← Search
Sample 79-61B
NavDat sample number 8391 · RHYOLITE
Sample
| Sample ID | 79-61B |
|---|
| Rock name | RHYOLITE |
|---|
| Rock type | VOLCANIC |
|---|
| Composition | FELSIC |
|---|
| Material | IGNEOUS |
|---|
| Comment | Obsidian sample, no phenocrysts; much of the glass has devitrified along perlitic cracks to a cryptocrystalline felsitic aggregate containing tiny feldspar microlites randomly oriented. |
|---|
Location
| Latitude | 41.6317 |
|---|
| Longitude | -121.393 |
|---|
| State / province | California |
|---|
| Volcanic field | Medicine Lake Highland |
|---|
| Location comment | 3.7 mi WSW of Tionesta and 1 mi S of the Lava Beds National Monument-State Rte 139 road |
|---|
Age
| Age (Ma) | Error | Min | Max | Geologic age | Dated by |
|---|
| 0.24 |
|
0.21 |
0.27 |
|
|
Analyses
Whole rock
| Item | Value | Std. dev. | Unit | Method |
|---|
| SIO2 | 74.76 | | WT% | XRF |
| AL2O3 | 13.27 | | WT% | XRF |
| FEO | 1.36 | | WT% | XRF |
| FE2O3 | 0.21 | | WT% | XRF |
| TIO2 | 0.26 | | WT% | XRF |
| MNO | 0.03 | | WT% | XRF |
| MGO | 0.22 | | WT% | XRF |
| CAO | 0.92 | | WT% | XRF |
| NA2O | 3.6 | | WT% | XRF |
| K2O | 4.6 | | WT% | XRF |
| P2O5 | 0.04 | | WT% | XRF |
