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人们都承认,对造山带变质矿物测得的放射性年龄,一般都反映该带的冷却史,而不是它最初结晶时代。Armstrong(1966)首先发展了这个概念,并加以详述。Harper(1967)首先把它应用于英国的加里东造山带。但这个论点得到公认,还得归因于Jager教授和她的伯尔尼大学的同事们对中阿尔卑斯的研究工作。在一个年轻的山岳地带中,某些计时体系的精确度,尤其是黑云母的Rb—Sr、黑云母和白云母的K—Ar、磷灰石的U—裂变径迹系统的精确度,都足以建立一幅岩石经过一系列不同的“封闭温度”逐步
It is acknowledged that the radioactive age measured for the metamorphic minerals in the orogenic belt generally reflects the cooling history of the belt, rather than its original crystalline age. Armstrong (1966) first developed this concept and described it in detail. Harper (1967) first applied it to the British Caledonian orogenic belt. This argument, however, is well recognized and is due to Professor Jager and her colleagues at the University of Bern for their work on the Central Alps. In a young mountainous area, the accuracy of some timing systems, especially the accuracy of biotite Rb-Sr, biotite and muscovite K-Ar, apatite U-fission track systems Enough to build a rock through a series of different “closed temperatures” step by step