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东喜马拉雅缺口位于西藏东南部米林地区 ,平均海拔高度只有 450 0 m,远远低于喜马拉雅山其它地段。我们的研究揭示 ,它的形成是由一条规模很大的 ,称之为米林韧性正断层的活动造成的。断层带的宽度至少有 2 0 km,大体倾向西 ,主要由眼球状糜棱岩组成 ,岩石中的拉伸线理以及眼球旋转的方式表明位于其东西两侧的高喜马拉雅深变质岩系和特提斯喜马拉雅中浅变质岩系之间发生过大规模的拆离运动 ,导致了东喜马拉雅构造结的最高峰——南迦巴瓦 (7756m)的早期抬升以及特提斯喜马拉雅的重力垮塌。该断裂的南西端和藏南拆离系 (STDS)相交 ,因此 ,它很可能是藏南拆离系的东翼断裂 ,同样形成于中新世。拆离构造的发生表明喜马拉雅山在中新世发生南北向构造缩短的同时还伴随着近东西向的拉伸。米林断裂的北东端和派区断裂相接。后者在中新世呈左旋剪切 ,构成东喜马拉雅挤入构造的西边界。米林断裂和上述两个断裂的衔接关系表明该断裂是一个协调高喜马拉雅和特提斯喜马拉雅之间斜向拆离运动的转换断层。
The East Himalayan gap is located in the Milling area in southeastern Tibet with an average altitude of 450 0 m, far below the rest of the Himalayas. Our research reveals that its formation was caused by a large scale activity called the Millington ductile normal fault. The fault zone has a width of at least 20 km and is predominantly westward and consists mainly of mylonitic mylonites. The stretching and rock rotation in the rock indicates that the high-Himalayan deep metamorphic rocks on both the east and west sides and the Large scale detachment occurred between the Middle and Lower Metamorphic rocks in the Tethys Himalayas, leading to the highest elevation of the East Himalayan structural knot - the early uplift of Namjagbarwa (7756m) and the gravity collapse of the Tethys Himalayas. The southern tip of the fault intersects with the South Tibetan Detachment (STDS), so it is likely to be the eastern wing of the southern Tibet detachment and also formed in the Miocene. The occurrence of the detachment structure indicates that the Himalayas were shortened in the north-south direction during the Miocene with a nearly east-west extension. The northeast end of the Milling fault is connected with the fault zone. The latter was left-handedly cleaved in the Miocene, forming the western boundary of the East Himalayan structure. The convergence between the Milling fault and the above two faults indicates that the fault is a transition fault that coordinates the oblique detachment movement between the Himalayan and Tethyan Himalayas.