应李鹏飞研究员邀请，澳大利亚麦考瑞大学 Nathan Daczko讲授将于7月4日（周五）访问我所并在综合楼701会议室做学术报告，欢迎大家参加并积极讨论！

        报告题目：Zircon Coupled Dissolution–Precipitation Replacement: Nature & Experiments - Understanding Melt–Zircon Reaction and Its Implications for Basement Geochronology

        报 告 人：Nathan Daczk教授（麦考瑞大学）
          报告时间：7月4日（周五）上午10:00
          报告地点：综合楼701会议室    

     报告人简介：

        Professor Nathan Daczko (Macquarie University, Australia) is a metamorphic petrologist whose work integrates field and laboratory approaches to investigate metamorphic processes across scales—from microstructures to orogenic evolution. His research constrains the geodynamic and metasomatic processes that shape metamorphic rock histories and contributes to broader understanding of crustal evolution and tectonics. He has authored more than 100 peer-reviewed papers in leading journals such as Geology, EPSL, and  Journal of Metamorphic Geology (23 papers).He has received Stillwell Award (2020)and Powell Medal (2003) from the Geological Society of Australia.

 Abstract： 

Zircon geochronology offers vital insights into the timing and duration of high-temperature geological processes. However, some datasets show complex age distributions without distinct populations, often interpreted as resulting from variable radiogenic Pb loss or prolonged geological events. We conducted melt–zircon reaction experiments to investigate this further. Short-term exposure (6 hours to 3.5 days) of Mud Tank zircon fragments to natural melts caused microstructural and chemical alterations, with U–Pb ages disturbed and smeared over a range of ~764 to 647 Ma. Complementary studies from the Pembroke Granulite (New Zealand), Entia Dome (Central Australia), and Mawson Charnockite orthogneiss (East Antarctica) support these experimental findings. In naturally modified grains, melt-induced dissolution features, microporosity, and disrupted zoning correspond with trace element redistribution and disturbed U–Pb ages. These results highlight that zircon affected by coupled dissolution–precipitation replacement in magmatic and high-grade metamorphic rocks may not reliably preserve their original geochronological signals. This underscores the importance of detailed microstructural analysis for accurate interpretation of zircon age data.