西昆仑-喀喇昆仑隆升剥露过程与机制研究

West Kunlun-Karakorum, located in the northwest of Tibet Plateau, which is also the crucial tectonic area to reveal the history and mechanism of the Tibet Plateau growth. Geological formation, tectonic evolution, magma active epoch, geological setting of ore-forming and some other basic questions in this area had been understood after several years’ work. But the research of which reasons caused the spatial-temporal differences of volcanism, mechanism/process/results of the volcano eruption in Cenozoic, uplift/exhumation history and mechanism during Mesozoic and Cenozoic all were weak, those scientific questions restrict the understanding of the uplift of Tibet Plateau directly. This application plan to choose the magmatic rocks (including intrusive rocks and volcanic rocks) as the main research objects, combined with sedimentary and structural features in the study area to quantify the process of uplift/exhumation since Mesozoic by thermochronology and numerical modeling. Then we analyze the reasons and results of volcanism, patterns/pathway/power of magma migration through volcanology, petrology and some other research methods. After that, we analyze the deep mechanism of uplift/exhumation based on the understanding of physical and chemical process of magma evolution. Ultimately, we will propose a dynamic model of the uplift/exhumation of West Kunlun-Karakorum which include quantified history and mechanism.

西昆仑-喀喇昆仑位于青藏高原西北部，是揭示青藏高原生长过程和生长机制的关键构造部位。经过多年研究，该地区地质组成、构造演化、岩浆活动期次、成矿地质条件等问题已基本得到回答，但对于火山活动明显的时空差异性及新生代火山喷发机理、过程、影响的认识仍然不足，对中、新生代隆升剥露过程及机制的研究仍较薄弱，这直接制约了对青藏高原隆升问题的理解。本项目拟以西昆仑-喀喇昆仑地区中、新生代岩浆岩为主要研究对象，结合山前及山间盆地沉积特征和构造发育情况，采取热年代学、数值模拟等方法对中生代以来的隆升剥露历史予以定量化约束，利用火山学、岩石学等方法对岩浆迁移的方式、途径、动力等问题进行探讨，在此基础上通过岩浆演化的物理化学过程分析地表隆升的深部机制，进而提出西昆仑-喀喇昆仑隆升剥露的动力学模型。

青藏高原的生长过程和机制是地球科学领域多年来持续受到关注的焦点问题。西昆仑-喀喇昆仑位于青藏高原西北部，是揭示青藏高原生长过程和生长机制的关键构造部位。项目通过系统的地貌学、岩石学、地球化学及热年代学研究，揭示了西昆仑-喀喇昆仑的地形地貌特征，提出现今的地形地貌是~50 Ma尤其是晚中新世以来强烈改造的结果，浅表的隆升剥露受控于构造及气候双重因素。西昆仑-喀喇昆仑地区的岩浆作用具有规律性的变化特征，记录了深部动力学机制的变迁过程。西昆仑-喀喇昆仑地壳的增厚与地表隆升不仅是新生代以来印亚碰撞的结果，更有中生代至早新生代期间岩浆作用引起地壳垂向增生的贡献，整体而言，喀喇昆仑地区的地壳厚度更多的是岩浆作用引起的地壳垂向增生，而西昆仑地区巨厚的地壳则主要是印亚碰撞以来构造增厚引起的。