Arc-transform magmatism in the Wrangell volcanic belt

The late Cenozoic Wrangell volcanic belt records a transition in magma supply and geochemistry from a subduction to transform margin between the northeastern Pacific and North American plates. The northwestern volcanic belt comprises calc-alkaline lavas that are above the Wrangell-Wadati Benioff zon...

Full description

Saved in:
Bibliographic Details
Published in:Geology (Boulder) 1991-01, Vol.19 (1), p.11-14
Main Authors: Skulski, Thomas, Francis, Don, Ludden, John N
Format: Article
Language:English
Subjects:
Alaska
alkalic composition
alkaline earth metals
Atoms & subatomic particles
basalts
Benioff zone
calc-alkalic composition
Chemistry
classification
composition
continental crust
crust
faults
geochemistry
Geology
Geophysics
hybridization
igneous and metamorphic rocks
igneous rocks
island arcs
isotopes
lava
magmas
major elements
mantle
metals
mid-ocean ridge basalts
North American Plate
ocean island basalts
Pacific Plate
petrology
plate tectonics
pollution
rock, sediment, soil
solid Earth (tectonophysics)
southern Alaska
Sr-87/Sr-86
stable isotopes
strike-slip faults
strontium
subduction
trace elements
transform faults
United States
upper mantle
volcanic belts
volcanic rocks
volcanism
Volcanoes
volcanology
Wrangellia
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:The late Cenozoic Wrangell volcanic belt records a transition in magma supply and geochemistry from a subduction to transform margin between the northeastern Pacific and North American plates. The northwestern volcanic belt comprises calc-alkaline lavas that are above the Wrangell-Wadati Benioff zone, whereas the southeastern belt comprises transitional lavas with minor alkaline and calc-alkaline lavas that overlie a leaky transform fault. The subduction-transform transition is marked by an increase in Fe/Mg and Nb/La ratios and a decrease in Ba/La ratios. Thus, the lavas of the transform regime display a geochemical signature that is intermediate to that of calc-alkaline and intraplate alkaline lavas. Whereas the effects of crustal contamination can be recognized in the evolved lavas of all suites, all primitive lavas in the transform regime are mantle derived and reflect the variable melting and mixing of depleted (mid-ocean ridge basalt) upper mantle, enriched mantle (ocean island basalt), and slab-derived components.
ISSN:0091-7613
1943-2682
DOI:10.1130/0091-7613(1991)019<0011:ATMITW>2.3.CO;2