地质通报2023，Vol.42Issue(12)：2096-2108,13.DOI:10.12097/j.issn.1671-2552.2023.12.006
内蒙古雅干地区晚石炭世白山组火山岩LA-ICP-MS锆石U-Pb年龄及其构造环境
Zircon LA-ICP-MS U-Pb dating and tectonic setting of volcanic rocks from Baishan Formation in Late Carboniferous in Yagan area,Inner Mongolia
摘要
Abstract
Arc igneous rocks play the key role in tracing the magmatic process in the subduction zone.The Baishan Formation in the Yagan region is mainly composed of rhyolite,dacite,rhyolitic crystal tuff and dacitic crystal tuff.LA-ICP-MS U-Pb dating were conducted on zircons from the rhyolites,and the weighted mean ages are 309±1 Ma,308±1 Ma and 300±2 Ma,suggesting that the volcanic rocks was erupted during Late Carboniferous.The rhyolites have high SiO2(70.98％～75.45％)and Na2O(2.90％～5.23％)contents,and all samples are relatively rich in Na and have the average Na2O/K2O ratios of 1.57.The volcanic rocks are relatively enriched in large ion lithophile elements,such as Rb,K and U,and depleted in high field strength elements,such as Nb,P and Ti.They show right-leaning chondrite-normalized patterns,which means enrichment in LREE and depletion in HREE,with(La/Yb)N ratios of 3.24～9.99,(La/Sm)N ratios of4.47～8.31 and significant Eu negative anomalies(average value of 3Eu is 0.22).The geochemical characteristics of Baishan Formation volcanic rocks are similar to arc-related magmatism.These rocks are likely formed in a continental margin arc setting,and products of the subduction of the paleo-Asian ocean during Late Carboniferous.关键词
白山组火山岩/流纹岩/LA-ICP-MS锆石U-Pb年龄/晚石炭世/陆缘弧环境/地质调查工程/内蒙古Key words
volcanic rocks of Baishan Formation/rhyolite/zircon LA-ICP-MS U-Pb ages/Late Carboniferous/continental arc/geological survey engineering/Inner Mongolia分类
天文与地球科学引用本文复制引用
雷聪聪,薄海军,丁海生,王文宝,马军,李卫星..内蒙古雅干地区晚石炭世白山组火山岩LA-ICP-MS锆石U-Pb年龄及其构造环境[J].地质通报,2023,42(12):2096-2108,13.基金项目
中国地质调查局项目《内蒙古自治区额济纳旗克克桃勒盖等4幅区域地质调查》(编号:DD20208005) （编号:DD20208005）
