Jumbo Dome reported activity

Event Name : Jumbo Dome 1026000 yBP

Start: 1026000 (± 57000 Years)

Years BP Ar/Ar

Lava dome:

Description: From Cameron and others (2015): "Jumbo Dome is a hornblende andesite dome of Pleistocene age located in the Healy Quadrangle of central Alaska, about 19 km northeast of Healy (Albanese, 1980; Athey and others, 2006) (fig. 1, 2, 3 [in original text]). Jumbo Dome is approximately 1.6 km long, 1.3 km wide, and 500 m high and intrudes the Devonian Keevy Peak Formation basement (slate, quartz-sericite schist, graphitic schist, calcareous schist, quartz-feldspar metawacke, and conglomerate) and overlying Tertiary Suntrana Formation (sandstone, clay, and coal) (Albanese, 1980; Wahrhaftig and others, 1969). A single 40Ar/39Ar date of a sample from Jumbo Dome yielded a plateau age of 1.026+/-0.057 Ma (Athey and others, 2006)."