华北克拉通胶莱盆地马山地区粗面英安岩磷灰石U-Pb年代学及其地质意义

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中文摘要：五莲—青岛—烟台断裂是胶莱盆地重要的控盆断裂之一,控制了盆地的形成与演化,主要由牟平—即墨断裂和桃村断裂等多条NNE向断裂组成.前人研究表明,五莲—青岛—烟台断裂运动学转换历史先后可划分为晚侏罗世左旋走滑、早白垩世伸展断陷和晚白垩世—古新世右旋走滑三个阶段,但其新生代右旋走滑事件的持续时间仍存在争议.已有研究表明,区域上同尺度断裂走滑运动温度为550～650 ℃,显著高于磷灰石U-Pb体系封闭温度(350～550 ℃),因此磷灰石可能是记录五莲—青岛—烟台断裂右旋走滑的理想对象.本文选取胶莱盆地马山粗面英安岩中的磷灰石进行U-Pb年代学研究,拟约束五莲—青岛—烟台断裂的右旋走滑持续时间.磷灰石U-Pb年龄为(64.1±3.7)Ma,明显晚于早白垩世寄主粗面英安岩锆石U-Pb年龄(119.3±1.6)Ma,表明自早白垩世以来磷灰石至少经历了一次热事件导致其U-Pb同位素体系重置.早白垩世以来,由于印度板块和欧亚板块的碰撞,以及古太平洋板块由NWW向俯冲转变为NW向俯冲,导致了古新世胶莱盆地N—S向拉分和牟平—即墨断裂右旋走滑.因此,本文认为马山粗面英安岩磷灰石U-Pb年龄记录了五莲—青岛—烟台断裂右旋走滑热事件,表明其右旋走滑可能持续到古新世.

外文标题：Apatite U-Pb Geochronology of the Trachy Dacite in Mashan Area,Jiaolai Basin,North China Craton,and Its Geological Significance

外文摘要：The Wulian-Qingdao-Yantai fault(WQYF)is one of the most important basin-controlling faults in the Jiaolai basin,where the fault dominates the formation and evolution of the basin.This fault is mainly com-posed of abundant NNE faults,such as Muping-Jimo fault and Taocun fault.The WQYF experienced sinistral strike-slip movement in Late Jurassic,extensional rift in EarlyCretaceous,and dextral strike-slip movement during Late Cretaceous-Paleocene.However,the most key question that the duration of the Cenozoic dextral strike-slip movement still remains unclear.Previous studies suggested that temperature of strike-slip movement in this region is about 550-650 ℃,which is higher than the closure temperature,350-550 ℃,of the apatite U-Pb system.Therefore,in this case apatite can be an ideal candidate to investigate the dextral strike-slip of the WQYF.In this study,we conducted U-Pb dating of apatite from the Early Cretaceous trachy-dacite in the Mashan area and obtained the U-Pb age of 64.1±3.7 Ma.The measured magmatic age of apatite is different from the crystallization age of the Mashan trachy-dacite,indicating that at least there was one geothermal event which reset the apatite U-Pb isotope system in Early Paleocene.Since Early Cretaceous,the collision between the Indian plate and Eurasian plate,and the switch of subduction direction of the paleo-Pacific plate from NWW to NW result in a north-south extension of the Jiaolai basin and the dextral strike-slip of the Muping-Jimo fault.Therefore,we propose that the apatite U-Pb age of the Mashan trachy-dacite documented the dextral strike-slip thermal event of the WQYF,and indicates that the dextral strike-slip may continue until Paleocene.

外文关键词：

apatite U-Pb geochronologytrachy-daciteWulian-Qingdao-Yantai faultPaleocene dextral strike-slip

作者：

朱拓、何登洋、黄雅琪、邱昆峰

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作者单位：

中国地质大学(北京)地球科学与资源学院,北京 100083

中国地质大学地质过程与矿产资源国家重点实验室,北京 100083

中国地质大学(北京)深时数字地球前沿科学中心,北京 100083

关键词：

磷灰石U-Pb年代学粗面英安岩五莲—青岛—烟台断裂古新世右旋走滑

基金：

国家自然科学基金中国地质大学(北京)创新创业训练计划山东省深部金矿探测大数据应用开发工程实验室项目山东省深部金矿探测大数据应用开发工程实验室项目深时数字地球前沿科学中心项目高等学校学科创新引智计划(111计划)

项目编号：

42261134535S202211415007SDK202211SDK2022142652023001BP0719021

出版年：

2024

DOI：

10.19657/j.geoscience.1000-8527.2023.053

现代地质

中国地质大学（北京）

现代地质

CSTPCD北大核心

影响因子：1.2

ISSN：1000-8527

年,卷(期)：2024.38(1)

参考文献量69