How do iron-ore deposits form?

A) as iron-rich layers, called iron formations, in sedimentary sequences
B) within granite or sandstone
C) the mixing of different types of groundwater
D) groundwater that encounters ancient buried hills
E) all of these

Iron-Ore Deposits

Concentrations of iron minerals within the Earth that can be mined and processed to extract iron metal.

Iron Formations

Geological formations composed of layered sediments and minerals, predominantly iron-rich, that were deposited in ancient oceanic and lake environments.

Sedimentary Sequences

Layers of sedimentary rocks that record the geological history of an area, often showing a progression of depositional environments.