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Sample JM-2A
NavDat sample number 9435 · TRACHYTE
Sample
| Sample ID | JM-2A |
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| Rock name | TRACHYTE |
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| Rock type | VOLCANIC |
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| Composition | INTERMEDIATE |
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| Material | IGNEOUS |
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| Comment | occurs as dikes, sills, and small intrusive masses; excellent trachytic texture defined by sanidine, the dominant mineral, in phenocrysts; also contains aegerine-augite, melanite, and analcite; groundmass comprises at least 70% of rock and consists mainly of sanidine and aegerine |
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Location
| Latitude | 47.2406 |
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| Longitude | -109.022 |
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| State / province | Montana |
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| Volcanic field | Linster Peak Dome |
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Age
| Age (Ma) | Error | Min | Max | Geologic age | Dated by |
|---|
| 67 |
|
64 |
69 |
|
|
Analyses
Whole rock
| Item | Value | Std. dev. | Unit | Method |
|---|
| SIO2 | 58.2 | | WT% | XRF |
| AL2O3 | 18.05 | | WT% | XRF |
| TIO2 | 0.67 | | WT% | XRF |
| FEOT | 5.77 | | WT% | XRF |
| MNO | 0.17 | | WT% | XRF |
| CAO | 3.65 | | WT% | XRF |
| MGO | 0.98 | | WT% | XRF |
| K2O | 7.45 | | WT% | XRF |
| NA2O | 4.91 | | WT% | XRF |
| P2O5 | 0.14 | | WT% | XRF |
| TOTAL | 99.99 | | WT% | XRF |
| RB | 204 | | PPM | XRF |
| SR | 761 | | PPM | XRF |
