试论中国东部中生代成矿大爆发

A PRELIMINARY DISCUSSION ON THE MESOZOIC METALLOGENIC EXPLOSION IN EAST CHINA

中国东部在中生代尤其是燕山期发生了大规模的金属成矿作用， 形成了一大批重要矿床， 其成矿强度之高、密度之大、矿种之丰富， 在全球中生代成矿作用中首屈一指， 故可称为中生代成矿大爆发。研究表明， 中国东部中生代成矿大爆发是该地区在特定地质背景下发生岩石圈大减薄和构造格局大转折相结合、从而导致大规模壳幔相互作用和构造圈热侵蚀事件的产物。深入研究中国东部中生代成矿大爆发的背景和过程， 不仅能解决矿床学学科发展中的许多重要科学问题， 为进一步寻找矿产资源指出方向， 而且对认识中国大陆乃至东亚＿西太平洋的地质构造演化史、探讨花岗岩类的形成环境。

Large_scale metallic mineralisation took place in East China during Mesozoic, especially in the Yanshanian period (180～80 Ma), which formed a great number of important mineral deposits. Compared with Mesozoic mineralizations in the other parts of the world, this metallogenic event of East China is unique in its very high intensity, great extent, relatively short time, and very rich ore species. It can thus be called Mesozoic metallogenic explosion. Researches have shown that the Mesozoic metallogenic explosion resulted from combined effect of lithosphere thinning and tectonic inversion, cuasing large_scale curst_mantle interaction and a series of thermal erosion events in the tectonosphere, which favored the formation of large mineral deposits. Situated in the junction of Eurasia, Tethys and Pacific, East China was an assembly of several terrains. This caused the uneven spatial distribution of Mesozoic large_scale ore_forming processes in this area. The intense mineralizations were usually concentrated in certain places to form ore_concentrated districts of great economic significance. The geological background, metallogenic mechanism and the tectonic positioning of major ore_concentrated districts are key problems of metallogenic research. Further studies on the background and process of Mesozoic metallogenic explosion are of great significance not only in the settlement of many important problems of mineral deposits, but also in the better understanding of the geotectonic evolution of Chinese continent, east Asia and west Pacific, the geologic environment of granite formation, and the connection and junction between Tethys and Pacific.