Petrogenesis and geodynamic implications of garnet-bearing dacitic volcanic rocks associated with Fuchuan ophiolite complex, Southeast China

Abstract Garnet-bearing silicic volcanic rocks are rare in fossil orogens and usually record a transient stage from regional compression to extension. This study reports newly identified 839 ± 3 Ma garnet-bearing dacitic volcanic rocks associated with the Fuchuan ophiolite complex (FOC) in the eastern Jiangnan Orogen (JO), Southeast China. The presence of these unusual rocks provides new constraints on the late Neoproterozoic tectonic evolution of the orogen. The garnet-bearing dacitic volcanic rocks of the garnets are weakly peraluminous and exhibit trace element and Nd isotopic signatures similar to those of post-orogenic, strongly peraluminous granites in the eastern JO, indicating a similar crustal source. The garnets are almandine-rich (76–79 wt%) and characterized by low CaO (