A refined late-Cryogenian – Ediacaran Earth history of South China: phosphorous-rich marbles of the Dabie and Sulu orogens

• Published in: Precambrian Research
• Main Authors: Prave, Anthony R, Meng, F., Lepland, Aivo, Kirsimäe, Kalle, Kreitsmann, Timmu, Jiang, C.Z.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Elsevier 2017
• Subjects: VDP::Mathematics and natural science: 400::Geosciences: 450::Mineralogy; petrology; geochemistry: 462; VDP::Matematikk og Naturvitenskap: 400::Geofag: 450::Mineralogi; petrologi; geokjemi: 462; Dabie Orogen; Sulu Orogen; Haizhou Group; Susong Group; Ediacaran; Marinoan glaciation; Phosphorite; Arctic
• Online Access: https://hdl.handle.net/10037/14335; https://doi.org/10.1016/j.precamres.2017.11.022

Accepted manuscript version. Published version available at https://doi.org/10.1016/j.precamres.2017.11.022 . Licensed CC BY-NC-ND 4.0. The late-Cryogenian – Ediacaran geological framework for South China is constructed principally from sedimentary successions preserved in the central and western regions of the Yangtze Block. New stratigraphic and carbonate-carbon isotope data allow us to extend that framework into the exhumed HP-UHP subduction complexes of the eastern Dabie and Sulu orogens that separate the South and North China cratons. Those data show that marble and phosphorous-rich (P-rich) units in those complexes were originally part of an Ediacaran shallow-marine shelf-carbonate platform. The basal pebbly schist (metadiamictite) and lowermost P-rich marble of the Jinping Formation (Haizhou Group) in the Sulu Orogen matches in both facies character and C-isotope profile that of the Marinoan-equivalent glacial-cap carbonate couplet of the Nantuo and Doushantuo formations. The Daxinwu Formation (Susong Group) in the eastern Dabie Orogen contains a marble unit that has, for several hundreds of metres, a strikingly uniform C-isotope profile of low δ 13 C positive values and is overlain by a P-rich graphitic schist; these features match those of the late Ediacaran to early Cambrian Dengying Formation. These correlations establish that the HP-UHP metasedimentary rocks, many of which were once considered to be Palaeo- to Mesoproterozoic in age, are a Neoproterozoic-age cover sequence of the continental margin of the Yangtze Block. Further, their widespread development limits their utility as indicators of offset across the Tan-Lu fault zone and, instead, favours tectonic models that interpret that feature as a continental-scale tear fault formed during the Mesozoic collision and suturing of the North and South China cratons.