. 2000). Future predicted changes include altered mass and energy inputs, with resultant increased precipitation in some areas and decreases in others. However, our understanding of the hydrological cycle in the Arctic is characterised by a relatively sparse observational network, and the length of monitoring records is often very short and sporadic. Hence it is difficult to detect trends and identify abnormal years. Although our contemporary monitoring programme is located in a crucial area of the Arctic, where present hydrological information is limited, by necessity it will provide only a short-term view of environmental variation. Our aim, however, is to use this contemporary hydrological and meteorological data to calibrate longterm lake response. High-resolution sediment core studies can then be used to identify decadal trends in lake water conductivity. These core records can be coupled with energy-balance models derived from modern hydrological data to estimate the past climate conditions that were required to produce the past lake level (and lake water conductivity) changes. The objective of the present project, therefore, is to integrate, as far as possible across a range of temporal scales, longer-term (102–103 years) to short-term (i.e. seasonal) processes. In a multidisciplinary approach to palaeoenvironmental reconstruction, it is also planned to couple geomorphic studies of large-scale landscape features, such as palaeoshorelines and terraces, with the finer scale record embedded in the sediment cores. Previously, a number of lake sites with finely laminated sediments have been recorded (Anderson et al. 1999). Although they are not annual (i.e. varves), the palaeoenvironmental significance of the changing structure of these laminations is considerable, if the dominant processes and frequency can be determined. Some of the structure can be readily interpreted, for example calcite precipitation and deposition of purple sulphur bacteria form unambiguous laminations. It is unknown, however, whether calcite precipitation in these lakes occurs under ice (due to salinisation effects associated with salt expulsion from ice) or during the summer due to photosynthesis (increasing pH), or how often this occurs. The processes underlying the interplay of other organic/inorganic fractions are even less clear. The Technicap sediment traps were originally developed for the marine environment but are ideally suited to remote Arctic lakes where regular emptying is problematical. Aspects of our catchment studies are aimed at determining how much minerogenic matter is derived from the catchment, as many of the lakes around the head of Søndre Strømfjord lack discrete inflows. The amount of material brought in during the spring thaw is also unknown. Thus the sediment traps will allow us to couple the lake sediment record with the climatic/meteorological processes giving rise to the sediment flux, both from the catchment and within the lake. Conclusion Understanding future changes in the hydrology of Arctic catchments will be difficult, because of the paucity of contemporary data. Similarly, our interpretation of past changes in the hydrological mass balance of lakes and catchments, as exemplified by fossil shorelines in the Søndre Strømfjord area, can only be strengthened by understanding contemporary processes. Combined with hydrologic mass balances and an assessment of the geomorphic setting, we aim to quantify seasonal sediment input through the use of sediment cores and sediment traps. These historical scenarios and the associated palaeoclimatic inferences can then be validated by lake energy balance models (Hostetler 1995). Acknowledgements The field work was undertaken with financial support from the Danish Natural Science Research Council (SNF), National Science Foundation (NSF, USA) and the European Commission (EMERGE). Assistance in the field was provided by William Clarke (Department of Agriculture Northern Ireland, UK), Ulf Thomas, Marianne Grauert, Mikael Kamp-Sørensen, Kim Edmunds (all University of Copenhagen) and Neil Rose, Simon Patrick, Sergi Pla, Chris Curtis, Mike Hughes and Martin Kernan (all University College London, UK). References Anderson, N.J. & Bennike, O. 1997: Holocene lake sediments in West Greenland and their palaeoclimatic and palaeoecological implications. Geology of Greenland Survey Bulletin 176, 89–94. 148
Anderson, N.J. & Brodersen, K.P. 2001: Determining the date of ice-melt for low Arctic lakes along Søndre Strømfjord, southern West Greenland. Geology of Greenland Survey Bulletin 189, 54–58. Anderson, N.J., Bennike, O., Christofferson, K., Jeppesen, E., Markager, S., Miller, G. & Renberg, I. 1999: Limnological and palaeolimnological studies of lakes in south-western Greenland. Geology of Greenland Survey Bulletin 183, 68–74. Anderson, N.J., Clarke, A., Juhler, R.K., McGowan, S. & Renberg, I. 2000: Coring of laminated lake sediments for pigment and mineral magnetic analyses, Søndre Strømfjord, southern West Greenland. Geology of Greenland Survey Bulletin 186, 83–87. Anderson, N.J., Harriman, R., Ryves, D.B. & Patrick, S.T. 2001: Dominant factors controlling variability in the ionic composition of West Greenland lakes. Arctic, Antarctic & Alpine Research 33, 418–425. Bindler, R., Anderson, N.J., Renberg, I. & Malmquist, C. 2001: Palaeolimnological investigation of atmospheric pollution in the Søndre Strømfjord region, southern West Greenland: accumulation rates and spatial patterns. Geology of Greenland Survey Bulletin 189, 48–53. Doran, P.T. et al. 2002: Antarctic climate cooling and terrestrial ecosystem response. Nature 415, 517–520. Hasholt, B. & Søgaard, H. 1976: Et forsøg på en klimatisk-hydrologisk regionsinddeling af Holsteinsborg Kommune (Sisimiut). Geografisk Tidsskrift 77, 72–92. Hostetler, S.W. 1995: Hydrological and thermal response of lakes to climate: description and modeling. In: Lerman, A., Imboden, D. & Gat, J. (eds): Physics and chemistry of lakes, 63–82. Berlin: Springer Verlag. Magnuson, J.J. et al. 2000: Historical trends in lake and river ice cover in the Northern Hemisphere. Science 289, 1743–1746. Overpeck, J.P. et al. 1997: Arctic environmental change of the last four centuries. Science 278, 1251–1256. Serreze, M.C., Walsh, J.E., Chapin, F.S., Osterkamp, T., Dyurgerov, M., Romanovsky, V., Oechel, W.C., Morison, J., Zhang, T. & Barry, R.G. 2000: Observational evidence of recent change in the northern high-latitude environment. Climatic Change 46, 159–207. Vörösmarty, C.J., Hinzman, L.D., Petersen, B.J., Bronwich, D.H., Hamilton, L.C., Morison, J., Romanovsky, V.E., Sturm, M. & Webb, R.S. 2001: The hydrological cycle and its role in Arctic and global environmental change: a rationale and strategy for synthesis study, 84 pp. Fairbanks, Alaska: Arctic Research Consortium of the U.S. Authors’ addresses N.J.A., Geological Survey of Denmark and Greenland, Øster Voldgade 10, DK-1350 Copenhagen K, Denmark. E-mail: nja@geus.dk S.C.F., Department of Geosciences, University of Nebraska, 214 Bessey Hall, Lincoln, NE 68588, USA. C.E.G., Department of Agriculture and Rural Development, Agricultural and Environmental Science Division, Newforge Lane, Belfast BT9 5PX, UK. B.H., Institute of Geography, University of Copenhagen, Øster Voldgade 10, DK-1350 Copenhagen K, Denmark. M.J.L., NERC Isotope Geoscience Laboratory, British Geological Survey, Keyworth, Nottingham, NG12 5GG, UK. 149
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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
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,
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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
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Page 120 and 121: ▲ Albert Heim Bjerge Wordie Gletc
Page 122 and 123: T D A CW NS placed the lowermost c.
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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
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Page 134 and 135: Piasecki, S. 1984: Preliminary paly
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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 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
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