Amak older volcanics
Start: 5000 yBP [1]
Stop: 4000 yBP [1]
Event Type: Effusive
Description: From Wood and Kienle (1990): "The earlier volcanism, perhaps some 4,000-5,000 yr ago, consisted mostly of thin (~3 m) platy to massive andesite."
From Marsh and Leitz (1978): "The older series of flows built a low-lying conical volcano with a summit crater about 300 m in diameter. These flows are predominantly massive to platy, grayish-black, but sometimes slightly dark pink, two-pyroxene andesites. They show no sign of brecciation. On the southwest side of the island a small U-shaped valley cut into the older series indicates local glaciation."
"According to Funlc (1973) the latest period of glaciation in this area was about 6,700 years B.P. The small U-shaped glacial valley cut into the older series was probably excavated during this period of glaciation. The older flows also show no sign of being extruded beneath ice. Thus Amak is probably not much older than 6,700 years."
From Marsh and Leitz (1978): "The older series of flows built a low-lying conical volcano with a summit crater about 300 m in diameter. These flows are predominantly massive to platy, grayish-black, but sometimes slightly dark pink, two-pyroxene andesites. They show no sign of brecciation. On the southwest side of the island a small U-shaped valley cut into the older series indicates local glaciation."
"According to Funlc (1973) the latest period of glaciation in this area was about 6,700 years B.P. The small U-shaped glacial valley cut into the older series was probably excavated during this period of glaciation. The older flows also show no sign of being extruded beneath ice. Thus Amak is probably not much older than 6,700 years."
References Cited
[1] Volcanoes of North America: United States and Canada, 1990
Wood, C. A., and Kienle, Juergen, (eds.), 1990, Volcanoes of North America: United States and Canada: New York, Cambridge University Press, 354 p.[2] Isotopic and incompatible element constraints on the genesis of island arc volcanics from Cold Bay and Amak Island, Aleutians, and implications for mantle structure, 1983
Morris, J. D., and Hart, S. R., 1983, Isotopic and incompatible element constraints on the genesis of island arc volcanics from Cold Bay and Amak Island, Aleutians, and implications for mantle structure: Geochimica et Cosmochimica Acta, v. 47, n. 11, p. 2015-2030.[3] Geology of Amak Island, Aleutian Islands, Alaska, 1979
Marsh, B. D., and Leitz, R. E., 1979, Geology of Amak Island, Aleutian Islands, Alaska: Journal of Geology, v. 87, n. 6, p. 715-723.Complete Eruption References
Volcanoes of North America: United States and Canada, 1990
Wood, C. A., and Kienle, Juergen, (eds.), 1990, Volcanoes of North America: United States and Canada: New York, Cambridge University Press, 354 p.
Hard Copy held by AVO at FBKS - CEC shelf
Isotopic and incompatible element constraints on the genesis of island arc volcanics from Cold Bay and Amak Island, Aleutians, and implications for mantle structure, 1983
Morris, J. D., and Hart, S. R., 1983, Isotopic and incompatible element constraints on the genesis of island arc volcanics from Cold Bay and Amak Island, Aleutians, and implications for mantle structure: Geochimica et Cosmochimica Acta, v. 47, n. 11, p. 2015-2030.
Geology of Amak Island, Aleutian Islands, Alaska, 1979
Marsh, B. D., and Leitz, R. E., 1979, Geology of Amak Island, Aleutian Islands, Alaska: Journal of Geology, v. 87, n. 6, p. 715-723.
