中文摘要：

利用已知可靠年代的黄土古土壤样品,采用逐级热解的方法,获取不同温度下的热解组分,运用加速器14C测年技术,测试各个组分的14C年龄,探讨获得可靠测年组分所需的逐步解热的实验条件。研究表明,逐级热解过程中,100℃～600℃温度段的热解挥发组分为年轻碳,而600℃～800℃温度段热解残余物（Py-R）则为老碳,600℃～800℃热解挥发组分（Py-V）是黄土-古土壤14C测年的可靠组分。

英文摘要：

The effective chemical pretreatment at the beginning is very important for acquiring the reliable 14C ages.We present a method in which pyrolysis-combustion is carried out to partition SOM（soil organic matter） into pyrolytic volatile（Py-V） and pyrolytic residue（Py-R） fractions.We got different pyrolytic residue（Py-R） fractions from different pyrolytic temperatures 200℃,400℃,600℃ and 800℃C,and dated corresponding 14C age of the Py-R fractions and Py-V fractions by Accelerator Mass Spectrometer（AMS）.The results show that the dated age increases as temperature increases and the ages of Py-V fractions are younger than ages of the Py-R fractions.Most of the young carbon in the Py-V fractions are extracted at 100℃-600℃,and old carbon in the Py-R fractions are extracted at 600℃-800℃.Further experiments show that,the Py-V organic carbon extracted at 800℃ represent the reliable ages for the sediments,and the method of temperature-step-pyrolyzing provides us a new way to understand the condition of contamination and evaluate the reliability of age.