云南个旧锡矿的成矿时代

云南个旧锡矿经历了印支期海底基性火山——沉积成矿、海底喷流——沉积成矿和燕山晚期的花岗岩叠加改造成矿的作用。用Ar-Ar、K-Ar和Pb-Pb法分析了3个成矿系列的成矿年龄,结果表明,成矿系列Ⅰ的Ar-Ar法坪年龄和等时线年龄为95.93±5.41～123.91±15.41Ma,K-Ar法表观年龄为112.50±2.25Ma,普通铅法年龄为210～240Ma;成矿系列Ⅱ的Ar-Ar法坪年龄和等时线年龄为191.81±2.26～205.11±4.38Ma,K-Ar法表观年龄为186.01±3.72Ma,普通铅法年龄为200～230Ma;成矿系列Ⅲ的Ar-Ar法坪年龄和等时线年龄为83.23±2.07～85.22±2.38Ma,K-Ar法表观年龄为43.49±0.87Ma,普通铅法年龄为83～116Ma。

METALLOGENIC AGES OF GEJIU TIN ORE DEPOSIT IN YUNNAN PROVINCE

The formation of the Gejiu tin ore deposits experienced three generation mineralizations, which were, in an ascending order, the seabed basic volcano-sedimentary mineralization in the Indosinian epoch (metallogenetic series Ⅰ), the seabed exhalative hydrothermal sedimentary mineralization in the Indosinian epoch (metallogenetic series Ⅱ) and the superimposed granitism-reformed mineralization in the Yanshanian epoch (metallogenetic series Ⅲ). The paper analyzed metallogenetic ages of the above-mentioned metallogenetic series by means of Ar-Ar, K-Ar and Pb-Pb methods. The dating results showed that the ages of metallogenetic seriesⅠby Ar-Ar, K-Ar and Pb-Pb methods yielded from 95.93±5.41 to 123.91±15.41 Ma, 112.50±2.25 Ma and from 210 to 240 Ma respectively. The ages of metallogenetic seriesⅡ yielded from 191.81±2.26 to 205.11±4.38 Ma, 186.01±3.72 Ma and from 200 to 230 Ma respectively. The ages of metallogenetic series Ⅲ yielded from 83.23±2.07 to 85.22±2.38 Ma, 43.49±0.87 Ma and from 83 to 116 Ma respectively. In other words, the Gejiu tin ore deposit should be a mine with multiple phases of mineralization.