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21 of 21 people found the following review helpful:
4.0 out of 5 stars
Grand Canyon Geology: Not a Simple Story, July 11, 2005
James Powell (no relation to John Wesley Powell) is one of the best authors of popular geology writing today. His previous books, "Night Comes to the Cretaceous" and "Mysteries of Terra Firma", provide fascinating accounts of important ideas in modern geology, such as the age of the Earth, plate tectonics, and the extinction of the dinosaurs. In this book, Powell tackles the complex geology of the Grand Canyon within the broader context of the Green-Colorado River systems. The focus is not on a description of the canyon but on understanding how it was formed. As Jim Powell tells us, the Colorado Plateau has played a major role in the history of American geology. Much of his book follows the lives and work of the great geologists of the nineteenth century, such as Powell, Gilbert, and Dutton. It was they who gradually came to an understanding of how rivers carve canyons, canyons that sometimes cut right through mountain ranges. Before their work, many people thought that the great canyons were rifts created by other forces, through which rivers later flowed. Most of the first half of the book is a fascinating mix of history and science, using the adventures of men like Powell to illustrate the birth of modern geology. The second half of the book takes on the more challenging task of explaining the complexities of the Grand Canyon story. As twentieth-century scientists looked more closely at the canyon and measured the ages of rocks through which it cuts, they saw that the simple and elegant theories of the nineteenth century broke down. Perhaps the Colorado River of today did not exist when parts of the canyon were cut. Perhaps the river flowed south-east rather than west, exiting the canyon via the Little Colorado and draining into the Rio Grande. Possibly two separate canyons joined to form the Grand. Maybe the canyon was carved, then filled with gravel and sediment, then cut again within the past few million years. Some of this is heavy going for the geological novice, but the rewards of reading this book are ample. It teaches us that the Earth and its geology are indeed complex, and the process of advancing science is a very human affair. It is sobering to realize that even such a huge geological feature as the Grand Canyon still holds its mysteries and stymies efforts to fit it into a single neat framework.
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10 of 10 people found the following review helpful:
4.0 out of 5 stars
Worth a read if you're somewhat technically curious, July 11, 2006
I think James Lawrence Powell had pretty big ambitions for this book when he set out to write it: to tell an adventure story or two about the early exploration of the Southwest, to give the history of the development of several important geological concepts, to go into the biographical details of a few of the leading figures in the field, and to bring the interested lay reader with some but not too much technical background up to date on where Grand Canyon science stands at the moment, the basic question being "How did this thing get here?". Yes, we know the Colorado River did it, but exactly how and when? For the most part he was successful at these somewhat disparate tasks, though I don't think I can give a grade higher than B+/A- for the overall product. Here were my "issues" with the book: 1) At times it went off in one direction a little too far for my tastes (mostly in the adventure/biography parts), and it was a bit of a confusing mish-mash at others if you can't keep the whole panoply of figures fully in mind. The multiple objectives led to a little gear-stripping at times as the topic changed back and forth. 2) I was most disappointed with the maps: they seem to be scattered around somewhat at random (I found myself flipping pages a lot trying to find this or that map), and I swear some important features mentioned in the text can't be found on the one where you'd think you'd find it - i.e., the maps don't seem to have been made for the book but rather pasted in from some other source. 3) Finally, while the "grandest puzzle" is at heart a science puzzle involving river system geology, I thought the author avoided going into too much scientific detail for fear of perhaps alienating the reader. I would have liked more science, and sooner in the book. I.e., I don't think downcutting rates (with actual numbers) were even mentioned until the very last pages. Powell has a clear talent for deftly explaining technical concepts and should have used it more. But if you're looking for the current state of the science on the Grand Canyon you'll have to plow through a lot of seemingly marginally relevant material first, as Powell seemed more determined to develop fully the whole history of all the relevant ideas involved. As the book had a "teachy" tone to it, it may have worked better for me if it had been in more of an actual textbook format; fundamental concepts layed out first, then assembled into a comprehensive model. Maybe one has to be an actual practitioner in the field to fully appreciate the history and biography. Still, Powell is a very good writer and the book is basically not hard reading in the least. I think it would be good for someone who wants to understand how the Grand Canyon came about but wants the telling occasionally spiced up with frequently colorful characters overcoming obstacles and limitations (both physical and mental). If you think this book might interest you, don't let the drawbacks I noted keep you from picking it up as they're not fatal flaws by any means. Almost any book on the Grand Canyon will give you a greater appreciation of it, and this is no different.
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10 of 10 people found the following review helpful:
5.0 out of 5 stars
Excellant overview, April 23, 2006
This is a lovely overview of the Grand Canyon, its discovery by Europeans, and its study by scientists from the mid 19th century to the present time. It is sort of a history of a history. While the author discusses early Spanish visits to or near misses of the Canyon, he spends most of the first several chapters discussing John Wesley Powell's voyage of discovery and his documentation of the Colorado River's course to the Gulf of California. This is almost an adventure story in itself, and serves to capture the imagination in a way that most geological works don't. Although the quotes from Powell's work seemed a little over-the-top, I still felt like getting a copy of his work to read it for myself. Certainly the discussion of his later life produces a much more rounded and engaging portrait of the man than most texts provide. Succeeding chapters deal with the careers of Powell and his various coworkers and successors and the development of theories regarding the Grand Canyon's origins. In the process, the author also discusses the history of geology and of the theory of earth history, covering among other things, the work of Nicholas Steno, James Hutton, Louis Agassiz, Charles Lyell, and Alfred Wegener. For the geology student these names will already be familiar; for others the brief introduction will offer a quick recitation of the Who's Who of geology without belaboring the point. Professor Powell's discussion makes it apparent that the science of geology is as much a work in progress as the Grand Canyon itself, since the concept of the canyon building processes have been reshaped as geology itself has matured as a field. He carries the reader through the thought processes of each of the researcher's contributions, ending the book with a final summation of his own on the subject that he admits is thoroughly tentative but is still a best approximation. Among the most interesting points on the Canyon is the fact that, while on first glance it seems so obvious with respect to its structure, dynamics and age, it is in fact much more complex than it appears. The author's style is very readable, although there were places where I got rather lost in the descriptions of channels, directions, etc. along the course of the river. Anyone intimately familiar with the terrain, however, will have little difficulty following the discussion, but those of us less familiar with the Canyon will find it somewhat confusing. The gist of the information is, however, quite clear. Those not familiar with geology will find the author provides explanations of terms in context, and will also find a glossary of terms at the back of the book. For the most part, the description of erosional and depositional processes is quite clear and does not require any background in the subject. It would probably serve as a good book for high school libraries, since its presentation of science as a profession and a discipline is quite clear. A thoroughly enjoyable book for those interested in the history of geology, history of science, history of the West, John Wesley Powell's expeditions and contributions, structural geology and geomorphology, the Colorado River, the Grand Canyon, and hydrodynamics.
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