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现代地质 ›› 2025, Vol. 39 ›› Issue (03): 752-773.DOI: 10.19657/j.geoscience.1000-8527.2024.137

• 机器学习与矿物学应用 • 上一篇    下一篇

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

张乐民1,2,3(), 张聚全1,2,3,*(), 吴晓贺1,2,3, 郭子桤1,2,3, 温雨菁1,2,3, 秦超1,2,3, 白富生1,2,3, 朱伊冰1,2,3   

  1. 1.河北地质大学河北省战略性关键矿产资源重点实验室,河北 石家庄 050031
    2.河北地质大学地球科学学院,河北 石家庄 050031
    3.河北省战略性关键矿产研究协同创新中心,河北 石家庄 050031
  • 出版日期:2025-06-10 发布日期:2025-07-03
  • 通信作者: *张聚全,男,博士研究生,教授,1983年出生,主要从事成因矿物学、矿床学研究工作。Email:juquan1983@163.com
  • 作者简介:张乐民,男,硕士研究生,1998年出生,主要从事成因矿物学研究工作。Email:1696251179@qq.com
  • 基金资助:
    河北省自然科学基金资助项目(D2021403028);国家自然科学基金项目(41602028);河北省自然资源厅地勘项目(13000022P00F2D4101216);河北省自然资源厅地勘项目(13000023P00F2D410251H);河北地震局震防中心项目(HBHY(2023)-02-38)

Origin and Tectonic Significance of the Hongshan Alkaline Volcanic-Intrusive Complex in the Southern Taihang Mountains: Constraints from Zircon U-Pb Geochronology and Geochemistry

ZHANG Lemin1,2,3(), ZHANG Juquan1,2,3,*(), WU Xiaohe1,2,3, GUO Ziqi1,2,3, WEN Yujing1,2,3, QIN Chao1,2,3, BAI Fusheng1,2,3, ZHU Yibing1,2,3   

  1. 1. Hebei Key Laboratory of Strategic Critical Mineral Resources, Shijiazhuang, Hebei 050031, China
    2. College of Earth Science, Hebei GEO University, Shijiazhuang, Hebei 050031, China
    3. Hebei Province Collaborative Innovation Center of Strategic Critical Mineral research, Shijiazhuang, Hebei 050031, China
  • Published:2025-06-10 Online:2025-07-03

摘要:

华北克拉通中部南太行邯邢地区发育大量中生代中基性侵入岩,其中的洪山碱性杂岩体具有特殊的岩石组成,是了解早白垩世克拉通构造演化的关键。对洪山岩体及其相关的火山岩中典型岩石类型进行了全岩地球化学和锆石U-Pb年代学分析,并与已发表的邯邢地区各岩体的全岩数据、锆石U-Pb年龄及Lu-Hf同位素数据进行了对比研究,解析了洪山岩体的成因与演化。本次研究显示洪山碱性火山-侵入杂岩为高硅、富铝、高碱的钾玄岩系列岩石,其La-La/Sm显示出正相关性,其锆石εHf(t)值介于富集地幔和古老下地壳的Hf同位素演化线之间(εHf(t)=-17~-10,TDM2=1800~2200 Ma),指示其壳幔混合成因。石英正长岩、石英正长斑岩、辉石正长岩和粗面质凝灰岩的锆石U-Pb年龄分别为129.6±2.9 Ma、128.6±3.0 Ma、126.5±0.47 Ma和130.6±3.0 Ma,与邯邢地区其它岩体形成时代一致。综合研究认为洪山碱性杂岩是钾玄质岩浆与壳源和幔源岩浆发生混合形成。钾玄质岩浆是地幔中残留的克拉通早期演化时形成的辉石岩发生部分熔融的结果;基性岩浆则是富集地幔部分熔融的产物。上述岩浆演化和岩石形成指示了岩石圈减薄引起软流圈上涌的过程,可能是早白垩世古太平洋板块回撤并导致包括邯邢地区形成弧后伸展区域。

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

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 exhibits a distinctive lithological composition and serves as a key to understanding the tectonic evolution of the craton 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 shoshonite 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, pyroxene 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 shoshonitic 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 development of a back-arc extensional setting in regions including Hanxing.

Key words: alkaline complex, magma evolution, fractional crystallization, magma mixing, southern Taihang Mountains region

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