Distribution and geochemical significance of trace elements in kerogens from Ediacaran–Lower Cambrian strata in South China

Some trace elements (TEs), both bio-essential and redox-sensitive, are promising tracers of Earth’s surface processes. As an essential sedimentary organic matter, kerogen may have inherited and retained the key TEs from organisms. In this study, the distribution of TEs in kerogens from two sections (Dongkanshang and Fengtan) in South China was analyzed to explore its biogeochemical significance during Ediacaran–Lower Cambrian. Compared with V and Zn, the relative concentrations of Co, Ni, Cu, and Mo were generally higher in kerogens than in the whole rocks. Enrichment of TEs in the kerogen was involved in the selective utilization of TEs by different organic precursors and the competition of sulfide in the depositional environment. The significant content of TEs in the kerogens from deep-water facies corresponded to a more negative δ 13 C ker as a result of the dominant taxa of chemoautotrophs with tremendous bioaccumulation potential for trace metals and the reduction conditions favorable for organic matter preservation. Furthermore, the content variations of trace elements in the kerogens coincided with the rise and fall of the Ediacaran biota, implying that the trace elements might have played an important role in early life evolution.