通过详细的野外地质工作和显微镜下观察,对云南兰坪盆地东北部维西-乔后断裂带上三叠统石钟山组(T3s)中产出的铅锌矿床成因进行厘定.研究结果表明,测区内存在大量典型的同生沉积矿床标志,如:纹层构造、条纹条带构造、网脉构造、黄铁矿条带软沉积构造、黄铁矿草莓状结构、黄铁矿胶状构造、闪锌矿同心环状构造等.青甸湾矿床金属硫化物硫同位素测试结果显示,黄铁矿的δ34S介于3.7‰～8.1‰,均值5.34‰;闪锌矿的艿34S介于5.2‰～10.0‰之间,均值为7.18‰;方铅矿的艿δ34S介于5.2‰～9.9‰之间,均值为7.275‰,铅锌矿床硫来源于海水硫酸根无机还原.结合矿床形成时代及大地构造背景,认为该区铅锌矿为喷流沉积作用形成.%A series of lead-zinc deposits such as Qingdianwan, Caizidi, Jinshantao and so on, which are situated in the Upper Triassic Shizhongshan Formation (T3s) at the Weixi-Qiaohou fault belt, northeast of Lanping Basin. The genesis studies of these lead-zinc deposits are relatively superficial.. In this paper, through detailed field geological survey and studies under the microscope, authors found a large number of typical signs of the synsedimentary deposit such as laminated structure, striped band structure, vein net structure, the soft sedimentary pyrite band structure, strawberry-like pyrite structure, colloidal structure of pyrite, sphalerite concentric structure etc. Sulfur isotopes analysis results of metal sulfide in Qingdianwan deposit are following; δ34S of pyrite at 3.7‰- 8.1‰, average 5. 34‰ (N =5); δ34S of sphalerite at 5. 2‰ ～ 10‰, average 7. 18‰(N =5); δ34 S of galena at 5. 2‰ ～ 9.9‰, average 7. 275‰ ( N =4). It demonstrates that S in the deposit come from deoxidize of sulfate radical in seawater. Combining to the age data of these deposits and the tectonic background, we think these deposits in this area are pertain to Sedimentary Exhalation (SEDEX) genesis which revised the previous viewpoint that these deposits simply controlled by structure.
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