近日，山东省地质调查局王来明最新等人的研究提供了华北克拉通胶东半岛伟德山高Ba-Sr花岗岩的地球化学、锆石U-Pb年代学和Hf同位素数据，研究结果对岩石成因和其构造意义提供了制约。相关论文发表在2024年10月28日出版的《地球化学学报》杂志上。

据悉，深入研究胶东半岛岩石圈减薄与大型金矿化，旨在更好地认识岩浆成岩作用的地球动力学背景，以及岩浆作用与大规模成矿作用的关系。

在此基础上，研究团队对胶东地区伟德山岩体进行了野外调查、地球化学、年代学和Hf同位素分析等详细研究，揭示了华北克拉通（NCC）东部破坏的构造意义。伟德山岩体由石英二长闪长岩、石英二长岩和二长花岗岩组成。SHRIMP锆石U-Pb定年结果表明，伟德山岩体于115-112Ma时期侵位，即早白垩世晚期。伟德山岩浆岩为高钾钙碱性系列和金属铝花岗岩。

微量元素以富集Rb、Ba、Sr、LREE为特征，Eu异常不明显，Nb、Ta、Zr、Hf、Ti亏损。Ba和Sr含量分别为(913.00-1562.00)/1199.29μ g/g和(373.00 ~ 793.00)/536.71μ g/g，显示了高Ba-Sr花岗岩（HBS）的特征。大量暗色包体的发育和负的εHf(t)值(-17.93到-12.19)表明，伟德山花岗岩来源于古元古代地壳，部分熔融的壳源长英质岩浆和富碱岩浆的混合。伟德山花岗岩的形成与晚中生代华北克拉通岩石圈，减薄过程中的软流圈上升流密切相关。

附：英文原文

Title: Geochemistry, zircon U–Pb chronology and Hf isotope of the Weideshan high Ba–Sr granites in Jiaodong Peninsula of the North China Craton: Constraints on their petrogenesis and tectonic implications

Author: Zhang, Zhigang, Wang, Laiming, Wang, Lijuan, Sun, Bin, Ren, Tianlong, Wang, Youping, Yang, Shipeng, Wang, Jingjing

Issue&Volume: 2024-10-28

Abstract: The lithospheric thinning and huge gold mineralization in the Jiaodong Peninsula is intensively studied, aiming to better understand the geodynamic setting of the magmatic petrogenesis and the relationship between magmatism and large-scale mineralization. Thus, we conducted detailed research on the Weideshan intrusions in the Jiaodong region, including field investigations, geochemical, geochronological and Hf isotope analysis, to reveal the tectonic implications for the destruction of the eastern North China Craton (NCC). The Weideshan intrusions consist of quartz monzodiorite, quartz monzonite and monzogranite. The SHRIMP zircon U-Pb dating results show that the Weideshan intrusions are emplaced at 115–112 Ma, namely, in the late Early Cretaceous period. Rocks of Weideshan intrusions are high-K calc-alkaline series and metaluminous granites. The trace elements are characterized by enrichment of Rb, Ba, Sr and LREE, with unobvious Eu anomalies and depletion of Nb, Ta, Zr, Hf and Ti. The contents of Ba and Sr are (913.00–1562.00)/1199.29 μ g/g and (373.00–793.00)/536.71 μ g/g, respectively, showing the features of high Ba–Sr granites (HBS). Development of numerous dark enclaves and negative εHf(t) values ( -17.93 to -12.19) indicate that the Weideshan granites originate from the mixture of crustal-derived felsic magma from partial melting of the Paleoproterozoic crust and alkali-rich magma from the enriched mantle. The generation of the Weideshan granites was closely related to the asthenospheric upwelling during the lithosphere thinning of the NCC in the late Mesozoic.

DOI: 10.1007/s11631-024-00739-6

Source: https://link.springer.com/article/10.1007/s11631-024-00739-6