Towards a precise timing of groundwater use in the lower Yellow River area during the late Bronze age: Bayesian inference from the radiocarbon ages of ancient water wells at the Liang'ercun site, north China

Abstract

The domestication of water played an important role in the emergence and development of settled societies. Although various features pertaining to groundwater use in the lower Yellow River area during the Neolithic and Bronze Age have been discovered, our knowledge about groundwater domestication in this area still remains fragmentary, due primarily to the large uncertainty in radiocarbon dating and calibration. For example, our previous attempt of radiocarbon dating of water well construction at an archaeological site situated on an alluvial fan was hindered by the Hallstatt radiocarbon plateau effect between 800 and 400 BC in the calibration curve, which also poses a great challenge to Bronze and early Iron Age archaeology elsewhere. Here we present more radiocarbon ages of charred millet grains from the primary fills of the water wells at this site and conduct age modeling using a hierarchical Bayesian model. Our results show that the wood lining technique in water well construction was first introduced to the lower Yellow River area sometime during 805–785 BC (68.2% credible interval). Groundwater use in this area may have lasted for about 240–380 years (68.2% credible interval). Comparing with proxy climate records suggests that the water wells may have been dug for securing drinking water when a cold and dry climate prevailed in the wake of the Bronze Age.