Banded iron formations (also known as banded ironstone formations or BIFs) are a distinctive type of rock often found in primordial
sedimentary rocks. The structures consist of repeated thin layers of
iron oxides, either
magnetite or
hematite, alternating with bands of iron-poor
shale and
chert. Some of the oldest known rock formations, formed around three thousand million years before present (3
Ga), include banded iron layers, and the banded layers are a common feature in
sediments for much of the
Earth's early history. Banded iron beds are less common after 1.8 Ga, although some are known that are much younger.
See more at Wikipedia.org...
A rock that is made up of alternating light silica-rich layers and dark-colored layers of iron-rich minerals, which were deposited in marine basins on every continent about 2 billion years ago.
Free Download Now!
