ages of major iron formations worldwide
Most of the world's important iron ore resources occur in iron-rich sedimentary rocks known as banded iron formations (BIFs) which are almost exclusively of Precambrian age (i.e. greater than 600 million years old). BIFs occur on all continents.ustralian Resources. Although iron ore resources occur in all the Australian States and Territories, almost 93% of identified resources (totalling 64 billion tonnes) occur in Western Australia, including almost 80% in the Hamersley Province, one of the world's major iron ore provinces. Banded iron formation, Karijini National Park, Western Australia. 2.1 billion year old rock showing banded iron formation. Banded iron formations (also known as banded ironstone formations or BIF s) are distinctive units of sedimentary rock that are almost always of Precambrian age.anded iron beds are an important commercial source of iron ore, such as the Pilbara region of Western Australia and the Animikie Group in Minnesota. Banded-iron formations are iron formations which formed about 2,000 million years ago and were first described in the Lake Superior region. Sediments associated with the last stage of the Great Lakes tectonic zone contain banded-iron formations.he Trommald Formation – the principal iron formation of the North Range – is a chemically precipitated unit. This formation is 14 to 150 m (46 to 492 ft) thick and is composed of carbonate-silicate iron formations and associated manganese oxide deposits. The iron oxidised to form hematite. Banded iron formations (BIFs) are different – they were all formed at a time where the earth was a decidedly different environment than it is today. Banded iron formations are critical to our current economy as they are by far the biggest source of economic iron deposits.China and Australia are the world’s largest iron producers, and both have enormous reserves of BIFs. Smaller deposits are mined elsewhere including the USA and Canada.ustralia is the world’s largest exporter, and second largest producer, after China of iron ore. It is thought that there may be an economic resource of some 24 billion tonnes, however at current extraction rates most would be gone within 30 to 50 years. Conditions of a reappearance of a sea with dissolved iron at 1,900 million years ago, and later in association with Snowball Earth BIF reappeared 750 million years ago, and that is problematic to explain (see below).anded iron beds are an important commercial source of iron ore, such as the Pilbara region of Western Australia and the Animikie Group in Minnesota. Earth is fortunate to have enormous bodies of iron ore, but they occur only in peculiar and extremely ancient settings. Whereas the human Iron Age began about 3000 years ago, a tiny fraction of our lifetime as a species, Earth's Iron Age lasted over two billion years.he clear, oxygenated atmosphere we know dates from about 1700 million years ago, after two-thirds of Earth history. The vast layers of iron minerals stayed behind in rocks called banded iron formation, or BIF. The term iron-formation is perhaps the most enigmatic and controversial term ever concocted for a rock type. Iron formations were deposited in many parts of the world during the Early Proterozoic (Precambrian) in formations that are 500 to 2,000 feet or more thick and that extend for hundreds of miles.Therefore, thousands of cubic miles of iron-rich sediments were deposited in a number of basins.innesota leads the nation with 70% of the production, while Michigan produces most of the rest (25%). More than 98% of the iron ore that is shipped in the world is used to make steel, while the rest is used in pigments, chemicals, or in other, minor uses. In 2009 Australia produced 394 million tonnes of iron ore of which 362 million tonnes was exported valued at $30 billion. Western Australia produced 97% of the total production in 2009. Australia is the world's largest iron ore exporter and, as a producer, ranks second (with 17%) after China (39%).ustralian Resources. Although iron ore resources occur in all the Australian States and Territories, almost 93% of identified resources (totalling 64 billion tonnes) occur in Western Australia, including almost 80% in the Hamersley Province, one of the world's major iron ore provinces. Hamersley Province, Pilbara. The Hamersley province of Western Australia contains the largest area of banded iron formations in the world. This remote and sparsely population region remained undiscovered until 1952. The Pilbara BIF’s were deposited about 2400 million years ago, in the late Archaen early Proterozoic era.ustralia is the world’s largest exporter, and second largest producer, after China of iron ore. It is thought that there may be an economic resource of some 24 billion tonnes, however at current extraction rates most would be gone within 30 to 50 years. So far, rocks older than 3.0 billion years have been found in North America, India, Russia, Greenland, Australia, and Africa. The oldest rocks in North America, found in Minnesota, give a U-Pb discordia age of 3.56 billion years (Figure 5).o determine the age of the Solar System and the Earth, we must search for the oldest, least disturbed meteorites. K-Ar ages on stone meteorites range from about 400 million years to nearly 5 billion years, with a large concentration at 4.4 to 4.6 billion years.
Banded iron formation, Karijini National Park, Western Australia. 2.1 billion year old rock showing banded iron formation.