Extended Data Fig. 6 | Stratigraphic prof ile and sampling sites at Isla
Manechi. Charcoal fragments for accelerated mass spectrometry^14 C dating
were collected during the excavation; yellow triangles indicate their depth.
Yellow squares indicate the locations of sediment samples that were analysed
for phytoliths; these were sampled after the excavation from the vertical
profile. The dashed line indicates the transition from the ceramic phase to the
pre-ceramic phase. This transition is characterized by a sharp increase in the
compactness of sediments and amount of burnt earth. Values in parentheses
are median cal. yr bp. A chronological gap of almost 4, 500 years exists between
the two phases (Extended Data Table 1). All of these differences make it possible
to exclude any contamination of the pre-ceramic contexts with phytoliths that
come from the ceramic contexts. Descriptions of the archaeological
excavations at Isla del Tesoro (SM1), La Chacra (SM3) and San Pablo (SM4) have
previously been published^13.