Ladda ner årsbok 2008 (6,5 MB) - Polarforskningssekretariatet

the early diversification of
brachiopods – new data
from the early Palaeozoic in
Northeastern spitsbergen
Brachiopods (two-valved organisms comparable
to living bivalves) represent one of the major
types of animal life, appearing at around 540
Ma ago, as well as one of the dominant groups
of marine benthic organisms. In a collaborative
project with the University of Tromsö, the aim
of the project is to systematically study the
succession of brachiopods, their pattern of
diversification and faunal changes.
Rock dating from this important part of
Earth’s history is well exposed in Northeastern
Spitsbergen, where fossiliferous successions
are known from costal and stream sections
from around Bassisletta, Hinlopenstretet, and
Ny-Friesland.
The 220 metre thick mid Ordovician Valhallfonna
Limestone is particularly rich in fossils
and may in fact have one of the richest
fauna from this interval of time. Although
this fauna has been intensely studied since the
1970s, resulting in a very significant number of
scientific publications, there are almost no studies
of the associated rich fauna of brachiopods.
Fieldwork
Fieldwork was carried out during July and the
beginning of August 2008 in the Profilbekken
section and along the coastal sections at
Bassisletta. The original plan was to transport
the heavy field equipment by ship, but due to
the severe ice conditions this proved impossible
and the equipment had to be brought by
helicopter, and as a result, the fieldwork was
delayed. The extensive snow cover made it
difficult to find a suitable site for setting up
the camp, but eventually a snow free area was
located some kilometres from the mouth of the
Profilbekken stream, next to the Valhallfonna
Glacier. The main objective of the first part
of the fieldwork was to make a detailed
lithological/straigraphical section through
the Profilbekken section, but again due to the
extensive snow and ice cover along the section,
it was only possible to access limited exposures
close to the mouth of the river, and at scattered
localities in the rived bed itself.
Weather conditions were far from ideal and
several days had to be spent in the camp due
to heavy snowfall and strong cold winds. The
camp also received a visit from a young polar
bear, which managed to enter the camp area
without setting off the tripwire.
By the end of July snow conditions had improved
and a more continuous profile could
be accessed so that by the end of the field
season a more complete sample series could be
obtained. In total, approximately 100 samples
were taken, the majority from the exposed
Cambrian-Ordovician sections in addition to
collected macrofossils.
Principal investigator
lars holmer
Department of Earth Sciences
Uppsala University
Figure 1
The water has eroded the stones
during a long time. Photo: Lars Holmer
åRSBoK YEARBooK 2008
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