海洋地质与第四纪地质2026，Vol.46Issue(4)：80-98,19.DOI:10.16562/j.cnki.0256-1492.2025110302
南大西洋沃尔维斯海岭岩浆作用
Magmatism in the Walvis Ridge,South Atlantic Ocean
摘要
Abstract
Walvis Ridge in the South Atlantic Ocean is in a typical hotspot track formed through mantle plume-mid-ocean ridge interaction.Its geological evolution fits the classical model of transition from a plume head to a plume tail,making it one of the global archetype examples for studying mantle plume activity.The International Ocean Discovery Program Expeditions 391 and 397T recently conducted systematic drilling across the ridge.This study combines the formation and evolutionary mechanisms of the Walvis Ridge,focusing on its petrography,chronology,geochemistry,magmatism,and mantle sources.Volcanic rocks from the Walvis Ridge are dominated by basalt and basanite,mainly composed of plagioclase,clinopyroxene,and olivine.The first stage corresponds to the EM I-type volcanism associated with the Tristan-Gough hotspot track,showing well-defined age progression.The second stage is characterized by the HIMU-type volcanism surrounding the Valdivia Bank,forming seamounts superimposed on the earlier basement.Volcanic rocks from these two stages indicate that the mantle sources of the Walvis Ridge are dominated by a Gough-type EM I component,which has persisted for more than 130 Ma throughout the system.In contrast,the Tristan-type EM I component appears only along the younger(<70 Ma)section of the hotspot track.Although the tholeiitic magmas of the Valdivia Bank and the alkaline magmas of the Gough track are both derived from the Gough-type EM I mantle source;their differences in major and trace element compositions reflect the variations in lithospheric thickness and degrees of partial melting during their formation.The long-lived Gough-type EM I component likely recorded recycled ancient crustal materials in the mantle source.In contrast,the late-stage HIMU-type volcanism surrounding the Valdivia Bank indicates a significant change in mantle source characteristics during the evolution of the Walvis Ridge.This transition may be linked to the Large Low Shear Wave Velocity Province(LLSVP)beneath the African continent,reflecting complex geochemical zonation and material cycling within and around the LLSVP.The temporal evolution from the EM I-type to HIMU-type signatures further suggests a spatial and genetic relationship between these two mantle end-members.Several key issues remain on the exact mechanism of Walvis Ridge formation,and future studies integrating high-precision isotope geochemistry,deep geophysical imaging,and geodynamic modeling are needed to elucidate the coupling between deep mantle dynamics and shallow lithospheric processes during the formation of the ridge,and advance our understanding of crustal recycling,supercontinent breakup,and the long-term evolution of Earth's interior.关键词
地幔柱/洋岛玄武岩/Sr-Nd-Pb-Hf 同位素/国际大洋钻探计划/沃尔维斯海岭Key words
mantle plume/ocean island basalt/Sr-Nd-Pb-Hf isotope/IODP/Walvis Ridge分类
海洋科学引用本文复制引用
朱恒睿,吴涛,李春峰,鲁江姑..南大西洋沃尔维斯海岭岩浆作用[J].海洋地质与第四纪地质,2026,46(4):80-98,19.基金项目
海南省自然科学基金"大西洋沃尔维斯海岭热点轨迹岩浆通道系统研究"(425RC803) （425RC803）
浙江省自然科学基金"岩浆水含量对热点轨迹深部岩浆系统时空演化的影响:来自南大西洋沃尔维斯海岭的研究"(LMS26D06005) （LMS26D06005）
国家自然科学基金"南大西洋沃尔维斯海脊(Walvis Ridge)的构造属性及其与相邻被动大陆边缘的相互作用"(42176055),"大陆裂解-初始大洋扩张与海洋大火成岩省岩浆活动的构造耦合关系"(42576050) （Walvis Ridge）
国家重点研发项目"东南亚环形俯冲系统的形成演化及资源环境效应"子课题(2023YFF0803404) （2023YFF0803404）
