Title

The Genesis of the Rocky Mountains

Date

6-1-2017 2:00 PM

End Time

1-6-2017 3:00 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 Rocky Mountains are the cumulative result of at least three orogenic events in western North America since the Paleozoic. During the Alleghenian orogeny, far-field stress from continent-continent convergence between Laurasia and Gondwana formed the Ancestral Rocky Mountains. Subsequently, the Modern Rocky Mountains began to form about 100 million years ago during the Sevier orogeny, which is associated with the eastward subduction of the Kula plate beneath North America. Uplift continued with the Laramide orogeny, which records subduction between the Farallon and North American Plates. With the onset of Laramide tectonism about 70 m.y.a., subduction slowed and the angle of the subducting plate flattened greatly causing the Farallon slab to scrape along the base of the North American lithosphere. This flat-slab subduction caused the focus of mountain building and magmatism to migrate much farther inland than expected compared to a normal angle subduction zone. The Rocky Mountains are the product of several distinct orogenic events and provide geologists with the opportunity to view large-scale mountain building from multiple perspectives.

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Jun 1st, 2:00 PM Jun 1st, 3:00 PM

The Genesis of the Rocky Mountains

RWEC 201

The Rocky Mountains are the cumulative result of at least three orogenic events in western North America since the Paleozoic. During the Alleghenian orogeny, far-field stress from continent-continent convergence between Laurasia and Gondwana formed the Ancestral Rocky Mountains. Subsequently, the Modern Rocky Mountains began to form about 100 million years ago during the Sevier orogeny, which is associated with the eastward subduction of the Kula plate beneath North America. Uplift continued with the Laramide orogeny, which records subduction between the Farallon and North American Plates. With the onset of Laramide tectonism about 70 m.y.a., subduction slowed and the angle of the subducting plate flattened greatly causing the Farallon slab to scrape along the base of the North American lithosphere. This flat-slab subduction caused the focus of mountain building and magmatism to migrate much farther inland than expected compared to a normal angle subduction zone. The Rocky Mountains are the product of several distinct orogenic events and provide geologists with the opportunity to view large-scale mountain building from multiple perspectives.