Serpentine Geoecology of Western North America
by Earl B. Alexander, Robert G. Coleman, Todd Keeler-Wolf, and Susan Harrison.
Expected publication September 2006, Oxford University Press. Please browse through the supplemental images and materials for the book
- Color domain photographs for browsing
Klamath Mountains, Trinity locality- Color photographs of serpentine from Baja California to the Klamath Mountains
- Color photographs of serpentine from the Blue Mountains to the Stillwater complex in the Rocky Mountain Range
- Color photographs of serpentine soils
Serpentine and other ultramafic rocks are a unique substrate for plants. Their composition resembles
that of the mantle that is many kilometers beneath the crust of Earth, rather than the composition of continental
masses.
Many plants will not grow in a chemical environment that is related to the mantle more than to the continental
crust, leaving serpentine landscapes open for special suites of plants that can compete well in them. Because of these
distinctive suites of plants and many plant species that are found only on serpentine (serpentine endemics), serpentine
landscapes are of special interest to botanists
Although ultramafic rocks are present on all continents, they are generally concentrated in orogenic (mountain) belts. One of these orogenic belts extends from the Brooks Range in Alaska to Baja California. Because there have been many botanical studies in the central part of this area, the serpentine of western North America was chosen as the platform for a comprehensive book on serpentine geoecology (rocks, soils, and vegetation); Serpentine Geoecology of Western North America, Oxford University Press. This web site is a supplement to that book. Because there are no color photographs in the book, the primary purpose of this site is to present color photographs of serpentine soils and vegetation from Alaska to Baja California. A soils section has complete descriptions of soils from the eleven orders (highest level of soil classification) of soils. The photographs, other than those in the soils section, are organized by domain. There are ten serpentine domains from Baja California (domain 1) to northern Alaska (domain 10). A map of these 10 domains in western North America is provided here.
Serpentine Domains of Western North America
Most ultramafic rocks of North America are set in allochthonous terranes that formed beyond the continental margin and subsequently have been annexed to the core of the continent, which is called a craton. They have been added, or accreted, to the continent in the last one-quarter of a billion years (0.25 Ga, or more specifically 245 Ma). All of the larger bodies of ultramafic rocks in western North America, west of the Canadian shield and the Rocky Mountains, are in these accreted terranes, with the exception of the Stillwater complex in the Rocky Mountains.
- Additional Serpentine domain photographs and descriptions
- Alaska serpentine - domain #10
- Baja California serpentine - domain #1
- Klamath Mountains serpentine - domain #5
- Northern California Coast Range serpentine - domain #4
- Northern Cascade, Blue Mountains and Fraser River serpentine - domains #6 & 7
- Sierra Motherlode serpentine - domain #2
- Southern California Coast Range serpentine - domain #3
Northern California Coast Ranges
The ultramafic bodies in the allochthonous terranes of western North America have been grouped into ten domains. A domain is a geographical area with somewhat similar geologic origins and climate. In some cases a domain corresponds to a major physiographic region (for example, the Klamath Mountains) and in other cases it does not (for example, Baja California). Each domain is described in a separate chapter (Chapters 13 to 22) of the book on Serpentine Geoecology of Western North America, Oxford University Press. In each chapter, a brief domain description, including definitive domain characteristics, topography, and climate, is followed by separate sections on (1) geology, (2) soils, and (3) vegetation. Discrete ultramafic bodies or ophiolitic suites within the domains are called localities. Most of the ultramafic bodies in western North America are included in 119 of these localities (or 120 including the Stillwater complex) that are described in the aforementioned book, but the coverage is not entirely complete.
