雅鲁藏布江航磁异常带性质及其意义

THE PROPERTY OF THE YARLUNG ZANGBO RIVER AEROMAGNETIC ANOMALY ZONE AND ITS SIGNIFICANCE

航磁概查发现雅鲁藏布江航磁异常带东西相连长达 140 0km ,它由北、南 2条线性异常带构成 ,并认为它由沿雅鲁藏布江缝合带侵位的北、南 2条蛇绿岩带引起 ,且以北带为主 ,即雅鲁藏布江缝合带是由 2条蛇绿岩带组成 ,而不是过去地学界所认同的一条。航磁异常带实质上是雅鲁藏布江缝合带存在的客观反映 ,不仅为识别缝合带提供了比较典型的磁场模式 ,也为探讨新特提斯洋演化、可能存在 2次开合过程 ,提供了新的依据。

Aeromagnetic reconnaissance has revealed that the EW trending Yarlung Zangbo River aeromagnetic anomaly zone, 1400 km in length, is composed of two linear anomaly zones respectively in the north and in the south. It is also considered that it results from two ophiolite belts emplaced along the Yarlung Zangbo River suture zone, with the northern belt playing the dominant role. This is to say that the Yarlung Zangbo River suture zone is comprised of two ophiolite belts instead of one belt as considered by previous geologists. The aeromagnetic anomaly zone is in essence the objective reflection of the existence of the Yarlung Zangbo River suture zone. It not only provides relatively typical magnetic field model for the recognition of the suture zone, but also supplies new grounds to the probable existence of two opening closing processes in the evolution of the Neo Tethys Ocean.