The largest iron deposit on Earth begins
Iron settles out of the ocean in banded layers holding tens of trillions of tonnes.
- When
- —
- Duration
- 180 million years
- Known to
- ± 20 million years
- Era
- Neoarchean, Archean
The Hamersley Group in Western Australia accumulates from about 2.63 to 2.45 billion years ago, and its Joffre Member alone is the single largest banded iron formation known — roughly 4.3 × 10¹³ tonnes of iron at deposition. Such volumes require an ocean saturated with dissolved iron and something steadily oxidising it. The Pilbara ore that resulted underpins the modern steel industry and Australia's largest export.