The Great Unconformty (Even More Fabulous Than It sounds)

This post by Dr. Jack Share about the Great Unconformity and the Grand Canyon is so fascinating, I have to share it (and preserve it on my own log so I can come back and visit it). The photographs are amazing, and worthy of a textbook (for all I know, they ended up in one). Follow the link and wallow in Deep Time!

Sedona Through Time

Sedona Through Time (3^rd edition), by Wayne Ranney, is the third book in what I like to call Ranney's Rock Trilogy. Book One, Ancient Landscapes Of The Colorado Plateau (co-written with Ron Blakey), takes us step-by-step through the landscape changes in the Four Corners area, beautifully illustrating each geologic occurrence with Paleogeographic maps. Book Two, Carving Grand Canyon, zooms in on the most breathtaking landform in North America, delving into a lesser-known feature called the Mogollon Highlands, which turns out to be one of the major forces in the formation of the Grand Canyon and of Sedona, the focus of Book Three.

By the time you read Sedona Through Time, you've got a much better idea of how the layers in Sedona formed, because they are many of the same layers present in the Grand Canyon. But once you go Southeast to Sedona, those layers have changed a bit in character, and some unique features appear, like the Schnebly Hill Formation. The helpful diagrams, maps, and photographs that are present in Books One & Two of Ranney's Rock Trilogy are also present in Book Three, and they are very effective in illustrating the geologic events that created Sedona.

Anyone who visits Sedona and nearby Oak Creek Canyon is struck by their beauty and serenity. They possess a profound spirit that is as beautiful as what you can experience in the Grand Canyon, but is much more up-close and personal. Having some knowledge of what the rocks are and how they got there enhances that experience. For visitors whose curiosity is piqued, the book also includes a point-by-point road and trail guide. So take it with you when you visit – you'll see Sedona and Oak Creek Canyon as you've never seen them before.   

Exploring A Grand Mystery

Carving Grand Canyon: Evidence, Theory, and Mystery, by Wayne Ranney, is the next logical book to read after the one he co-wrote with Ron Blakey, Ancient Landscapes of the Colorado Plateau. In Ancient Landscapes, the authors describe the environments in which the layers of the Colorado Plateau formed and illustrate those concepts with paleogeographic maps. As you study those maps, you can't help but try to impose the Grand Canyon on them, since it's the feature that best exposes the layers. At what point, you may wonder, does the canyon begin to be carved?

Carving Grand Canyon is the best answer to that question. It narrates the attempt by geologists to formulate a unified theory of how the Grand Canyon formed and how long it took to do so. Once you've started reading it you'll realize that theory is – complicated.

Fortunately, it's also fascinating – a story of rivers and basins, faults and frost wedging, lava flows and karst collapse, personalities and plate tectonics. If you look at a map of the Canyon, from Lee's Ferry to Grand Wash Cliffs, you may suspect that it's not simply a question of how old the Colorado River is (though that's the most pertinent question). It's a question of what else can happen in a region that large, over millions of years during which several unique conditions persist.

One of the most interesting controversies is whether a paleocanyon may have existed, one that continued to be cut down to current levels in parts of the Grand Canyon. The graphic on page 124 beautifully illustrates the argument that a paleocanyon existed in Mesozoic layers above Eastern Grand Canyon that have since eroded away. The relatively new study of karst collapse near the Kaibab Upwarp also sheds some light on the mystery of how the river cut through the southern tip of the upwarp.

This book is for people whose curiosity burns when they look at the Grand Canyon, trained geologists and armchair geologists alike. It is lavishly illustrated with photographs, cross-sections, maps (some of which are paleogeographic), and diagrams that make the text clear and easy to understand. It offers a coherent answer to a question that is far more complicated than it seems. And best of all, it sparks as much curiosity as it satisfies. Buy two copies – one for your reference library, and one to take with you as you explore Grand Canyon, a place with enough wonder to fill a lifetime.

Wayne Ranney: Geologist, Adventurer, and Mapmaster Flash

You may recall that I mentioned, sometime in the recent past, the paleogeographic maps are fabulous. Or you may not. But they are. And what's even more wonderful is that Wayne Ranney, one of the guys behind those afore-mentioned fabulous maps will be speaking at the Heard Museum on Tuesday, December 11, at 1:30 p.m. To 3:00 p.m. He'll be signing copies of his books in our book store afterward. I've posted a review of the book he co-wrote with Ron Blakey, Ancient Landscapes of the Colorado Plateau, which features maps that depict what the Colorado Plateau may have looked like millions and even billions of years ago.

 I will soon be posting a review of Carving Grand Canyon: Evidence, Theories, and Mystery (2nd Edition) which casts light on past and recent arguments about when the Grand Canyon began to form.

 And I look forward to diving into Sedona Through Time, which delves into the formation of one of the most beautiful places on Earth: Oak Creek Canyon.

We have all three titles available at the Heard Museum Book Store, and Mr. Ranney will be signing there after his lecture. Don't miss it!