逐级温度热解法在黄土古土壤样品^(14)C测年中的应用  

The application of temperature-step-pyrolyzing to ^(14)C dating of Loess paleosoil sample

作　　者：程鹏[1,2] 吴书刚[1,3] 杜花[1,2] 陈清敏[1,3] 卢雪峰[1,2] 

机构地区：[1]中国科学院地球环境研究所黄土与第四纪地质国家重点实验室,西安710075 [2]西安加速器质谱中心,西安710052 [3]中国科学院研究生院,北京100049

出　　处：《干旱区资源与环境》2012年第12期81-85,共5页Journal of Arid Land Resources and Environment

基　　金：国家重点基础研究发展计划(973计划)项目(2010CB833400);国家自然科学基金项目(41023006)资助

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。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.

关 键 词：14C测年 测年物质 逐级热解 黄土古土壤 

分 类 号：P534.63[天文地球—第四纪地质学]