中国西北甘肃地区华夏和安加拉混生植物群形成机制研究

系统总结了我国西北甘肃地区晚二叠世华夏和安加拉混生植物群的研究现状和研究进展,讨论了华夏和安加拉混生植物群的形成机制。早二叠世,塔里木板块和华北板块向西北运移,与此同时,哈萨克斯坦板块和西伯利亚板块向东南漂移。中二叠世,华夏古陆沿天山、阴山和大兴安岭一线与西伯利亚古陆碰撞导致古海洋闭合和山脉隆升,板块的碰撞为华夏植物群和安加拉植物群两者之间提供了"混生"的条件。来自这两个植物群的少数混生分子出现在本区的中二叠世晚期。晚二叠世,由于塔里木板块和华北板块与哈萨克斯坦板块和西伯利亚板块碰撞与联合,从而使华夏古陆和安加拉古陆对接,形成了华夏和安加拉混生植物群。华夏和安加拉混生植物群的分布模式可以归于陆地生态系统的板块运动、气候分异、环境变化、植物迁移和植物自身演化的结果。

Study on the Formative Mechanism of the Mixed Cathaysian-Angaran Floras in Gansu of Northwest China

This paper sums up systematically present situation and recent progress of the mixed Late Permian Cathaysian-Angaran floras in Gansu of Northwest China.The paper discusses the formative mechanism of the mixed Cathaysian-Angaran floras.During the Early Permian,the Tarim Plate,together with the North China Plate,moved northwestwards,meanwhile,the Kazakhstania and Siberia plates drifted southeastwards.During the Middle Permian,the Cathaysian continent collided with the Siberian continent along the line from the Tian-shan Mountains,Yinshan Mountains and Da Hinggan Mountains to cause the closure of an ancient ocean and the uplifting of mountain systems so that the plate collision provided 'a mixing' condition between the Cathaysia flora and the Angara flora.A few mixed elements of the two floras occured in the region during the late Middle Permian.The Cathaysian and Angaran continents began to merge with each other due to the collision and connection of the Tarim and North China plates with the Kazakhstan and Siberian plates,which formed the mixed Cathaysian-Angaran floras during the Late Permian.In addition,the distribution patterns of the mixed floras may be due to plate movement,climatic differentiation,environmental change,plant migration and plant evolution in terrestrial ecosystems.