Deposit types/Iron ore

Banded iron formation (Superior and Algoma types)

Thin layers of iron-rich rock alternating with chert, in beds of great lateral extent.

What it is

Thin layers of iron-rich rock alternating with chert, in beds of great lateral extent.1

How it forms

Superior-type formations were laid down in shallow marine water on stable continental shelves. Algoma-type formations formed in volcanically active ocean belts. Later weathering can enrich the iron into high-grade ore.1

Host rocks

Quartzite, shale and dolomite (Superior); submarine volcanic rocks and deep-water sediment (Algoma).1

Where it forms

Stable shelf or intracraton basins (Superior); volcanic belts preserved in Precambrian shields (Algoma).1

How old

Superior mostly Early Proterozoic (about 2.0 Ga); Algoma mostly Archean1

Mines of this type

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Mines

An example ofHamersley Mines - Mount Tom PriceSee Hamersley Mines - Mount Tom Price, an example of this deposit type.1An example ofHamersley Mines - ParaburdooSee Hamersley Mines - Paraburdoo, an example of this deposit type.1An example ofMount NewmanSee Mount Newman, an example of this deposit type.1An example ofCarajas S11D / Northern SystemSee Carajas S11D / Northern System, an example of this deposit type.1An example ofKoolyanobbingSee Koolyanobbing, an example of this deposit type.1An example ofRoy HillSee Roy Hill, an example of this deposit type.1An example ofCloudbreakSee Cloudbreak, an example of this deposit type.1

Sources

  1. Mineral Deposit Models (Bulletin 1693, Cox and Singer, eds., 1986) US Geological Survey

From the Prospector Trails mining history dataset: each fact links to the source it was checked against. Figures are as the source gives them, in the money of their day. Not investment advice.

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