Outcrop or artificial surface exposure, Hornblende andesite
| Geographic location |
-158.483333, 56.233333
158°
29'
"
W,
56°
14'
"
N
AK
Chignik A-2
1:63,360 scale map quadrangle
Accurate to within 0.1 minute (~500 feet)
along S fork of the river which flows into Mallard Duck Bay
|
|---|---|
| Source of sample | Outcrop or artificial surface exposure |
| Rock name | Hornblende andesite |
| Description | epidotized |
| Laboratories | USGS Menlo Park |
| Compiler name | Moscati, R. |
| Date compiled | 1992 04 |
| Precision of location | Accurate to within 0.1 minute (~500 feet) |
| Location comment | along S fork of the river which flows into Mallard Duck Bay |
| Bibliographic reference | Wilson, F.H., 1978, Map showing preliminary results of K-Ar studies in the Chignik and Sutwik Island quadrangles, Alaska: U.S. Geologica Survey Open File Report 78-1064. |
| (click for info) | |
| Geologic map unit | -158.483333, 56.233333 |
| Nearby scientific data | Find additional scientific data near this location |
| Age estimate | 27.1 ± 0Ma age of volcanism
|
|---|---|
| Type of analysis | conventional K-Ar |
| Rock or mineral analyzed | hornblende |
| Analytical details | |
| Lab sample ID | 77AMs 001 |
| Decay constants | 4.962E-04, 0.581E-04, 1.1167E-04 |
| K2O concentration | 0.343 % |
| Radiogenic 40Ar concentration | 0.1345 |
| Radiogenic Ar | 23 % |