Foidolite
A rock classification type
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About Foidolite
Foid-rich rocks in which >60% of the light coloured minerals are foids.
A coarse-grained crystalline rock with <90% mafics, >60% of felsics being foids.
A coarse-grained crystalline rock with <90% mafics, >60% of felsics being foids.
Unique Identifiers
Mindat ID:
48384
Long-form identifier:
mindat:1:1:48384:7
Classification of Foidolite
Foidolite is in section 15 of the QAPF diagram.
Sub-divisions of Foidolite
Mineralogy of Foidolite
Essential minerals - these are minerals that are required within the classification of this rock:
| Feldspathoid | A family of rock-forming minerals consisting of aluminosilicates of sodium, potassium, or calcium and having too ... |
Non-essential minerals - these minerals are common, sometimes major components, but are not always present:
| Amphibole > Hornblende | AnCa2(Z2+5-mZ3+m)(Si8-(n+m)Al(n+m))(OH,F,Cl)2 |
| Mica > Biotite | K(Fe2+/Mg)2(Al/Fe3+/Mg/Ti)([Si/Al/Fe]2Si2O10)(OH/F)2 |
Age distribution
Recorded ages:
Paleoproterozoic to Triassic : 1910 Ma to 220 ± 1 Ma - based on 9 recorded ages.
Sample ages:
| Sample ID | Recorded age | Geologic Time | Dating method |
|---|---|---|---|
| 1 | 220 ± 1 Ma | Late/Upper Triassic | Sm-Nd |
| 2 | 239.8 Ma | Middle Triassic | K-Ar |
| 3 | 373.3 ± 8.1 to 367.4 ± 4.9 Ma | Late/Upper Devonian | Rb-Sr |
| 4 | 418 to 374 Ma | Devonian | K-Ar |
| 5 | 462 Ma | Middle Ordovician | Sm-Nd isochron |
| 6 | 1790 to 1710 Ma | Statherian | K-Ar |
| 7 | 1910 to 1830 Ma | Orosirian | K-Ar |
Sample references:
Chemical Analysis
Oxide wt%:
| 1 | |
|---|---|
| TiO2 | 0.30 % |
| ZrO2 | 0.41 % |
| Al2O3 | 22.30 % |
| Fe2O3 | 3.07 % |
| FeO | 2.21 % |
| MnO | 0.13 % |
| MgO | 0.09 % |
| CaO | 1.4 % |
| Na2O | 15.76 % |
| K2O | 3.58 % |
| P2O5 | 0.03 % |
| H2O | 1.46 % |
| Cl | 2.86 % |
| F | 0.29 % |
| CO3 | 0.16 % |
| SiO2 | 46.85 % |
| Total: | 100.9 % |
Sample references:
| ID | Locality | Reference | Notes |
|---|---|---|---|
| 1 | Ilímaussaq complex, Kujalleq, Greenland | Average of 7 analyses of naujaite consisting of K‑feldspar/perthite (25.7 vol%), nepheline (9.9 vol%), altered pyroxenes (6.6 vol%), amphiboles (5.6 vol%), aenigmatite(1.7 vol%), eudialyte (4.9 vol%), sodalite (40.2 vol%), analcime (3.6 vol%), natrolite (1.7 vol%), fluorite (0.1 vol%), apatite (tr), others (tr). The analytical method not given, presumably wet chemical. |
Synonyms of Foidolite
Common Associates
Associations Based on Photo Data:
| 2 photos of Foidolite associated with Feldspar Group | |
| 1 photo of Foidolite associated with K Feldspar | |
| 1 photo of Foidolite associated with Microcline | K(AlSi3O8) |
| 1 photo of Foidolite associated with Quartz | SiO2 |
| 1 photo of Foidolite associated with 'Amphibolite' | |
| 1 photo of Foidolite associated with 'Metagabbro' | |
| 1 photo of Foidolite associated with 'Granite' | |
| 1 photo of Foidolite associated with 'Hornblende-rock' |
Internet Links for Foidolite
mindat.org URL:
https://www.mindat.org/min-48384.html
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References for Foidolite
Reference List:
Ice River Alkaline Complex, Golden Mining Division, British Columbia, Canada