THE SEDIMENTARY STRATIGRAPHIC RECORDS OF COPPER CASTING ACTIVITIES DURING THE LATE SHANG-EARLY WESTERN ZHOU PERIODS AT THE TIAOTOU SITE IN YUHANG,ZHEJIANG PROVINCE
The utilization of bronze ware holds significant importance in human society.As a place for the production of bronze ware,the site of workshop preserves many traces of copper casting activities in the environment.However,there are few research reports focusing on the sedimentary stratigraphic records of copper casting activities to date.In this study,two profiles T1614S(400 cm)and T1510S(255 cm)were selected from the Tiaotou copper casting site in Yuhang,Zhejiang Province(30° 15′00″N,119°53′39″E),together with collection of channel sediments from the present-day river near the site.As for research methods,74 samples from profile T1614S,20 samples from profile T1510S and 12 samples from the present-day river channel were analyzed for grain size;20 samples from profile T1510S were tested for magnetic susceptibility and 74 samples from profile T1614S were analyzed for organic geochemistry(including total carbon(TC),total organic carbon(TOC),total nitrogen(TN)and stable isotope of organic carbon(δ13C));22 samples from profile T1614S and 20 samples from profile T1510S were analyzed for heavy metals Cu,Zn,and Pb.The purpose of this study is to explore the evolutional process of buried paleo-river channel and the influence of ancient society's copper casting activities on the environment.The results show that the Mz of buried paleo-river channel in profile T1614S increased from 13.0 μm to 23.5 μm during 1045～830 B.C.(late Shang-early Western Zhou),compared with the previous stage,the sorting declined and the sand component(4.7％～19.0％)increased,indicating weak water currents.So the channel is presumed to be the reservoir or ditch excavated by Pre-Yue people for copper casting.The hydrodynamic force increased after 830 BC(late Western Zhou),and then reached a similar level to the modern Tongshan River channel.The flood deposits accumulated in the river channel after 85 A.D.(Eastern Han),and the paleo-river channel disappeared and finally became a lacustrine environment.At 1045 B.C.,the organic geochemical indexes such as TOC,C/N and δ13C also changed from 0.21％,3.39 and-21.05‰ to 6.7％,14.38 and-27.74‰,respectively,while contents of Cu and Zn suddenly increased from 21.90 ppm and 88.62 ppm to 33.60 ppm and 136.63 ppm contemporaneously.These changes show that the Pre-Yue people artificially transformed the environment at the Tiaotou site,including the digging of waterway,utilization of large amount of fuels and the copper casting in the late Shang period.The content of Pb increased sharply from 6.46 ppm to 23.40 ppm later,which may reflect the progress of copper casting technology of Pre-Yue people.The xfd％of profile T1510S reached 6.82％～8.13％in the cultural layer from the late Shang to the West Zhou,reflecting the behavior of fire in the workshop area,while the content of heavy metals continuously increased in the cultural layer of the West Zhou,indicating the variation of stratigraphic records in different functional areas of the copper casting site.It is worth noting that after the end of the copper casting activities at the Tiaotou site,the heavy metal contents in the two profiles continued to show high values,which may reflect that mining and even smelting activities had always existed in the Tongshanxi basin upstream of the site throughout the historical period.Meanwhile,Yuhang area is located in Qin-Hang metallogenic belt.Therefore,this paper speculates that the copper source of the Tiaotou site may also come from the Tongshanxi catchment in the Shang and Zhou Dynasties.Comparing the natural environment and social background,it is speculated that the rise and decline of copper casting activities at Tiaotou site is mainly related to the social factors.
万方数据
维普
