广西珊瑚钨锡矿床成矿年代学研究及其地质意义

摘要

The Shanhu tungsten-tin deposit, which is located in the middle part of the Fuchuan-Hezhou-Zhongshan W-Sn-polymetallic metallogenic province, northeastern Guangxi, is a typical hydrothermal quartz vein type deposit in the Nanling metallogenic belt. In this paper, both40Ar-39Ar age of muscovite and Rb-Sr isotopic age of fluid inclusions in quartz vein are reported for this deposit. The muscovite40Ar-39Ar yields a plateau age of 101.7±0.7 Ma (MSWD=0.34) (with isochron age of 102.0±1.0 Ma, MSWD=1.17), which is consistent with the Rb-Sr isochron age of 106.4±3.5 Ma (MSWD=0.83) for the fluid inclusions. These ages show that this deposit is part of the extensive late Yanshanian magmatism and mineralization in the South China. Through preliminary analysis of fluid inclusions in quartz, we suggest that a “re-equilibrated magmatic water-hydrothermal” ore forming fluid for this deposit. Mineralization regulation drawn from this study can provide guidance for exploration in the areas of such kind, and thus of great significance.%珊瑚钨锡矿床位于富贺钟钨锡多金属成矿集中区的中部，是南岭钨锡多金属成矿带内典型的热液石英脉型矿床之一。本文采用白云母40Ar-39Ar法和石英流体包裹体Rb-Sr法，对矿床V32号含矿石英脉进行精细年代学研究，获得石英脉中白云母40Ar-39Ar坪年龄为101.7±0.7 Ma(MSWD=0.34)，正等时线年龄为102.0±1.0 Ma(MSWD=1.17)；石英流体包裹体Rb-Sr等时线年龄为106.4±3.5 Ma(MSWD=0.83)。它们在误差范围内一致，是华南地区燕山晚期成岩成矿高峰期的产物。同时通过石英包裹体 H-O 同位素组成的初步分析，认为成矿流体属于“再平衡岩浆水”，主要来自岩浆，在矿床深部可能存在隐伏花岗岩体。该成果对研究区域成矿规律，指导类似地区的找矿勘查工作具有重要意义。