Landscape evolution and site formation of two mesolithic sites in the lower Rhine-Meuse delta (Hardinxveld, The Netherlands)

In the downstream part of the Rhine-Meuse river delta a geoarchaeological study of two mesolithic wetland sites, Polderweg and De Bruin, was undertaken. The sites were located on top of Lateglacial aeolian sand dunes, which became progressively covered by Holocene mire deposits as a result of sea-level rise. The sand dunes were inhabited during three different phases. During phase 1, dated to 5500–5200 cal. BC (6150–6400 BP), considerable areas of the dunes were beyond and unaffected by processes of mire deposition. These higher places were surrounded by carr and open water, where floodplain clays were deposited by the Middelkoop River System. During phase 2, dated to 5200–4800 cal. BC (6000–6150 BP), the highest parts of the dunes were progressively covered by alder carr, separated by small ponds. During phase 3, dated to 4450–4700 cal. BC (5500–5850 BP), only a fraction of the dune system remained uncovered. This area, a small isle near the De Bruin site was surrounded by open water, local carr and channels of the Schaik River System. During phase 3, the site at Polderweg could no longer be used.