地质科学2024，Vol.59Issue(4)：870-888,19.DOI:10.12017/dzkx.2024.063
中祁连西段盐池湾地区大青沟杂岩体中侵入岩与火山岩的岩石成因关系研究
The connection of volcanic-plutonic rocks of the Daqinggou complex pluton in the central Qilian belt,NW China
摘要
Abstract
Investigating the genetic relationship between intrusive and volcanic rocks in large silicic magma systems can provide insights in revealing magma dynamics processes and the compositional evolution of continental crust.The Daqinggou intrusive-volcanic complex from the Yanchiwan area in the central Qilian belt provides a best opportunity for the genesis of intrusive rocks and volcanic rocks.This paper focuses on the Daqinggou volcanic rocks and related intrusive rocks.Field geology,geochemical,zircon U-Pb dating,zircon Hf isotope combined with zircon trace element analysis indicate the formation ages of rhyolite,monzogranite and granodiorite in the Daqinggou volcanic-intrusive complex were 456±2 Ma,454±3 Ma and 455±4 Ma,respectively.These intrusive and volcanic rocks share similar zircon Hf isotopic composition with the εHf(t)value ranging from-5.2 to 0.3.Geochemical analyses indicate that the Daqinggou intrusive-volcanic complex is enriched in Si and K,and it exhibits enrichment in LILE sand depletion in HFSE as well as pronounced Eu-negative anomalies.Integrated analyses suggest these three types of intrusive-volcanic rocks are derived from the same magma reservoir and formed by continuous crystal-melt crystal fractionation in the magma chamber.The rhyolite is the product of the activation and fractionation of pre-existing crystal mush,while the monzogranite is the intrusive fractioned magmas without eruption and the granodiorite represents the product of crystal mush with low degree of fractionation.关键词
大青沟杂岩体/火山—侵入杂岩/晶粥模型/结晶分异/岩浆补给Key words
Daqinggou complex/Volcanic-plutonic complex/Crystal mush/Crystal differentiation/Magma recharge分类
天文与地球科学引用本文复制引用
刘柯,王超,张吉衡,李雪,孙晓奎,郝江波,喻遵谱..中祁连西段盐池湾地区大青沟杂岩体中侵入岩与火山岩的岩石成因关系研究[J].地质科学,2024,59(4):870-888,19.基金项目
国家自然科学基金项目(编号:42272054,42030307)和科技部大陆动力学国家重点实验室课题项目资助 （编号:42272054,42030307）
