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Sample USGSD8271
NavDat sample number 19142 · DACITE
Sample
| Sample ID | USGSD8271 |
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| Rock name | DACITE |
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| Rock type | VOLCANIC |
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| Composition | FELSIC |
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| Material | IGNEOUS |
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| Collected by | R.G. Tysdal |
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| Comment | hornblende dacite porphyry sill; since sill intrudes Cretaceous strata that could not be as old as 96 Ma based on megafaunal data; spurious age is probably due to excess radiogenic argon |
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Location
| Latitude | 45.2397 |
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| Longitude | -111.517 |
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| Location | central Madison Range; Madison County |
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| State / province | Montana |
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| Volcanic field | intrusive complex at Lone Mountain |
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Age
| Age (Ma) | Error | Min | Max | Geologic age | Dated by |
|---|
| 95.9 |
|
89.9 |
101.9 |
|
|
Analyses
No chemical analyses are stored for this sample.
References
- Marvin, Richard F; Mehnert, Harald H; Naeser, Charles W; Zartman,Robert E (1989) U. S. Geological Survey radiometric ages; Compilation C; Part five;Colorado, Montana, Utah, and Wyoming. Isochron/West, vol.53, pp.14-19, Jun 1989
