Structural & metamorphic evolution of the Zanskar Himalaya in the Suru Valley region(India), from crustal thickening through to melting and exhumation

喜马拉雅山脉是了解大陆碰撞造山过程的最佳造山带之一，因为它是地球上最年轻、仍在进行、暴露最好、研究最深入的山带。与阿尔卑斯山不同，喜马拉雅山脉相对简单，从西边的印度到东边的不丹，所有的地形都非常相似。最深的地壳暴露在大喜马拉雅序列(GHS)中，变质作用归因于大陆碰撞后地壳缩短和增厚的区域性巴罗型事件(例如Searle 2015)。沿着最高的山峰，暴露出一系列绿片岩、柱石-蓝晶石和硅线石级别的片麻岩，其中心核心是混合岩和地壳熔融的淡色花岗岩。变质等值线的测绘已将GHS的底部描述为沿主要中央冲断带的逆变变质带(Stephenson等人)。2000,2001)，板的顶部沿着Zanskar剪切区作为沿等轴线向上的直达区域(Honegger 1983；Searle等人)。1999年；Walker等人。1999、2001)。位于赞斯卡尔西部(印度西北部)的苏鲁河谷横断面贯穿了整个GHS的顶端，提供了区域变质作用的完整轮廓，几乎75%-80%裸露，不像喜马拉雅中部和东部的任何地方，那里的森林覆盖率要高得多)。这一山谷剖面提供了一个理想的野外断面，可以在其中详细绘制构造图，并通过喜马拉雅加厚的地壳在至少20公里的构造剖面上收集样品，用于温压测量和地质年代学。

The Himalaya is one of the best orogenic belts to understand orogenic processes involved in continental collisions because it is the youngest, still ongoing, best exposed and most intensively studied mountain belt on Earth. Unlike the Alps, the Himalaya is relatively simple with profiles across the range from India in the west to Bhutan in the east all remarkably similar. The deepest levels of the crust are exposed in the Greater Himalayan Sequence (GHS) where metamorphism is attributed to a regional Barrovian type event in response to crustal shortening and thickening following continental collision (e.g. Searle 2015). A series of greenschist, staurolite- kyanite- and sillimanite-grade gneisses with a central core of migmatite and crustal melt leucogranites are exposed along the highest peaks. Mapping of metamorphic isograds has characterised the base of the GHS as a zone of inverted metamorphism along the Main Central Thrust zone (Stephenson et al. 2000, 2001) and the top of the slab along the Zanskar Shear zone as a zone of right way up isograds (Honegger 1983; Searle et al. 1999; Walker et al. 1999, 2001). The Suru Valley transect in western Zanskar (NW India) cuts through the entire top section of the GHS - providing a complete profile of regional metamorphism and is almost 75-80% exposed, unlike everywhere in the central and eastern Himalaya where there is far more forest cover). This valley section provides an ideal field transect in which to map out in detail the structures and collect samples over at least 20 km structural profile through the thickened crust of the Himalaya for thermobarometry and geochronology.