Sample: 81ASj-30
| Sample ID: | 81ASj-30 [1] |
| Station ID: | 81ASj-30 |
| AT Num: | |
| Volcano: | |
| Possible source: | |
| Eruption: | |
| Collector: | Unknown, Unknown |
| Date sampled: | 1981-00-00 |
| Sample type 1: | |
| Color: | |
| Final unit: | |
| Text Description: | Wrangell Lava. Young Creek volcanic and volcaniclastic rocks. Andesite lavas and mudflows (Tertiary) - A sequence of tilted and interlayered porphyritic to aphanitic andesite lava flows and mudflows that dip 20-30 degrees north. Two whole-rock K-Ar determinations on the same sample give ages of 18.6 and 19.1 Ma (map letter C). These ages are too young, and probably have been reset, because unit is unconformably overlain by shield lavas of the Sonya Creek volcano (about 20 Ma) and is intruded and tilted by subvolcanic rocks (unit Tdd) that are probably 23 Ma or older. Unit has an aggregate thickness of about 1,000 m, but base is not exposed. |
| Sample Location: |
References Cited
[1] Geologic map of the McCarthy D-1 Quadrangle, Alaska, 2000
Richter, D. H., Ratte, J. C., Leeman, W. P., and Menzies, Martin, 2000, Geologic map of the McCarthy D-1 Quadrangle, Alaska: U.S. Geological Survey Miscellaneous Investigations Series Map I 2695, unpaged, 1 sheet, scale 1:63,360.
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