Geochemical characteristics of organic-rich intervals within the Cryogenian non-glacial Datangpo Formation in southeastern Yangtze Block-implications for paleoenvironment and its control on organic matter accumulation

•High-resolution geochemical data were presented for the Cryogenian non-glacial strata.•Organic-rich intervals with TOC greater than 2% occurred in basal Mn-rich deposition and overlying black shales.•Hydrothermal activities and improved postglacial water mass exchange promoted OM enrichment for the Mn-rich deposition.•Our results suggest elevated primary productivity due to enhanced chemical weathering during deposition of the black shales.