河南嵩县车村地区合峪花岗岩体成岩序列及其地球动力学意义  

Diagenetic Sequence of Granites of the Heyu Pluton in the Checun Area in Song County,Henan Province,China and Its Geodynamic Implication

作　　者：董文超[1] 庞绪成[1] 杨东潮[2] 刘畅 DONG Wen-chao;PANG Xu-cheng;YANG Dong-chao;LIU Chang(Institute of Resources and Environment,Henan Polytechnic University,Jiaozuo Henan 454000,China;No.2 Institute of Geological&Mineral Resources Survey of Henan,Zhengzhou 450000,China)

机构地区：[1]河南理工大学资源环境学院,河南焦作454000 [2]河南省地质矿产勘查开发局第二地质矿产调查院,郑州450000

出　　处：《矿物岩石地球化学通报》2022年第2期388-396,共9页Bulletin of Mineralogy, Petrology and Geochemistry

基　　金：中国地质调查局地质调查项目(12120114035401)。

摘　　要：合峪花岗岩体位于华北地台南缘,为豫西地区规模最大的燕山期花岗岩基。通过对该岩体花岗岩类进行的锆石U-Pb同位素年代学研究,厘定了合峪花岗岩体的成岩序列,为研究华北地台中生代构造演化提供依据。结果显示,合峪花岗岩体中正长岩脉的年龄为(144.7±3.2)Ma,细晶岩脉的年龄为(130.7±2.5)~(128.1±2.9)Ma,二长花岗岩脉的年龄为(126.3±2.1)Ma。研究认为,合峪花岗岩体共经历了4次岩浆侵入事件:第一阶段(144.7 Ma之前)主要为斑状黑云母二长花岗岩;第二阶段(138.0~134.5 Ma)主要为似斑状黑云母二长花岗岩;第三阶段(130.7~128.1Ma)主要为黑云钾长花岗岩;第四阶段岩浆侵位时间为126.3~123 Ma,以二长花岗岩岩脉为主。结合区内大地构造演化背景,可以认为合峪花岗岩记录了中生代华北地台南缘所经历的板块碰撞造山(144 Ma之前)→构造体制的转换(144 Ma左右)→板块的伸展、减薄(144~120 Ma)的全部构造演化过程的信息。The Heyu granite pluton is located in the southern margin of the North China platform.It is the largest Yanshanian granite batholith in the western Henan.In this paper,the zircon U-Pb chronology has been used to study the diagenetic sequence of various granites in the Heyu pluton in order to provide a basis for studying the Mesozoic tectonic evolution of the North China platform.The zircon U-Pb dating results show that formation ages of the syenite,aplitic granite,and monzongranite dykes in the Heyu pluton are(144.7±3.2),(128.1±2.9)to(130.7±2.5)Ma,and(126.3±2.1)Ma,respectively.Based on the petrological characteristics,it is believed that granitic rocks in the Heyu pluton were mainly formed in following 4 magma emplacement events.The first one occurred before 144.7 Ma by magma of porphyritic biotite monzongranite;The second one occurred from 138.0 Ma to 134.5 Ma by magma of irregularly porphyritic biotite monzongranite;The third one occurred from 130.7 Ma to 128.1 Ma by magma of biotite moyite;The fourth one occurred from 126.3 to 123 Ma by magma of monzongranite dykes.Combined with the geotectonic setting of the area,it is believed that rocks of the Heyu granite pluton had completely recorded information of the Yanshanian tectonic evolution process varying from plate collisional orogeny(before 144 Ma)to tectonic system transformation(around 144 Ma)then to plate extension and thinning(144-120 Ma)of the southern margin of the North China platform.

关 键 词：锆石U-PB定年 合峪花岗岩体 华北地台 中生代 

分 类 号：P597[天文地球—地球化学]