重庆中坝遗址地层Na- Ca 元素含量 揭示的制盐业兴衰史

在对中坝和玉溪遗址考古断代和AMS14C 测年基础上, 根据对中坝遗址201 个地层样品ICP 等离子发射光谱的Na、Ca、Mg 元素测定及玉溪遗址47 个地层样品的Na、Ca 元素测 定, 发现中坝制盐遗址地层中存在明显的Na、Ca 元素含量反向相关期有35 处之多, 即: 当Ca 元素为峰值时, Na 元素为谷值, 反之亦然。其中, Ca 元素为峰值、Na 元素为谷值的反向相关期有21 次, 揭示出中坝遗址近5 ka 来制盐业有过近21 个兴盛期。另有14 个Na 元素为 峰值、Ca 元素为谷值的反向相关期, 揭示中坝遗址近5 ka 来制盐业也有过近14 个衰落期。考古发掘得出的“中坝制盐业萌发于新石器时代、夏商发展、西周至汉代为鼎盛期、唐宋时代维持稳定发展、宋以后由于海盐进入川江地区导致中坝制盐业逐渐衰落、但20 世纪70-80 年代仍有生产”的结论证明本文Na、Ca 元素含量反向相关性得出的研究结果是正确的。以上研究结果表明, 中坝制盐遗址中Na、Ca 元素含量有明显的反向相关规律, 这一规律可以用于揭示盐业遗址的制盐业兴衰过程历史。

Rise and Decline of Ancient Salt Industry Revealed by the Concentrations of Naand Cain Sediments at Zhongba Site

On the basis of archeological period division and AMS14C dating to the sedimentary layers at Zhongba and Yuxi sited, and according to the analysis results of Na, Ca and Mg in 201 sedimentary samples from Zhongba site and that of Ca and Na in 47 sedimentary samples from Yuxi site by using an inductively coupled plasma-mass spectrometry (ICP), we found that there were 35 correlation periods when the contents of Ca and Na were reversely correlated, that is to say, whenever the content of Ca was the highest, the content of Na was the lowest, and vice versa. Among them, there were 21 correlation periods when the content of Ca was the highest, and Na was the lowest, indicating that there were about 21 prosperous periods of ancient salt production at Zhongba site since 3000 BC. Other 14 correlation periods with the peak values of Na while the low values of Ca indicate that there were about 14 declined periods of salt production at Zhongba site since 3000 BC. The conclusion obtained from the reverse relationship between Ca and Na contents in this paper is consistent with that "the salt production at Zhongba site started in the new stone age, developed in the Xia and Shang dynasties, reached at the heyday in periods from the Western Zhou to the Han Dynasties, maintained stable to develop in the Tang and the Song dynasties, and gradually declined after the Song Dynasty because the sea salt was conveyed into Sichuan region, however, still had production in the 1970s and 1980s educed from archeological exploration.