Late Jurassic Intracontinental Extension and Related Mineralisation in Southwestern Fujian Province of SE China:Insights from Deformation and Syn-Tectonic Granites

• 来源期刊: 地球科学学刊（英文版）
• 年，卷（期）: 2021,（1）
• 所属期刊栏目: Special Colume on Mesozoic Magmatism,Gold Mineralization and Deep Exploration in East China
• 页码范围: 158-173
• 页数: 16页
• 语种: 英文

摘要

Late Mesozoic igneous intrusions and extensional structures in Carboniferous to Permian sequences in the SW Fujian region acted as important controls on the localisation of Fe-polymetallic de-posits.Here we document the identification of extensional deformation at shallow crustal levels and syn-tectonic granites related to normal faults.Based on spatial distribution and structural features,the extensional deformation can be divided into cover-only and basement-intersecting styles.A series of syn-tectonic plutons were emplaced into the footwall of normal faults.Representative samples of the Tangquan Granite have high SiO2(66.4 wt.％-73.9 wt.％)assays and Mg# values(37-59).The samples also have relatively homogenous initial 87Sr/86Sr(0.708 3-0.708 9)and εNd(-9.2--10.2)values.Geochemical and isotopic evidences indicate that the Tangquan granite originates from a hybrid source including lower crustal-derived felsic and lithospheric mantle-derived mafic magmas.Zircon U-Pb dating indicates that the granodiorite phase from the pluton crystallised at 161±4 Ma and the monzogranite phase crystallised at 159±1 Ma.Combined with the granitic rocks in a wider region of SE China,the widespread granitic magmatism and polymetallic mineralisation have been synchronous during the Late Mesozoic,probably resulting from extensional tectonics related to the lithospheric thinning.