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

结构性

• 批准号: 2099916
• 金额: --
• 依托单位: University of Oxford
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2018
• 资助国家: 英国
• 起止时间: 2018 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2099916
• 关键词: Structural; metamorphic; evolution; Zanskar; Himalaya

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.

喜马拉雅山是了解大陆碰撞中涉及的造山过程的最佳造口腰带之一，因为它是地球上最年轻，仍在进行，最裸露和最深入研究的山带。与阿尔卑斯山不同，喜马拉雅山相对简单，整个范围从西部到东方的不丹都非常相似。最深的地壳水平暴露在更大的喜马拉雅序列（GHS）中，其中变质归因于大陆碰撞后的地壳缩短和增厚，归因于区域巴罗夫型事件（例如Searle 2015）。一系列的绿色绿石 - kyanite-和sillimanite级的片麻岩，沿着最高峰暴露于Migmatite和Crustal Melt Leucogranites的中心核心。 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).西部Zanskar（西北印度）的Suru Valley横断面横穿了GHS的整个顶部 - 提供了区域变质的完整概况，几乎暴露了75-80％，与Himalaya中部和东部的森林覆盖率更高的喜马拉雅山脉无所不处）。该山谷部分提供了一个理想的田间样带，可以详细绘制结构并在至少20 km的结构曲线上通过喜马拉雅山的增厚外壳收集样品，以进行热压仪和地球学。