Alagogshak Volcano: A Pleistocene Andesite-Dacite Stratovolcano in Katmai National Park 1614
Hildreth W, Fierstein J, Lanphere M, Siems D. 1999. Alagogshak Volcano: A Pleistocene Andesite-Dacite Stratovolcano in Katmai National Park 1614. In Kelley KD (ed). Geologic studies in Alaska by the U. S. Geological Survey, 1997. U.S. Geological Survey. U.S. Geological Survey (USGS) Professional Paper
Alagogshak volcano, a newly recognized volcanic-front stratovolcano on the Alaska Peninsula rangecrest, 15 km southwest of Katmai Pass, produced 10-18 km3 of andesite-dacite eruptive products during several episodes of activity in the middle and late Pleistocene. From a central vent marked by hydrothremal alteration and remnants of a cratered fragmental cone on the present-day drainage divide, glacially incised stacks of lava flows (57-66 percent SiO2) dip radially and extend 6-10 km in most directions. Lava flows that make up four ridge-capping outliers well west of the volcano may also have erupted there. The medium-K calcalkaline Alagogshak eruptive suite is compostionally varied, probably reflecting independent evolution of different magma batches supplied in several episodes spread intermittently over at least 600,000 years. In contrast, the exclusively Holocene anddesite-dacite suite (59-64 percent SiO2) produced by the Mount Martin Cone, which is centered 3 km northeast of Aloagogshak, yields far more co herent compositionl trends.
- Type
- Published Report Section
- Authors
- Hildreth, Wes; Fierstein, Judy; Lanphere, Marvin; Siems, David
- Units
- KATM
- Keywords
- Alagogshak, Andesite-Dacite, Mt. Martin, Pleistocene, Statovolcano, Volcano