Do still waters run deep? Formation processes of natural and anthropogenic deposits in the Neolithic wetland site Zug‐Riedmatt (Switzerland)

Abstract

AbstractMicromorphological analysis is used to improve our understanding of wetland site taphonomy and stratigraphy. Twelve profile columns from the Neolithic lakeshore site of Zug‐Riedmatt are macroscopically described here, microscopic analyses are applied to sediment facies, defining 14 sedimentary units (U): The natural basal sediment (U1) is carbonate‐rich, U2 a transition phase to the anthropogenic units U3 to U12. Uppermost are the natural carbonate‐rich U13 and U14. The creation of a micromorphological database and the application of 27 defined indices allow a better understanding of the natural, anthropogenic and taphonomic processes taking place at the site. Natural sediment input originated from Lake Zug, the nearby river Lorze with its delta, and a local marshy waterbody. Organic rich accumulations and calcitic ash played a major role in pH changes, leading to carbonate and silica dissolution, alongside bone alteration. Signs of degradation processes under aerobic and anaerobic conditions within a single layer points to complex, multiphase processes under changing water levels, a milieu belonging to both land and water, an amphibious environment. Finally, good layer preservation seemingly correlates to low aquatic reworking in a stable depositional context linked to the marshy area.