Ancient Bronze Source And Origin Of The Mineral Aggregate Research Progress

Study on ores source and casting place of bronze vessel is one of important and difficult subjects in archaeology, which can reflect the origin and spreading route of metallurgy, politics, economy, cultural intercourse, social structure, producing mode, acquiring means of copper and tin ores, etc.Trace elements analysis is one of natural science means used earliest to determine ores source of the bronze vessels. Because of unknown of variation regularity of trace elements during the copper smelting process, this means doesn't make progress. Except for pure copper artifact, many scholars think that the application of trace elements analysis is unsatisfactory in study on copper ores source of bronze vessels. Therefore, since 1960s, this method is rarely applied. In this dissertation, trace elements analysis is improved. Study on copper ores source of bronze vessels is transformed into study on exporting rout of copper ores. According to the improved trace elements method, this dissertation firstly probes into variation regularity of trace elements during copper smelting and their potential application in the study on the exporting route of the ancient copper ores. All samples of copper ores, slag and copper ingots are from several Pre-Qin sites of mining and smelting, such as Tonglushan, Tongling, Nanling, Zhongtiaoshan, Zhaobishan and Dajing sites, and trace element analysis is conducted by Inductively Coupled Plasma Atomic Emission Spectrometer (ICP-AES). The results reveal that trace elements Au, Ag, As, Sb, Bi, Se, Te, Co, Ni, etc. mostly enriched in the copper during copper smelting and they are indicative of copper ores source of the bronze vessels. Meanwhile, this research indicates that trace element characteristics of copper ores and copper ingots from different site of mining and smelting are obviously varied, and it is feasible to determine the exporting route of ancient copper ores using trace element tracing technology, especial for copper ores from different ore belt.Based on the above research, this dissertation also probes into the copper ores source of the bronze vessels in Shang and Zhou Dynasties from some areas in China through trace element analysis. Results show that the copper of the bronze vessels from Anhui Province comes from ancient copper ores of the middle and lower reaches of Yangtse Rive, while the copper of bronze vessels from Western Liaoning Province and Houma comes from Dajing copper ores. At the same time, this research indicates that the copper ores used for the bronze vessels in the central area in China can mostly come from copper ores of the middle and lower reaches of Yangtse Rive, Zhongtiaoshan copper ores in Shanxi Province and Dajing copper ores in Inner Mongolia Municipality.Many scholars identified the foundry area of the bronze vessels through researching into the style, decoration and inscription of the bronzes. This research method is subjected to the subjective experience and knowledge of archaeologists. Some scholars analyzed lead isotope and trace elements of bronze vessels and attempt to ascertain foundry area of the bronzes using natural science means. However, signature of lead isotope and trace elements of the bronzes provide information on ores source which metal minerals used to cast the bronzes derive from, not foundry area. The composition of casting clay core might provide clue to the foundry area of the bronze vessels. Therefore, this dissertation studies the casting place of the bronze vessels on the basis of analysis of clay core residues of the bronze vessels. Samples of the fragments of the casting clay cores were removed from the bronze vessels unearthed at Jiuliandun tombs of Chu state, in Zaoyang City, Hubei province, dated back to Warring States Period, and were analyzed by polarized light microscope, XRD, XRF, NAA and ICP-AES, etc.. The results reveal the casting clay cores of extraneous bronze vessels from Jiuliandun tombs are different from those of local bronze vessels excavated in Jiuliandun tombs 1 and 2 in phase composition, microstructure, major elements, trace elements, REE, phytolith assemblages, etc.. The contents of CaO in casting clay cores of extraneous bronze vessels are very high and the contents of Na₂O are low, which are representative characteristic of loess in the northern China. Combining with the analysis of phytolith assemblages, it is possible that extraneous bronze vessels are cast in the loess area of the northern China. Meanwhile, this research indicates it is feasible to restrict the possible foundry area of the bronze vessels according to analysis of casting clay cores residues on the bronzes.