地球化学块体——概念和方法学的发展

Geochemical blocks-Development of concept and methodology

中国的全国区域化探扫面计划(RGNR)迄今已进行了24年,已经覆盖了全国600余万平方千米的国土面积,获得了高质量元素分析的海量数据,通过对这些数据进行的综合研究,笔者发现了比传统意义的分散晕分散流更为宽广的地球化学模式:区域异常、地球化学省、地球化学巨省和地球化学域。这种更为宽广的所谓套合着的地球化学模式谱系实际上是地球上富含各种金属的巨大岩块的内部结构特征在地表的表现,这种“地球化学块体”是原始地球的不均一性以及地球从起始演化到现在的过程中元素的分布再分配的最终结果的体现,笔者从中得到了这种大的地球化学块体能够为大型巨型矿床的形成提供其所必需的足够的物质供应量的新认识。而追索某元素地球化学块体的内部结构则可揭示该元素在地球化学块体中逐步浓集成矿的轨迹。尽管地球化学块体的理论与方法学研究虽然尚在初期阶段,但已为勘查地球化学、矿床学与成矿学开拓了眼界,并提供了新的研究思路。

Geochemical distribution data(several tens of millions )of 3 9elements were obtained in China's national geochemical mapping program carried out for 24years over more than6million km 2 of China's territory.By examining the flood of data,the authors have fo und much broader geochemical patterns other than dispersion halos and dispersi on trains which have been the main subjects of study during the60years' deve lopment of exploration geochemistry.Such broader geochemical patterns are ge ochemical anomalies,geo chemical provinces,geochemical megaprovinces and geoch emical domains.They are surface expressions of the internal structural featur es of large blocks of rock with higher metal contents.Those large'geo-chemi cal blocks'are the net results of the Earth's original heterogeneity and the d istribution and redistribu-tion of metals from the initiation and evolution of the Earth up to the present days.The authors got a new idea that the large can provide large metal endowments necessary for the formation of large to sup er-large geochemical blocks ore deposits.To explore the internal structure of the geochemical block of a cer-tain element may reveal the trajecto ry of gradual concentration and formation of ore deposits of that ele-ment in the geochemical block.The new geochemical block concept is changing the mineral ex ploration strategy and methodology in China,providing a powerful tool for gl obal mineral potential assessment and inspiring new ideas for exploration geoc hemistry,ore-genesis and metallogeny.