ON THERMAL HISTORY OF TIANSHAN GEOSYNCLINE ACCORDING TO THE DATA ON K-Ar DATING OF EASTERN TIANSHAN

On the basis of the data of 45 K-Ar ages in the Eastern Tianshan, Uygur AutonomousRegion of Xinjiang, China, and the geological environment, the following conclusions aregiven. The Tianshan Hercynian geosyncline had passed through about 200 m.y. before itsformation, and it was in the late Kercynian at about 234.9±20 m.y. ago. The Yenshanmagmatism in this region has been first verified by the authors, and its K-Ar age is esti-mated at 196.6-157.6±20 m.y. The Hercynian magmatic activities may be divided intotwo substages: the early substage is of 300-350±20 m.y., and the later is of 230±20 m.y. By using the results of the determination of the ages, the thermal history ofTianshan geosyncline is preliminarily discussed.     

据天山东段K-Ar年龄测定结果对天山地槽热历史的探讨

本文根据我国新疆天山东段的45个K-Ar年龄数据,结合地质实际,得出结论认为,天山海西期地槽的形成大约经历了200百万年,海西晚期约234.9±20百万年为天山海西地槽形成的时间上限。初步证实了本区有燕山期岩浆活动的存在,其年龄值在196.6—157.6±20百万年之间。应用各项年龄测定结果,初步讨论了天山地槽的热历史。