Modern and Palaeozoic iron ooids—a similar volcanic origin

The discovery of an unconsolidated deposit of iron ooids of a kind not previously described, and in the vicinity of a volcanic island in Indonesia has shed new light on the genesis of many ancient iron oolites. The discovery shows that iron ooid formation is geologically a rapid process. The ooids form by chemical precipitation of cryptocrystalline iron oxyhydroxides on available grains on the seafloor, from seawater enriched with Fe, Al and …