Adagdak Younger Cone
Start: 1020000 yBP ± 150000 Years [1]
Event Type: Effusive
- Lava flow [2]
- Lahar, debris-flow, or mudflow [1]
Description: From Baten (2002): "Mt. Adagdak (650 m asl) was built from three stages of volcanism (Figure 1.5 [in original text])."
"The second stage of volcanism resulted in the formation of two composite cones. The older cone formed on the southern portion of the remnant shield and the younger cone formed on the eroded northern flank of the older composite cone (Coats, 1956). Both cones are primarily andesitic in composition."
"...the younger cone yields a date of 1.02 +/- 0.15 Ma..."
From Meyers and Frost (1994): "A renewed phase of volcanism produced a younger composite cone on the northern flank of the older, eroded composite cone (Fig. 2 [in original text])."
From Coats (1956): "Younger composite cone-A sequence of mudflows consisting largely of fragments of hornblende andesite, capped by two thin hornblende andesite lava flows, makes up the western flanks of Mount Adagdak. These rocks represent a younger cone built after the sea had partly eroded the older composite cone."
"The second stage of volcanism resulted in the formation of two composite cones. The older cone formed on the southern portion of the remnant shield and the younger cone formed on the eroded northern flank of the older composite cone (Coats, 1956). Both cones are primarily andesitic in composition."
"...the younger cone yields a date of 1.02 +/- 0.15 Ma..."
From Meyers and Frost (1994): "A renewed phase of volcanism produced a younger composite cone on the northern flank of the older, eroded composite cone (Fig. 2 [in original text])."
From Coats (1956): "Younger composite cone-A sequence of mudflows consisting largely of fragments of hornblende andesite, capped by two thin hornblende andesite lava flows, makes up the western flanks of Mount Adagdak. These rocks represent a younger cone built after the sea had partly eroded the older composite cone."
References Cited
[1] Eruptive history and assessment of volcanic hazards of Mt. Adagdak, Adak Island, Aleutian Islands, Alaska, 2002
Baten, S. K., 2002, Eruptive history and assessment of volcanic hazards of Mt. Adagdak, Adak Island, Aleutian Islands, Alaska: Northern Arizona University unpublished M.S. thesis, 181 p.[2] Geology of northern Adak Island, Alaska, 1956
Coats, R. R., 1956, Geology of northern Adak Island, Alaska: in Investigations of Alaskan volcanoes, U.S. Geological Survey Bulletin 1028-C, p. 45-67, 1 sheet, scale 1:50,000.
full-text PDF 831 KB
plate 9 PDF 3.3 MB Complete Eruption References
Eruptive history and assessment of volcanic hazards of Mt. Adagdak, Adak Island, Aleutian Islands, Alaska, 2002
Baten, S. K., 2002, Eruptive history and assessment of volcanic hazards of Mt. Adagdak, Adak Island, Aleutian Islands, Alaska: Northern Arizona University unpublished M.S. thesis, 181 p.
A petrologic re-investigation of the Adak volcanic center, central Aleutian arc, Alaska, 1994
Myers, J. D., and Frost, C. D., 1994, A petrologic re-investigation of the Adak volcanic center, central Aleutian arc, Alaska: Journal of Volcanology and Geothermal Research, v. 60, n. 2, p. 109-146.
Geology of northern Adak Island, Alaska, 1956
Coats, R. R., 1956, Geology of northern Adak Island, Alaska: in Investigations of Alaskan volcanoes, U.S. Geological Survey Bulletin 1028-C, p. 45-67, 1 sheet, scale 1:50,000.
full-text PDF 831 KB
plate 9 PDF 3.3 MB 