油气有机质与MVT铅锌矿床的成矿——以四川赤普铅锌矿为例  

The Relationship between Oil-gas Organic Matter and MVT Mineralization:A Case Study of the Chipu Lead-zinc Deposit,Sichuan

作　　者：吴越[1,2] 张长青[3] 毛景文[3] 张望生[4] 魏成[5] 

机构地区：[1]长江大学地球环境与水资源学院,湖北武汉430100 [2]中国地质大学(北京)地球科学与资源学院,北京100083 [3]中国地质科学院矿产资源研究所,北京100037 [4]中国地质大学(武汉)地球科学学院,湖北武汉430074 [5]四川省甘洛县国土资源局,四川甘洛616850

出　　处：《地球学报》2013年第4期425-436,共12页Acta Geoscientica Sinica

基　　金：国家自然科学基金项目(编号:40902029);中央级公益性科研院所基本科研业务费专项资金(编号:K0904;200911007);地质过程与矿产资源国家重点实验室开放课题基金项目(编号:GPMR2011);成矿作用与资源评价重点实验室开放基金(编号:ZS1102)联合资助

摘　　要：四川赤普MVT铅锌矿床成矿与古老油气藏关系密切。通过对矿床不同成矿阶段硫化物硫同位素和热液碳酸盐碳、氧同位素系统研究,结合沥青有机质的有机地球化学特征,探讨油气参与金属成矿的详细过程。取得主要认识如下:(1)油气系统中先存的H2S是成矿早阶段主要的硫源,TSR作用启动后还原硫酸盐,为成矿提供另一硫源。Mg2+可能是控制成矿过程中TSR作用的一个因素;(2)热液碳酸盐矿物碳(氧)同位素组成指示了TSR作用氧化的有机碳与流体溶解围岩碳酸盐岩中碳的不均匀混合作用;(3)矿床中与成矿作用有关的有机质(沥青)具有高-过成熟度特征和低芳烃含量,或是其参与了TSR作用的一个标志;(4)川滇黔地区油气成藏-破坏和赤普铅锌成矿可能是盆山演化过程中不同阶段或是同一阶段不同时代的产物,铅锌矿床形成与古老油气藏破坏密切相关。There is a close relationship between mineralization of the Chipu MVT deposit and oil-gas reservoirs.Through a systematic study of sulfur isotope of sulfides and carbon and oxygen isotopes of hydrothermal carbonates,combined with organic geochemical characteristics of bitumen,the authors suggest a possible lead-zinc mineralization process in this deposit.The conclusions are as follows：（1） H 2 S,derived from cracking of crude oil was the main sulfur source for early-stage mineralization,whereas the thermochemical sulfate reduction provided reduced sulfur once TSR process was triggered.Mg 2＋ could be a key factor controlling the TSR reaction.（2） The carbon and oxygen isotopic variation of hydrothermal sparry carbonates was contributed by heterogeneous mixture of the host-rock dolomite isotope source and the lighter organic one.（3） The bitumen has the features of high-degree degradation and low aromatics content,which is considered to have been involved in the lead-zinc mineralization of the Chipu MVT deposit as well as other deposits.（4） The Pb-Zn mineralization and oil-gas field formation in this area were products of basin fluids,corresponding to the different stages of the basin-and-range system.

关 键 词：赤普MVT铅锌矿 硫碳氧同位素 有机质TSR作用 成矿与油气破坏 四川 

分 类 号：P618.42[天文地球—矿床学] P618.4[天文地球—地质学]