Geochemistry and geochronology of the TTG-sanukitoid suite in the Zhulagou area: Constraints on the Neoarchean crustal evolution of the western North China Craton

作者：Xiao‐Lei Wang, Jian Zhang, Liu Jin, Hai Zhou, Xiaoguang Liu, Shuhui Zhang, Chenying Yu, Changquan Cheng · 发表于：Lithos · 年份：2024 · DOI：10.1016/j.lithos.2024.107636 · 被引用次数：7 · 研究领域：Geological and Geochemical Analysis、Geochemistry and Geologic Mapping、Geochemistry and Geochronology of Asian Mineral Deposits

The Archean basement in the Yinshan Block of the western North China Craton consists of a variety rock of assemblage, including TTG (tonalite-trondhjemite-granodiorite) rocks and some dioritic gneiss (sanukitoid). Understanding the petrogenesis of these rocks is crucial for comprehending the late Neoarchean crustal evolution of the western North China Craton. This study provides a new geochronological, geochemical, and Sr-Nd-Pb-Hf isotopic data for the TTG-sanukitoid suit that was newly identified in the Zhulagou area. The late Neoarchean TTG gneisses were emplaced around 2.54–2.50 Ga, while dioritic gneiss was emplaced between 2.53 and 2.50 Ga. The TTG gneisses exhibit high SiO 2 (64.46–72.24 wt%) and Al 2 O 3 (13.37–16.48 wt%) contents, relatively elevated (La/Yb) N and Sr/Y ratios, as well as low Y and Yb contents. They display variable ε Hf ( t ) (+0.94 to +3.57) and ε Nd ( t ) (−1.02 to +0.82) values, with relatively low Pb isotopic compositions , suggesting that they were derived from the partial melting of a thickened mafic lower crust . On the other hand, dioritic gneiss shows moderate SiO 2 (58.05–61.87 wt%) content, high MgO (2.62–4.06 wt%), Al 2 O 3 (14.42–18.44 wt%) and Cr contents, but relatively low (La/Yb) N values, showing geochemical affinity to the Archean sanukitoids. The dioritic gneiss exhibits variable ε Hf ( t ) values (−2.29 to +5.56) and ε Nd ( t ) (−2.05 to +2.02), with relatively low Pb isotopic compositions. Furthermore, the presence of amphibolite...