The Wangjiazhuang granitic pluton is located in the central Zanhuang Domain, the cen-tral part of the North China Craton, which is mainly composed of biotite monzogranite with few mafic microgranular enclaves. Biotite is an important ferromagnesian mineral in most of the intermediate-felsic igneous rocks, and its mineral chemistry can record the properties of magma and the petrogenet-ic physicochemical conditions. In this study, we carried out a detailed petrographic study by electric probe microanalysis on biotite for the biotite monzogranite and mafic microgranular enclaves, to dis-cuss the source, physicochemical conditions, and the magma mingling/mixing processes of the Wangjia-zhuang granite. The results show significantly different chemical compositions from the biotite monzo-granite and mafic microgranular enclaves. The crystallization of these biotite grains from the biotite monzogranite and mafic microgranular enclaves all occurred in low oxygen fugacity. The biotite grains in biotite monzogranite are rich in Fe, poor in Mg, which belong to siderophyllite. The ratios of [(Fe3++Fe2+)/(Fe3++Fe2++Mg2+)] are between 0.78 and 0.86. The average of FeOT (total FeO)/MgO of biotite grains in biotite monzogranite is 9.02. The MF values [2 × Mg/(Fe2++Mg+Mn)] of biotite monzogran-ite are between 0.31 and 0.47, suggesting biotite monzogranite derived from crustal source rocks (metasedimentary rocks). The formation of granitic rocks including the Wangjiazhuang granite was re-lated to the subduction event at ca. 2.5 Ga which resulted in the melting event, and then induced the early partial melting of TTGs and metasedimentary rocks. The biotite in mafic microgranular enclaves varies from siderophyllite to ferrobiotite, and MF values range from 0.63 to 1.06, suggesting that mag-ma of mafic microgranular enclaves had experienced magma mixing/mingling in various degrees. Bio-tite monzogranite and parts of mafic microgranular enclaves have a similar crystallized condition, while other mafic microgranular enclaves are different from biotite monzogranite. The differences be-tween biotite monzogranite and mafic microgranular enclaves may be a consequence of continuous in-teraction between granitic and mafic magmas.

Junpeng Wang;Kang Jiang;Deng Xiao;Fenfang Li;Fupeng Li;Xiaofeng Li;Song Jin;Guanghuo Tao

School of Earth Sciences,Center for Global Tectonics,China University of Geosciences,Wuhan 430074,China;State Key Laboratory of Geological Processes and Mineral Resources,China University of Geosciences,Wuhan 430078,China;Hebei Institute of Geological Survey,Shijiazhuang 050081,China

地球科学学刊（英文版）

[1]Junpeng Wang;Kang Jiang;Deng Xiao;Fenfang Li;Fupeng Li;Xiaofeng Li;Song Jin;Guanghuo Tao-.Mineral Chemistry of Biotite and Its Petrogenesis Implications in ca. 2.5 Ga Wangjiazhuang Granitic Pluton, North China Craton)[J].地球科学学刊（英文版）,2022(06):1535-1548

Biotite,Wangjiazhuang,Pluton,Zanhuang,microgranular,ferromagnesian,petrogenet,Wangjia,zhuang,monzo,siderophyllite,Fe3++Fe2+,Fe3++Fe2++Mg2+,Fe2++Mg+Mn,monzogran,TTGs,ferrobiotite,tite

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