华东地质2026，Vol.47Issue(1)：50-71,22.DOI:10.16788/j.hddz.32-1865/P.2025.05.009
扬子西北缘鱼洞子杂岩斜长角闪岩研究与早期大陆地壳演化
Amphibolite from the Yudongzi Complex on the northwestern margin of the Yangtze Block and related early continental crustal evolution
摘要
Abstract
The formation and evolution of the Earth's early continental crust remain a central theme in Pre-cambrian geology.As a key natural laboratory for studying early crustal growth,the Yangtze Block exhibits de-bated regional variations in its early evolutionary history.This study presents integrated field investigations,zir-con U-Pb geochronology,and whole-rock geochemical analyses of amphibolites from the Yudongzi Complex in the northwestern Yangtze Block.The amphibolites yield a metamorphic age of(2 492±22)Ma,recording a sig-nificant tectono-thermal event in the Early Paleoproterozoic.Geochemically,they show light rare earth element(LREE)enrichment and high-field-strength element(HFSE)depletion,indicative of protolith-derived magmas originating from a metasomatized lithospheric mantle.Combined with previous data,these results reveal four ma-jor tectono-thermal episodes in the northwestern Yangtze margin:Meso-to Neoarchean crustal rejuvenation and reworking;Neoarchean juvenile crustal growth and crustal recycling;Early Paleoproterozoic crustal remelting and high-grade metamorphism;and Late Paleoproterozoic regional metamorphism.By synthesizing petrological,geochronological,and zircon Hf isotopic data from basement rocks across the northern,northwestern,and south-western margins of the Yangtze Block,we propose that these regions experienced divergent Archean but conver-gent Paleoproterozoic crustal evolution.The Early to Middle Paleoproterozoic crustal reworking(peaking at 1.90 Ga)likely reflects the amalgamation of isolated ancient micro-blocks to form the proto-Yangtze Craton,syn-chronous with the assembly of the Columbia(Nuna)supercontinent.In contrast,Late Paleoproterozoic vertical crustal accretion was associated with extensional tectonics during supercontinental breakup.These findings pro-vide important constraints on the Yangtze Block's incorporation into global Precambrian supercontinent cycles.关键词
扬子板块/鱼洞子杂岩/早前寒武纪/大陆地壳/Nuna超大陆Key words
Yangtze Block/Yudongzi Complex/Early Precambrian/continental crust/Nuna supercontinent分类
天文与地球科学引用本文复制引用
闫树萱,惠博,董云鹏,孙圣思,何登峰,李永成,臧儒韬..扬子西北缘鱼洞子杂岩斜长角闪岩研究与早期大陆地壳演化[J].华东地质,2026,47(1):50-71,22.基金项目
中国石油天然气股份有限公司科技专项"叠合盆地中下组合油气成藏与保持机制研究(编号:2023ZZ0201)"和西安市科协青年人才托举计划"扬子西北缘早前寒武纪构造-岩浆作用与早期大陆地壳演化(编号:959202313087)"项目联合资助. （编号:2023ZZ0201）
