THE GEOLOGIC HISTORY OF REDOUBT VOLCANO, ALASKA

Citation
Ab. Till et al., THE GEOLOGIC HISTORY OF REDOUBT VOLCANO, ALASKA, Journal of volcanology and geothermal research, 62(1-4), 1994, pp. 11-30
Citations number
34
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Geology
ISSN journal
0377-0273
Volume
62
Issue
1-4
Year of publication
1994
Pages
11 - 30
Database
ISI
SICI code
0377-0273(1994)62:1-4<11:TGHORV>2.0.ZU;2-L
Abstract
Redoubt Volcano is a composite cone built on continental crust at the northeast end of the Aleutian are. Magmas erupted at Redoubt are mediu m-K calc-alkaline basalts, andesites, and dacites. The eruptive histor y of the volcano can be divided into four parts: the early explosive s tage, early cone-building stage, late cone-building stage, and post-gl acial stage. The most silicic products of the volcano were erupted dur ing the early explosive stage about 0.888 Ma and include pumiceous pyr oclastic flow deposits, block-and-ash flow deposits, and a dome or sha llow intrusive complex. Basalt and basaltic andesite lava flows and sc oria and ash flows were produced during the early cone-building stage, which was underway by 0.340 Ma. During the late cone-building stage, andesitic lava flows and block-and-ash flows were emplaced. Airfall de posits produced during post-glacial eruptions are silicic andesite in composition. Since the early cone-building stage, magmas have become p rogressively more silicic, but none are as silicic as those in the ear ly explosive stage. Limited Pb and Sr isotopic data suggest that Redou bt magmas were contaminated by North American continental crust.