Early Paleozoic and Late Mesozoic crustal reworking of the South China Block: Insights from Early Silurian biotite granodiorites and Late Jurassic biotite granites in the Guangzhou area of the south-east Wuyi-Yunkai orogeny

• Published in: Journal of Asian earth sciences Vol. 219; p. 104890
• Main Authors: Liu, Xiao, Wang, Qiang, Ma, Lin, Yang, Jin-Hui, Ma, Yi-Ming, Huang, Tong-Yu
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.10.2021
• Subjects: Continental crust reworking; Crust–mantle interaction; Granitoids; SE Wuyi-Yunkai orogen; South China; SE Wuyi-Yunkai orogen; Continental crust reworking; Crust–mantle interaction; South China; Granitoids
• ISSN: 1367-9120; 1878-5786
• DOI: 10.1016/j.jseaes.2021.104890

[Display omitted] •Two periods (442 Ma and 164–159 Ma) of granitoids occur at the Guangzhou area.•Early Paleozoic reworking of Guangzhou area was caused by crust double-thickening.•Late Mesozoic reworking of Guangzhou area was heated by underplating mafic magmas. The South China Block (SCB) is considered to have undergone extensive reworking of continental crust. However, the processes and mechanisms of this reworking remain uncertain. Here, we investigated Early Silurian (442 Ma) biotite granodiorites and Late Jurassic (164–159 Ma) biotite granites in the Guangzhou area of SE Wuyi-Yunkai orogen (WYO), South China. The biotite granodiorites and biotite granites show major and trace element characteristics similar with crustal-derived melts. They have enriched whole-rock Sr–Nd ((87Sr/86Sr)i = 0.7108–0.7210; εNd(t) =  − 11.7 to −7.6) and zircon Hf (εHf(t) =  −17.2 to −1.7) isotopic compositions. Early Silurian biotite granodiorites have relatively homogeneous zircon δ18O values (8.6‰–9.3‰) while Late Jurassic biotite granites show a wide range of zircon δ18O values (7.4‰–10.6‰). We suggest that the Early Silurian biotite granodiorites were formed by partial melting of amphibolites and that the Late Jurassic biotite granites were formed by partial melting of a hybridized crustal source containing metasedimentary rocks with subordinate juvenile crustal rocks. Combining our results with those of previous studies in the SCB, we suggest that Early Paleozoic intracontinental reworking of the SCB can be divided into three stages: crust double-thickening, orogenic collapse, and post-orogenic lithospheric extension. During the Late Ordovician to Early Silurian, Guangzhou area of the SE WYO underwent reworking mainly of middle–lower-crustal rocks in response to crust double-thickening. In addition, during the Late Jurassic, the area underwent reworking mainly of middle–lower-crustal metasedimentary rocks, which was induced by heating from mantle-derived mafic magmas.