现代地质2025，Vol.39Issue(3)：752-773,22.DOI:10.19657/j.geoscience.1000-8527.2024.137
太行山南段洪山碱性火山-侵入杂岩成因与构造意义:锆石U-Pb年代学和地球化学的约束
Origin and Tectonic Significance of the Hongshan Alkaline Volcanic-Intrusive Complex in the Southern Taihang Mountains:Constraints from Zircon U-Pb Geochronology and Geochemistry
摘要
Abstract
The Hanxing region of the southern Taihang Mountains,located in the central North China Craton,hosts numerous Mesozoic intermediate-mafic intrusive rocks.Among them,the Hongshan alkaline complex ex-hibits a distinctive lithological composition and serves as a key to understanding the tectonic evolution of the cra-ton during the Early Cretaceous.This study conducted whole rock geochemistry and zircon U-Pb chronology analysis on typical lithology in the Hongshan intrusion and related volcanic rocks,and compared which with the published geochemical data,zircon U-Pb ages,and Lu-Hf isotopes of various intrusions in the Handan-Xingtai region.The genesis and evolution of the Hongshan complex were analyzed.This study shows that the Hongshan alkaline volcanic-intrusive complex consists of high-silica,Al-rich,and high-alkali rocks belonging to the shos-honite series.The La and La/Sm ratios exhibit a positive correlation.Hf isotopic compositions of zircons vary between enriched mantle and ancient lower crust(εHf(t)=-17--10,TDM2=1800-2200 Ma),indicative that it is of crust-mantle mixed origin.The zircon U-Pb ages of quartz syenite,quartz syenite porphyry,pyrox-ene syenite,and trachytic tuff are 129.6±2.9 Ma,128.6±3.0 Ma,126.5±0.47 Ma,and 130.6±3.0 Ma,respectively,which are consistent with the magmatic timeframe of other intrusions in the Handan-Xingtai region.Comprehensive research suggests that the Hongshan alkaline complex was formed through the mixing of shosho-nitic magma with both crustal-and mantle-derived magmas.The shoshonitic magma originated from the partial melting of pyroxenite residues formed during the early evolution of the craton and retained in the mantle.The mafic magma,on the other hand,was generated by partial melting of an enriched mantle source.This magmatic evolution and rock formation reflect a process of lithospheric thinning and asthenospheric upwelling,which was likely triggered by the rollback of the Paleo-Pacific Plate during the Early Cretaceous,leading to the develop-ment of a back-arc extensional setting in regions including Hanxing.关键词
碱性杂岩体/岩浆演化/结晶分异/岩浆混合/南太行地区Key words
alkaline complex/magma evolution/fractional crystallization/magma mixing/southern Taihang Mountains region分类
天文与地球科学引用本文复制引用
张乐民,张聚全,吴晓贺,郭子桤,温雨菁,秦超,白富生,朱伊冰..太行山南段洪山碱性火山-侵入杂岩成因与构造意义:锆石U-Pb年代学和地球化学的约束[J].现代地质,2025,39(3):752-773,22.基金项目
河北省自然科学基金资助项目(D2021403028) （D2021403028）
国家自然科学基金项目(41602028) （41602028）
河北省自然资源厅地勘项目(13000022P00F2D4101216 （）
13000023P00F2D410251H) （）
河北地震局震防中心项目(HBHY(2023)-02-38). （HBHY(2023）
