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Sample SW-75-191
NavDat sample number 8389 · RHYOLITE
Sample
| Sample ID | SW-75-191 |
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| Rock name | RHYOLITE |
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| Rock type | VOLCANIC |
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| Composition | FELSIC |
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| Material | IGNEOUS |
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| Comment | Cream to buff colored lava, often platy due to flow jointing; plagioclase An40, orthopyroxene, clinopyroxene, resorbed hornblende, and titanomagnetite as small <1 mm phenocrysts set in a trachytic cryptocrystalline groundmass composed of plagioclase microlites, granular opaques, and devitrified glass. |
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Location
| Latitude | 41.5325 |
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| Longitude | -121.743 |
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| State / province | California |
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| Volcanic field | Medicine Lake Highland |
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| Location comment | 1/2 mi SW of summit of Red Cap Mountain along the ridge crest |
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Age
| Age (Ma) | Error | Min | Max | Geologic age | Dated by |
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| 1.01 |
|
0.96 |
1.06 |
|
|
Analyses
Whole rock
| Item | Value | Std. dev. | Unit | Method |
|---|
| SIO2 | 72.53 | | WT% | XRF |
| AL2O3 | 15 | | WT% | XRF |
| FEO | 1.17 | | WT% | XRF |
| FE2O3 | 0.79 | | WT% | XRF |
| TIO2 | 0.24 | | WT% | XRF |
| MNO | 0.04 | | WT% | XRF |
| MGO | 0.5 | | WT% | XRF |
| CAO | 1.82 | | WT% | XRF |
| NA2O | 3.51 | | WT% | XRF |
| K2O | 3.36 | | WT% | XRF |
| P2O5 | 0.05 | | WT% | XRF |
