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Sample 131sh
NavDat sample number 15257 · SHONKINITE
Sample
| Sample ID | 131sh |
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| Rock name | SHONKINITE |
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| Rock type | VOLCANIC |
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| Composition | MAFIC |
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| Material | IGNEOUS |
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| Comment | main shonkinite; medium grained, massive, broadly homogeneous; subequal proportions of augite and K-feldspar sanidine; minor amounts of biotite, olivine, magnetite, and apatite |
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Location
| Latitude | 47.47 |
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| Longitude | -110.24 |
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| Location | Square Butte |
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| State / province | Montana |
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| Volcanic field | Square Butte laccolith of Central Montana Alkalic Province |
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Age
| Age (Ma) | Error | Min | Max | Geologic age | Dated by |
|---|
| 44.5 |
|
34 |
55 |
|
|
