Event Name : Capital 1090000 yBP
|Start: 1090000 || Years BP K-Ar || |
|Stop: 1020000 || Years BP K-Ar || |Description:
|Eruption Product: || other ||
From Richter and others (1990): "Capital Mountain is the erosional remnant of a relatively small andesitic shield volcano with a roughly circular, 4-km-wide summit caldera, filled with more than 900 m of andesite flows (Richter and others 1989). Near the center of the caldera, a prominent volcanic plug is the locus of a postcaldera, predominantly andesitic, radial dike swarm that is unique in the WVF. A rhyolite dike that extends more than 10 km across the shield and caldera, probably represents the last magmatic activity of the volcano. K-Ar ages of 1.02- 1.09 Ma for the andesite shield lavas (nos. 48, 49), andesite dike (no. 50), and rhyolite dike (no. 51) suggest that Capital volcano was active during a relatively short time period as compared to other western WVF volcanoes."