by Marli Miller and Lauren Wright
Death Valley impresses more than a million visitors each year, and anyone with a feeling for geology surely considers it a choice destination. It is a vast showcase of rocks and landforms, testifying to geologic events over billions of years. And most compelling for specialists, Death Valley displays the evidence and effects of extreme crustal extension, revealing the rarely seen doings of the deep crust in a setting where the faults and rocks are exposed in extraordinary detail.
The authors of this book are well equipped to present deep geologic knowledge and splendid photos. Wright has trod these lands for over 50 years, while Miller is both a researcher in continental tectonics and an able photographer who captures scenes that are as informative as they are beautiful. Their up-to-date content is of great value to the serious student of Death Valley or of Earth science.
This is a slim volume whose meat amounts to about 60 pages in three chapters, devoted respectively to landforms, crustal extension features and a regional geologic history. (The second edition has a fourth chapter of excellent road logs and eliminates many flaws of the first edition.)
Landforms of the park include fresh fault scarps, widespread alluvial fans, badlands, dune fields, lava flows, mountain ranges, and flat-bottomed basins bearing playas and salt flats. Any one of these categories is worth a field trip. In addition, Miller and Wright discuss the distinctive wineglass canyons plus the enigmatic fault surfaces called turtlebacks. They don't leave out the welcome presence of desert springs, or out-of-the-way Racetrack Playa with its mysterious sliding stones.
The second chapter connects many of these landforms to Death Valley's formation during the last 16 million years as the region stretched apart. The process consisted of great bodies of crustal rocks slipping crabwise on geologic faults. These faults are surveyed and then the bodies of rock, which are now mountain ranges. The basins between the ranges contribute their own information about the erosion and movement of the rocks around them. There are many basins of different ages and sizes; aside from today's Death Valley basin, the other sizable one is Furnace Creek Basin, whose Miocene-age deposits are spectacularly exposed around Zabriskie Point. And the rock palette of the Artist Drive Formation, among other notable instances, is the product of recent volcanism.
The third chapter is a systematic march through time as chronicled in Death Valley's rocks, from Proterozoic time nearly 2 billion years ago up to today. As in the earlier chapters, Miller and Wright mention localities where these rock units are well exposed. The publisher has signaled these in 21 places with "Stop and Look" icons.
Those icons are one of the few ways the publisher has enhanced Miller and Wright's material. The high-quality paper and photo reproduction are also worth noting. But in adapting the authors' earlier treatment of this subject (the Death Valley chapter in Geology of National Parks, 5th edition), the publisher has tried to retrofit it for readers new to geology. That effort involves adding several one- or two-page "Basics" sections to present the rudiments of faults or major rock types. Miller, a teacher, does her best, but these interruptions are as distracting as advertisements in a magazine, nor do they really bring the nongeologist reader up to speed.
The publisher has also added an unneeded glossary, being sure to sprinkle the same definitions through the text in the page margins. But this solicitude for the tenderfoot reader does not extend to providing truly important basic advice, such as safe behavior in the desert or the rules for collecting specimens in National Parks (in a word: don't).
Design, layout and editorial flaws also mar the book's ease of use. Some photos appear far from the places where they're discussed in the text. The numbering scheme for illustrations is baroque and confusing. The geologic mapsurely the most precious item in such a book as thisis small, dark and insufficiently labeled. Still worse, the map of locations is printed back-to-back with the geologic map, not on a facing page. And for a continual irritation, all measurements in U.S. feet are simultaneously converted to metric units with spurious precision, yielding such inanities as "averaging about 1828.8 m (6000 feet) in combined thickness."
Geology of Death Valley National Park is a colorful, compact, authoritative summary of its subject. Although it pretends to be, it is not a real field guide to Death Valley, nor is it a real introduction to geology. Readers who want those must get a second or third book before they can make full use of this one. But professionals will welcome the book, despite its flaws, as a useful compendium of recent thinking about this fascinating region. Look for the much-improved second edition.