首页|地幔榴辉岩包体的同位素定年方法研究进展

地幔榴辉岩包体的同位素定年方法研究进展

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地幔榴辉岩包体是寄主岩浆从地球深部地幔携带到地表的俯冲洋壳碎片,作为一种高压变质岩,它可能记录着有关大洋地壳原岩、板块俯冲以及后期交代变质过程等重要信息,因此其年龄也显得格外重要.通过统计全球超过500个已发表的地幔榴辉岩包体的年龄结果,对比几种常用的地幔榴辉岩包体同位素定年方法,讨论了不同方法的优缺点及适用情况.结果表明:金红石U-Pb和全岩Rb-Sr、Sm-Nd、Lu-Hf全岩等时线法一般给出的是寄主岩浆的年龄或地幔交代的时间,而榴辉岩中的硫化物Re-Os等时线年龄,锆石U-Pb上交点年龄,Sm-Nd、Lu-Hf石榴子石-单斜辉石双矿物等时线年龄以及锆石Hf亏损地幔模式年龄对于其原岩年龄及板块俯冲时代有较为可观的应用前景;地幔榴辉岩包体最古老年龄的峰值分布在3.1～2.8Ga,与Kaapvaal和西伯利亚克拉通构造拼合的时间吻合,可能代表着全球地幔榴辉岩包体的最早形成时代,也预示着板块构造可能于中太古代开启.
Review on Isotopic Dating Methods of Mantle Eclogite Xenoliths
Mantle eclogite xenoliths are subducted oceanic crust fragments carried by host magma from the deep mantle.As a high-pressure metamorphic rock,mantle eclogite xenoliths may record important information about ancient oceanic crust,plate subduction and later metasomatic metamorphism.Therefore,their ages are particularly important.More than 500 published age results of mantle eclogite xenoliths in the world were selected,and several commonly used isotopic dating methods of mantle eclogite xenoliths were compared,and the advantages and disadvantages of different methods and their applicability were discussed.The results show that the rutile U-Pb,and Rb-Sr,Sm-Nd and Lu-Hf whole-rock isochron methods generally date the age of host magma or the time of mantle metasomatism;the sulfide Re-Os isochron age,zircon U-Pb age and the garnet-clinopyroxene isochron ages of Sm-Nd and Lu-Hf,as well as zircon Hf depleted-mantle model age,have a considerable prospect for the ages of protoliths and tectonic subduction;moreover,the peak of the oldest ages for mantle eclogite xenoliths mostly ranges from 3.1 Ga to 2.8 Ga,which coincides with the age of tectonic amalgamation of Kaapvaal and Siberian cratons.Therefore,it may represent the earliest formation age of mantle eclogite xenoliths,and also indicate that plate tectonics may have started in Mesoarchean.

plate tectonicsmantel eclogite xenolithradioisotopedating methodzircon U-Pb ageSm-Nd isochron ageLu-Hf isochron agesulfide Re-Os isochron age

蒋蕾茵、孙晶、黄铖铮、吴琪

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中国石油大学(北京)地球科学学院,北京 102249

中国石油大学(北京)油气资源与探测国家重点实验室,北京 102249

自然资源部信息中心,北京 100812

板块构造 地幔榴辉岩包体 放射性同位素 定年方法 锆石U-Pb年龄 Sm-Nd等时线年龄 Lu-Hf等时线年龄 硫化物Re-Os等时线年龄

国家自然科学基金自然资源部部门预算项目

42072060121101000000180044

2024

10.19814/j.jese.2023.09010

地球科学与环境学报
长安大学

地球科学与环境学报

CSTPCD北大核心
影响因子：1.422
ISSN：1672-6561
年,卷(期)：2024.46(1)
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