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本文对辽东地区什司县变质基性岩墙群中的斜长角闪岩进行了锆石LA-ICP-MS年代学研究。锆石呈现不规则状、椭圆状、港湾状形态,显示遭受后期构造热事件的影响;CL图像显示扇形分带、杉叶形分带及无分带的特征,且Th/U值较低,为0.03~0.14,为典型的变质锆石;20粒锆石给出了1874±31 Ma的207Pb/206Pb加权平均年龄。1874±31 Ma的变质年龄代表华北板块东部辽吉古元古裂谷带闭合时的区域变质事件的时代。
In this paper, zircon LA-ICP-MS chronology was studied on the amphibolite from the metamorphic basement dikes in the Shishan area, eastern Liaodong area. The zircons showed irregular, oval and bay-like morphology, showing the influence of post-tectonic thermal events. The CL images showed fan-shaped zoning, cedar-shaped zonation and no banding with lower Th / U values, From 0.03 to 0.14 for typical metamorphic zircons and 20 zircons for a 207Pb / 206Pb weighted average age of 1874 ± 31 Ma. The metamorphic age of 1874 ± 31 Ma represents the era of regional metamorphic events during the closing of the Paleoproterozoic rift zone in the eastern part of North China Plate.