阿尔金山喀拉大湾地区早古生代火山岩岩石学特征、U-Pb年龄及构造环境特征
Petrological Characteristics,U-Pb Age and Tectonic Environment Characteristics of the Early Paleozoic Volcanic Rocks in the Kaladawan Area of the Altun Mountains
刘兵 1王磊 2刘伟 1陈威1
作者信息
- 1. 新疆维吾尔自治区地质矿产勘查开发局第一区域地质调查大队,新疆 乌鲁木齐 830013
- 2. 新疆维吾尔自治区地质矿产勘查开发局第七地质大队,新疆乌苏 833000
- 折叠
摘要
阿尔金山喀拉大湾地区出露一套海相火山岩,据火山岩组构特点及岩性组合划分出6个喷发韵律、3个喷发亚旋回、1个火山喷发旋回.通过对铅锌赋矿层顶底板晶屑凝灰岩进行锆石U-Pb测年,获得年龄为487.9～489.8 Ma,时代为晚寒武—早奥陶世.与铅锌矿有关的火山岩主要为钙碱性高钾英安岩、流纹岩类火山岩,岩石地球化学具Nb,Ta,Sr,Hf,Y相对亏损和Ba,Th,Zr,U相对富集及形成于俯冲带环境的钙碱性火山岩微量元素地球化学特征,即轻稀土富集,Eu极度亏损.结合前人研究成果,认为大地构造环境属拉张弧后盆地.
Abstract
A set of marine volcanic rocks are exposed in the Kaladawan area of Altun Mountain.Based on the volcanic rocks'structural characteristics and lithological associations,they are divided into six eruption rhythms,three eruption sub-cycles,and one volcanic eruption cycle.By conducting zircon U-Pb dating on the crystal tuff at the top and bottom of the Pb-Zn Ore bearing stratum,an age of 487.9-489.8 Ma formed during the Late Cambrian-Early Ordovician(∈3-O1)was obtained.The volcanic rocks related to the Pb-Zn deposit are mainly the high potassium calc alkali dacite,rhyolite,etc.It has apparent relative depletion of Nb,Ta,Sr,Hf,Y,and relative enrichment of Ba,Th,Zr,and U,and has trace ele-ment geochemical characteristics of calc-alkaline volcanic rocks formed in subduction zone environments characterized by light rare earth enrichment and extreme Eu depletion.Combined with previous research results,we speculate that the tectonic environment belongs to the spreading back-arc basin.
关键词
阿尔金山/锆石U-Pb测年/火山岩/岩石地球化学特征/构造环境Key words
Zircon U-Pb age/Volcanic rocks/Geochemical characteristics/Tectonic Environment/Altun tagh引用本文复制引用
出版年
2024
NETL
NSTL
万方数据