Slab breakoff beneath the northern Yangtze Block: Implications from the Neoproterozoic Dahongshan mafic intrusions

The Neoproterozoic magmatism in South China may have been related to assembly and breakup of the supercontinent Rodinia. The ca. 815-Ma mafic intrusions in the Dahongshan region at the northern Yangtze Block are composed of fine- to medium-grained gabbro and diabase, which show variable major and trace element compositions with (La/Yb)N ratios of 0.53–3.43. The mafic rocks also have large ranges of initial 87Sr/86Sr ratios (0.70318–0.70810), ƐNd...