Title

The Influence of Tectonics on the Evolution of the Cascade Volcanic Arc

Date

6-1-2017 3:00 PM

End Time

1-6-2017 4:00 PM

Location

RWEC 201

Department

Earth Science

Session Chair

Jeffrey Templeton

Session Title

Earth Science Senior Seminar: Understanding the Tectonic Development and Framework of western North America

Faculty Sponsor(s)

Jeffrey Templeton

Presentation Type

Presentation

Abstract

The north-south trending Cascades volcanic arc is divided into stages, which include the Western Cascades (35-7.5 Ma), Early High Cascades (7.4-4 Ma), and Late High Cascades (3.9-0 Ma). Each records changes in the tectonic framework with corresponding shifts in eruptive style. The change in subduction style from normal to oblique caused changes in arc magmatism. Along with the uplift of the Western Cascades, this change in style is interpreted as the driving force for thinning and retreat of the Cascade arc into a narrower volcanic chain. Late High Cascades volcanoes display differences in magma composition, subduction style, uplift rates, volcanic activity, and magnitude of eruptions. Basin and Range impingement on the arc and related extension is a possible explanation for differences seen between volcanoes in the northern Cascades compared to those in the south. Image noise-wave tomography has been used to analyze differences seen within the subducting Juan de Fuca Plate to understand effects of subduction rates on volcanoes along the length of the Cascasde arc.

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Jun 1st, 3:00 PM Jun 1st, 4:00 PM

The Influence of Tectonics on the Evolution of the Cascade Volcanic Arc

RWEC 201

The north-south trending Cascades volcanic arc is divided into stages, which include the Western Cascades (35-7.5 Ma), Early High Cascades (7.4-4 Ma), and Late High Cascades (3.9-0 Ma). Each records changes in the tectonic framework with corresponding shifts in eruptive style. The change in subduction style from normal to oblique caused changes in arc magmatism. Along with the uplift of the Western Cascades, this change in style is interpreted as the driving force for thinning and retreat of the Cascade arc into a narrower volcanic chain. Late High Cascades volcanoes display differences in magma composition, subduction style, uplift rates, volcanic activity, and magnitude of eruptions. Basin and Range impingement on the arc and related extension is a possible explanation for differences seen between volcanoes in the northern Cascades compared to those in the south. Image noise-wave tomography has been used to analyze differences seen within the subducting Juan de Fuca Plate to understand effects of subduction rates on volcanoes along the length of the Cascasde arc.