Geology Guides for Travelers

April 16, 2013

Dear Doctor Rock,
Where can I find geology guidebooks to use while I'm traveling? I don't have academic or technical training in geology, but am very interested. Are there guidebooks written for the general public that would help travelers understand the landscape?
Bill DeSpain
Los Angeles

Bill,

Are you ever in luck. Their is an entire series of geology guidebooks that should fit the bill (oooooh, bad pun. Sorry.) Mountain Press Publishing in Missoula publishes the very popular 'Roadside Geology' series. They are state-by-state guides. written by card-carrying geologists for the general public. Not every state is covered, alas, not yet. Each book includes an introduction with the requisite beo basics you'll need to follow the descriptions. The authors then describe the geology you see as you drive on a number of routes through the state. There are maps and explanatory figures, too. The books can be found in many bookstores, or ordered directly from the publisher .  You'll find they have a lot more geology- related titles, all written for the non-geologist. Here is the list of available titles- click to go to the publisher's webpage for the title.

Roadside Geology of Arizona

Roadside Geology of Colorado

Roadside Geology of Connecticut and Rhode Island

Roadside Geology of Idaho

Roadside Geology of Indiana

Roadside Geology of Louisiana

Roadside Geology of Maine

Roadside Geology of Maryland, Delaware, and Washington, D.C.

Roadside Geology of Massachusetts

Roadside Geology of Minnesota

Roadside Geology of Missouri

Roadside Geology of Montana

Roadside Geology of Nebraska

Roadside Geology of New York

Roadside Geology of Northern and Central California

Roadside Geology of Ohio

Roadside Geology of South Dakota

Roadside Geology of Southern British Columbia

Roadside Geology of Texas

Roadside Geology of Virginia

Roadside Geology of Washington

Roadside Geology of Wyoming

Roadside Geology of Yellowstone

Another series that they have begun is 'Geology Underfoot'. These are oriented toward the traveler who wants to get out of the car to look more closely. Each book consists of individual field trips to specific locations where the geology is bold, beautiful, or particularly relevant to human developement. Very highly recommended!

Geology Underfoot Along Colorado's Front Range

Geology Underfoot in Death Valley and Owens Valley

Geology Underfoot in Illinois

Geology Underfoot in Northern Arizona

Geology Underfoot in Southern California

Geology Underfoot in Southern Utah

Geology Underfoot in Yellowstone Country

Geology Underfoot in Yosemite National Park

Each of these books gets you out of the car at specific sites in the area covered. There are fewer titles in the Geology Underfoot series, but more are added each year. I'm writing a new volume for the series, Geology Underfoot in Western Washington. If you want to read more about it, please visit my Northwest Geology Field Trips blog.

Another good resource is the internet. The Walter Geology Library at the University of Texas has compiled a long list of guidebooks. Some are technical, but there are plenty for the general reader.

Why is the midwest flat?

Doc,
Why is the midwest so flat? We travel back and forth from coast to coast. From the west coast to about central Colorado and Wyoming, the landscape is dramatic- there are mountains, or cliffs of exposed bedrock. The east has the Appalachians. The real odd ball seems to be the Plains Statesand also way up into central Canada. Why is the landscape so flat? Is this due to something about the geology?
Henry Wolston,
Sacramento, CA

Dear Henry,

The geology in the Great Plains is, well, subtle. Much of it
is understood by looking at cores drilled deep into the Earth.

It is ALL about geology. Everything is, didn't you know? Heh. The eastern and western thirds of the continent are generally mountainous with lots of rock visible. The rocks that lie below the thick soil of the midwest states of the Great Plains have not been buckled upward by plate collisions to form mountains. Sure, bedrock is exposed in some places, but these are often few and far between. In the long stretch of time between 570 and 70 million years ago, the central part of the continent was covered by shallow salt water seas. Flat-lying sediment was deposited on the sea floor. Marine fossils are abundant, including ancient armored fish and huge, long-necked swimming reptiles called Plesiosaurs (look 'em up!). The marine sediment was compressed by the weight of the steadily accumulating sediment into rocks: mostly limestone, shale or sandstone. In some places, these rock layers are 10,000 feet thick. Over the past 70 million years, the rocks have been slowly and gradually uplifted above sea level, and the interior sea drained off the land.
The northern part of the Great Plains are covered with sediment from repeated glaciations coming south out of the Canadian interior. Rivers and streams flowed outward from the terminus of these glaciers, and deposited river sediment, mostly sand, for hundreds of miles further south, covering the ancient sea beds and the soils that had developed on top of them.
The geologic story of the Great Plains is more complex than I can go into on this page. A website hosted by North Dakota State University explains the geologic history in some detail, with figures.
http://library.ndsu.edu/exhibits/text/greatplains/text.html
The mountains that bound the Plains on east and west are another topic. We can get into that later.

Doctor Rock