Scientific research on white potteries from the Nanzuo site in Qingyang, Gansu province

Located in Qingyang, Gansu province, China, the Nanzuo site on the Loess Plateau is a large-scale, high-ranking central settlement of the late Yangshao period with capital city characteristics. We used a thermal dilatometer, energy-dispersive X-ray fluorescence (EDXRF), optical microscope, scanning electron microscopy with energy-dispersive spectroscopy (SEM-EDS), X-ray diffraction (XRD) and Raman spectrometer to analyse the firing temperature, composition, microstructure and phase composition of the white potteries in the Nanzuo site. The results indicate that kaolin, china stone and local fusible white clay are the raw materials of the body. The surface coatings of white potteries are formed from shells. The main constituents that make up the internal surface coating are aragonite and calcite, which are derived from the prismatic and nacreous layers of shells. The external surface coating is composed of CaCO₃ nanoparticles that arrange themselves as aragonite tablets within the nacreous layer. This exceptional pottery-making technique is exclusive to Nanzuo and has not been reported at any other site in the world. This technique is significant for researchers to deepen our understanding of pottery-making technology history in China.