Climate variability during the late Ediacaran: Insights from episodic deposition of black shale-hosted Mn‑carbonates in South China

Abstract

The Ediacaran period witnessed events that were of significance to the evolution of Earth's environment and early life, especially the Neoproterozoic Oxygenation Event during the Shuram Event (ca. 570–562 Ma) that was followed by the rise of animal life. However, the nature of the climate change that followed the Shuram Event in South China remains unclear. Black shale-hosted Mn‑carbonate deposits have the potential to reveal valuable information about paleo-seawater conditions and paleoclimate. This paper presents results of an investigation of the unique Ediacaran mudstone succession of South China, especially black shale-hosted Mn‑carbonate deposits, and offers a new perspective of the interconnected nature of paleoclimate and Ediacaran deposits. Relying on detailed petrological, sedimentological, and geochemical data, we posit that Ediacaran Mn‑carbonates accumulated in a semi-enclosed basin that experienced oscillating water column redox conditions and enhanced primary productivity. Chemical index of alteration (CIA) values, Rb/Sr ratios, and δ13C − δ15N stratigraphy of the analyzed deposits provide evidence of episodic warming during an otherwise protracted cooling trend following the Shuram Event (ca. 562–551 Ma). This study highlights the significant utility of black shale-hosted Mn‑carbonate strata in reconstructing Earth's paleoclimate during transitions.