热解法用于礼村黄土-古土壤地层<sup>14</sup>C测年

热解法用于礼村黄土-古土壤地层¹⁴C测年

摘要: 采用简单的热解方法分离黄土-古土壤不同有机组分进行¹⁴C测年的探索,通过加热使黄土-古土壤有机质发生裂解,选择400℃作为试验温度,对陕西省岐山县礼村剖面黄土-古土壤粉末样品在400℃下挥发出的Py-V组分和残留下的Py-R组分分别进行¹⁴C (AMS)测年,并结合该剖面同层位黄土地层与考古文化层接触关系,认为礼村剖面受人类活动影响强烈的地层中,Py-V组分年龄能代表真实年龄;在未受人类活动影响自然沉积地层中,Py-R组分年龄能代表真实年龄。

Abstract: The onerous chemical extractions for soil organic matter (SOM) fractions do not always produce satisfactory ¹⁴C dates. In an effort to develop an alternative method, the pyrolysis-combustion technique was investigated to partition SOM into pyrolysis volative (Py-V) and pyrolysis residue (Py-R) at 400℃, and dated the two component parts separately by Accelerate Mass Spectrometry (AMS). Compared with the environmental archaeology sequence at the Licun Holocene profile, the Py-V fractions yielded ¹⁴C data more reasonable than the counterpart Py-R fractions in the culture sequence, but on the contrary, the Py-R fractions yield ¹⁴C data more convinced in the loess stratigraphic sequence. Zhouyuan loess was probably developed about 9 300 BP ago, and accumulated for 6 000 years.