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Sample Y-B2-7
NavDat sample number 2913 · ANDESITE
Sample
| Sample ID | Y-B2-7 |
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| Rock name | ANDESITE |
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| Rock type | VOLCANIC |
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| Composition | INTERMEDIATE |
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| Material | IGNEOUS |
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| Collected by | Charles J. Vitaliano |
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| Comment | Dark gray to black, noticeably porphyritic andesite, consisting of 0.5-cm phenocrysts of zoned labradorite An50-66; 68% of the rock, 1-mm olivine 8%, augite 16%, magnetite 6%, and phlogopite 3% in a groundmass of microlites of these same minerals plus accessory apatite. The plagioclase phenocrysts are very slightly altered to clay, whereas the plagioclase microlites are unaltered. All the olivine is iddingsitized. There is a little interstitial glass in the groundmass. See Y-58441. |
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Location
| Latitude | 37.6958 |
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| Longitude | -117.156 |
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| Location | Nye County, NV |
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| State / province | Nevada |
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| Volcanic field | Goldfield-Tonopah region, West-Central Nevada |
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| Location comment | Upper labradorite andesite flow of the capping of Blackcap Mountain; 18 m above Y-B2-3 in the cliff face |
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Age
| Age (Ma) | Error | Min | Max | Geologic age | Dated by |
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| 12.1 |
|
11.7 |
12.5 |
|
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Analyses
Whole rock
| Item | Value | Std. dev. | Unit | Method |
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| SR87_SR86 | 0.7043 | | | MS |
