摘要
New integrated geochemical studies are reported for Jurassic granites of the Xingcheng area in the northeastern North China Craton.U-Pb zircon data indicate that the Huashan and Taili monzogranites were emplaced during the Early(189±2 Ma)and Late(155±1 Ma)Jurassic,respectively.They are typical of high-K calc-alkaline series rocks and I-type granites,according to our whole-rock geochemical researches.Both Early and Late Jurassic monzogranites show adakitic rock characteristics because of their high Sr contents(221-347 ppm)and Sr/Y ratios(28.7-37.5),and low Y contents(7.83-14.7 ppm).The Early Jurassic monzogranite samples have an(^(87)Sr/^(86)Sr)i ratio of 0.7046,ε_(Nd)(t)values of -11.62 to -11.51,and ε_(Hf)(t)values of -13.6 to-6.4,whereas the Late Jurassic monzogranites have higher(87Sr/86Sr)i ratios of 0.7069-0.7071and lower ε_(Nd)(t)(-20.65 to-20.46)and ε_(Hf)(t)(-27.6 to-20.0)values.We suggest that the Early Jurassic adakitic rocks were derived from partial melting of thickened lower crust contaminated with mantle-derived materials,related to subduction of the Paleo-Pacific Plate.The Late Jurassic adakitic rocks were derived from partial melting of thickened lower crust in an extensional tectonic setting associated with an active continental margin.
基金
financially supported by the Natural Science Foundation of China(Grant No.41722204,42072063)
the Basic Scientific Research Foundation of Central Universities of China(Jilin University)。
作者简介
Corresponding author:YANG Debin,male,born in 1979 in Suibin City,Heilongjiang Province,Professor of College of Earth Science,Jilin University,he is now interested in mineralogy,petrology,mineral deposit geology.E-mail:yangdb@jlu.edu.cn;MU Maosong,male,born in 1995 in Shanxian City,Shandong Province,Ph.D.student of the College of Earth Science,Jilin University,Changchun,he is now interested in mineralogy,petrology,mineral deposit geology.E-mail:502706020@qq.com。
