中坝遗址约4250aB.P.以来古气候和人类活动记录

重庆中坝遗址地层Rb、Sr、Hg及TOC研究表明:Rb、Sr和Rb/Sr值较好地反映了约4250a B.P.以来气候变化过程,主要干冷期可与敦德冰川δ¹⁸O曲线谷值、湖光岩沉积物磁化率和Ti曲线峰值、以及大气¹⁴C浓度峰值和太阳活动水平较长期变化的低谷对比,反映出地层中Rb、Sr不易受人类活动干扰的特性。结合考古遗存对比还发现,Hg、P、Ca、Mg和TOC记录了该遗址约4250a B.P.以来人类活动的三个不同演变阶段。进一步研究认为,盐业遗址的衰落可能与洪水事件、盐泉资源的过度消耗以及由此造成的利用难度加大有关

Records of Paleo-climate and Mankind Activities Since 4250 a B.P. in Zhongba Site, Chongqing

Stratigraphical research on Rb, Sr, Hg and TOC in Zhongba site, Chongqing indicates that Rb, Sr and Rb/Sr can reflect basically the process of climate change since 4250 a B.P., the major dry-cold periods can contrast to the low values of δ¹⁸ O curve in Dunde Glaciar, the high values of magnetic susceptibility and Ti curves from the settings in Huguang Maar Lake, the high values of ¹⁴C density in the atmosphere and the low values of relative long term variation on the solar activity, which response the characteristics that Rb and Sr in the stratums are not prone to be disturbed by mankind activities.Combining with archaeological remains and contrast the variation curves of Hg, P, Ca, Mg and TOC, we can still discover that Hg, P, Ca, Mg and TOC record three different stages of evolution that mankind activities go through since 4250 a B.P.Further studying, we think that the decline of salt industry site is probably interrelated with the palaeo-flood events, excessively utilizing the salt wells resources and the increased difficulty of using them.