华北板块北缘东段柳河盆地早白垩世鹰嘴砬子组碎屑锆石U-Pb定年及其地质意义  

Detrital Zircon U⁃Pb Dating of Early Cretaceous Yingzuilazi Formation in Liuhe Basin,Northern Margin of North China Plate and Its Geological Significance

作　　者：梁云怡 许中杰[1,2] 周洋 程日辉 蓝艺植[1] 何奕言 Liang Yunyi;Xu Zhongjie;Zhou Yang;Cheng Rihui;Lan Yizhi;He Yiyan(College of Earth Sciences,Jilin University,Changchun 130061,China;Key Laboratory of Mineral Resources Evaluation in Northeast Asia,Ministry of Natural Resources,Changchun 130061,China)

机构地区：[1]吉林大学地球科学学院,吉林长春130061 [2]自然资源部东北亚矿产资源评价重点实验室,吉林长春130061

出　　处：《地球科学》2024年第3期907-921,共15页Earth Science

基　　金：吉林省教育厅科研项目(No.JJKH20231139KJ);国家自然科学基金面上项目(No.41872101);国家自然科学基金重大项目(No.41790453)。

摘　　要：华北板块北缘在晚中生代受到古太平洋板块西向俯冲作用的影响,发育强烈的构造变形及大规模的岩浆活动.研究区柳河盆地地处华北板块北缘,对其开展研究能够为约束华北板块北缘晚中生代构造演化阶段提供沉积方面的证据.依据对盆地早白垩世鹰嘴砬子组样品碎屑组分、岩性序列、沉积相演化特征的研究,结合碎屑锆石U-Pb年代学判断,盆地样品矿物组成具有石英含量较低,岩屑和长石含量较高的特点,显示沉积物物源主要来自岩浆弧物源区.两组碎屑锆石U-Pb年龄组成相似,以晚中生代为主,古元古代为辅.L1-B178样品(岩心)碎屑锆石存在约127Ma的主峰和约2553Ma的次峰;P303-B3样品(剖面)存在约126Ma的主峰和约2545Ma的次峰,中生代沉积物物源可能来自盆地东北侧丰富的岩浆岩.早白垩世鹰嘴砬子组最年轻碎屑锆石颗粒的U-Pb年龄限定岩层的最大沉积年龄为(125±4)Ma,介于早白垩世巴雷姆阶与阿普特阶,与层内流纹岩样品(124.3±0.7)Ma的锆石加权平均年龄吻合.通过对柳河盆地样品矿物组成特点、沉积相演化和碎屑锆石U-Pb年代学特征综合判断,盆地在(125±4)Ma已接收到古太平板块俯冲作用带来的物源.The Late Mesozoic westward subduction of the Paleo-Pacific Plate impacted the northern border of the North China Plate,causing significant tectonic deformation and large-scale magmatic activity.The Liuhe basin is situated on the North China Plate’s northern border.The study of the Liuhe basin can be used to constrain the Late Mesozoic tectonic development of the North China Plate’s northern border.The mineral composition of the basin samples is characterized by low quartz content and high rock debris and feldspar content,indicating that the sediment provenance primarily comes from the magmatic arc provenance area,according to mineral composition characteristics,sedimentary facies evolution,and detrital zircon U-Pb chronological characteristics of the basin samples.The age composition of detrital zircons from the two groups of samples from the Early Cretaceous Yingzuilazi Formation in the research area is similar,mainly in Late Mesozoic,supplemented by Paleoproterozoic.The major peak of the detrital zircons in L1-B178 samples is around 127 Ma,and the secondary peak is around 2553 Ma.The Mesozoic sediment provenance may come from the igneous rocks of the basin,as the P303-B3 sample contains a major peak of around 126 Ma and a secondary peak of about 2545 Ma.The maximum sedimentary age of the strata is(125±4)Ma,which is between the Early Cretaceous Barremian and Aptian stages and is compatible with the weighted average zircon age of(124.3±0.7)Ma for the rhyolite samples.The Liuhe basin,located on the northern boundary of the North China Plate,obtained its provenance from the ancient Pacific Plate subduction about(125±4)Ma,according to mineral composition features,sedimentary facies history,and detrital zircon U-Pb dating characteristics of basin samples.

关 键 词：柳河盆地 早白垩世 鹰嘴砬子组 锆石U-PB定年 物源 地质年代学 岩石学 

分 类 号：P583[天文地球—岩石学]