Den postglaciale landskapsutviklingen på Dragvoll universitetsområde, Trondheim

Abstract

Stratigraphic studies, pollen analyses and 14C-datings have revealed the landscape evolution at the university area at Dragvoll since it was deglaciated. In the central bog area the nearly 50 m deep glaciofluvial clay is overlain by (a) marine clay mud deposited 11,500 years ago, when the area up to 175–180 m was a branch of Trondheimsfjorden, (b) limnic nekron mud precipitated after 10,500 BP, when the central part of the area became a lake, (c) telmatic peat formed after 8500 BP, when the lake changed into a reed and sedge swamp, and (d) terrestric peat formed after the sedge swamp 6000 years ago shifted into a peat bog. Open birch-juniper forest shifted 9500 years ago into dominant pine forest and 8500 years ago into local alder forest surrounded by hazel and elm groves which culminated 6500 years ago. Elm and hazel had disappeared 4000 years ago, whereas only pine, birch and alder remained. After 1300 BP spruce became dominant. Local grain raising might have started in the Bronze Age, but a more radic...