夹皮沟金矿床的成矿时代讨论

产于太古宙中深变质岩中的金矿床在我国华北东北地区分布很广，成矿时代主要靠同位素年龄及其与后期岩浆活动的关系来确定。夹皮沟金矿是该型矿床中工作较多且有代表性的一个矿床，对其成矿时代有前寒武纪（Ar、Pt）成矿、显生宙（海西、海西一印支、燕山）成矿及前寒武纪十显生亩成矿等不同认识。本文根据矿脉与海西期花岗闪长岩及脉岩的关系，以及含金石英包裹体Rb－sr等时线年龄资料，认为成矿属海西期或海西一印支期，可能有燕山期的叠加。由于石英含过剩氩，故所得元古宙Ar－Ar、K－Ar表面年龄无地质意义，锆石可能具继承性，其太古宙年龄不能肯定为成矿时代。该矿是否有前寒武纪成矿期尚待进一步工作。

A PRELIMINARY DISCUSSION ON METALLOGENIC AGE OF THE JIAPIGOU GOLD DEPOSIT IN NORTHERN CHINA

Gold deposits in medium-high grade metamorphic rocks of the Archean are widespread in north and northeast China. Their metallogenic ages were/are dated mainly by both the isotopic methods and the relationship between ore and late magmatic rocks. The Jiapigou mine is a typical one of that type gold deposits. UP to now, different opinions on the age of ore formation in this deposit have been actived at, which mainly include: 1 The ores were formed during the Precambrian(Ar, Pt);2 The ores were formed during the Phanerozoic (Hercynian, Hercynian-Indosinian, Yanshanian); and 3 the ores were formed at the Precambrian combined with the Phanerozoic. The authors in this paper think that the gold ore at the Jiapigou dePOsit were formed during either the Hercynian or the Hercynian-Indosinian period, and PrDbably superimposed by later Yanshanian period, based on detailed field observation on relations between gold vein, and Hercynian granite-diorite and dykes as well as on results from Rb-Sr isochron dating on fluid inclusions of gold-bearing quartz.