青藏高原蛇绿岩和古洋壳恢复重建研究中的问题讨论

Discussion on the rehabilitation and reconstrcution of the ophiolites and paleo-oceanic crust in Qinghai-Tibet Plateau

蛇绿岩成带出现于青藏高原各板块单元边界,其中雅鲁藏布江蛇绿岩带和北祁连山蛇绿岩带规模最大、最为典型,分别代表了秦祁昆和特提斯古大洋的洋壳物质。根据南北2个典型蛇绿岩带的研究实践,讨论了构造背景与岩石地层相结合、结构构造特征与矿物岩石分析相结合、物理化学成因与区域地质工作相结合、岩石类型年代学与地层年代学研究相结合的蛇绿岩研究方法。综合恢复重建古洋壳的古地磁资料分析、扩张速度分析、俯冲速率分析和古生物地球环境分析4种新技术,便可结合蛇绿岩研究比较容易地重建已经消亡了的古大洋岩石圈,这对研究青藏高原岩石圈的演化是有益的。

Based on the studies of typical ophiolite belts of Yarlung Zangbo and North Qilian where they are the largest in scale and are respectively in representative in paleo-oceanic crust substances of Qirding-Qilian-Kunlun and Tethys,a study using four technique combinations of ophiolite has been put forward. That is combining the tectonic background with rock stratigraphy, combining the structural and tectonic characteristics with minerals and rocks （strata） , combining physicochemical genesis with regional geological works ,and combining the petrologic chronology with stratigraphic chronology. By means of palaemagnetic data, expanding velocity, subduction rate, and paleontology and environment analysis, based on ophiolite belt research, it is possible to reconstruct the paleo-oceanic lithosphere, which is a great help to understand the evolution history of Qinghai-Tibet Plateau.