试论中国东南地区大陆边缘构造演化的特征

ON THE CHARACTERISTICS OF TECTONIC EVOLUTION OF SE CHINA CONTINENTAL MARGIN

廖宗廷 周祖翼 陈焕疆 景学立

Liao Zongting Zhou Zuyi Chen HuanJiang Jing Xueli

同济大学海洋地质及地球物理系 上海200092

Department of Murine Geolgy and Geophysics, Tongji University, Shanghai

中国东南地区大陆边缘构造演化整体表现为一长期的、连续的和不断发展的过度,但由于其性质不断变化而又体现出队段性特征。在印支期(或晚华力西期)前的古全球构造阶段,地壳向洋的蠕散增生和不同时间、不同性质地体的碰撞拼合造山增生是本区大陆边缘构造演比的主要形式,以“手风琴式”演化为特征。发生于印支运动的变格作用使本区大陆边缘构造的运动体制发生重大变化,进入以“传送带武”板块构造运动为特征的新全球构造阶段,主要表现为特提斯洋板块和太平洋扳块的形成、俯冲挤压以及时以往不同时期大陆边缘构造的叠加改造。由于拼合是块与块间的干挤以及地体来源、拼合时间、拼合方式、拼合后固结程度等不同,中国东南大陆边缘构造有别于阿尔卑斯阿帕拉契亚区;由于块与块间干挤后岩石强烈变形、变质、混合岩化、岩浆活动以及大陆边缘地体组成的差异,中国东南大陆边缘构造也有别于日尔曼型和科迪勒拉型造山构造。中国东南大陆边缘构造及演化具有自己独特的风格。

As viewed from the tectonic evolution of the SE China continental margin as a whole,it has experienced a long,continueous and successive developing process though the variation of geological evolution is characterized by stages, During the pre-Indosinian (or late Variscian)of the ancient global tectonic stage,the tectonics of the continental margin was characterized by continental growth or accretion in the mode of ductkile creeping or variotis terrane collisions at different times. The lndosinian diktygenesis broiight ab0ut the trans-formation of tectonic regimes,i.e, from the accient global tectoiiic regime into the new global tectonic regime of plate tectonics,indicated by the generation,development and stib-duction of the Tethvan and Pacific plates. Since the tectonic deformation and the stJperim-position of the later tectonics on those of the former continued to go on by collision after convergence or interblock squeezing reactivated along pre-collisional belts.This is indeed a type of thin-crusted collision tectonics that occurred in the new global tectonic stage of plate tectonic regime. However,the tectoiiics of the SE China continental margin differs from both of the Alps and S.Appaliachian types since the interblock collision followed by continental squeezing and various derived terrane collision took place at different times and in different stvles. Moreover,it differs also from the Germano and Cordileran types of oro-genic tectonics siiice the interblock squeezing was accompaiiied by severe deformation,a profuse of metamorphism,magmatism,migmatization and magma intrusion,as well as the various highly heterogeneous terranes which welt to each other in different times and stvles. Therefore,it is concluded that the tectonics and their evolution of the SE China con-tinental margin should have its unique geological characteristics.

https://doi.org/10.11781/sysydz199403234