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本文报道甜水海地块西段古元古界布伦阔勒岩群中片理化变流纹岩的单颗粒锆石LA-ICP-MS测年为(2481±14)Ma.这套流纹岩与玄武岩、玄武安山岩互层状产出,可能共同组成布伦阔勒岩群中的古元古界组分.其中玄武岩、玄武安山岩主体属于低铝拉斑玄武岩系列,流纹岩属于低铝钙碱性系列;岩石富集大离子亲石元素和轻稀土,亏损亲石元素P及高场强元素Nb,Ta和Ti等,铕异常不明显.εNd(t)值(3.14～4.88之间)及微量元素地球化学特征显示具有亏损地幔源区特征,并受到强烈的地壳混染.基性火山岩多元素原始地幔标准化分配曲线及Zr/Y-Zr图解表明其形成于大陆板内构造环境.综合喀喇昆仑区域地质资料,参考华北克拉通新太古代基性火山岩研究成果,推测布伦阔勒岩群火山岩与地幔岩浆底侵作用有关.
In this paper, the LA-ICP-MS single-grain zircon dating of the Middle Pleistocene Boulonglao Group in the western part of the Tianshuihai block is dated (2481 ± 14) Ma. The rhyolite With basalts and basalts andesite interbedded with each other and may form the Paleoproterozoic component in the Blenunkuolan group, in which basalt and basaltic andesite belong to the low-aluminum tholeiite series and rhyolites belong to the low-aluminum-calcium Alkaline series. The enrichment of lithopones and LREEs, loss of lithophile elements P and high-field-strength elements such as Nb, Ta and Ti show that the Eu anomalies are not obvious.εNd (t) (between 3.14 and 4.88) And trace element geochemical characteristics show that it has a depleted mantle source zone and is strongly crushed by the crust.Multi-element primitive mantle normalized distribution curves and Zr / Y-Zr patterns of basic volcanic rocks indicate that they formed in the continental intracontinental tectonic setting. Based on the research results of the Neoproterozoic basic volcanic rocks in the North China Craton, it is speculated that the volcanic rocks in the Blenongkuole Group are related to magma underplating.