Blanket mire formation on a drumlin in Nord- Trøndelag,central Norway

Abstract

Pollen analysis, ¹⁴C datings and macro-subfossil examination of a series of peat cores collected along a transect across a drumlin covered by blanket mire in eastern Levanger, Nord-Trøndelag, Norway, indicate that peat formation started on the top about 8500 years ago. At that time the drumlin had a vegetation of scattered birch trees. About 5000 years ago much of the drumlin top was covered with mire, which then started to spread slowly down the slopes of the drumlin; on the southwestern slope the mire had reached almost 200 m downslope by about 2300 years ago. There is no evidence for any upslope spread on this slope. Peat formation on the lower part of the northeastern slope, however, started about 7500 years ago, spreading up the slope apparently to join the upper mire and produce a complete blanket on this slope by about 4500 years ago. Pine trees have also grown on the drumlin during various periods, but their disappearance does not seem to have had any overall effect on peat formation. The blanket mire started and expanded as a climatically determined ecosystem, but human activity may have affected the mire surface for a period in the late Holocene.