青藏高原东南缘玉龙斑岩铜矿床表生氧化富集过程及剥蚀保存程度研究

This proposed research involves detail field observations and intensive investigations on the mineralogy, petrology, geochemistry, Fe-Cu isotopes, and (U-Th)/He and 4He/3He geochronology to understand the chemical weathering, supergene enrichment, and erosion processes in the Yulong porphyry copper deposits, southeastern Tibet Plateau. Mineralogical and geochemical results are important to determine the spatial and temporal distribution of supergene minerals and geochemical zones in weathering profiles of the Yulong porphyry deposit. Iron-copper stable isotopes will be used to investigate the chemical weathering processes that are related to supergene enrichment of sulfide ores in oxidation zones. Apatite and iron-oxides (U-Th)/He and 4He/3He geochronology will provide the precisely and directly timing constraints on chemical weathering and exhumation history in southeastern Tibet Plateau, and serve as an excellent tool to quantify and evaluate the degree of the preservation and erosion of porphyry deposits. These new data, in combination with the previous weathering geochronological, tectonic, paleoclimatic, and geomorphological data in this district and the Yunnan-Guizhou Plateau, will be used to understand the regional controls on the supergene oxidation and enrichment. This is important to discuss and reconstruct the regional chemical weathering history, geomorphological evolution, and tectonic and paleoclimatic changes during the late Cenozoic in southeastern Tibet Plateau. This project has potential to provide the new method for studies on economic geology and earth's critical zone.

本项目拟以青藏高原东南缘玉龙斑岩铜矿床氧化带为研究对象，在详细的野外地质调查基础上，综合利用各种测试方法开展系统的矿物学、地球化学、金属稳定同位素地球化学、(U-Th)/He和3He/4He年代学研究：建立矿床氧化带精细的矿物和地球化学分带模型；弄清表生富集成矿过程及机制；精确限定矿床的化学风化历史；实现对斑岩矿床保存和剥蚀程度的定量计算和评价；为斑岩铜矿床氧化带中铜的综合利用和区域斑岩铜矿床的深部资源评价提供理论依据。综合其他学科研究成果并结合云贵高原和华南表生矿床的年龄，深入探讨玉龙矿床表生富集成矿过程中区域控制因素（晚新生代以来的区域大规模化学风化、古气候条件、地貌演化和高原隆升等）之间的联系和时空耦合。本项目的顺利实施将为矿床学和地球关键带的研究提供思路和方法上的借鉴。

本项目以玉龙斑岩铜矿床的氧化带为研究对象，在详细的野外地质观察基础上综合利用各种先进测试方法开展系统的矿物学、元素地球化学、Fe-H同位素和（U-Th）/He年代学研究，理解了该矿床氧化带次生富集作用过程和精确限定表生富集时间和剥蚀深度，为全面深入地理解青藏高原东缘地区新生代大规模化学风化和矿床次生富集提供重要的年代学资料。查明玉龙斑岩铜矿床氧化带的铁帽中伴生的铜达到工业品位，可以综合回收利用。通过元素-同位素地球化学的对比研究揭示矿床的次生富集过程，为区域深部原生矿体的找矿勘探提供理论指导。在本项目的研究基础上综合其他学科的研究成果并结合其他区域资料探讨区域晚新生代以来的大陆化学风化历史、地貌演化和古气候条件。