Scientific analysis on decorative sheet metals of the Spring and Autumn period unearthed from Zaoshulin cemetery, Hubei, China

A large number of decorative sheet metals were unearthed from elite tombs of the Eastern Zhou period (770–221 BCE), especially in the Zeng state. However, the technological analysis and comparison between sheet metals unearthed from different states and regions in this context remain limited. In this paper, 16 samples of sheet metals excavated from the tomb of the Marquis of Zeng in Hubei province, dated to the middle Spring and Autumn period (664–559 BCE), were studied. Elemental analysis shows that these sheet metals are made of gold-copper, gold-silver, copper–gold and copper-tin alloys. It appeared that the craftsmen of the Zeng state had the knowledge to adjust the gold-copper alloy compositions to obtain different colours, creating the earliest rosy gold reported to date used in ancient China. The use of bronze sheets reflects a continuation of the Zhou cultural tradition in the Zeng state. Furthermore, a variety of bonding techniques were mastered by the craftsmen: the mixture of clay and some sorts of binding materials such as lacquer was used for bonding copper sheets and rosy gold sheets, while gold-mercury amalgam was used to bond multiple layers of rosy gold sheets. The appearance of these sheet metals on a large scale and the use of rosy gold as a new colour may reflect the aesthetic trends and cultural choices during the middle Spring and Autumn period.