柴北缘-南阿尔金俯冲碰撞期后地壳构造演化特征  

Characteristics of Crust Tectonic Evolution in Post-Collision from the Northern Qaidam Margin to the Southern Altun with Subduction

作　　者：于龙 提振海 郭金城 刘思林 YU Long;TI Zhenhai;GUO Jincheng;LIU Silin(Regional Geological Survey Institute of Hebei Province,Langfang 065000,China)

机构地区：[1]河北省区域地质调查院,河北廊坊065000

出　　处：《有色金属设计》2021年第3期106-108,共3页Nonferrous Metals Design

摘　　要：柴北缘—南阿尔金俯冲-碰撞杂岩带主要产于阿南次级构造岩浆岩带中,以杂岩带中石英二长岩、石英正长岩为研究对象,通过锆石U-Pb测年,显示为128.99±0.64 Ma,岩浆活动为燕山期。岩体分异指数DI=83.26→73.33,固结指数SI=2.96→13.56,岩浆分异程度较高;里特曼指数σ=6.09,属碱钙性系列;Rb/Sr=0.86→3.25,明显高于陆壳,岩浆物质来源具地壳属性。A/NKC=1.12~1.38,均值1.25,>1.1,显示“S”型花岗岩特征;根据岩石地球化学特征判别,该岩体可能形成于陆内造山晚期→非造山的过渡环境。From the northern Qaidam to the southern Altun with subduction,the collision complex rock zone mainly originated in Anan secondary structural magmatic zone.The result of quartz monzonite and quartz syenite in complex zone,which are as the objects of study,is 128.99±0.64 Ma tested by zircon U-Pb dating.And it indicates that the magmatic activity was in Yanshanian.The differentiation index of rock mass is DI=83.26→73.33,the solidification index is SI=2.96→13.56,the degree of magmatic differentiation is higher.The Rittmann index ofσ=6.09,which belongs to the alkali calcium series.Rb/Sr=0.86→3.25,the result is significantly higher than it in continental crust,and the source of igneous material is with the nature of crusts attribution.A/NKC=1.12~1.38,with an average of 1.25,>1.1,indicates the characteristics of“S”type granite.Differentiated by the characteristics of geochemistry,the rock mass may formed in the transition from intercontinental late-orogenic to anorogenic stage.

关 键 词：柴北缘-南阿尔金俯冲碰撞带 锆石U-PB测年 造山运动晚期 

分 类 号：P313.2[天文地球—固体地球物理学]