华东地质2026，Vol.47Issue(1)：82-97,16.DOI:10.16788/j.hddz.32-1865/P.2025.10.013
扬子陆块西南缘东川大窑湾古元古代晚期辉长岩年代学、地球化学特征及地质意义
Geochronology,geochemical characteristics and geological implications of the Late Paleoproterozoic gabbro in Dayaowan,Dongchuan southwestern margin of the Yangtze Block
摘要
Abstract
The southwestern margin of the Yangtze Block is extensively intruded by Paleoproterozoic mag-matic rocks;however,significant controversy persists regarding their tectonic setting and dynamic mechanisms.Gabbro,as the direct crystallization product of mafic magma,provides zircon U-Pb isotopic chronology data that can precisely constrain the timing of tectonothermal events.Furthermore,its major and trace element composi-tions effectively record the material exchange and energy transfer processes between the lithosphere and astheno-sphere,offering critical geochemical constraints for discriminating tectonic environments.This paper presents a systematic isotopic chronological and geochemical study of the Dayaowan gabbro in the Dongchuan area.The re-sults show that the zircon U-Pb age of the gabbro is(1 674±16)Ma,indicating its emplacement during the Late Paleoproterozoic.The rock belongs to the subalkaline series,exhibiting flat or slightly right-inclined patterns in chondrite-normalized rare earth element(REE)diagrams.In primitive mantle-normalized trace element spider dia-grams,it displays enrichment in large-ion lithophile elements(LILEs)including Ba,Sr,and La,along with rela-tive depletion in high-field-strength elements(HFSEs)such as Nb,Ta,and Hf.These geochemical characteristics share affinities with both within-plate basalts(WPB)and enriched mid-ocean ridge basalts(E-MORB).Compre-hensive analysis suggests that this magmatic activity likely formed in an intracontinental rift setting associated with mantle plume activity,representing a tectonic-magmatic thermal event response on the southwestern margin of the Yangtze Block during the breakup of the global Columbia Supercontinent.关键词
大窑湾辉长岩/Columbia超大陆/地球化学/同位素年代学/东川Key words
Dayaowan gabbro/Columbia Supercontinent/geochemistry/isotopic geochronology/Dongchuan分类
天文与地球科学引用本文复制引用
胡创,王子正,危隆隆,詹宏宇,李宸,刘宝嵩,魏云虓..扬子陆块西南缘东川大窑湾古元古代晚期辉长岩年代学、地球化学特征及地质意义[J].华东地质,2026,47(1):82-97,16.基金项目
中国地质调查局"滇东北铝磷矿大型资源基地综合地质调查(编号:DD20242114)""上扬子西缘成矿带战略性矿产调查(编号:DD20240071)"和四川省科技计划项目"川西甘孜—理塘成矿带金矿成矿规律与富集机制(编号:2024NSF-SC1954)""川西甘孜—理塘金矿带成矿物质来源限定:来自Hg-Ag同位素的联合制约(编号:2025ZNSFSC1196)"项目联合资助. （编号:DD20242114）
