胶北地体晚侏罗世花岗岩地球化学和锆石年代学和同位素特征  

Bulk Geochemistry, Zircon Chronology and Isotope Characteristics of Late Jurassic Granites in Jiaobei Terrane

作　　者：屈鑫 毛先成[1] 钟慧婷 段宇玺 

机构地区：[1]中南大学地球科学与信息物理学院,湖南 长沙

出　　处：《地球科学前沿（汉斯）》2022年第5期591-606,共16页Advances in Geosciences

摘　　要：华北克拉通(NCC)东部胶北地体在晚侏罗世发生了大规模的岩浆活动。前人对晚侏罗世花岗岩进行了大量研究,但在花岗岩具体的岩浆物质来源方面一直存在争议。本研究对胶西北地层的两期晚侏罗世花岗岩(玲珑和栾家河)进行了岩石学和全岩地球化学、锆石U-Pb定年、O同位素研究。LA-ICP-MS锆石U-Pb测年表明,玲珑花岗岩的形成比栾家河花岗岩早约6 Myr (分别为158 Ma和152 Ma),与两者侵入关系一致。全岩地球化学特征表明,玲珑和栾家河花岗岩,同属亚碱性岩石,具有高Sr,Sr/Y值,低Y的埃达克质岩石特征。花岗岩高δ18O值和继承锆石年龄频谱,表明玲珑和栾家河花岗岩是由NCC和杨子克拉通的古代加厚的下部大陆地壳部分熔化形成的。Large-scale magmatism occurred in the Late Jurassic in Jiaobei Terrane, east of the North China Craton (NCC). Previous studies on Late Jurassic granites have been carried out, but the magma source of granites has been controversial. In this study, petrological and bulk geochemistry, zircon U-Pb dating, and O isotope studies were carried out on two phases of Late Jurassic granites (Linglong and Luanjiahe) in northwest Jiaojiang. LA-ICP-MS zircon U-Pb dating indicates that the Linglong granite formed about 6 Myr earlier than the Luanjiahe granite (158 Ma and 152 Ma, respectively), consistent with an intrusive relationship between them. The bulk geochemical data show that Linglong and Luanjiahe granites, both subalkaline rocks, are characterised by high Sr, Sr/Y and low Y adakitic rocks. The high δ18O values and inherited zircon age statistics suggest that the Linglong and Luanjiahe granites were formed by partial melting of the ancient thickened lower continental crust of the NCC and Yangtze Craton.

关 键 词：胶北地体 全岩地球化学 锆石U-PB定年 O同位素 

分 类 号：P597[天文地球—地球化学] P588.121[天文地球—地质学]