摘要
黑龙江省木兰县双合屯地区出露一套酸性火山岩,前人根据岩性组合将其划分为下二叠统五道岭组,通过对其中的流纹岩进行锆石U-Pb测年,获得年龄为303±4 Ma,结合岩石地层特征,将其重新厘定为唐家屯组,形成时代为晚石炭世。该套火山岩属于准铝质-过铝质高钾钙碱性火山岩,具有A型花岗岩的地球化学特征。轻、重稀土元素分异明显,具有强烈的负Eu异常,富集大离子亲石元素Rb、K、U等,亏损高场强元素Nb、P、Ti等,表明岩浆来源于下地壳的部分熔融,可能为碰撞造山后伸展机制下的产物。结合区域地质构造背景,火山岩可能形成于额尔古纳-兴安地块与松嫩-张广才岭地块发生碰撞造山后的伸展环境,表明研究区在晚石炭世已由碰撞造山转向造山后伸展阶段。
A set of acidic volcanic rocks are exposed in Shuanghetun area,Mulan County,Heilongjiang Province.According to the lithologic association,they were divided into Early Permian Wudaoling Formation.In this work,the zircon U-Pb age of the rhyolite is 303±4 Ma.Based on the lithostratigraphic characteristics and zircon U-Pb dating data,they are redefined as Tangjiatun Formation and formed in Late Carboniferous.The quasi aluminous-peraluminous high-K calc alkaline volcanic rocks have geochemical characteristics of A-type granite.The obvious differentiation of LREE and HREE,with strong negative Eu anomaly,enrichment of large ion lithophile elements Rb,K,U,etc.,and depletion of high field strength elements Nb,P,Ti,etc.,indicate that the magma originated from partial melting of the lower crust,which may be the product of post collisional orogenic extension mechanism.Combined with the regional geological tectonic setting,it may have formed in the collision between Erguna-Xing'an block and Songnen-Zhangguangcailing block.The post orogenic extensional environment indicates that the study area changed from collisional orogeny to post orogenic extension in the Late Carboniferous.
作者
尹志刚
张志浩
周小刚
陈军典
姜然
张凯强
李萌萌
YIN Zhigang;ZHANG Zhihao;ZHOU Xiaogang;CHEN Jundian;JIANG Ran;ZHANG Kaiqiang;LI Mengmeng(College of Mining Engineering,Liaoning Technical University,Fuxin 123000,Liaoning,China;Ccteg Shenyang Research Institute,Fushun 113123,Liaoning,China;Geophysical Measuring Exploration Institute of Liaoning Province,Shenyang 110031,Liaoning,China)
出处
《地质通报》
CAS
CSCD
北大核心
2022年第12期2146-2157,共12页
Geological Bulletin of China
基金
黑龙江省地勘基金项目《黑龙江省1∶5万爱林林场幅、六合屯幅、凤山屯幅区域地质矿产调查》(编号:HLJKD2015-18)
辽宁工程技术大学学科创新团队资助项目(编号:LNTU20TD-14)。
关键词
唐家屯组
锆石U-PB年龄
火山岩
岩石地球化学特征
构造环境
黑龙江省
Tangjiatun Formation
zircon U-Pb age
volcanic rocks
geochemical characteristics
tectonic environment
Heilongjiang Province
作者简介
尹志刚(1962-),男,博士,教授,从事区域矿产资源的研究。E-mail:yzg63@163.com。
