俄罗斯白海地区太古代榴辉岩的金红石Zr温度计应用及其地质意义
发布时间：2019-06-14 02:46
【摘要】：金红石Zr温度计在研究高级变质岩的热演化过程中可以发挥重要的作用。而电子探针显微分析技术得益于其较小的分析束斑(直径1~2μm)和适中的轰击能量,通过合理的实验条件设定和仪器参数设置,是对薄片中金红石Zr含量进行原位分析的理想实验手段。本文中,我们对俄罗斯白海地区的太古代榴辉岩-退变榴辉岩中的金红石Zr含量进行了电子探针原位分析,并进行了金红石Zr温度计计算。结果表明,其中石榴子石包裹体类型(产状1)金红石的Zr含量比较稳定,主要集中在400×10~(-6)~500×10~(-6)范围,个别金红石颗粒中的Zr含量可以达到1000×10~(-6);而基质后成合晶中(产状2)金红石的Zr含量的波动范围则相对更广一些(200×10~(-6)~1000×10~(-6)),这可能与后期退变过程中的Zr重置和/或扩散有关。总体上,不同产状金红石的Zr温度计计算结果都给出了两个主要的温度区间:T1=700~750℃和T2=800~850℃。结合前人对白海榴辉岩变质温压条件的研究以及金红石Zr体系封闭温度的控制,我们认为金红石Zr温度计的计算结果区间T1更有可能代表的是榴辉岩的退变冷却温度,而温度区间T2则反映的是榴辉岩在抬升过程中受到高温麻粒岩相变质作用阶段的温度峰期条件。
[Abstract]:Rutile Zr thermometer can play an important role in the study of thermal evolution of advanced metamorphic rocks. The electron probe microanalysis technique benefits from its small analytical beam spot (diameter 1 ~ 2 渭 m) and moderate bombardment energy. Through reasonable experimental condition setting and instrument parameter setting, it is an ideal experimental method for in situ analysis of rutile Zr content in thin sheet. In this paper, the Zr content of rutile in Archean eclogite-degenerative eclogite in Baihai area of Russia is analyzed by electron probe in situ, and the rutile Zr thermometer is calculated. The results show that the Zr content of garnet inclusions (occurrence 1) rutile is relatively stable, mainly concentrated in the range of 400 脳 10 ~ (- 6) ~ 500 脳 10 ~ (- 6), and the Zr content in individual rutile particles can reach 1000 脳 10 ~ (- 6). However, the fluctuation range of Zr content in (occurrence 2) rutile is relatively wider (200 脳 10 ~ (- 6) ~ 1000 脳 10 ~ (- 6), which may be related to the replacement and / or diffusion of Zr in the process of late degeneration. Generally speaking, the calculation results of Zr thermometer for different occurrence rutile show two main temperature ranges: T1 鈮，
本文编号：2499036
[Abstract]:Rutile Zr thermometer can play an important role in the study of thermal evolution of advanced metamorphic rocks. The electron probe microanalysis technique benefits from its small analytical beam spot (diameter 1 ~ 2 渭 m) and moderate bombardment energy. Through reasonable experimental condition setting and instrument parameter setting, it is an ideal experimental method for in situ analysis of rutile Zr content in thin sheet. In this paper, the Zr content of rutile in Archean eclogite-degenerative eclogite in Baihai area of Russia is analyzed by electron probe in situ, and the rutile Zr thermometer is calculated. The results show that the Zr content of garnet inclusions (occurrence 1) rutile is relatively stable, mainly concentrated in the range of 400 脳 10 ~ (- 6) ~ 500 脳 10 ~ (- 6), and the Zr content in individual rutile particles can reach 1000 脳 10 ~ (- 6). However, the fluctuation range of Zr content in (occurrence 2) rutile is relatively wider (200 脳 10 ~ (- 6) ~ 1000 脳 10 ~ (- 6), which may be related to the replacement and / or diffusion of Zr in the process of late degeneration. Generally speaking, the calculation results of Zr thermometer for different occurrence rutile show two main temperature ranges: T1 鈮，
本文编号：2499036
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