Geoarchaeological and archaeobotanical investigations in the environs of the Holsterburg lowland castle (North Rhine-Westphalia) – evidence of landscape changes and saltwater upwelling
Fischer, Peter; Meurers-Balke, Jutta; Gerlach, Renate; Bulla, Andrea; Peine, Hans-Werner; Kalis, Arie J.; Hadler, Hanna; Willershäuser, Timo; Röbke, Björn Roman; Finkler, Claudia; Emde, Kurt; Vött, Andreas
published: Apr 1, 2016
ArtNo. ESP023106001004, Price: 29.00 €
The excavations at the Holsterburg site started in 2010 and revealed an octagonal castle from the medieval Staufer era of the 12th and 13th centuries AD of which only a few are known in Europe. The castle was built before 1170/1180 AD and its destruction is dated to 1294 AD. The site is located south of Warburg in North Rhine-Westphalia in the loess landscape of the so called Warburger Börde. As specific characteristic the castle is located in the midst of the floodplain of the Holsterbach which is a creek draining a small catchment towards the Diemel River valley. While archaeological investigations concentrated on the architecture and structure of the octagonal castle, geoarchaeological and archaeobotanical studies yielded substantial information on the hydro-geological characteristics of the castle subground and on the overall landscape evolution. The interpretation of earth resistivity transects in combination with vibracores showed that the castle was built on a construction layer which was founded on silt dominated alluvial and colluvial deposits within the valley bottom. This result is contrasting the former assumption that the castle was founded on gravels of the Weichselian Lower terrace. Geochemical studies of vibracore samples give evidence for salt enrichment within greyish laminated colluvial and alluvial deposits and for saltwater upwelling right underneath the castle. Most likely, these phenomena are due to the position of the castle in the midst of the Warburg fault system and to leaching processes bound to salt resources within the Röt or Zechstein formations in the subground. Archaeobotanical investigations by means of pollen analysis of samples from the castle infill and of core samples, both from below and above the construction layer, document a rapid accumulation of more than 3.5 m of sediments within less than 400 years prior to the construction of the castle. After its destruction in 1294 AD, the castle was filled up artificially with top soil material of the surrounding area.