西藏成煤大地构造基本特征——西藏板块构造及其演化

西藏是介于古代南北大陆板块之间的过渡地带,自石炭纪以来,依次经历了前特提斯洋→古特提斯洋→特提斯洋的兴衰变迁过程:金沙江、怒江、雅鲁藏布三条缝合线分别是不同地史时期南北大陆坂块的分界线。本文总结了西藏板块构造的基本特征,论述了板块构造对西藏成煤条件的控制作用,认为西藏板块构造的特殊演化经历,是造成西藏各成煤期含煤性普遍不好的主要根源。指出昌都板片成煤条件相对较好,是西藏的主要找煤远景区。

BASIC FEATURES OF COAL FORMING GEOTECTONICS IN XIZANG (TIBET)-THE XIZANG PLATE TECTONICS AND ITS EVOLUTION

Xizang region is a transitional zone between the North and South palaed-continental plates. Since the Carbonizerous Period, it has undergone in turn the long career from pre-tethys ocean period, paleo-tethys ocean period and tethys ocean period. The three sutures of Jinshajiang, Nujiang and Yaluzhangbu seem to be the border lines of the North and South continental plate in different geological history. This paper summarize the basic features of the Xizang plate tectonic. It discusses how the coal-forming conditions were controlled by the plate tectonic in Xizang. It believes that the special evolution of the Xizang plate tectonic is the main reason for the forming of the bad coal. The author points out that the conditions of the Changdu-slab were favourable for the forming of coal beds, therefore, it is the promising area for coal prospecting in Xizang.