US Route 89-The West
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Geography & Geology


by Wayne Ranney

By any measure, the vistas and landscapes viewed along the route of US Route 89 are spellbinding. For decades, this highway has mesmerized curious travelers with its bare-bone deserts, red rock canyons and snow capped mountains—which often cradle vibrant cities and storybook farms and towns. The sheer number of national parks and monuments along this road attest to the noteworthiness of this special geography. Saguaro, Zion, Teton and Tuzigoot offer a few of the enchanting names that encompass parts of this magical landscape. Highway 89 pierces the heart of the Great American West and in so doing reveals the richness of the American dream. It weaves together the fabric and tapestry of this raw and rugged land with the energies and hopes of its optimistic people.

There are many US Highways that traverse our country latitudinally and so, take in the wide variety of backdrops that could be expected on a coast to coast excursion. But Highway 89 is perhaps the king of the north-south routes, its only possible competition coming perhaps from Highway 101 along the Pacific Coast. Some might argue for that route as the logical champion in the category of scenic masterpiece. Yet with all of it’s wave-washed beaches, cliffhanging bridges and Redwood trees, it still cannot compete with the variety and world class significance of places such as the Grand Canyon, Yellowstone and Glacier national parks. What US Route 101 may represent as the best in coastal scenery, Route 89 equals or exceeds with its multitude of deserts, plateau’s, mountains and plains.

This spectacular geography owes its origin to the awe-inspiring geology of the intermountain west, for this is an area that has been alternatively inundated by seawater, scorched in Sahara-like deserts and cooled by equatorial rains. Mountains have risen here before, only to be subdued and completely eroded away by the eons of wind, water and time. Each of these ancient settings left subtle but distinctive clues upon the landscape. These hidden secrets are now recovered by geologists in their quest to obtain riches from the land - oil, coal, gas and hard rock minerals. Along this path to treasure emerge stories that have no monetary value, yet they increasingly serve to enrich a population of residents and travelers alike who are keen on recapturing a sense of discovery. What once was known only to scientists is now becoming an open book to anyone with an smattering of interest in the history of our planet. Once complex theories are now guideposts to discovery for interested travelers.

The story of US Route 89 cannot entirely be told without saying something about the origin of the land it traverses. And although a small segment of people may continue to insist that it was “the hand of God that made it”, they miss the spiritual and intellectual rewards that await those who open their eyes to the details of exactly how and when “he” did it. Geology shaped this land and thus determined the specific path of Route 89. It is anything but arrow straight. In the first half of the 20th century, before the development of the Interstate Highway System, road builders used far less dynamite in constructing roads and utilized a lot more curvature. In this way, roads were more gently placed upon the land and were made to fit to its shape. Route 89 yields to the lay of the land and this undulatory routing may be the ultimate source of its attraction.

It may seem ironic then, that this highway is also squarely directed at the momentous landscape features that lay astride its path, including seven national parks. One could drive this road from the Mexican border to Canada and feel like they had seen much of America, such is the diversity of landforms found here. On this geologic journey, one encounters deserts, plateaus, mountains and plains and each of these generic settings harbors a formal name, some of which are familiar to travelers. These are the Basin and Range, the Colorado Plateau, the Rocky Mountains and the Great Plains. Highway 89 touches them all and anyone who studies this route will want to become familiar with the geologic history of these provinces. The purpose of this project is to give travelers a sense that they are embarking not only on a physical journey on Route 89, but also on multifarious journeys which take them through time. These journeys are resurrected from secrets long held within the rocks and landforms seen along US Route 89. A short introduction to each of these landscapes may be in order:

Basin and Range
Found from the Mexican border to central and northern Arizona, it contains down-faulted valleys (basins) separated by uplifted mountains (ranges). It attained its present shape beginning between 25 and 17 million years ago, when the earth’s crust was stretched and thinned. Much higher mountains here, preceded the Basin and Range.

Colorado Plateau
Stretching from northern Arizona to northern Utah, this broad, uplifted series of plateaus has escaped the rigorous deformation and faulting of rocks seen in other nearby provinces. It is characterized by colorful, flat-lying sedimentary rocks that have been deeply incised by rivers and streams and is a unique place on our planet.

Rocky Mountains

An area found along Highway 89 from the Wasatch Front in Utah to the Canadian border, these mountains were formed beginning 70 million years ago when tectonic forces uplifted rocks along a broad front. The Rockies are the stuff of legends in our culture and much of this revolves around its rich mineral heritage, which was emplaced during the creation of these stunning mountains.

Great Plains
Found in the northern half of Montana where the Rockies give way to the Plains. At first it may seem that nothing interesting could be said about “flat land” but the Plains hold many surprises. They originated on the floor of an ancient sea that was last here 70 million years ago. This sea floor has been uplifted and covered by gravel and sand washed out of the Rockies.

These are the provinces that one travels along the route of US Route 89 from Mexico to Canada. Their history is written in the rocks and beautifully exposed for everyone to enjoy.

Wayne Ranney is a guide, educator, and author who specializes in making the diverse landscapes and geologic history of our planet come alive for curious and interested travelers. Trained as a professional geologist in the American Southwest, he is an adjunct faculty member at Coconino Community College in Flagstaff and frequently travels to exotic landscapes worldwide. His primary interests are in understanding landscape development through time and how human cultures intersect with these landscapes. This confluence of landscapes and cultures has, in many instances, helped to determine the course of human history.


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