华北地质2025，Vol.48Issue(2)：78-89,12.DOI:10.19948/j.12-1471/P.2025.02.03
松辽盆地东南缘早白垩世营城组玄武粗安岩年代学、岩石地球化学和Sr-Nd-Hf同位素特征
Geochronology,lithogeochemistry and Sr-Nd-Hf isotopic characteristics of basaltic trachyandesite from early Cretaceous Yingcheng Formation in the southeastern margin of Songliao Basin
摘要
Abstract
This paper is the result of lithogeochemstry study. [Objective]The volcanic rocks associated with the Songliao Basin are of great significance to the study of the formation and evolution of the basin,and also provide important information for studying the Mesozoic magmatic activity and tectonic evolution in Northeast Asia.[Methods]In this study,the LA-ICP-MS zircon U-Pb dating,whole rock major and trace element compositions,Sr-Nd isotope and zircon in situ Hf isotope were analyzed on the basaltic trachyandesite from the early Cretaceous Yingcheng Formation in the southeastern margin of Songliao Basin.[Results]The zircon U-Pb dating yielded the age of 119.1±0.7 Ma for basaltic trachyandesite.The basaltic trachyandesite belongs to the alkaline rock series,total alkali(Na2O+K2O)=6.21%～6.41%,moderate MgO(3.16%～3.97%)and high Al2O3(16.21%～16.90%),relatively enriched in LILE(such as Rb,Ba、Th and K),and depleted in HFSE(such as Nb,Ta and Ti);The fractionation between LREE and HREE is obvious(La/Yb)N=9.37～10.05,and slight negative Eu anomalies(δEu=0.84～0.96).The basaltic trachyandesite have positive whole-rocks εNd(t)values(+2.12 to+2.65)and zircon εHf(t)values(+6.51 to+14.93),and low(87Sr/86Sr)i(0.704 569～0.704 896).[Conclusions]Isotope and elemental geochemical evidences studies indicate that the basaltic trachyandesite derived from the partial melting of the newly formed lithospheric mantle,and suffered a certain degree of crustal contamination,and formed in an intraplate extension setting.The extension mechanism is relate to the rapid subduction and retreat of the ancient Pacific plate.关键词
地球化学/早白垩世/玄武粗安岩/Sr-Nd-Hf同位素/岩石成因/松辽盆地东南缘Key words
geochemistry/early Cretaceous/basaltic trachyandesite/Sr-Nd-Hf isotope/petrogenesis/southeastern margin of Songliao Basin分类
天文与地球科学引用本文复制引用
李艳锋,程银行,王少轶,李志丹,王树庆,孙立新..松辽盆地东南缘早白垩世营城组玄武粗安岩年代学、岩石地球化学和Sr-Nd-Hf同位素特征[J].华北地质,2025,48(2):78-89,12.基金项目
中国地质调查项目"辽西—太行成矿带战略性矿产调查(DD20240057)",新一轮找矿突破战略行动科技支撑项目"含铝岩系共伴生钛等矿产成矿模式和找矿预测(ZKKJ202404)" Supported by the project of China Geological Survey(No.DD20240057)and a new round of strategic action for breakthroughs in mineral exploration(No.ZKKJ202404) （DD20240057）
