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华北徐淮地区元古界地层中发育巨型辉绿岩(床)群,目前尚未见其侵入到年轻于寒武纪的地层.徐淮地区辉绿岩中分离出的锆石在阴极发光下具有3种不同的内部结构特征,皆属于岩浆成因.SHRIMP法U-Pb定年结果显示,尽管206Pb/238U表面年龄分布于2600~124Ma区间,但是在谐和图解上只定义了两个有意义的地质事件:(1)976±24~1038±26Ma,对应于辉绿岩浆结晶时代;(2)2523±52Ma,对应于混染的古老地壳物质形成时间.结果指示,在华北地块南缘存在中元古代末期至新元古代初期的基性岩浆活动,可能与Rodinia超大陆聚合过程中全球范围的Grenvill期大洋板块俯冲活动有关,这对于恢复华北板块在Rodinia超大陆重建中的位置具有重要意义.
The Jurassic diabase beds developed in the Proterozoic strata in the Xuhuai area of North China have not yet been intruded into younger Cambrian strata. The zircons isolated from the diabase in the Xuhuai area have cathodoluminescence The results of U-Pb dating of SHRIMP method show that although the surface ages of 206Pb / 238U range from 2600 to 124Ma, there are only two meaningful geology (1) 976 ± 24 ~ 1038 ± 26Ma, corresponding to the diabase age, and (2) 2523 ± 52Ma, corresponding to the time of formation of ancient crusts mixed with dye.The results indicate that there are The basic magmatic activity from the late Proterozoic to early Neoproterozoic may be related to the worldwide Grenvillian oceanic plate subduction during the polymerisation of the Rodinia continent, which is of great significance for the restoration of the North China plate in the Rodinia supercontinent reconstruction.