Early Holocene environment on Bjørnøya (Svalbard) inferred from multidisciplinary lake sediment studies.

• Bjornoya, a small (178 km(2)) island situated between the mainland of Norway and southern Spitsbergen, provides the opportunity for the reconstruction of early Holocene terrestrial and limnic palaeoenvironments in the southwestern Barents Sea. The AMS C-14 dating technique, geochemical, mineral magnetic, micro- and macrofossil analyses were applied to sediments recovered from lake Stevatnet and the results are interpreted in terms of palaeoenvironmental conditions between 9800 and 8300 C-14 BP. After the disappearance of local glaciers before ca 9800 C-14 BP, the lake productivity increased rapidly at the same time as pioneer plant communities developed on soils which gradually became more stable. Insect data indicates that strong seasonal contrasts with mean July temperatures around 9 degrees C and mean January temperatures around -12 degrees C prevailed between 9500 and 8300 C-14 BP. These high summer temperatures, possibly as much as 4-5 degrees C higher than the present, favoured the development of a flora including Dryas and Angelica cf. archangelica. The enhanced freeze/thaw processes led to an increased erosion of minerogenic and organic material. After 8000 C-14 BP the temperatures may have gradually declined. The environmental reconstruction derived from our data set supports the conceptual insolation model which proposes maximum Holocene seasonality for the Northern Hemisphere at ca 9000 C-14 BP.

Keyword

Paleoecology

Paleoekologi

Publication and Content Type

ref (subject category)

art (subject category)