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68 measured in the field, and the carbon content of the sediment will be analysed later in the laboratory. The methanogenic association in the sediments will be determined via fluorescence-in-situ-hybridization at cores collected at the sites, where the measurements of methane emission were performed. These sediment cores provide also material for additional micro- and molecular biological investigations, as for example the measurement of the methane production and oxidation capacity. 6.5 Surface exposure dating Lena Håkansson In 1976 a Swedish-Danish party visited Hochstetter Forland and Shannon Island. Their field season also included a one-day helicopter trip to Store Koldewey. The results from the fieldwork were published by Hjort (1981). He suggested that only the southern lowland of Store Koldewey was overridden by Weichselian glaciers, meaning that both the plateau mountains and the area east thereof were ice free during this period. Also a glacial chronology for northern East Greenland was presented, which identifies three stadials with glacial advances of successively smaller extent. It was suggested that the earliest of these, the Kap Mackenzie stadial, is of early Weichselian age or older. During this period the ice reached onto the continental shelf, covering more or less the whole investigated area. The Muschelbjerg and Nanok stadials represent younger periods with more restricted glacial advances. However, this chronology was re-evaluated by Hjort & Björck (1984) based on pollen data, 14 C dates and amino acid ratios in mollusc shells from Hochstetter Forland and Shannon Island. The re-evaluated chronology suggests that the Weichselian glacial maximum occurred around 15 000 BP during the Nanok stadial. Contrary to the earlier interpretation it is suggested that the Muschelbjerg and Kap Mackenzie stadials have a Saalian or pre-Saalian age. More recent work on the shelf south from the working area has questioned the extent of the Weichselian extent of Hjorts chronology. In contradiction they point out that the ice during this period reached onto the continental shelf. In order to solve these contradictions geomorphological investigations and sampling for surface exposure dating (SED) have been conducted. These investigations will shed light on the glacial history of northern East Greenland through absolute dating and further knowledge about the geomorphology of Store Koldewey. Fieldwork During the fieldwork on Store Koldewey eleven rock samples were collected both from the top of the plateau mountains and from the lowland east and south from the mountain range. Additionally, three rock samples were collected on north eastern Geographical Society Ø. In most cases boulders were sampled, however, two localities are represented by bedrock samples (Tab. 6.5-1). They are all collected using a hammer and chisel (Fig. 6.5-1). Additionally the orientation of glacial striae were measured and moraine ridges were mapped.
Methods Cosmic ray particles entering the earth’s atmosphere produce a shower of secondary particles (e. g. neutrons, protons and muons). Those particles that reach the terrestrial surface can produce terrestrial cosmogenic nuclides (TCN) in the uppermost tens of cm in a rock. Here TCN is referred to the six nuclides that are most commonly used in geological applications ( 3 He, 10 Be, 14 C, 21 Ne, 26 Al and 36 Cl). The production takes place in-situ in minerals, from which quartz is most commonly used for analyses. Its simple chemical composition (SiO2), resistance to erosional processes and its abundance in many different lithologies makes it an ideal target mineral for the production of TCN. The concentration of these nuclides in a rock is time dependent and can therefore be used to measure the time interval of exposure to cosmic radiation. If assumed that the sampled surface of a rock is related to a geological process, surface exposure dating yield an absolute timing of the event. Depending on the nuclide analysed the method has a time range from millions of years down to a few thousand years. sample no. latitude longitude alt. (m a.s.l.) size Store Koldewey 001 N76°06’37.0’’ W018°34’34.0’’ 630 0.7 x 1 x 1 002 N76°06’17.0’’ W018°35’00.3’’ 214 1 x 2 x 3 003 N76°04’02.8’’ W018°35’21.7’’ 51 0.7x 2 x 1.5 004 N76°05’07.7’’ W018°38’30.9’’ 93 0.6 x 1 x 0.5 005 N76°10’32.6’’ W018°40’37.5’’ 617 1.5 x 2 x 3 006 N76°07’43.7’’ W018°39’35.5’’ 198 bedrock 007 N76°23’01.9’’ W018°57’07.4’’ 686 bedrock 008 N76°23’20.9’’ W018°51’20.6’’ 568 1 x 3 x 4 009 569 1.2 x 2 x 3 010 N76°15’14.4’’ W018°45’08.8’’ 704 bedrock 011 N76°15’35.4’’ W018°44’52.4’’ 652 0.5 x 1.5 x 2 Geographical Society Ø 012 N72°45’07.3’’ W021°54’45.6’’ 013 N72°53’26.7’’ W021°54’25.3’’ 108 0.12 x 0.3 x 0.5 014 N72°53’10.6’’ W021°54’46.1’’ 127 small Tab. 6.5-1: Rock samples from Store Koldewey and Geographical Society Ø Fig. 6.5-1: Rock sampling on Geographical Society Ø. 69
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the Expedition ARKTIS-XIX/4 of the
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1 Cruise summary W. Jokat The exped
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6 1.1 Wetterverlauf ARK XIX/4a Bei
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8 noch vor der Küste, fern davon a
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10 northerly wind increased steadil
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12 In the latest stages of the proj
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Profile Date/Time Start Date/Time T
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Station Typ Extra Lat Long Höhe [m
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Page 22 and 23: Date Flight Start Time End Time No
Page 32 and 33: 30 Preliminary results Along profil
Page 34 and 35: 32 In addition to the deep seismic
Page 36 and 37: 34 Fig. 2-5: Flight statistics for
Page 38 and 39: 36 Fig. 3-1: Seafloor topography of
Page 40 and 41: 38 In total, the PARASOUND system o
Page 42 and 43: 40 Figure 4.1-3: Example of PARASOU
Page 44 and 45: 42 Station Latitude Longitude Date
Page 46 and 47: 44 After PCR was finished, samples
Page 48 and 49: 46 Potsdam Lake (Shannon Island) Sc
Page 50 and 51: 48 In den Schmelzwassertümpeln kon
Page 52 and 53: Temp. Sal. Tiefe max. Tiefe Trübe
Page 54 and 55: 52 Store Koldewey Store Koldewey is
Page 56 and 57: 54 In the shallow ponds the hydrolo
Page 58 and 59: 56 The low amounts of solubles in t
Page 60 and 61: 58 lake core no. latitude longitude
Page 62 and 63: 60 6.3 Diatom phytoplankton and phy
Page 64 and 65: 62 Generally, all sampled benthic s
Page 66 and 67: 64 shaped profile at the top were i
Page 68 and 69: 66 depth horizon description sample
Page 72 and 73: 70 Summary of results The summit pl
Page 74 and 75: 72 Pre-Holocene shell material Pre-
Page 76 and 77: 74 Christensen, T.R. (1993): Methan
Page 78 and 79: 76 No EVK2-2001-00215 (ASOF-N). The
Page 80 and 81: 78 Altimeters Model 2110-2, SN 189
Page 82 and 83: 80 Mooring Latitude Longitude Water
Page 84 and 85: 82 Mooring Latitude Longitude Water
Page 86 and 87: 84 30° W 20° W 30° W Greenland 2
Page 88 and 89: Fig. 7-4: Vertical transects of pot
Page 90 and 91: 88 8 Bericht zur akustischen Vermes
Page 92 and 93: 90 Quality control sheet - Profile
Page 94 and 95: 92 Quality control sheet - Profile
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142 Beteiligte Institutionen / Part
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