粤北连平地区钨锡多金属矿床成矿时代研究

Metallogenic ages of tungsten-tin polymetallic deposits in Lianping area,northern Guangdong Province

粤北连平地区钨锡多金属矿床类型主要为石英脉型。采用云母Ar-Ar法和石英包裹体Rb-Sr法,分别获得锯板坑含钨锡石英脉中的云母Ar-Ar坪年龄为(139.2±1.5)Ma(等时线年龄为143.6±3.9Ma,MSWD=0.30);鸡啼石含钨石英脉中石英包裹体Rb-Sr等时线年龄为(155.4±5.1)Ma(MSWD=2.1)。结果表明该区存在燕山早期和燕山早晚过渡期两期钨锡多金属成矿作用,并且认为(1)鸡啼石钨矿为南岭地区中生代大规模成岩成矿作用高峰期(150～160Ma)的产物;(2)南岭地区140Ma左右也有大型钨锡多金属矿的形成。这一成果为研究区域成矿规律,指导区域找矿提供了重要同位素年代学依据。

Quartz veins constitute the main metallogenic type of tungsten-tin polymetallic deposits in Lianping area,northern Guangdong Province.In this study,40Ar-39Ar dating of mica from tungsten-tin bearing quartz veins in the Jubankeng ore deposit yielded a plateau age of（139.2 ±1.5）Ma with an isochron age of（143.6 ± 3.9）Ma（MSWD =0.30）,and Rb-Sr dating of fluid inclusions in quartz from the Jitishi tungsten deposit produced an isochron age of（155.4 ±5.1）Ma（MSWD=2.1）.These results show that there exist two metallogenic epochs in Lianping area：one is Early Yangshanian,during which the Jitishi tungten deposit was formed and the gigantic diagenetic and metallogenic peak of Nanling region occurred,and the other is the transitional period from Early to Late Yangshanian,during which the Jubankeng tungsten-tin polymetallic deposit was formed.These data provide important geochronologic constraints for regional metallogenic regularity research and mineral exploration in this region.