Archaeopedological reconstruction of Middle Bronze Age subsistence farming in SW-Germany from sedimentary archives in the Western Allgäu

Abstract

In the northern Alpine foreland, there was a shift at the transition from the Early Bronze Age (EBA, 2200–1600 BCE) to the Middle Bronze Age (MBA, 1600–1250 BCE). This shift was associated with a widespread abandonment of the pile-dwelling settlements around the pre-Alpine lakes and an expansion and intensification of low- and mid-altitude inland settlements. A research gap exists regarding the nature of MBA subsistence in these inland areas, which are considered unfavourable for agriculture.

We analysed multi-layered colluvial and alluvial deposits in the agriculturally unfavourable Western Allgäu region to gain insights into MBA subsistence farming. Phases of deposition were determined by optically stimulated luminescence (OSL) technique and AMS radiocarbon (14C) measurements of charcoal. They provide a chronostratigraphic framework that is correlated to the local archaeological record. Subsistence farming was reconstructed using land use proxies such as phytoliths, charcoal spectra, urease activity to microbial biomass carbon (Cmic) ratios, faecal biomarkers, polycyclic aromatic hydrocarbons (PAHs) and heavy metals.

The OSL and 14C ages indicate phases of deposition and land use during the MBA. They correlate with two recently excavated MBA inland settlements in the Western Allgäu. Human-induced vegetation change promoted open woodland comprising of Juniperus and Quercus at the expense of Abies and Fagus. The accumulation of charcoal and PAHs in MBA related colluvial horizons is most likely associated with the use of fire to maintain an open landscape. Partially increased urease activity to Cmic ratios and the appearance of Juniperus indicate the importance of livestock farming within the MBA subsistence.

Our results show that there was an extensive and diversified subsistence economy in the Western Allgäu during the MBA. They thus reflect an adaptation of MBA farmers to the harsher climatic conditions of the Western Allgäu, where crop yields were certainly less predictable than, for example, in regions near Lake Constance.