地质与资源2025，Vol.34Issue(6)：689-697,9.DOI:10.13686/j.cnki.dzyzy.2025.06.002
吉林中部琵河口地区新生代碱性侵入体:岩石地球化学、年代学及地质意义
The Cenozoic alkaline intrusions in Pihekou area,Central Jilin:Petrogenesis,geochronology and geological implication
摘要
Abstract
Cenozoic intrusive rocks are rarely exposed in Northeast China,making the Oligocene granite porphyry and syenite porphyry in the Pihekou area of central Jilin Province particularly significant for deciphering the region's Cenozoic tectonic evolution.The petrogeochemical study and LA-ICP-MS zircon U-Pb geochronological dating show that the Pianshishan pluton is aged of 29.0±0.4 Ma,consisting with the age range of other alkaline bodies(27.3-31 Ma)in the study area.Together,they constitute the Pihekou alkaline complex,interpreted as the product of a single Oligocene alkaline magmatic intrusive-eruptive event.The alkaline intrusions exhibit coherent geochemical features,including very high total rare earth element(REE)contents,strong negative Eu anomalies,and significant depletions in Sr,Ba,P and Ti.These characteristics indicate an alkaline A-type granite affinity and suggest that the magmas experienced considerable fractional crystallization.The rocks form a comagmatic alkaline assemblage,comprising felsic granite porphyry and intermediate aegirine-augite syenite porphyry(trachyte),which are temporally,spatially and genetically consistent.The petrogeochemical characteristics further reveal that these intrusions were formed in a continental rift setting through fractional crystallization of mantle-derived alkaline basaltic magma,with the source being either an enriched mantle or a metasomatized depleted mantle.关键词
碱性侵入体/渐新世/大陆裂谷/地球化学/吉林省Key words
alkaline intrusion/Oligocene/continental rift/geochemistry/Jilin Province分类
天文与地球科学引用本文复制引用
任龙,赵院冬,王存柱,王春晖,张彬,时林..吉林中部琵河口地区新生代碱性侵入体:岩石地球化学、年代学及地质意义[J].地质与资源,2025,34(6):689-697,9.基金项目
中国地质调查局项目"吉林那尔轰一带金铜多金属找矿靶区优选与评价"(DD20230371)、"吉林大车背沟等8幅1∶5万矿产地质调查"(ZD20221302). （DD20230371）
