铜石杂岩体~(40)Ar/~(39)Ar 年龄,兼论归来庄金矿成矿时代

THE ~(40)Ar/~(39)Ar AGE OF TONGSHI SUBVOLCANIC COMPLEX AND THE MINERALIZATION PERIOD OF GUILAIZHUANG GOLD DEPOSIT

摘要:

铜石次火山杂岩体由三个岩浆侵入阶段岩石组成,石英二长闪长斑岩~(40)Ar/~(39)/Ar坪年龄为189.8±0.2Ma,二长斑岩坪年龄为188.4±1.6Ma,为同时代产物,属早侏罗世。随后是该区隐爆角砾岩及金矿的生成。中侏罗统汶南组不整合覆盖于蚀变的石英二长闪长斑岩之上,斑岩体有一个古风化壳,汶南组底砾岩中有蚀变的斑岩及灰岩砾石,灰岩砾石及钙质、泥质胶结物均无蚀变现象,说明金矿成矿作用发生于汶南组沉积之前,金的成矿年龄介于188—178Ma 之间。成矿与铜石杂岩体在时代上及成因上是有联系的。

Abstract:

Three intrusive stages of the same epoch are difined in Tongshi subvolcanic complex.The ~(40)Ar/~(39)Ar ages of quartz monzodiorite porphyry and monzonite porphyry hare been measured,to be 189.8±0.2 Ma and 188.4±1.6Ma,respectively.After the formation of these rocks,the cryptoenplosion breccia and related gold deposit were followed with.A plain of denudation was formed on the part of the altered quartz monzodiorite porphyry body,whlck,then,was overlied uncon-formably by the Wennan formation of the Mid Jurass...