在卡林型金矿中有机质常与矿石共生,根据有机地球化学理论,可利用有机质示踪地质热事件.以桂西北卡林型金矿为例,研究有机质的基本类型及地球化学特征,探讨了桂西北地区卡林型金矿中有机质对地质热事件的示踪及其与金矿成矿的关系:①桂西北地区各矿区的有机质可划分为原生型干酪根和迁移型有机流体两种基本类型,其中,迁移型有机质主要为凝胶化有机质,主要是地层原生有机质在地质热事件的影响下由于热降解作用生成的有机流体的残余物,其形成、演化与成矿关系极为密切；②桂西北地区卡林型矿区地层中的有机质成熟作用由矿体向近矿围岩、再过渡到矿体外围,其氯仿沥青A含量及其A/C值由大逐渐变小,反映成矿过程中,成矿的地质热事件对于地层原生有机质影响所产生的热效应,从矿体到外围地层逐渐减弱；③地质热事件对于金矿区赋矿地层中有机质产生了明显的改造.%Organic matters in carlin-type gold deposits and ores are always paragenetic,according to organic geochemistry theory.Organic matters can be used to trace geological thermal events.Based on the carlin-type gold deposits in the northwest of Guangxi,the basic types and the geochemical characteristics of organic matters are studied in geological thermal events and the relationship with gold deposits mineralization is discussed in this area.Results show that:① Organic matters in mining districts of northwest of Guangxi can be divided into two basic types,primary kerogen and migration-type organic fluid.The latter,mainly the gelatinization organic matter,is the residual substance of organic fluid from the primary organic matter of stratum under the influence of thermal degradation.Its formation and evolution have a intimate connection with mineralization.② The "A" content and A/C ratio of organic matters of carlin-type gold deposits stratum in this area gradually become small by ore body to wall rock close to ore body.The transition to the outside suggests that the heating effect of primary organic matter in stratum caused by geological thermal events of mineralization in metallogenic process gradually becomes weak form ore body to wall rock.③ Geological thermal events make a significant transformation to organic matter in the stratum of gold deposit mining area.
展开▼
