Iron-rich sedimentary rocks

Iron-rich sedimentary rocks are sedimentary rocks which contain 15 wt.% or more iron. However, most sedimentary rocks contain iron in varying degrees. The majority of these rocks were deposited during specific geologic time periods: The Precambrian (3800 to 539 million years ago), the early Paleozoic (539 to 419 million years ago), and the middle to late Mesozoic (205 to 66 million years ago). Overall, they make up a very small portion of the total sedimentary record.

Iron-rich sedimentary rocks have economic uses as iron ores. Iron deposits have been located on all major continents with the exception of Antarctica. They are a major source of iron and are mined for commercial use.^[1] The main iron ores are from the oxide group consisting of hematite, goethite, and magnetite. The carbonate siderite is also typically mined. A productive belt of iron formations is known as an iron range.^[2]