太平洋板块俯冲作用在东北亚大陆边缘的地质记录述评

Geological Records of the Pacific Plate Subduction in the Northeast Asian Continental Margin: An Overview

古太平洋起源于泛大洋,为晚古生代-早中生代环绕泛大陆的全球性大洋。随着古特提斯洋盆的关闭和泛大陆的裂解,逐渐形成了古太平洋板块,以及大西洋、北冰洋和印度洋板块等等。本文综合了近年来这方面的研究进展,提出古太平洋板块(或伊佐柰琦板块)向东北亚大陆边缘的俯冲作用始于早侏罗世,俯冲带逐渐由西向东迁移,其中夹杂着微陆块或地体,构成了多岛洋的构造格局。

The Paleo-Pacific Ocean was originated from the Panthalassa,which was a vast global ocean surrounding the Pangea Supercontinent.With the breakup of the Pangea and the closure of the Paleo-Tethyan Ocean,the Paleo-Pacific, Atlantic,Arctic and Indian Oceanic plates were in turn formed.About 190Ma,the Pacific Plate was initially generated at the junction of the oceanic rift among the Izanagi,Farallon and Pheonix plates.Although most geologists considered a co-herent genetic relationship between Meso-Cenozoic tectonic evolution of NE Asian continental margin and subduction of the Pacific Plate,there still exist some key problems.The main issues include：（1）the formation,motion trait and evolution paths of the Pacific Plate,especially the Izanagi Plate which subducted beneath the NE Asian continental margin at least since early Jurassic;（2）the beginning time of the Pacific Plate subduction;（3）the identification of subduction-related magmatism;and （4 ）physical conditions of subduction processes.Based on the recent research progress of the above issues,this paper synthesizes that the subduction of the Paleo-Pacific Plate（or Izanagi Plate）beneath the NE Asian conti-nent started in the early Jurassic.The subduction zone was gradually migrated eastward and constituted anarchipelagic oce-anic framework with the involvement of old microblocks or foreign massifs.