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Sample 3-27-89-10
NavDat sample number 30303 · TUFF
Sample
| Sample ID | 3-27-89-10 |
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| Rock name | TUFF |
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| Rock type | VOLCANIC |
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| Composition | FELSIC |
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| Material | IGNEOUS |
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| Comment | on southeast-facing slope, west side of Deadman Canyon; elevation 1,100 ft. Light- to dark-gray, fine-grained crystal vitric tuff; devitrification is pervasive, original bubble-wall glass shards approximately0.01-0.02mm have been replace by smectite; contains crystals approximately0.005- 0.03mm of quartz, plagioclase, hornblende, biotite, opque minerals, and rare sphene; 80% glass, 20% crystals; tuff unit is thinly to thickly laminated with silt laminae, interbedded with shale beds 2-3 in 5-8 cm thick; rare bivalved mollusk Platyodon colobus Woodring in situ in shale interbed; basal contact is sharp and planar, upper contact is intermixed with overlying fossiliferous sandstone; 10 ft 3 m thick. Low K content reflects diagenetic alteration of glass shards; age is too old based on stratigraphic position and fission-track, K-Ar, and Sr isotope data |
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Location
| Latitude | 36.0353 |
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| Longitude | -120.375 |
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| Location | Etchegoin Formation |
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| State / province | California |
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Age
| Age (Ma) | Error | Min | Max | Geologic age | Dated by |
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| 8.1 |
|
7.2 |
9 |
|
|
