“岩浆热场”说及其成矿意义(下)

Granite and metallogenic relationship discussion(2):THE THEORY OF “MAGMA THERMAL FIELD”AND ITS METALLOGENIC SIGNIFICANCE

上篇(张旗等[1])初步讨论了岩浆热场说的概念,本文为下篇,主要谈应用,探讨它与成矿作用的关系。研究表明,岩浆热场说对热液成矿作用有重要的意义,可能解决了岩浆热液成矿作用中许多很难解释和争议很大的问题:如钨锡与金铜为什么相伴的问题,矿床为什么大多是多金属成矿的问题,远离侵入体的夕卡岩成因问题,成矿为什么滞后于花岗岩的问题,为什么有些岩体成矿,有些岩体不成矿的问题,为什么大规模岩浆活动与大规模成矿作用息息相关的问题等。岩浆热场与煤和油气成藏有关是一个重要的发现。岩浆热场对煤和油气生成、运移、聚集的影响主要表现在加速烃源岩的热演化,使生油门限变浅,使烃源岩进入高成熟或过成熟,使烃源岩中残余有机质丰度降低。令人感兴趣的是,岩浆热场说还导出了一个"成矿组合"的概念,所谓成矿组合是指在一个或大或小的区域内,在岩浆活动集中的时间段范围内,在热场的统一作用下所形成和影响的所有矿床,不论成因和矿种,均属于一个成矿组合。它包括下述4种类型的矿床:岩浆热液矿床、热泉型矿床、层状热液矿床及生物有机质矿床等。岩浆热场说对于找矿也有启示:首先,我们可以从3个不同的级别上(大规模岩浆活动级别;成矿带、成矿区、矿集区级别;单个矿床级别)规划找矿布局;其次,在岩浆热场的统一影响下将金属矿床和非金属矿床、热液矿床和沉积矿床、无机质矿床和有机质矿床联系起来;第三,推进不同类型矿床研究的互补和交流。看来,岩浆热场对于成矿的作用是最值得学术界关注的,它也许可以改变我们目前对成矿作用的某些根深蒂固的认识,开拓出一个新的领域,推进矿床学研究进入新的时代。

The authors discussed the concept of magma-thermal field in the first part of the article（Zhang et al.[1]）. The authors discuss applications of magma-thermal field and the relationship with mineralization in the second part of the article. Studies show that magma-thermal field has great significance for hydrothermal mineralization, and it may solve many difficult and controversial issues（such as why gold copper deposits and tungsten tin deposits are concomitant, why mostly polymetallic metallogenic is, why skarn is away from the intrusion, why mineralization lag behind of granite, why some rock mass is minerogenic rock, others are not,why large-scale magmatic activity and large-scale mineralization is closely related） on magmatic hydatogenesis.There is an important discovery that magma-thermal field is associated with coal and oil and gas reservoir. The influence of magma-thermal field on coal and oil and gas generation, migration and accumulation is mainly manifested in accelerating the thermal evolution of hydrocarbon source rock, making the oil threshold depth becomes shallow, making the hydrocarbon source rocks enter in high mature or over mature phase, reducing residual organic matter abundance in hydrocarbon source rocks. Metallogenic combination is an interesting concept that all deposits within the areas within the scope of the concentration of magmatic activity, regardless of the cause and minerals, all belong to a metallogenic combination. It includes the following four types of ore deposits, magmatic hydrothermal deposits, the hydrothermal deposits, the layered hydrothermal deposits and biological organic matter deposits. Magma-thermal field is of enlightening revelations to prospecting： first of all,we can plan prospecting layout from three different levels（large magmatic activity level; metallogenic belt,metallogenic area, ore concentration area level; a single deposit level）; Second, under the influence of the magma-thermal field, we can associate metallic deposits with nonmetallic ore deposits, hydrothermal deposit with sedimentary deposit, inorganic qualitative deposit with organic matter deposit together; Third, promoting the complementary of different types of ore deposit research and exchange. Magma-thermal field, it seems, for the function of mineralization is the most worthy of attention by academic, it may be able to change our current some deep-rooted understanding of mineralization, carve out a new field, advance deposit study entered a new era.