what type of rock is iron
Iron-rich sedimentary rocks are sedimentary rocks which contain 15% 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 570 million years ago), the early Paleozoic (570 to 410 million years ago), and the middle to late Mesozoic (205 to 66 million years ago).