New SIMS U-Pb zircon age and its constraint on the beginning of the Nantuo glaciation.

A new SIMS U-Pb zircon age of 654.2 ± 2.7 Ma was reported from the middle Datangpo Formation in Changyang County of Hubei Province, China. The age is identical with that of 654 ± 3.8 Ma from the top Datangpo Formation in western Hunan Province, revealing that the volcanic activities (~654 Ma) may have occurred widely in South China. The occurrence of the tuff beds (~654 Ma) at different intervals of the Datangpo Formation indicates that the erosion process after the Datangpo deposition varied significantly in different areas. It is thus consequently suggested that the rift in South China was active until the Nantuo glaciation. In addition, the new age confirms that the Nantuo glaciation started much later than 654 Ma. [ABSTRACT FROM AUTHOR]