AVO Logo
Site Map | FAQ |
Alaska Volcano Observatory
About Alaska's Volcanoes | Hazards from Alaska's Volcanoes | Map & Alphabetical List | Interactive Map | Eruption Search | Volcano Search | Wilcox 
You are here: Home > Volcano Information > Wilcox

Wilcox description and information


Most Recent Activity:
Seismically Monitored: No
Elevation: 0 ft ( m)
Latitude: 52.3335° N
Longitude:172.37089° W
CAVW Number:
Nearby towns:Atka 78 mi (125 km) SW
Nikolski 153 mi (246 km) NE
Adak 183 mi (295 km) SW
Unalaska 264 mi (425 km) NE
Anchorage 1040 mi (1674 km) NE
From Jicha and Singer, 2006 [1]: Wilcox is composed of "tens of basaltic to rhyolitic flows (wvl) of variable thickness that dip 30-40 degrees radially away from the former central vent now occupied by a 0.6 cubic km rhyolitic cone. Several of the andesitic to rhyolitic lavas making up the northern flank (rdf, awf, afp, rfc) spread out laterally as they approached the shoreline. It is unclear how far the lavas extended to the south because intense wave action has eroded away much of the southern flank of the volcano.///The lowest exposures of the stratocone consist of basalt flows intercalated with thick pyroclastic breccias and subvertical dikes. Several of the flows in this section are moderately oxidized, contain chlorite and serpentinized olivine, and are weakly hydrothermally altered. Nonetheless, 40Ar/39Ar ages of 98 +/- 18, 85 +/- 14, and 66 +/- 14 ka were obtained from stratigraphically successive basaltic lavas. These basal units are capped by numerous basaltic andesitic to rhyolitic flows that erupted from 62 to 27 ka. At 23 +/- 5 ka, the eruption of a >or= 0.02 cubic km andesitic (62 wt.% SiO2) ignimbrite filled a valley between Finch Cove rhyolite (rfc) and Finch Cove rhyodacite (rdf). The ~25 m thick ignimbrite is moderately welded throughout and contains ~20% phenocrysts (12% plagioclase; 4% clinopyroxene, 2% olivine; 2% oxides), abundant lithics (up to 20 cm), and pumice (15-40 cm). Some of the last activity at Wilcox volcano prior to the sector collapse at ca. 9 ka included the eruption of dacitic to rhyolitic lavas, which formed Moundhill Point and the adjacent region to the south."
Volcanic history and magmatic evolution of Seguam Island, Aleutian island arc, Alaska, 2006
citation imageJicha, B.R., and Singer, B.S., 2006, Volcanic history and magmatic evolution of Seguam Island, Aleutian island arc, Alaska: Geological Society of America Bulletin, v. 118, n. 7-8, p. 805-822.

Contact AVO Privacy Accessibility Information Quality FOIA
URL: www.avo.alaska.edu/volcanoes/volcinfo.php
Page modified: September 29, 2020 12:19
Contact Information: AVO Web Team

twitter @alaska_avo
facebook alaska.avo
email Receive volcano updates by email: USGS VNS

This website is supported by the U.S. Geological Survey under Cooperative Agreement Grant G22AC00137

Mention of trade names or commercial products does not constitute their endorsement by the U.S. Geological Survey.