Pedogenesis and geochronology of Cretaceous adakitic, I- and A-type granitoids in the NE Yangtze block: Constraints on the eastern subsurface boundary between the North and South China blocks: Comment

摘要

A careful literature investigation for the North China and Yangtze Precambrian basements shows a distinct overlap of the Nd-Pb-Hf isotopes between these two cratonic basements. The isotopes of Early Cretaceous adakitic granitoids from Chuzhou (east of the Tanlu fault zone) in the northeastern Yangtze block fall into the overlap fields. These isotopes therefore cannot be used to distinguish the derivation of the Chuzhou adakitic rocks from the North China or Yangtze basements. Moreover, high-resolution deep seismic probing across the Dabie, Sulu UHP terranes and east-central China all indicates the Yangtze craton was thrust beneath the North China craton. The Chuzhou adakitic rocks were most likely derived from the Archean to Paleoproterozoic lower crust of the Yangtze craton. The North China and Yangtze cratons are most probably separated by the Dabie-Tanlu-Sulu-Imjingang belts, and a subsurface North China-Yangtze boundary located near Nanjing is unsuitable.