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Aniakchak reported activity





Event Name : Aniakchak Blocky Cone

Start: 400 Years BP Tephrochronology
Stop: 1931 Tephrochronology

Tephrafall: BibCard BibCard
Eruption Type:Explosive

Description: From Bacon and others (2014): "The well-preserved, 60-m-high cinder cone with ~20-m-deep crater near the southwest caldera wall opposite Birthday Pass is informally known as Blocky Cone (figs. 12Dand 14 [in original text]). Although Blocky Cone is mantled by lithic debris from the nearby 1931 vent, fresh basaltic andesite scoria is exposed on the southeast flank of the cone. This is some of the most mafic postcaldera magma (52.2-52.5 weight percent SiO2), comparable only to products of Breezy Cone. Blocky Cone appears to be younger than the Half Cone Pink and Brown Pumice (fig. 5C [in original text]) and to overlie older lava of Vent Mountain. Blocky Cone tephra has not been reported to be on the surface of the youngest Vent Mountain lava that nearly reaches the cone's eastern base, which suggests that this late-erupted Vent Mountain lava is younger than Blocky Cone."

Neal and others (2001) classify the eruption of Blocky Cone as strombolian.

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Page modified: March 30, 2017 14:36
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