the Expedition ARKTIS-XIX/4 of the research vessel POLARSTERN ...

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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.