摘要
小兴安岭美丰组火山岩广泛出露,对于研究美丰组火山岩岩石地球化学特征具有重要意义。笔者等通过对小兴安岭孙吴地区美丰组火山岩进行岩相学、锆石U-Pb年代学、全岩主—微量元素地球化学研究,探讨了其形成时代、岩石成因及其构造环境。锆石U-Pb结果表明,美丰组形成于早白垩世(105.2±0.5 Ma)。美丰组以基性火山岩为主,属高钾钙碱性系列;富集Rb、Ba、Th、U、La、Ce,相对亏损Nb、Ti等元素;δEu=0.71~0.94,轻稀土略富集。轻、重稀土分馏不明显。岩石地球化学特征表明,美丰组火山岩的原始岩浆起源于地幔,受地壳物质的混染改造。研究区美丰组火山岩形成于伸展环境,是古太平洋板块向亚洲大陆板块俯冲背景下的产物。
The volcanic rocks of Meifeng formation in Lesser khingan mountains are widely exposed,which is of great significance to study the geochemical characteristics of the volcanic rocks of Meifeng formation.This paper makes research on the petrographic,geochemical and chronological characteristics of the volcanic rocks of Meifeng formation in Sunwu area of Lesser khingan mountains,and discusses their formation age,petrogenesis and tectonic environment.Zircon U-Pb results show that the Meifeng formation was formed in the early Cretaceous(105.2±0.5 Ma).Meifeng formation is dominated by basic volcanic rocks,belonging to high potassium calc alkaline series.Enrichment of Rb,Ba,th,u,La,CE,relative loss of Nb,Ti and other elements;δEu=0.71~0.94,light rare earth is slightly enriched,heavy rare earth fractionation is not obvious.The above rock geochemical characteristics show that the original magma of the volcanic rocks of Meifeng formation originated from the mantle and was modified by the contamination of crustal materials.The volcanic rocks of Meifeng formation in the study area were formed in an extensional environment and were the product of the ancient Pacific plate’s subduction to the Asian continental plate.
作者
岳洪举
陆胜
于庆洋
翟艳超
张庆
YUE Hongju;LU Sheng;YU Qingyang;ZHAI Yanchao;ZHANG Qing(The Sixth Geological Prospecting Institute of Heilongjiang Province,Jiamusi,Heilongjiang,154002;The Fifth Geological Prospecting Institute of Heilongjiang Province,Harbin,150090)
出处
《地质论评》
CAS
CSCD
北大核心
2022年第6期2138-2146,共9页
Geological Review
基金
黑龙江省财政项目“黑龙江省1:5万疙疸敏顶、东茅兰河、新鄂民族乡、幸福林场幅区域地质矿产调查报告”(项目编号:HLJKD2015-11)成果。
作者简介
岳洪举,男,1987年生,本科,高级工程师,主要从事矿产资源勘查与评价工作,Emai:yuehongju@139.com;通讯作者:陆胜,男,1985年生,博士,工程师,主要从事岩石地球化学方面的研究工作,Email:396688457@qq.com。
