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Banded Iron formations occur in Proterozoic rocks, ranging in age from 1.8 to 2.5 billion years old. They are composed of alternating layers of iron-rich material (commonly magnetite) and silica (chert).
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Banded iron formations are very large bodies of sedimentary rock laid down some 2.5 billion years ago. At that time, the Earth still had its original atmosphere of nitrogen and carbon dioxide.
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This history is documented by the geologic preservation of oxygen-sensitive minerals, deposition banded iron formations, and development of continental "red beds" or BIFs.
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Banded iron formation - Wikipedia, the free encyclopedia
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Banded Iron Formation (BIF) Banded iron formation is iron rich chert (cryptocrystalline silica (SiO...
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PRECAMBRIAN BANDED IRON-FORMATIONS (BIFS) WORLD-WIDE: THEIR GEOLOGIC SETTING, MINERALOGY, METAMORPHISM, AND ORIGIN...
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Banded Iron Formations (BIFs)
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Banded iron formations (also known as banded ironstone formations or BIFs) are a distinctive type of rock often found in primordial sedimentary rocks. Some of the oldest known rock formations, formed around three thousand million years before present (3 Ga), include banded iron layers,
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FIGURE 1. A 2.5-Gyr-old banded iron formation from Hamersley, Australia.
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Subducted banded iron formations as a source of ultralow-velocity zones at the core-mantle boundary. Here we suggest that ULVZs might instead be relics of banded iron formations subducted to the core-mantle boundary between 2.8 and 1.8 billion years ago.
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