论文部分内容阅读
滇西北兰坪中—新生代沉积盆地产有中国最大的铅锌矿床,巨量铅锌矿石集中产在金顶穹窿内,矿石中不同产状的干酪根、轻质原油、重油、烃类气、沥青等多种成熟形式的有机物质丰富。对矿区有机物质进行了岩相学、生物标志化合物、碳同位素及铅同位素分析,结果显示:有机物质中氯仿沥青“A”的质量分数为(72~395 415.42)×10-6,w(饱和烃)/w(芳香烃)普遍大于1,饱和烃中检测出丰度较高的正构烷烃、Pr、Ph和iC18等生物标志化合物,烃源母质为藻类生物Ⅰ型有机质;相对于区域岩石,矿石中有机物质的有机转化率较低(0.5%~7.2%,平均为3.05%),已明显受热而成熟;透射全色光和紫外光显微镜在矿石光薄片样品中鉴别出较多原油和烃类气体包裹体。研究表明:金顶穹窿具有油气成藏“生、运、储、盖、闭”等配套发育的良好条件,矿区油气显示和古油气藏遗迹明显,铅锌成矿前或成矿中可能已形成油气藏;这个可能的油气藏以富含原油、烃类和H2S等还原性气体为成分特征;金顶古油气藏中H2S等还原性气体的聚集及其导致铅锌硫化物快速集中沉淀是大规模成矿的关键,成藏—成矿是金顶穹窿中一个连续发生、发展的动力学过程,成藏是成矿的前提。
The Lanping Meso-Cenozoic sedimentary basin in northwestern Yunnan has the largest lead-zinc deposit in China. Large quantities of lead-zinc ore are concentrated in the Jinding Dome, and the kerogen, light crude oil, heavy oil and hydrocarbon gas , Asphalt and other mature forms of organic matter rich. The petrographic, biomarker, carbon isotope and lead isotope analysis of organic matter in the mining area showed that the mass fraction of chloroform bitumen “A” in organic matter was (72-395 415.42) × 10-6, w (Saturated hydrocarbons) / w (aromatics) are generally greater than 1. The higher abundance n-alkanes, Pr, Ph and iC18 biomarkers were detected in saturated hydrocarbons, and the hydrocarbon parent was algal bio-organic type I. Compared with Organic conversion rates of organic matter in regional rocks and ores are relatively low (0.5% -7.2% with an average of 3.05%), which have been obviously heated and mature. Transmission crude light and ultraviolet light microscope identified more crude oil And hydrocarbon gas inclusions. The results show that the Jinding dome has favorable conditions for supporting the development of hydrocarbon accumulation, such as “generation, transport, reservoir, cap and closure”. The oil and gas in the mining area and the relics of ancient reservoirs are obvious. Has formed a reservoir; this possible reservoir is rich in crude oil, hydrocarbons and H2S and other reducing gases as a component of the characteristics; Jinding oil and gas reservoirs of H2S and other reducing gas accumulation and lead lead-zinc sulfide quickly concentrated precipitation It is the key to large-scale mineralization. Accumulation-mineralization is a continuous dynamic process of development in Jinding Dome, and accumulation is the precondition of mineralization.