华北北部古生代大陆地壳增生过程中的岩浆作用与成矿效应

包括前寒武纪克拉通与显生宙造山带两大构造单元的华北北部,古生代时期板块构造体制下古亚洲洋的裂解-扩展-消亡与汇聚大陆边缘的俯冲-碰撞-伸展循环构成了其大陆地壳增生与再造演化的基本图景,并形成了一系列记录这些因果演变连续过程的岩浆侵入与喷发事件。这些物质记录无疑是研究汇聚大陆边缘壳-幔作用和物质交换、大陆地壳演化与大规模成矿作用耦合关系的绝佳窗口。本文在系统总结最近几年积累的年代学和岩石地球化学资料的基础上,以一些带有特定过程印记的标志性岩浆事件为纲领,表征这些古生代岩浆作用形成过程中的地球动力学演变,揭示其所记录的华北北部大陆地壳的多阶段增生与再造演化机制,并初步探讨了有利地球动力学过程制约下的岩浆行为引起的成矿物质聚集效应。

Magmatism and its metallogenetic effects during the Paleozoic continental crustal construction in northern North China: An overview

The northern North China, tectonically composed of a Phanerozoic orogen and a Precambrian craton, witnesses a panoramic scenario of continental crustal accretion and reworking in the model of plate tectonics during the Paleozoic times. It is driven by rifting-spreading-extinction cycle of paleo-oceans and subduction-collision-extension processes at convergent plate margin, with a series of the associated magmatic events produced. These magmatic expressions constitute an excellent window through which the relationship among crust-mantle interaction at convergent plate margin, continental crustal evolution and large-scale metallogenesis can be fully characterized. Based on an overview on the geochronological and geochemical data concerning the Paleozoic magmatic rocks from the northern North China, the paper outlines the evolved geodynamic scenarios inherent in these magmatic sequences, envisages multi-stage crustal accretion and reworking mechanism during the Paleozoic continental construction in northern North China and ends with a tentative evaluation of promising magmatic and tectonic reservoirs for metallogenesis.