L. A. Frakes, B. R. Bolton; Origin of manganese giants: Sea-level change and anoxic-oxic history. Geology ; 12 (2): 83–86. doi: https://doi.org/10.1130/0091-7613(1984)12<83:OOMGSC>2.0.CO;2
Download citation file:
Inversely graded pisolites of manganese oxide in the mid-Cretaceous manganese giant at Groote Eylandt, Australia, were deposited during a regional fall in sea level, as indicated by their relationships to wave-cut benches. Dissolved manganese was concentrated in relatively anoxic waters of the intracratonic basin during a marine transgression and precipitated as oxides and carbonates during a regression. Ore bodies ultimately formed by concentration of abundant particulate manganese by a tidal-lag mechanism.