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地球科学(中国地质大学学报) 2018
热年代学方法、技术手段及其在矿床地质中的研究进展
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Abstract:
同位素地质年代学(isotopic geochronology)是一门传统的定年学科,广泛应用于地质各个领域研究中.随着同位素地质年代学理论创新与技术进步,现在逐步发展成为地质热年代学(thermochronology),即将地质年代数据赋予相应封闭温度(closure temperature)属性,使之不仅揭示地质事件年龄,而且反映该事件发生的温度条件.不同定年方法以及测试样品的不同,其对应的封闭温度不同,从而可以揭示地质体在更大温度或年龄范围的形成演化过程,定量研究矿区或矿体的隆升与剥露,评价矿床形成后的保存与变化状况,提高找矿预测效果.主要总结和论述诸如Ar-Ar、裂变径迹(FT)和(U-Th)/He等中-低温热年代学技术方法及其在矿床地质中的应用研究状况,分析热年代学技术与应用发展趋势,以期为成矿作用研究提供新的应用技术手段.
Isotopic Geochronology,a traditional subject to obtain absolute isotopic ages based on radioactive decay theory, has been widely used to date geological time in various fields. With theoretical innovation and technical developments the Isotopic Geochronology gradually develop into the Thermochronology that is of closure temperature feature and could not only date geological event, but also ascertain both temperature and thermal history of economic geological event. Since various methods have different closure temperatures several thermochronology techniques could be synthetically applied to recover whole geological evolution history in a wide range of temperature and/or age. The thermochronology methods are especially used to reveal mineralization age and epochs, rates of exhumation-erosion of ore deposit or ore district, and ore deposit preservation potential, providing evidences for deep ore prospecting and mineralizing potentiality evaluation.This paper summarizes the middle-low temperature thermochronology methods that have been utilized in mineralization, such as 40Ar/39Ar, fission track and (U-Th)/He techniques, and then presents research developments. It is expected that this work should provide new research contents and helpful technical methods for ore deposit field