泛华夏大陆群与东特提斯构造域演化

EVOLUTION OF THE PAN-CATHAYSIAN LANDMASS GROUP AND EASTERN TETHYAN TECTONIC DOMAIN

本文以板块构造理论为基础．根据全球各大陆陆块和微陆块的相对亲缘性、统一性和独立性，提出晚前寒武纪末一早古生代初泛大陆解体后，整个古生代期间，全球大陆可划分为三大陆块群，即冈瓦纳大陆群、劳亚大陆群，和泛华夏大陆群。论述了三大陆块群，特别是泛华夏大陆群的形成演化及其作为独立大陆群存在的统一性。指出泛华夏大陆群的独立性和统一性表现在：①早古生代末，扬子、华夏（包括黄海－东海－南海古陆）、中朝、柴达木、塔里木、昆仑－北羌塘－昌都－印支等陆块曾一度拼贴在一起，形成统一的大陆；②晚古生代中晚期形成独立的华夏植物群区系；③晚古生代末－早中生代，泛华夏大陆群主体部分的扬子－华夏和中朝陆块向西运移楔入，导致其南北两侧古特提斯洋的同步消亡和全球泛大陆的最终形成。泛华夏大陆群的形成演化历经了晚前寒武纪末－早古生代初各陆块的裂离、割据；早古生代末的拼贴、统一；晚古生代的再次分裂和晚古生代末－早中生代与南北大陆群拼贴４个发展阶段。同时指出在东特提斯构造域内，古特提斯既表现出对原将提斯的继承性，又有新生性；中特提斯不是古特提斯的延续和发展，它是标志还大陆裂－聚巨旋回演化中另一旋回的开始。最后讨论了显生宙地球上大陆由南聚北散到北聚南散，?

Based on the theory of plate tectonics, the present paper separates.according to theaffinity,unity and independence of the global palaeocontinents,landmasses and microlandmasses, the global palaeocontinents during the whole time of the Palaeozoic into threelandmass groups i e the Gondwana,Laurasis and Pan-Cathaysian landmass groups,all ofwhich are described with the emphasis oil the formation and evolution of the PanCathsysian landnlass group. The independence and unity of the Pan-Cathaysian landmassgroup are manifested in: (1)the united continent consisting of the Yangtze, Cathaysia (including the Yellow Sea-East China Sea-South China Sea oldland),Sino-Korean,Qaidam,Tarim, Kunlun-North Qangtang-Qamdo-Inclosinian landmasses during the latest EarlyPalaeozoic ; (2)the independent Cathaysia flora during the middle-late Late Palaeozoic,and(3)the westward migration of the Yangtze-Cathaysia and Sino-Korean landmasses as thebulk of the Pan-Cathaysian landmass group,resulting in the simultaneous obliteration of the Palaeo-Tethyan Ocean on the northern and southern sides of the landmass group,andthe final formation of the global Pangea during the latest Late Palaeozoic and Early Mesozoic. Four stages are recognized for the formation and evolution of the Pan-Cathaysianlandmass group: (1)The divergence stage of all the global landmasses at the end of theLate Precambrian to Early Palaeozoic; (2)the partly ccnvergence stage of the landmassesand the formation of the initial Pan-Cathaysian landmass group during the latest EarlyPalaeozoic; (3) the divergence and rifting stage of the southwestern margin of the PanCathaysian landmass group during the Late Palaeozoic,and (4)the collision and convergence of the Pan-Cathaysian landmass group with the Laurasis landmass group during thelatest Late Palaeozoic to Early Mesozoic. In the eastern Tethyan tectonic domain, thePalaeo-Tethys not only has inherited the features of the Proto-Tethys,but also possessesthe newly emerging features. The Mid-Tethys marks the beginning of a new tectonic cyclein the divergence-convergence megacycle of the Pangea rather than the continuation anddevelopment of the Palaeo-Tedlys. This paper deals finally with the geodynamic mechanisms for the divergence and convergence of various landmasses, and reorganization anddisintegration of the Pangea. In other words,the internal material of the earth migrated toward the southern semisphere,giving rise to the expansion of the southern semisphere anddisintegration of the Pangea. The southward migration of the internal material of the earthalso caused the northward movement of the material in the asthenosphere,leading +O thenorthward movement of the microlandmasses. In addition to the vertical circulation andconvection, the horizontal eddy motion of varying sizes also occurred in the creeping asthenosphere, resulting in the rotation,corlver!4erlce (the formation of the Pangea) and rapiddivergence (the disintegration of the Pangea) of the landmasses.