岩石矿物学杂志2024，Vol.43Issue(4)：821-846,26.DOI:10.20086/j.cnki.yskw.2024.0403
崂山早白垩世高分异Ⅰ型花岗岩地球化学特征及岩石成因机制
Geochemical characteristics and petrogenetic mechanism of Early Cretaceous highly fractionated Ⅰ-type granites in Laoshan
摘要
Abstract
Laoshan granites are widely distributed in Jiaodong area.Their typology,magma source and petrogenesis are still controversial,and the magmatic evolution and petrogenesis of highly fractionated Ⅰ-type granite have not been well constrained.In this study,the Laoshan Early Cretaceous granites are selected as the research theme.The granites are analyzed by petrology and petrography,whole rock major and trace elements,zircon U-Pb dating and Lu-Hf isotopes,plagioclase electron probe analysis.LA-MC-ICP-MS zircon U-Pb dating results show that the dia-genetic ages of quartz monzonite,monzogranite,syenogranite and granitic porphyry in Laoshan are 128.6±2.7 Ma,122.8±2.5 Ma～118.6±1.2 Ma,121.5±2.7 Ma～121.3±1.2 Ma and 114.5±1.2 Ma,respectively,indicating that they were all emplaced during the Early Cretaceous.The geochemical composition of Laoshan granites show high contents of silicon and alkali,low abundances of aluminum,magnesium and iron.They are also depleted in Rb,Th,U,Ba and Sr,with significant negative Eu anomaly.The zircons εH f(t)values of Laoshan granites range from-21.0 to-15.1,and Hf isotope second-stage model ages(tDM2)range from 2 482 to 2 149 Ma.Based on mineralogical,petrological and geochemical evidence,the quartz monzonite and monzogranite are Ⅰ-type granites,and the syenogranite and granitic porphyry are classified are high fractionated Ⅰ-type granites.Combined with the previous researches results in Jiaodong area,in the extensional tectonic setting generated by the subduction of the Paleo-pacific plate,magmas from the asthenosphere underplated into the lower crust,inducing partial melting of the lower crust material to form felsic magmas.After different degrees of fractional crystallization and evolution of felsic magmas,granites with varying degrees of differentiation in Laoshan area are formed ultimately.关键词
胶东地区/高分异Ⅰ型花岗岩/岩石成因/岩浆分异/古太平洋俯冲Key words
Jiaodong area/highly fractionated I-type granites/petrogenesis/magmatic differentiation/paleo-pacif-ic subduction分类
天文与地球科学引用本文复制引用
杜娟,于胜尧,高翔宇,蒋兴洲,彭银彪,纪文涛,李传志..崂山早白垩世高分异Ⅰ型花岗岩地球化学特征及岩石成因机制[J].岩石矿物学杂志,2024,43(4):821-846,26.基金项目
国家自然科学基金委创新群体项目(42121005) （42121005）
111项目(B20048) （B20048）
泰山学者项目(Notstp20221112) Science Fund for Creative Research Groups of the Nation Natural Science Foundation of China(42121005) （Notstp20221112）
111 Project(B20048) （B20048）
Taishan Scholar Project(Notstp20221112) （Notstp20221112）
