Capital


Facts


  • Official Name: Capital Mountain
  • Seismically Monitored: No
  • Color Code: UNASSIGNED
  • Alert Level: UNASSIGNED
  • Elevation: 2356m (7729ft)
  • Latitude: 62.4238
  • Longitude: -144.1127
  • Smithsonian VNum:
  • Nearby Towns:
    • Slana 20 mi (32 km) NE
    • Chistochina 20 mi (32 km) NW
    • Mentasta Lake 37 mi (59 km) NE
    • Gakona 39 mi (63 km) SW
    • Gulkana 42 mi (68 km) SW

Description

From Wood and Kienle (1990) [1] : "Capital Mountain is a relatively small andesitic shield volcano with a roughly circular summit caldera 4 km in diameter. The shield consists chiefly of lava flows and subordinate volcaniclastic rocks that dip 3 to 25 degrees away from the summit area. The caldera, apparently of non-explosive origin, is filled with thick, flat-lying flows. Talus, flow breccias, and pillow lavas occur locally between the caldera wall and intracaldera flows. A prominent andesite plug, 100 m high, marks the general center of an area of post-caldera-fill activity and is the locus of a spectacular radial dike swarm. Shield and intracaldera lavas are chiefly hypersthene andesite, but shield lavas range in composition from basalt to dacite. Dikes are also chiefly andesite; one prominent rhyolite dike originating from a small rhyolite laccolith extends almost completely across the volcano."

Name Origin

The name Capital Mountain was recorded by T.G. Gerdine as a local name (Mendenhall, 1905; Orth, 1971).


References Cited

[1] Volcanoes of North America: United States and Canada, 1990

Wood, C. A., and Kienle, Juergen, (eds.), 1990, Volcanoes of North America: United States and Canada: New York, Cambridge University Press, 354 p.

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