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 
You are here: Home > Volcano Information

Gas Rocks, the reported activity



Event Name : Gas Rocks Dome 600

Start: 23300 (± 1200 Years) Years BP Ar/Ar

Lava flow: BibCard
Lava dome: BibCard
Eruption Type:Explosive
Eruption Product: dacite BibCard

Description: From Hildreth and others (2006): "The larger domes, Domes 600 and 700 (figs. 10, 12 [in original text]), have 180 and 210 m relief, respectively, above the lake. Dome 600 appears to be a single simple extrusion, as shown by the steep jointing that flares slightly outward toward the top of its northeast face (fig. 13 [in original text]). Nonetheless, a pair of lava flows, each 10 to 15 m thick, extends to the shoreline from the foot of that face (fig. 13 [in original text])."

"Little or no glassy or pumiceous carapace remains on any of the domes, which were all completely submerged and scoured by glacial ice."

Hildreth and others (2006) estimate a volume of 15 million m cubed for Dome 600.

"We [Hildreth and others, 2006] determined two 40Ar/39Ar ages on groundmass concentrates from samples of The Gas Rocks dacite (fig. 9; table 2 [in original text]). Sample U-1, from the small North Point Dome (fig. 3B [in original text]), yielded a weighted-mean plateau age of 25.7+/-1.4 ka, and sample U-2, from Dome 600, 23.3+/-1.2 ka. At their extremes, the two error envelopes just overlap, although nothing on the ground is known to contradict a younger age for the larger dome. Because of their petrographic and compositional similarity, it cannot be excluded that the three domes are essentially contemporaneous, plausibly fed by a common dike, the northwesterly strike of which would be similar to the present-day plate-convergence direction (which might in turn influence the direction of maximum horizontal compression)."

Contact AVO Privacy Accessibility Information Quality FOIA
URL: www.avo.alaska.edu/volcanoes/activity.php
Page modified: March 30, 2017 14:36
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.