西北地质2024，Vol.57Issue(6)：300-317,18.DOI:10.12401/j.nwg.2024072
西藏革吉县一带下白垩统则弄群火山岩地球化学特征及其地质意义
Geochemical Characteristics and Its Geological Significance of the Lower Cretaceous Zenong Group Volcanic Rocks of Geji Country,Tibet
摘要
Abstract
The Zenong Group is exposed widely in the Geji area of Tibet and is composed of Duo'ai Formation,Tuo'cheng Formation,and Langjiu Formation from bottom to top.This study carried petrography,geochem-istry,and chronology on the Zenong Group volcanic rocks.It was found that these volcanic rocks show obvious eruption unconformity and pulsed magmatism.According to the major element composition,the igneous rocks of the Duo'ai,and Tuo'cheng Formations belong to the alkaline-calc-alkaline series,while the rocks of the Langjiu Formation belong to the alkaline series.The trace elements,REE distribution,and tectonic discrimina-tion diagram show that the Duo'ai,and Tuocheng Formation formed in the island arc environment,while the Langjiu formed in the island arc environment near the active continental margin.The average weighted zircon U-Pb age of the hornblende andesite from the Duo'ai Formation is(111.2±2.1)Ma.Combination with previous work and this study,we suggest the Zenong Group volcanic rocks are the marginal continental arc of the south-ward subduction of the Slainajap ocean basin represented by the Shiquanhe-Yongzhu-Namco-Jiali ophiolitic melange belt.关键词
早白垩世/则弄群/冈底斯带/地球化学/火山岩Key words
early Cretaceous/Zenong Group/Gangdese belt/geochemistry/volcanic rocks分类
天文与地球科学引用本文复制引用
杨永锋,姜亚国,唐静,程犬..西藏革吉县一带下白垩统则弄群火山岩地球化学特征及其地质意义[J].西北地质,2024,57(6):300-317,18.基金项目
中国地质调查局项目"西藏革吉县尕尔穷地区4幅1:5万地质矿产调查"(12120113036800)资助. （12120113036800）
