中国东北及邻区白垩纪岩浆活动与古太平洋板块俯冲的关系

Cretaceous Magmatism in NE China and Adjacent Areas and Its Relationship with the Paleo-Pacific Plate Subduction

本文简要综述了古太平洋构造演化历史和中国东北及邻区构造单元,总结了中国东北及邻区白垩纪岩浆活动的时空分布规律及岩石组合特征,认为中国东北额尔古纳-兴安-松辽-佳木斯地块145-88Ma岩浆活动显著,从西向东由老变新,特征岩石组合为软流圈地幔来源玄武质岩石,以及Ⅰ型和A型花岗岩类;88-65Ma岩浆活动较弱,仅少量OIB型玄武岩。完达山-锡霍特-阿林-延边地区白垩纪岩浆活动也具有从西向东由老变新的规律,特征岩石组合为高镁安山岩、埃达克岩、Ⅰ型及S型花岗岩等中酸性岩石。上述岩浆活动分别形成于弧后（板内）及大陆弧。中国东北早白垩世大陆弧具有弧后伸展,与年老大洋岩石圈的俯冲有关,是现代地球上少见的俯冲类型;晚白垩世中晚期,弧后发生构造挤压,与智利型大陆边缘相似。

This paper briefly reviewed the tectonic evolution history of the Paleo-Pacific Plate and tectonic regimes of NE China and adjacent areas.It also summarized the spatial and temporal association and petrogenesis of Cretaceous igneous rocks,proposing its relationship with Paleo-Pacific Plate subduction.The Erguna,Xing’an,Songliao,and Jiamusi blocks of NE China have significant igneous activities in 145-88Ma,characterized by a spatial and temporal eastward migration and an association of I-and A-type granites and asthenosphere-derived basaltic rocks,with minor OIB-type basalts after-88Ma.The Cretaceous magmatism in the Wandashan-Sikhote-Alin and Yanbian area is also characterized by eastward mi-gration but an association of intermediate to acidic rocks including high-Mg andesites,adakites,and I-and S-type granites. Cretaceous magmatism in Erguna-Xing’an-Songliao-Jiangmusi and Wandashan-Sikhote-Alin-Yanbian areas was thought to be formed in back-arc（intra-plate）and continental arc settings,respectively,and was controlled by roll-back of the Paleo-Pacific Plate.The Early Cretaceous continental arc accompanied with back-arc extension was most likely to result from subduction of old oceanic lithosphere,which rarely occurred in the modern earth.The Late Cretaceous continental arc at NE China,characterized by back-arc compression,was similar to the present Chilean continental margin.