What is this layer?
SiO2 content in weight per cent for iron-formation rocks, derived from the GSWA geochemistry database.
Legend
|
Legend |
Range (wt%) |
Classification |
Description |
Reference |
|---|---|---|---|---|
|
SiO2 wt% SOURCE-TRAP |
0–20% |
Manual breaks |
Equivalent to 55–73 wt% Fe total. Considered to be representative of higher grade iron formation hosted deposits by some researchers and explorers |
|
|
20–40% |
Manual breaks |
Equivalent to 40–55 wt% Fe total |
||
|
40–60% |
Manual breaks |
Equivalent to 30–40 wt% Fe total |
||
|
60–80% |
Manual breaks |
Chert-rich BIF, equivalent to 15–30 wt% Fe total |
||
|
80–100% |
Manual breaks |
Unlikely to be BIF based on its classification (i.e. a sedimentary rock containing at least 15 wt% Fe total, or 20 wt% Fe2O3 total). Possibly a silica-altered BIF? |
BIF classification after James (1954) |
References
Duuring, P, Angerer, T and Hagemann, SG 2017, Iron ore deposits of the Yilgarn Craton, in Australian ore deposits edited by GN Phillips, G.N: Australasian Institute of Mining and Metallurgy, Melbourne, p. 181–184.
James, HL 1954, Sedimentary facies of iron-formation: Economic Geology, v. 49, p. 235.