The hydrology and preservation condition in the flat-topped burial mound – Klangshøj at Vennebjerg in Vendsyssel

Klangshøj is a flat-topped burial mound similar to the Royal Jelling mounds, although smaller.
The myths tell that a well has existed on top of the mound as at Jelling and a spring had flown at
the base of the mound. In order to verify the myths and a similar hydrology in Klangshøj as found
in Jelling, several borings have been carried out in a north-south line across the mound.
The investigation showed that Klangshøj is built of sods mainly harvested from heathland. The
sods are of different grain sizes from fine sand to clay. The preservation conditions were excellent
in three of the six borings, where undecomposed plant remnants, occasionally greenish, were
observed. A 14C-dating showed that the mound was built in the Viking Age. The hydrology in
Klangshøj is the same as in the Jelling mounds, with a permeable bioturbation zone covering
almost impermeable, distinct sod layers. This form a perched groundwater table in the transition
zone, which keeps the distinct sod layer below anaerobic, i.e. the preservation conditions
extremely favourable. The perched water table drains internally as in the Jelling mounds, and
there are no current nor fossil evidence to suggest a spring was ever present at the foot slope, as
the local legend suggests. Moreover, it seems unlikely that a well, similar to the one on the Jelling
mound, has existed on the top of the north-facing slope, as the amount of water the well would
have been able to collect is little.