Research On Erligang Period Bronzes From Zhenghou Area

The Erligang period, which succeeded to Erlitou and opened up the Yinxu, was the transition period of bronze production from rising to ripening, and it was also the establishing period of thriving and prosperous bronze production in Yunxu. So it had a significant position on the bronze phylogeny. As the Bronzes from Shang capital, the research of which is very-important for exploring the regulation of Chinese bronzes, comprehending the civilization tradition of Xia, Shang and Zhou, even apprehending the property of the Erlitou culture and the Yanshi Shang city.Previous research on Erligang period bronzes from Zhengzhou area mainly focuses on the periodization and the typological characteristics such as shapes, decorations and so on. However, the melting and casting studies, especially the alloy technology and the ore source, are less and scattered. In existing literature, there are only17bronzes whose chemical compositions have been analyzed and12bronzes whose lead isotope ratios have been analyzed. Unfortunately, it is ambiguous to know the setting or characteristic of these bronzes, and it is difficult to further discuss the periodization and other relating problems. In this paper, it is the first time that24bronzes of Erligang period from Zhengzhou area are systematically investigated. Especially, the sampling bronzes are explicit in the appearance characteristics such as shapes and decorations and the quality and numbers are assured. In order to investigate the casting mark, the chemical compositions, metallograph and lead isotope ratios, the sampling bronzes are divided into two phases according to the shapes and the decorations. Up to the present, the work not only provides the largest number of important data for the research on bronze industry of the capital of early Shang-Dynasty, but also makes the comparison of Erligang bronzes in different areas based on the considerable data and information.The mould design research on Erligang period bronzes from Zhengzhou area shows that most bronzes were cast integrally except some bronzes were cast separately such as Lei (罍) and Zun (尊) with animal head on the shoulder and You (卣) with handle. In Erligang period, new techniques had appeared like separately casting and pattern mould, and former techniques renewed and developed basing on Erlitou like transversely dividing mould, shim installing, repair casting and hollowed-out location. Some appearance characteristics were the results restricted with the technology at that time such as the monolayer decoration, the thicker level rim and the hollowed-out ring foot and so on.The chemical composition and metallic phase research on Erligang period bronzes from Zhengzhou area shows that the bronzes were all produced by casting rather than by hot or cold forging which used Inductively Coupled Plasma Optical Emission Spectrum (ICP-OES), Micro-examination, and Scanning Electron Microscope (SEM). The alloy technology in Erligang period succeeded to the route of Erlitou period, which the leaded tin bronze as main part and the tin bronze as subsidiary part, but improved better. Compared to Panlongcheng bronzes, Zhengzhou bronzes contain more copper while less lead.Lead isotope analysis shows that the ore sources between the Lower Erligang period and Upper Erligang period have a significant change. In Lower Erligang period, the ore whose207Pb/206Pb in the range of0.90～0.94are mainly used, and the provenance can be located in Yanliao and Jiao Area. This metal resource was used from Erlitou Phase II, and reached its using peak in Erlitou Phase IV and Lower Erligang period, but it sharp cutoff in Upper Erligang period. In Upper Erligang period, the ore whose lead isotope data was in highly radiogenic lead range was mainly used, and the provenance can be located in southwest China. This metal resource was used from Lower Erligang period, and reached its using peak in Upper Erligang period and Yinxu Phase I and II, but decreased fleetly in Yinxu Phase III and then few can be found in Yinxu Phase IV. Except for Bronzes from Zhengzhou Area, the bronzes from other sites such as Yanshi Shang city, Panlongcheng, Yuanqu Shang city, and Yueyang Tonggushan also used the ore materials from above two provenance. It showed that the circulation net of bronze products or bronze resource was very huge. According the distribution of bronzes and Shang culture in Erligang period, as so as the provenance change of bronze resource, it could be deduced that for the Shang capital area, the ore materials were imported, and the bronze products were consumed not only in local, but also in other area. Obtaining the high quality bronze resource was the motive of Shang expanding southward and westerly in Erligang period.This work definitely shows the historical facts that bronze resource circulated among different regions, and the homology and dissimilarity among the capital area of early Shang dynasty and other regions in resource acquisition, distribution, supply and process of bronze production. All these research results provide a valuable clue on rebuilding the raw material of bronze industry, the product supply and distribution system; investigating property of culture relationships between Shang capital and other archaeological sites; probing into early empire expanded, national strength change and regional material and cultural exchanges. Furthermore, it is also a significant and important assistant research to solve many related problems.