滇西北兰坪盆地金顶超大型矿床有机岩相学和地球化学  

Organic petrography and geochemistry of the giant Jinding deposit,Lanping basin,northwestern Yunnan,China.

作　　者：薛春纪[1] 高永宝[2] 曾荣[2] CHIGuoXiang QINGHaiRuo 

机构地区：[1]中国地质大学地质过程与矿产资源国家重点实验室地球科学与资源学院,北京100083 [2]长安大学地球科学与国土资源学院,西安710054 [3]DepartmentofGeologyUniversityofRegina,SaskatchewanS4S0A2,Canada

出　　处：《岩石学报》2007年第11期2889-2900,共12页Acta Petrologica Sinica

基　　金：国家自然科学基金(40772061;40472054;40272050);高等学校创新引智计划(B07011);国家重点基础研究发展计划(2002CB4126007)共同资助。

摘　　要：云南兰坪金顶矿床是世界上形成时代最新且唯一陆相沉积岩容矿的超大型铅锌矿床,也是中国目前最大的铅锌矿床,有机物质在金属成矿中可能发挥重要作用,受人关注。矿石及矿化岩石中产有包括干酪根、轻油、烃类气、重油、沥青及方解石中石油、甲烷包裹体等多种形式、产状和成熟度的有机物质,油气显示突出,古油气藏遗迹明显,是金顶古油气藏在铅锌成矿过程中热成熟、裂解和被改造、破坏不同阶段的产物。有机物质的氯仿沥青'A'变化大(72×10^(-6)～395415.42×10^(-6))。'A'的族组分中,总烃(58.47%)大于'非烃+沥青烯'(41.53%),饱和烃/芳香烃比值大于1,具Ⅰ型有机母质特征。有机转化率(A/C=0.5%～7.2%)较矿床外围岩石低,有机热成熟度高。矿石及矿化岩石中有机质的饱和烃包括正构烷烃、Pr、Ph和iC_(18)等化合物,碳数分布介于C_(10)～C_(34)之间,C_(21+22)/C_(28+29)=0.78～3.582,Pr/C_(17)=0.25～0.646,Ph/C_(18)=0.39～1.57,有机母质为海相菌藻类。有机质中检测出萘、菲、三芳甾烷、联苯、荧蒽等芳香烃类化合物,菲系列化合物最为明显,MPI_1 =0.215～0.434,MPI_2=0.252～0.588,菌藻等有机母质发育在高盐度还原沉积环境,烃源岩主要是三叠系残留海相碳质泥岩和泥灰岩。伴随金顶局部穹隆过程,很可能在金顶穹隆中形成油气藏,它是矿区铅锌快速大规模集中成矿的重要还原剂之一。The Jinding giant ore deposit,Lanping,Yunnan,is the youngest and the only continental sediment-hosted super-large Zn-Pb deposit in the world,and also the largest Zn-Pb deposit in China and followed with interests.Various kinds of organic matte, such as the kerogen,light oil,hydrocarbon gases,heavy oil,bitumen with different occurrences and maturation,and the oil-and methane-inclusions in calcites,and their petrography have been revealed in this paper.The showing of oil-gas and old oil-pool traces are evident in the Jinding ore district.The organic matter may be the every stage's products of heat-maturation,splitting and disruption of the Jinding old oil-gas pool and play an important role on the mineralization.The chloroform bitumen'A'in the organic matter is variation(72×10^(-6)～395415.42×10^(-6)).The total hydrocarbon(58.47%)is more than'non-hydrocarbon+asphaltic olefin'(41.53%),the ratio of saturated-/aromatic-hydrocarbon is over 1,and the primary organic matter is I-type.The organic transformation ratio(A/C =0.5%～7.2%)is over of the rock's in the field,and the organic matter had maturated,The saturated hydrocarbon of the organic matter in the ores and the ore-beating rocks include normal paraffin hydrocarbon,Pr,Ph,iC_(18),and so on, the carbon number is C_(10)～C_(34),C_(21+22)/C_(28+29)=0.78～3.582,Pr/C_(17)=0.25～0.646,Ph/C_(18)=0.39～1.57,and the primery organic matter is marine algae.The aromatic hydrocarbon in the organic matter include naphalin,phenanthrene,triaromatic steroid, biphenyl and fluoranthene,and the phenanthrene compounds the most evident,MPI_1=0.215～0.434,MPI_2=0.252～0.588. The marine algae developed in the reduced environment with high salinity,and the hydrocarbon source rock is the carbon-rich mudstone and marl.A oil pool might form in the Jinding dome during the doming and be the one of important reduction in the large-scale metal mineralization.

关 键 词：有机岩相学 有机地球化学 成藏与成矿 金顶超大型矿床 兰坪盆地 

分 类 号：P618.4[天文地球—矿床学]