Sample 221
NavDat sample number 2706 · PHONOLITE
Sample
| Sample ID | 221 |
|---|---|
| Rock name | PHONOLITE |
| Rock type | VOLCANIC |
| Composition | INTERMEDIATE |
| Material | IGNEOUS |
| Comment | microcrystalline porphyry; holocrystalline groundmass of alkali fedspar, plagioclase, analcite, nepheline; phenocrysts of pyroxene and amphibole |
Location
| Latitude | 44.2974 |
|---|---|
| Longitude | -103.72 |
| Location | Bear Butte Creek |
| State / province | South Dakota |
Age
| Age (Ma) | Error | Min | Max | Geologic age | Dated by |
|---|---|---|---|---|---|
| 49 | 39 | 60 |