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Sample 4
NavDat sample number 4366 · TRACHYANDESITE
Sample
| Sample ID | 4 |
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| Alternate ID | 778 |
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| Rock name | TRACHYANDESITE |
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| Rock type | VOLCANIC |
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| Composition | INTERMEDIATE |
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| Material | IGNEOUS |
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| Comment | Hornblende-pyroxene trachyandesite lava. Rock crops out about 3 km northeast of fissure vent within the inferred cauldron. It contains about 27 percent phenocrysts comprising the following percentages of minerals: plagioclase, 59; hornblende, 28; clinopyroxene, 6.1; orthopyroxene, 6.9; opaque minerals are confined to dense groundmass. |
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Location
| Latitude | 38.9135 |
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| Longitude | -118.159 |
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| Location | Gabbs Valley, northeastern Mineral County, NV |
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| State / province | Nevada |
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Age
| Age (Ma) | Error | Min | Max | Geologic age | Dated by |
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| 25 |
|
22.5 |
27.5 |
|
|
Analyses
Whole rock
| Item | Value | Std. dev. | Unit | Method |
|---|
| SIO2 | 58.1 | | WT% | XRF |
| AL2O3 | 20.75 | | WT% | XRF |
| FEO | 5.51 | | WT% | XRF |
| MGO | 2.84 | | WT% | AAS |
| CAO | 5.48 | | WT% | AAS |
| NA2O | 4.21 | | WT% | AAS |
| K2O | 2.15 | | WT% | AAS |
| TIO2 | 0.85 | | WT% | XRF |
| MNO | 0.1 | | WT% | XRF |
