^(40)K-^(40)Ca法的初步研究  

A preliminary study on dating and tracing of the ^(40)K-^(40)Ca system

作　　者：王俊新[1,2] 彭子成[1,2] 刘桂建[1] 房明惠[1] 桂和荣[1] 

机构地区：[1]中国科学技术大学地球和空间科学系 [2]中国科学院地球环境研究所黄土与第四纪国家重点实验室,西安710054

出　　处：《核技术》2003年第3期197-201,共5页Nuclear Techniques

基　　金：国家自然科学基金项目(49973011);科技部973项目(G1999043401);中国科学院创新工程项目(KZCX2-SW-118);中国科学技术大学资源与环境基地项目资助

摘　　要：报道了样品中钾、钙化学分离和纯化,以及质谱测定流程的建立。测试了国家球团矿标样W7220和W7107、国家40K-40Ar法标准矿物黑云母(ZBH-25)和角闪石(ZBJ)的钾钙含量,以及国际二级钙标样Tachiti和国家钾含量标样的钙和钾同位素比值。实测结果与相应的标称值在误差范围内一致。在此基础上,用实验所得的两组黑云母和角闪石的(40Ca/42Ca) 和 (40K/42Ca)数据,构筑了40K-40Ca法等时线年龄为(133.532.1)Ma, 此与标称值年龄132.7Ma在误差范围内一致。而所得的初始值(40Ca/42Ca)i为151.4160.003, 相应的xCa 值为+26.5,示踪了该矿物组合的原岩具有陆源性质,为固体地球化学的研究提出了新的判据。The K and Ca contents in the national standards of pellets (W7220, W7107), biotite (ZBH-25) and hornblende (ZBJ), as well as, the K and Ca isotopic ratios of the national K standard and an international standard (Tachiti) have been determined by using mass spectrometry and atomic absorption spectrometry . The measured results are in agreement with the standard values within a reasonable error range. On the basis of the standard measurement, the slope of the regressive line between (40K/42Ca) and (40Ca/42Ca) data is equal to 0.068730.01732, corresponding to the age of (133.532.1)Ma, which is consistent with the 132.7Ma in the error range reported by using the 40K-40Ar method. The primitive ratio (40Ca/42Ca)i deduced from the isochrone is 151.4160.003, corresponding to +26.5 of the xCa value. It means that the original rock of the biotite and hornblende minerals appears in the terrestrial behavior.

关 键 词：质谱 钙40 钾40 放射性同位素 地质年代学 同位素定年 示踪法 地球化学 矿物 

分 类 号：P597[天文地球—地球化学] P575[天文地球—地质学]