西藏班戈－那曲地区晚白垩世时期的深部过程与地表抬升

可靠约束碰撞造山带深部过程发生的时限，是研究造山带大陆地壳演化和地表抬升过程的关键。在充分分析拉萨－羌塘碰撞带晚白垩世岩浆岩和地表抬升研究现状的基础上，本项目拟以拉萨－羌塘碰撞带南侧班戈－那曲地区以往研究程度极低的、具有独特地球化学特征的不同时期晚白垩世岩浆岩为对象开展系统的岩石学、年代学、元素和同位素地球化学研究，以拉萨－羌塘碰撞带南北两侧侵位于100 Ma以前的代表性岩体为对象开展锆石和磷灰石(U-Th)/He低温热年代学测试，分析晚白垩世岩浆活动的岩浆起源和岩石成因，论证其深部过程，查明代表性岩体的冷却剥露历史，建立拉萨－羌塘碰撞带晚白垩世深部过程与地表抬升之间的耦合关系。本项目不但可为拉萨－羌塘碰撞带晚白垩世时期的深部过程提供关键约束，而且还可为青藏高原是否在晚白垩世发生了隆升提供深部与浅部相结合的可靠证据。

Constraining effectively the timing of deep process operating at collision orogenic belt is crucial for better understanding the crustal evolution and surface uplift in orogenic belt. Current situation-based intensive analysis for the Late Cretaceous magmatic rocks and surface uplift, this project is planning to conduct systematical petrological, geochronological, elemental, and isotopic geochemical studies on the Late Cretaceous magmatic rocks with distinct geochemical signatures from Baingoin and Nagqu located south side of the Lhasa-Qiangtang collision zone, and perform low-temperature thermochronology analysis (including zircon and apatite U-Th/He dating) for representative plutons emplaced by 100 Ma from both sides of the Lhasa-Qiangtang collision zone. This project will explore the origin and petrogenesis of the Late Cretaceous magmatic rocks, trace the deep process involved in the generation of the magmatic rocks, and reconstruct the cooling and exhumation histories of representative plutons emplaced by 100 Ma, with scientific objective for unraveling the coupling relationship between deep process and surface uplift occurred in the Lhasa-Qiangtang collision zone during the Late Cretaceous. This project is expected to provide not only crucial constraints on the deep process operating at the Lhasa-Qiangtang collision zone during the Late Cretaceous, but also solid lines of evidence for the uplift of the Tibetan Plateau at this time in terms of interplay of deep and surface processes.