Fróðskaparrit - 01.01.1998, Page 268

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MACROFOSSIL STUDIES OF LACUSTRINE SEDIMENTS FROM SKÁLAFJØRÐUR,
THE FAROEISLANDS, PRELIMINARY RESULTS
The Faroe Islands were covered by a lo-
cal ice sheet during the last glacial stage
(Jørgensen and Rasmusen, 1986; Humlum
et al, 1996), and the oldest minimum dates
for the deglaciation are slightly older than
10,000 radiocarbon years BP (S. Bjðrck,
personal communication, 1997). Jóhansen
(1985) reports an age of 9,660 years BP for
Hoydalar lake sediments, that were de-
posited after the area became ice-free. In
our core, nearly 40 cm of lacustrine sedi-
ments is present below the Saksunarvatn
ash, overlying the glaciolacustrine clay
unit. A comparison with the thickness (c.
40 cm) of the lacustrine sediment section
overlying the Saksunarvatn ash suggests
that the deglaciation of Skálafjørður may
also be dated at around 10,000 radiocarbon
years BP.
There are no traces of marine deposits or
shorelines above the present sea level in the
Faroe Islands, whereas some submarine
peat deposits are known (Jessen and Ras-
mussen, 1922), so the global eustatic rise of
the sea level has surpassed the glacio-iso-
static rebound. The presence of submarine
lake sediments in Skálafjørður shows that
the 25 m deep threshold of this fjord was
transgressed by the sea in the early
Holocene, around 7,800 radiocarbon years
BP. Moreover, we may conclude that
deglaciation of the Skálafjørður occurred at
least c. 1,000 years before the Saksunarvatn
ash was deposited, i.e. not later than about
10,000 radiocarbon years BP.
Acknowledgements
We acknowledge funding from the Swedish Natural
Science Research Council (NFR), through a grant to
Bjom Malmgren, Goteborg University, and from the
Geological Survey of Denmark and Greenland. The
master and crew of R/V Skagerak are thanked for excel-
lent co-operation during the cruise, which was charac-
terized by some days of hard sailing due to aderse
weather conditions. Ursula Schwarz, Goteborg Univer-
sity, is thanked for her assistance with the coring opera-
tions. The AMS radiocarbon measurements were con-
ducted at the Institute of Physics and Astronomy,
Aarhus University, under the supervision of Jan Heine-
meier.
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