Fróðskaparrit - 01.01.1998, Side 150

Peat depth (cm)
156
HOLOCENE CLIMATIC VARIABILITY IN THE NORTH ATLANTIC REGION
AS SHOWN BY PEAT BOG RECORDS
Colorimetric humification indices
Fig. 1. Peat humification profile from Rystad, Norway
(after Nilssen and Vorren, 1991). Radiocarbon ages
are shown where available.
Mynd I. Tvørskurður av torvvæting úr Rystad í Noreg
(eftir Nilssen og Vorren, 1991). Kolevni 14-aldrar
síggjast, har teir eru tøkir.
time-scale construction and correlation,
and the development of additional methods
of reconstruction (quantitative macrofossil
analysis, analyses of non-pollen microfos-
sils such as testate amoebae, fungi and algal
remains) has increased the precision of
palaeoenvironmental inferences. There re-
main a series of basic assumptions, howev-
er, that apply to most palaeoclimatic work
on peat bogs. These include the following:
Mire vegetation assemblages respond to
changes in the water table, which is it-
self responsive to changing climate.
The sub-fossil remains of that vegeta-
tion, preserved in mires, are a true re-
flection of the original vegetation cov-
er at the time of peat deposition.
More decomposition occurs when the
mire surface is dry, resulting in more
humified peat, a darker colour and few-
er identifiable remains than in peat that
accumulates when the mire surface is
relatively wet.
Reliable age-estimates of the peat pro-
files, and each point within the pro-
files, can be obtained.
Coincident dates
A body of published and unpublished re-
search now exists including studies of
mires from northern Norway to the south of
the British Isles, and from westem Ireland
to Germany and Poland. The north-south
axis forms a discontinuous transect along
the eastern coast of the North Atlantic, with
clusters of data from some areas, particu-
larly in Norway (Nilssen and Vorren,
1991), Scotland (Anderson et al., 1998;
Chambers et al., 1997), northem England