摘要
锆石广泛存在于固体地球的岩浆岩、变质岩和沉积岩中,因其具有耐高温及风化等稳定特性,从而可以记录岩石的结晶年龄、温度、氧逸度以及地球化学特征等信息,对岩石成因及深部过程研究具有重要意义。该研究对锆石在岩石成因研究中的进展做了分析发现,锆石含有大量放射性同位素及其稳定的衰变产物,其中^(238)U衰变为^(206)Pb,^(235)U衰变为^(207)Pb,^(232)Th衰变为^(208)Pb,因此U-Pb同位素衰变体系是示踪锆石寄主岩石结晶年龄的最优途径。锆石中,^(176)Lu可衰变为^(176)Hf,可以利用Lu-Hf放射性同位素体系很好地示踪锆石寄主岩石的岩浆源区。同时,锆石的O稳定同位素很好地记录了其源区O同位素特征,可用来示踪寄主岩石源区物质的壳幔属性特征。新开发的锆石Zr稳定同位素为揭示锆石寄主岩石的岩浆过程提供了新的视角(比如示踪酸性岩浆分异及岩浆演化的动力学过程)。利用锆石晶格中的微量元素建立的温度计和氧逸度计等可定量约束锆石记录的结晶温度和氧逸度等物理化学参数。依托于锆石的同位素体系、温度计和氧逸度计等各种方法,在岩石成因研究中发挥了重要科学价值,锆石是地学研究者广泛使用的科学研究载体,为解决地学及相关行星学问题将持续发挥作用。
Zircon is ubiquitously distributed in magmatic,metamorphic,and sedimentary rocks of the solid Earth.Owing to its exceptional stability under high temperatures and weathering conditions,zircon preserves critical information about the crystallization age,temperature,oxygen fugacity,and geochemical characteristics of its host rocks,making it a vital tool for studying petrogenesis and deep Earth processes.This paper provides a preliminary analysis of recent advances in zircon applications for petrogenetic research.Zircon contains abundant radioactive isotopes and their stable decay products.Notably,the decay of^(238)U to^(206)Pb,^(235)U to^(207)Pb,and^(232)Th to^(208)Pb enables the U-Pb isotopic decay system to serve as the most reliable method for determining the crystallization age of zircon-bearing rocks.Additionally,the decay of^(176)Lu to^(176)Hf in zircon allows the Lu-Hf isotopic system to effectively trace the magma source regions of host rocks.Meanwhile,the oxygen stable isotopes(δ18 O)in zircon faithfully record the oxygen isotopic signature of its source,providing insights into the crustal or mantle affinity of the parental material.The recently developed zircon Zr stable isotope system offers novel perspectives for understanding magmatic processes,such as tracking felsic magma differentiation and dynamic magma evolution.Furthermore,trace elements(e.g.,Ti,Ce,Eu)within the zircon lattice can be utilized to construct thermometers and oxygen fugacity sensors,quantitatively constraining physicochemical parameters like crystallization temperature and redox conditions.Methods based on zircon isotopic systems(U-Pb,Lu-Hf,O,Zr),thermometers,and oxygen fugacity meters have played a significant scientific role in petrogenetic studies.As a robust scientific medium,zircon remains indispensable for geoscientists and will continue to address fundamental questions in Earth and planetary sciences,from crustal evolution to magmatic dynamics.
作者
朱韧之
王榕漳
张宇
ZHU Renzhi;WANG Rongzhang;ZHANG Yu(State Key Laboratory of Continental Evolution and Early Life/Department of Geology,Northwest University,Xi’an 710069,China)
出处
《西北大学学报(自然科学版)》
北大核心
2025年第3期539-552,共14页
Journal of Northwest University(Natural Science Edition)
基金
国家自然科学基金(42472085,42172056)。
