| 华南诸广山一带桂东岩体加里东期花岗岩的成岩时代研究及其地质意义 |
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| 关键词:Zhuguangshan Guidong Batholith U-Pb age Caledonian Hf isotope |
| 基金项目:中国地质调查局项目(编号: D1912);河北省自然科学基金面上项目(编号: D2019403015);河北省青年科学基金项目(编号: D2020403101);河北地质大学教学改革研究项目(编号: 2014J17; 2016J19) |
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| Geochronology and Geological Significance of Caledonian Granites in Guidong Batholith from Zhuguangshan Area, South China |
| The Guidong Batholith is located in the middle of the Zhuguangshan–Wanyangshan granitic magmatic rock belt. It forms an irregular strip in a NE direction from the junction of Hunan and Jiangxi provinces. The batholith, which records the formation and magmatic origin of the Zhuguangshan–Wanyangshan rock belt and the evolution of the interaction between the regional crust and the crust-mantle, is the main component of the Zhuguangshan–Wanyangshan granitic magmatic rock belt. Based on the detailed geological survey of the Guidong Batholith, in this study we have carried out petrography, LA-ICP-MS zircon chronology and Hf isotope composition studies. The results show that the Guidong Batholith is a compound batholith, with magmatic activity that lasted >60 Ma (474–411 Ma). The magmatic activity can be divided into four stages: 474–464 Ma, 452–442 Ma, 435–425 Ma, and 415–411 Ma, and the main rock types of these stages are granodiorite-biotite granite, biotite granite-two-mica granite, biotite granite-biotite monzogranite and hornblende biotite granite-biotite granite. The magmatic activities during 474–464 Ma, 452–425 Ma and 415–411 Ma are consistent with the three tectonic episodes of the Caledonian orogeny in South China. The Hf isotope characteristics of the in-situ zircon show that, the εHf(t) values of most of the samples located below the chondrite evolution line, between ?2.20 and ?9.84, indicating that the diagenetic material may be mainly derived from the lower crust of South China orogenic belt. The diagenetic material or may also include a small amount of mantle-derived material or the partial melting of early magmatic rocks. The Hf isotope two-stage model age (TDM2) is 1969–1577 Ma. Therefore, the source magma mainly formed by the remelting of lower crust materials in the South China Orogenic Belt, and the degree of participation of these mantle-derived materials is a process from weak to strong to weak, which coincides with the important crustal accretion events in the study area during the Archean–aleoproterozoic time period. |
| ZHANG Su-mei,WANG Yang,REN Ji-shun,ZHANG Min-jie,YU Ling-yan,JING Tian-jing.2022.Geochronology and Geological Significance of Caledonian Granites in Guidong Batholith from Zhuguangshan Area, South China[J].Acta Geoscientica Sinica,43(5):593-608. |
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