雅鲁藏布江缝合带的深部结构和构造——INDEPTH—2的初步结果

DOUBIE INTRACONTINENTAL UNDERTHRUSTING STRUCTURE OFTHE YARLUNG ZANGBO SUTURE——A Preliminary Discussion of INDEPTH-Ⅱ

印度大陆和欧亚大陆的拉萨地块于第三纪初会聚、碰撞后形成雅鲁藏布江碰撞缝合带(YZS),缝合带的位置是以现存的日喀则弧前盆地和蛇绿岩套为标志。 这一缝合带的深部结构是什么样?碰撞后发生的陆内俯冲带位于什么地方?

The paper suggests a 'Double Intracontinental Underthrusting structure' model within the Yarlung Zangbp Suture along with a deep architecture that there is a separate partial melting mass occurred on both southern and northern sides of the suture, respectively , with their genetic origins being different one from another. The faults within the YZS have limited extensions to the depth. Here altogether four mechanisms of crustal thickening are suggested; Da thickening due to crust-scale underthrusting ; 2)a thickening within the upper crust due to underthrusting and back-thrusting ; 3)a thickening within the lower crust due to bottom uplifting from below and compression; 4)a thickening due to an upward intrusion of deep molten mass. It is, therefor, inferred that there is a likelihood of existence of two big extension faults, resulting in great elevation and subsidence.