美国卡林型金矿定年史的启示

Implication of the History to Dating the Carlin-type Gold Deposit of Nevada,USA

成矿时代研究是矿床学研究中非常重要的一部分,美国内华达州卡林型金矿作为矿床中的典型代表,其成矿时代的探索过程对于相同领域的研究必然有重要的启示作用。本文在回顾前人利用Rb-Sr、K-Ar、Ar-Ar、FT及U-Th/He等方法对内华达州卡林型金矿进行成矿时代研究的基础上,探讨分析了成矿时代研究过程中可能存在的一些问题及不妥之处,认为具有不同封闭温度的同位素计时体系适用于不同成因类型的矿床,成矿时代的研究与成矿温度、封闭温度及冷却速率的研究相结合方能获得更加准确的成矿年龄。

The study of metallogenic epoch is a very important branch in the study of deposits.The Carlin-type gold deposits in Nevada is a typical deposit.Therefore,the exploration on its metallogenic age will surly generate important implications for forth-coming researches conducted in the same field.This paper will analyze the problems which may exist in the study of metallogenic epoch through reviewing the previous researches of Carlin-type gold deposits in Nevada which are conducted by using methods like Rb-Sr,K-Ar,Ar-Ar,FT and U-Th/He.It is argued that different closure temperatures of isotope dating systems is applicable to different genetic types of ore deposits,and that accurate metallogenic age can be obtained only with the combination of the researches of metallogenic epoch and those of metallogenic temperature,closure temperature and cooling rate.