Abstract:
In the late Mesoproterozoic period, a series of major plate tectonics, biological and environmental events occurred on the Earth, attracting more and more attention in the geosciences circle. Stratigraphic successions spanning this critical period are well developed and exposed in the northern part of Yangtze Block, laying the foundation for studying these late Mesoproterozoic major events. Although extensive stratigraphic, paleontological and geochemical studies have been carried out on these successions, their sedimentation period and geochronological frameworks are not well established. In this paper, we summarize the geochronological data of upper Mesoproterozoic in the northern part of Yangtze Block, discuss their consistency against the stratigraphic sequence, and propose a temporary geochronological framework and correlation scheme for these successions. The new framework shows that the Shennongjia Group lacks age constraints on its lower boundary and its deposition ended at ca 1.1 Ga; the lower part of Macaoyuan Group could be correlated to the upper part of Shennongjia Group and the deposition of its upper part may last till Neoproterozoic; the middle part of Dagushi Group is correlative with the upper part of Shennongjia Group, and the lower part of Dagushi Group including the Taiyangsi and Hanjiawa formations were deposited during the early Neoproterozoic, younger than the overlying Luohanling Formation, which indicates a reverse stratigraphic sequence within Dagushi Formation partially.