论华夏成矿省燕山期岩浆成矿大爆发的核幔式扩展模式与动力机制——纪念李四光先生诞辰130周年

中国东南部的华夏成矿省为滨太平洋成矿域最重要的钨锡贵稀多金属非金属成矿省。大量的地质调查与同位素测年资料表明,该区燕山期陆内活化造山引发的岩浆成矿大爆发启于陆内陆壳脆弱地带,中侏罗世（172±Ma）初动于钦杭结合带中段,晚侏罗世激化于南岭地区,早白垩世向外侧大面积扩展,结束于早白垩世末（99±Ma）,呈现出以钦杭带中段和南岭地区为核心、以外侧为幔的核幔式扩展模式,制约着区域岩浆活动与成矿特征以及由早而晚、由核及幔、由深到浅、由浅及表的岩浆成矿规律。由于这场运动发生于陆壳硬化程度较高的背景,大规模的岩石圈物质调整与岩浆成矿活动引发的上地壳蠕散效应十分显著,其与欧亚板块和古太平洋板块之间的强烈的左行扭动及弱俯冲作用复合,构成了岩浆成矿核幔式独特的动力机制。 

Core-mantle-type extensional mode and dynamic mechanism of the magmatic metallogenic explosion of the Yanshanian in the Cathaysian metallogenic province

The Cathaysian metallogenic province in the southeastern China is the most important multi-metal and non-metal metallogenic province with W, Sn and precious metals along the marginal-Pacific metallogenic megaprovince. The geological investigation results and the isotopic dating data show that the magmatic metallogenic explosion caused by the intracontinental active orogeny in this region came from intracontinental crustal vulnerable zones, originally occurred in the middle section of the Qinzhou-Hangzhou juncture during the middle Jurassic period (172±Ma), intensified in the Nanling region during the Late Jurassic period, and extensively extented to outside, lastly ended in the late early Cretaceous (99±Ma), thus forming the core-mantle extended mode centred with the middle section of the Qinzhou-Hangzhou and Nanling region and the outer side as the mantle. Meanwhile, it restricted the regional magmatism, ore-forming features as well as the magmatic metallogenic regularity from early to late, core to mantle, deep to shallow and shallow to surface. The creep effection of the upper crust caused by the large-scale adjustment of the lithosphere materials and the magmatic mineralization is significant, due to the movement taking place under the sitting of the higher degree of the crustal hardenability. Therefore, the unique dynamic mechanism of the magmatic metallogenic core-mamtle-type was formed as a result of the intensive left-lateral sinistral shearing and the recombination of the weak subduction.