Geochemistry, petrogenesis and tectonic significance of the late Triassic A-type granite in Fujian, South China

摘要: The late Permian–Triassic granites in southeastern China have important tectonic significance for the evolution of South China. Here, we present detailed geochronological, geochemical and petrological analyses Jinlongyan (JLY) granite northwest Fujian Province, southeast LA–ICP–MS zircon U–Pb dating yielded a weighted average 206Pb/238U age 224.1 ± 3.3 Ma. is mainly comprised K-feldspar, plagioclase, quartz, biotite minor amphibole. It characterized by enrichments Rb, Th, REEs (total REE = 295.1–694.3 ppm), HFSEs (e.g., Zr = 289–520 ppm, Hf = 9.3–15.0 ppm, Y = 36.2–68.2 ppm) but depletions Ba, Sr, Eu Ti. metaluminous to weakly peraluminous show clear A-type signature with high SiO2 (70.89 wt%–75.76 wt%), total alkalis (Na2O + K2O = 7.51 wt% –8.72 wt%), Ga/Al ratios (10000 Ga/Al = 2.72–3.43). In-situ Hf isotope analysis shows their eHf(t) values ranging from −7.2 −3.2, Mesoproterozoic T2DM ages (1308–1525 Ma). Whole-rock Nd data eNd(t) range −9.5 −9.1 yield paleoproterozoic TDM (1606–1985 Ma). These characteristics indicate that JLY magma was formed partial melting Meso-Paleoproterozoic crust rocks Cathaysia Block. Our study granite, together other Triassic China, defines an extensional environment which probably caused collision Block Indochina