Work

The genetic relationship between the metallogenesis of polymetallic nodules in the West Pacific and the evolution of the Antarctic ice sheet

Year: 2025

Type: article

Abstract: Polymetallic nodules are exceptionally enriched in critical metals such as cobalt (Co), nickel (Ni), and copper (Cu), drawing significant attentions from researchers. While previous studies have primarily focused on the metal enrichment aspect, the interactions and cycling processes of metals across Earth's various spheres are often overlooked. This study focuses on polymetallic nodules from the West Pacific, integrating multi-method dating and geochemical analysis to reconstruct the metallogenic chronology, geochemical signatures and the enrichment of critical metals, with the aim of exploring the link between the Antarctic ice-sheet's evolution and polymetallic nodule formation. The growth structure of the polymetallic nodules is divided into four layers (I, II, III, IV) from the center outward, with three sedimentary unconformities identified. Dating analyses reveal that the core formed between 32 and 34 Ma, with sedimentary unconformities occurring at >25 Ma, 10–17 Ma, and ~ 3.2 Ma. Notably, the core's formation age aligns with the initial development of the Antarctic ice-sheet, while the sedimentary unconformities coincide with global warming periods. Since 25 Ma, the variations in 1/Ce₂O₃, Mn/Fe, and Ni/Co exhibit a coupled relationship. Most notably, the variation pattern of Mn/Fe closely track the evolution of the Antarctic ice-sheet. A positive correlation is observed between Mn/Fe ratios and the contents of Co, Ni, Cu, and Ca in the polymetallic nodules. The temporal correlation between key metallogenetic events in the polymetallic nodules and Antarctic ice-sheet fluctuations, along with the coupled variations in geochemical growth curves, strongly suggests that the Antarctic ice-sheet's evolution has played an important role in altering the characteristics of Antarctic bottom water (AABW). These changes, in turn, have influenced the metal enrichment processes in the polymetallic nodules of the West Pacific.

Source: Global and Planetary Change

DOI: 10.1016/j.gloplacha.2025.105117