Meadow, marsh and lagoon: Late Holocene coastal changes and human–environment interactions in northern Denmark

Abstract

This paper presents a study of past coastline dynamics and their consequences for prehistoric societies living in the glacio‐isostatically uplifted central Limfjord area, northern Denmark. The consequences of the gradual relative sea level (RSL) changes have been investigated to develop a local RSL curve, study settlement patterns on newly exposed marine foreland, and estimate changes in the area and quality of grazing and forage for livestock. This was achieved by a multidisciplinary approach involving existing regional and local beach ridges dated by optically stimulated luminescence, a comprehensive database of archaeological finds, and extrapolation based on a digital elevation model. The beach‐ridge dates suggested a near‐linear local RSL change in the study area of ~1.2±0.2 m per 1000 years for the last 3000 years. Based on this, a palaeo‐coastline development model was produced that correlated well with a comprehensive database of archaeological finds. The model indicates that (i) few human settlements moved to the newly exposed marine foreland prior to modern times, though clusters of burial mounds (barrows) suggest that some of the new lands were colonized during the Late Roman Iron Age until 400 CE, (ii) winter‐flooded marine foreland with high‐quality livestock grazing increased steadily until c. 750 CE and then remained stable at approximately 150 km2, and (iii) due to high salinity of the inundating water, the palaeo‐Limfjord probably had Wadden Sea‐like fertile saltmarshes until c. 1 CE. The improved chronologies yield a better understanding of the spatial and temporal prehistoric human–nature interactions in the study area. The findings highlight the need for accurate local RSL curves in order to interpret concomitant terrestrial environment drivers and trajectories, and thereby understand causal relationships and consequences for prehistoric human–environment interactions in coastal areas.