华北中生代岩浆作用与去克拉通化

Mesozoic magmatism related to decratonization of the North China Craton

华北是全球古老克拉通遭受破坏最明显和最典型的地区,其去克拉通化作用的时间、范围和机制等重要科学问题是国内外研究的热点。大规模岩浆作用是去克拉通化作用的地质表现之一,通过对华北地区侵入岩侵位时代、源区、成岩过程的研究,可有效反演其去克拉通化作用的时空范围、过程及可能的动力学机制。华北东部广泛发育大面积的中生代侵入岩,本文在作者近十年研究的基础上,通过总结华北东部中生代侵入岩的锆石U-Pb年代学资料,厘定了华北东部中生代岩浆活动主要分为三叠纪、侏罗纪和早白垩世三期;通过岩浆源区、岩石成因研究,探讨不同时期岩石圈(地幔和大陆地壳)性质和厚度的转变及破坏的空间范围;在此基础上,结合区域地质特征初步探讨了华北去克拉通化的地球动力学机制。

The North China Craton is the most obvious and most typical area for the study of the destruction of the craton. The timing, scale and geodynamics of decratonization are hot issues among the geoscientists both in China and abroad. Large-scale magmatism is one of the geological responses to decratonization. The ages, sources of magmas and petrogenetic processes of magmatic rocks can be used to constrain the timing, scale and possible geodynamics of decratonization. Mesozoic intrusive rocks are widely distributed in the eastern North China Craton. Based on research works conducted in the past ten years or so, the authors summarize zircon U- Pb ages of the Mesozoic intrusive rocks in eastern North China Craton, which show mainly three stages of mag- matism in eastern North China Craton, i. e. , Triassic, Jurassic and Early Cretaceous. Geochemical features were used to trace their magma sources and petrogenesis, and the transition of the nature and thickness of the lithosphere and the spatial scale of decratonization were further constrained. On such a basis, the possible geody- namic mechanism of decratonization of the North China Craton is discussed in combination with regional geology.