地质与勘探2025，Vol.61Issue(4)：751-761,11.DOI:10.12134/j.dzykt.2025.04.007
吉南地区晚三叠世斑状花岗岩锆石U-Pb年代学、地球化学及Hf同位素特征
Zircon U-Pb Chronology,Geochemistry and Hf Isotope Characteristics of the Late Triassic Porphyritic Granite in Southern Jilin Province
摘要
Abstract
The southern Jilin region experienced complex tectonic evolution and intense magmatic activity during the Late Paleozoic to Early Mesozoic,making it a key area for studying the evolution of the Paleo-Asian Ocean and the subduction of the Paleo-Pacific Plate.Taking the exposed porphyritic granites in southern Jilin Province as an example,this work employed LA-ICP-MS zircon U-Pb dating,whole-rock geochemical analysis,and zircon Hf isotope analysis to investigate their formation age,petrogenesis,and tectonic setting.The results indicate that the LA-ICP-MS zircon U-Pb age of the porphyritic granites is 221.6±2.9 Ma(MSWD=1.8,N=13),belonging to the Late Triassic.The rocks exhibit high silica(SiO2=75.24%～75.40%),alkali enrichment(K2O+Na2O=9.45%～9.60%),and aluminum enrichment(Al2O3=13.06%～13.13%),with A/CNK=1.01～1.03,belonging to peraluminous,high-K calc-alkaline granites.The zircon saturation temperatures(TZr)range from 780 to 788℃(mean=784℃),and δEu=0.14～0.15.The rocks are significantly enriched in light rare earth elements(LREE)and large-ion lithophile elements(LILE,e.g.,Rb,K,U,Th),while moderately depleted in heavy rare earth elements(HREE)and high-field-strength elements(HFSE,e.g.,P,Ti),consistent with I-type granites.Zircon Hf isotopic compositions yield εHf(t)=0.2～4.6,with two-stage model ages(tDM2)=1240～959 Ma,suggesting that the granites were derived from partial melting of Mesoproterozoic-Neoproterozoic juvenile crust and formed in an extensional setting following the closure of the Paleo-Asian Ocean.关键词
斑状花岗岩/晚三叠世/地球化学/锆石U-Pb年龄/Hf同位素/古亚洲洋/吉南地区Key words
porphyritic granite/Late Triassic/geochemistry/zircon U-Pb age/Hf isotope/Paleo-Asian ocean/southern Jilin area分类
天文与地球科学引用本文复制引用
张潇,王晰,王鹏,郭嘉..吉南地区晚三叠世斑状花岗岩锆石U-Pb年代学、地球化学及Hf同位素特征[J].地质与勘探,2025,61(4):751-761,11.基金项目
吉林省自然科学基金(编号:20230101076JC)和吉林省地质勘查基金(编号:2015-16(XZ))联合资助. （编号:20230101076JC）
