晚古生代泛大陆聚合的全球构造背景：板块漩涡运动轨迹含义的探讨

摘要

Since the formation of plate tectonic theory,the relativity between different plates are described deeply.However,movement process during the convergence of a series of plates are often overlooked. Based on global paleomagnetic data and paleo-plate reconstruction,paleolocation and motion trajectory can be obtained.The plate’s motion trajectory indicates that major continents converged to the northern mid-latitudes during Silurian (about 443Ma)-Permian (about 250Ma).It displays as:global plate motion have a characteristic of clockwise rotation during the formation of Pangea.And larger plates (South America, Baltica,Siberia,Australia,etc.)significantly showed a higher latitudinal drifting rate and rotation rate than smaller blocks (North China,Tarim,Yangtze block,etc).Trajectory of some major plates and continental blocks shows an asymmetric “e”type with a clockwise rotation.Central Asia is the convergent center with a symbol of Kazakhstan orocline.The scroll-shaped trajectory is controlled by long-term vortex motion in the upper mantle.This convective motion kept a relatively steady status in a certain period of time (late Paleozoic),leading to the formation of Pangea.%板块构造理论形成以来，不同板块之间的相对作用得到深入阐述，但对多板块聚合的运动过程的研究常被忽略。依据全球古地磁数据和古板块再造，可以获得板块运动轨迹，这些板块轨迹指示全球主要大陆在志留纪（约443Ma）-二叠纪（约250Ma）期间发生向北半球中纬地区的汇聚，具体表现为在泛大陆的形成过程中，全球板块运动具有顺时针旋转的特征，并且大板块（南美、波罗的、西伯利亚、澳大利亚等）纬向移动速率和板块自转速率明显高于小陆块的（华北、塔里木、扬子陆块等）。一些主要陆块显示不对称的“e”型顺时针旋转的漩涡轨迹，汇聚中心在中亚地区，以哈萨克斯坦马蹄形的最终形成和保留为标志。板块聚合的涡旋状运动轨迹，受控于上地幔流动过程产生长期的漩涡运动。这种对流运动在一定时间内（晚古生代）保持相对稳态的流动形式，导致泛大陆的形成。