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Titre du document / Document title

The 40Ar/39Ar chronology and eruption rates of Cenozoic volcanism in the eastern Bering Sea Volcanic Province, Alaska

Auteur(s) / Author(s)

MUKASA Samuel B. (1) ; ANDRONIKOV Alexander V. (1) ; HALL Chris M. (1) ;

Affiliation(s) du ou des auteurs / Author(s) Affiliation(s)

(1) Department of Geological Sciences, University of Michigan, Ann Arbor, Michigan, ETATS-UNIS

Résumé / Abstract

[1] The eastern sector of the Bering Sea Volcanic Province, Alaska, consists of a number of large late Cenozoic volcanic fields that occur in a broad region inboard from the Aleutian arc front to the Arctic Circle. We estimate that about 750 km3 of magma were erupted in the volcanic centers that we have studied, all within the past 6.0 Ma. Several discrete eruption episodes have been identified with the new 40Ar/39Ar data at circa 6.0 Ma (Imuruk volcanic field), circa 3.5 Ma (Teller volcanic field), circa 2.5-1.5 Ma (St. George Island), circa 1.0 Ma (St. Lawrence Island), and the youngest activity which started at circa 0.7 Ma and continued throughout region until historic times. Combining age information with volume estimates reveals that the intensity of volcanic activity in the Bering Sea Volcanic Province has increased through time, with only about 15% of lava erupted before 3 Ma and about 30% of all late Cenozoic magma erupted within the last 500 ka. Eruption rates also increase toward more recent times, from the 6 Ma Imuruk basalts, which erupted at the rate of ∼70 ± 15 m3kn-2 yr-1, to the <0.7 Ma Nunivak Island and St. Michael volcanic field basalts, which erupted at a rate of ∼165 ± 25 m3 km-2yr-1. High volumes of erupted lava accompanied by high eruption rates for the youngest volcanic rocks suggest significant changes in the melting rates, which are best explained by either an evolving tectonic regime or significant changes in the melting processes.

Revue / Journal Title

Journal of geophysical research    ISSN  0148-0227 

Source / Source

2007, vol. 112, noB6, [Note(s): B06207.1-B06207.18] (1 p.)

Langue / Language

Anglais

Editeur / Publisher

American Geophysical Union, Washington, DC, ETATS-UNIS  (1949-2012) (Revue)

Mots-clés anglais / English Keywords

polar regions

;

North America

;

United States

;

Pacific Ocean

;

West Pacific

;

igneous rocks

;

volcanic rocks

;

Phanerozoic

;

Nunivak Island

;

Arctic region

;

Alaska

;

Bering Sea

;

tectonics

;

melting

;

basalts

;

lava

;

intensity

;

age

;

volcanic centers

;

magmas

;

Circle

;

volcanic fields

;

volcanism

;

Cenozoic

;

eruptions

;

chronology

;

Mots-clés français / French Keywords

Région Polaire

;

Amérique du Nord

;

Etats Unis

;

Océan Pacifique

;

Océan Pacifique Ouest

;

Roche ignée

;

Roche volcanique

;

Phanérozoïque

;

Ile Nunivak

;

Arctique

;

Alaska

;

Mer de Bering

;

Tectonique

;

Fusion

;

Basalte

;

Lave

;

Intensité

;

Age

;

Centre volcanique

;

Magma

;

Cercle

;

Champ volcanique

;

Volcanisme

;

Cénozoïque

;

Eruption

;

Chronologie

;

Mots-clés espagnols / Spanish Keywords

America del norte

;

Estados Unidos

;

Océano Pacífico

;

Roca ignea

;

Roca volcánica

;

Fanerozoico

;

Isla Nunivak

;

Ártico

;

Alaska

;

Mar de Bering

;

Tectónico

;

Fusión

;

Basalto

;

Lava

;

Intensidad

;

Edad

;

Magma

;

Circulo

;

Cenozoico

;

Erupción

;

Cronología

;

Localisation / Location

INIST-CNRS, Cote INIST : 3144, 35400014669197.0130

Nº notice refdoc (ud4) : 18973779



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