风化矿物黄钾铁矾40Ar/39Ar测年的基本方法--从样品采集到年龄测试

摘要

At present, the research on 40Ar/39Ar dating of supergene minerals in the arid zone of China is rarely conducted due to the complexity of the geochronology of weathering minerals. This paper introduces the experimental procedure of 40Ar/39Ar dating of su⁃pergene jarosite mineral composed mainly of systematic sampling, mineral identification and careful selection. With a variety of testing methods (XRD, SEM, EMPA), pure minerals can be obtained, and in combination with 40Ar/39Ar step heating analysis, reliable weath⁃ering ages can be acquired.%由于40Ar/39Ar定年方法在技术上极具复杂性，目前，国内在开展干旱区研究中很少使用风化矿物定年研究手段。重点介绍黄钾铁矾矿物40Ar/39Ar定年法的基本流程，并针对该方法的技术问题初步探讨了解决办法。研究表明，科学的野外采集样品、仔细的挑选矿物并综合采用多种测试手段（X衍射、扫描电镜、电子探针）进行监测可以获得纯净的风化矿物，并结合精细的40Ar/39Ar阶段加热技术，能够获得比较可靠的风化矿物40Ar/39Ar年龄。