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27 of 27 people found the following review helpful:
5.0 out of 5 stars
Geology of the American Southwest: A Journey Through Two Billion Years of Plate-Tectonic History, November 9, 2006
An excellent introduction to the geology of the American Southwest, including most of the Colorado Plateau in Utah, Colorado, New Mexico, and Arizona, as well as parts of California (in particular Death Valley), Nevada, and Texas. All chapters devote considerable space to a discussion of the plate tectonic settings and paleogeography of the geologic period under consideration. The tectonic settings and processes are of central importance in understanding the amazing and extensive rock record being described. This book contains a host of useful maps, stratigraphic and correlative diagrams, and crisp images of many rock formations discussed in the text. For example, a figure on page 170 I found particularly useful displays a cross section of the famous Jurassic sedimentary rocks spanning the Arizona-Utah border (which is equally applicable to southwestern and far western Colorado), showing schematically but clearly the complex horizontal and vertical relationships, including unconformities, of the major Jurassic rock units present in what can be at times a confusing area of geological terrain. The geology of many of the National Parks and Monuments in the American Southwest, particularly Grand Canyon National Park, is interwoven very nicely with the overall theme and level of the book. All in all, a very useful reference covering 2 billion years of Earth history in this part of the United States, particularly appropriate for undergraduates and graduate students studying geology and the Earth sciences. An extensive bibliography, cited frequently in the text, provides many points of introduction to the supporting literature, and opportunities for further exploration. Undergraduates who plan on participating in a geology field camp in the American Southwest will no doubt benefit by reading this book before their departure.
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21 of 21 people found the following review helpful:
5.0 out of 5 stars
The big geologic picture on a land where geology dominates the view, April 2, 2007
The title of this book says it all. The story begins two billion years ago and follows the formation of the continental crust of what is now the southwestern US. It then follows that chunk of land to the present, as supercontinents form and disintegrate, island chains collide, and mountains rise and fall. Unlike so many books about the geology of the southwest, Baldridge focuses on the plate tectonics behind the processes. This approach allows the reader to understand the "why" behind advancing and retreating seas, uplifts, faults and volcanoes. The geographic area studied is the southwest, although the Colorado Plateau seems to gather the most attention. It is seen in a broad geological context that includes what happened in places like Death Valley, the Rio Grande Rift and Southern Rocky Mountains. Baldridge places his explanation in standard geologic time, but his chapter breaks are in locations driven by the regional geology, not the standard hierarchy. For a Grand Canyon example, the Chuar and Tonto groups are a single chapter, a fresh (and justifiable) perspective. The story that comes through is a "life story" of the southwest, in which a reader can see the region's geology evolve, illustrating how events in its past shape its response to new conditions.
The book's broad scope means that the history of individual rock layers are often not there - indeed, many layers are not even mentioned (although the fame of Grand Canyon's rock column is evident, most of ours are). The layers serve to illustrate a "story line" driven by the forces acting on the land, they do not break the story into pieces because of what is (or is not) preserved in today's exposures. In developing this evolutionary presentation, Baldridge has to sort through many, often conflicting, hypotheses. He does a good job of finding common threads. In many cases, he presents different mechanisms but concludes with the salient points that seem to be areas of agreement or with the conditions that a solution must explain.
This book is not for the geologically faint of heart. It assumes a pre-existing general understanding of plate tectonics and other geological principles. It is not the place to learn how plate tectonics works, but is the best place I have found to understand how plate tectonics worked on the Colorado Plateau. It will not tell you how the Grand Canyon was carved, how Monument Valley formed, what makes the Supai Group red, or other specific questions. But it does provide the vast historical panorama against which such questions can be asked. From a degree of technicality, it is less technical than Beus and Morales' Grand Canyon Geology, but certainly well beyond Price's Introduction to Grand Canyon Geology. In the preface, Baldridge says his target audience is "upper level undergraduates and graduates." I would expand this to include anyone with a real interest in the Colorado Plateau, and who wants the "big picture" only hinted at in most treatments of the region (like Baars' The Colorado Plateau: A Geologic History). For readers with a more casual familiarity with geology, it could be a difficult read, but the rewards are great for a comprehensive understanding of the area's history.
I liked it - a lot!
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1 of 2 people found the following review helpful:
2.0 out of 5 stars
Geology of Arizona, New Mexico and north-central Mexico, February 22, 2009
This is book for a geologist, not a beginner. As professional scientist I found it very interesting but struggled with the geology verbiage and endless names of different formations. If you know the subject well already you will gain insight through the concentration on plate tectonics, the reason I chose the book. But, it soon gets you buried in the lingo of geologists of these areas and it is easy to lose track of what has been covered. The author covers a vast range of time, from 4 billion years ago to the present and, using plate tectonics as the background you gain some insight into how the area came to be. The main problem for me, as a non-specialist, is that I got buried in the detail and in the stilted text so beloved of authors on similar subjects.
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