Recognition of the sedimentation age of a series of purple-red colored glutenite sedimentary rocks in Dahong Mountain area, northern Hubei Province: Detrital zircon U-Pb geochronology and its geological significance

The sedimentary age of a series of purple-red colored glutenite sedimentary rocks in Dahong Mountain area of northern Hubei Province is controversial. Some researchers hold that it is of late Jurassic period, while others believe it is of early Nanhua peri-od. In this paper, the authors studied detrital zircon geochronology of this layer and obtained 125 groups of effective age data which range from 3223Ma to 771Ma, and the age data are focused on three periods:late Neo-Archean to early Paleoproterozoic (~2500Ma), Paleoproterozoic (~2000Ma), and Neoproterozoic (~800Ma). The authors compared the petrological features and the detri-tal zircon age distribution of Liantuo Formation in southeastern Hubei, Three Gorges area, and the purple-red colored glutenite. It is considered that the Liantuo Formation in southeastern Hubei, Three Gorges area and the purple-red colored glutenite have similar sources. The sedimentary age of this series of purple-red colored glutenite sedimentary rocks in Dahong Mountain area of northern Hubei Province is early Nanhua period rather than the late Jurassic period. Based on a comprehensive analysis of the Precambrian age of Yangtze block, the authors hold that there may exist lots of Neo-Archean to early Paleoproterozoic concealed rocks, and the rocks around 2500Ma may be an important part of the basement of Yangtze block. There existed a magmatic activity around 2000Ma in Yangtze block, and it may be connect to the aggregate event of Columbia supercontinent. There is a Neoproterozoic rift on the northern margin of Yangtze block, which might be connected to the breakup of Rodinia supercontinent, and the basic rock was probably the source of the mafic gravel in the purple-red colored glutenite sedimentary rocks.