Large amounts of shellfish debris, but only a few grains of rice, have been recovered at these sites. Many archaeologists assume that poor preservation of rice grains obscures extensive Neolithic rice cultivation in the Fuzhou Basin, Rolett says.
Radiocarbon measurements of wood and plant fragments in sediment cores allowed Rolett’s group to estimate when and for how long particular environmental conditions persisted in the Fuzhou Basin.
Peat layers, chemical composition of soil sections and other data indicate that flooding of the Fuzhou Basin began about 9,000 years ago, reached a peak by 7,000 years ago and remained stable until an abrupt sea level decline nearly 2,000 years ago. When Neolithic villagers lived in the basin, their island homes rose about 23 meters above the water’s surface, Rolett estimates.
The amount of grass pollen seen in Fuzhou Basin cores increases dramatically around 2,000 years ago, Rolett adds. Rice pollen is hard to distinguish from other types of grass pollen, but this general trend probably reflects a late shift from maritime pursuits to rice farming, in his view.