Tectonic Landforms and Mountain Building

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Find Your Park illustration of 2 hikers on a mountain top, text "see the power of tectonic plates"

Introduction

Tectonic processes shape the landscape and form some of the most spectacular structures found in national parks, from the highest peaks in the Rocky Mountains to the faulted mountains and valleys in the Basin and Range Province. Understanding a park's plate tectonic history and setting can help you make sense of the landforms and scenery you see.

For more information on Plate Tectonics, visit:

Below you will find a list of parks that share in common geologic landforms and features based on similar plate tectonic origins.

block diagram of horst and graben

Divergent Plate Boundaries in Parks

Almost all the Earth’s new crust forms at divergent boundaries, but most are not well known because they lie deep beneath the oceans. These are zones where two plates move away from each other, allowing magma from the mantle to rise up and solidify as new crust. When divergent motion occurs beneath a continental plate, rift structures and normal faults form.

Continental Rifts - Active

Basin and Range Rio Grand Rift

Continental Rifts - Ancient

Keweenawan Rift

Passive Continental Margins

Atlantic Coast Gulf Coast
diagram of convergent plates

Convergent Plate Boundaries in Parks

The way that plates behave when they collide depends mostly on what type of lithosphere they are made of. In oceanic-contentental subduction, the oceanic plate is pulled beneath another, forming a deep trench. The long, narrow zone where the two plates meet is called a subduction zone. In continental-continental plate collision, the crusts are pushed together and faulted forming towering mountain ranges.

Ocean-Ocean Subduction Zones

Alaska Peninsula

Western Pacific

Collisional Mountain Ranges

Appalachain Mountains

Ouachita Mountains

Marathon Mountains

Brooks Range

Ocean-Continent Subduction Zone

Active Volcanic Arc - Cascades

Active Volcanic Arc - Alaska

Ancient Arc - Sierra Nevada Mountains

Accretionary Wedge - Coast Ranges

Low-Angle Subduction - Laramide Uplifts

block diagram of transform fault

Transform Plate Boundaries in Parks

At transform plate boundaries plates grind past each other side by side. This type of boundary separates the North American plate from the Pacific plate along the San Andreas fault, a famous transform plate boundary that’s responsible for many of California’s earthquakes.

Continental

San Andreas Fault

Oceanic

Caribbean
diagram of a hotspot

Hot Spots in Parks

A hot spot is area of concentrated heat in the mantle that produces magma that rises to the Earth’s surface to form volcanic features. The volcanic activity of the Hawaiian Islands is one example. Hot spots may persist for millions of years.

Continental

Yellowstone

Oceanic

Hawaii - Emperor
diagram of accreted terrains

Accreted Terrains in Parks

Accreted terrains are portions of crust that are too thick and buoyant to be subducted which are "scraped off" and become added to the over-riding tectonic plate along a convergent (collisional) plate boundary.

North American Cordillera

Alaska Pacific Northwest

Photo Gallery

Geological Monitoring

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    Parks and Plates Textbook

    Parks and Plates cover

    Parks and Plates: The Geology of Our National Parks, Monuments & Seashores. Lillie, Robert J., 2005.

    W.W. Norton and Company.

    ISBN 0-393-92407-6

    9" x 10.75", paperback, 550 pages, full color throughout

    Ever have questions about the fascinating natural dynamics working in our national parks? This book aims to provide answers to some of them. The spectacular geology in our national parks provides the answers to many questions about the Earth. The answers can be appreciated through plate tectonics, an exciting way to understand the ongoing natural processes that sculpt our landscape. Parks and Plates is a visual and scientific voyage of discovery!

    Last updated: December 3, 2018

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