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Southern California Geology

Geologic Basics

If you are not familiar with geological things like rocks and faults and geologic hazards and the Earth's crust, you might want to spend some time browsing and (or) downloading the online geologic-information resources listed below. They will help you understand the geologic setting and geologic history of southern California, and will give you a better appreciation for the kinds of investigations conducted by the Southern California Areal Mapping Project (SCAMP).

Where to Start?

To understand geologic processes and geologic features, you need to understand how geologists think about geologic time

An elegant website maintained by the National Park Service and the U.S. Geological Survey introduces many basics of geology, and is a wonderful starting place for understanding the concepts and language of earth science. The site has excellent links to such items as:


  • What is a Geologic Map? introduces you to the main geologic-information product produced by the Southern California Areal Mapping Project
  • Plate Tectonics, including descriptions of the Earth's crust and interior (mantle and core), and how geologists reconstruct the long-term movements of tectonic plates and the continents that form their upper parts.
  • A discussion of Geomorphic Provinces will allow you to understand how earth scientists distinguish regions like southern California's Transverse Ranges Province and Peninsular Ranges Province

Other Online Geologic-Information Resources

  • Check out the University of British Columbia's online geologic tutorials, including:
  • A coordination hub for links to geologic subjects
  • A geoscience image gallery. This site contains images of geologic features, including thumbnail photographs that you can browse, clicking those that you want to examine for interesting or representative geologic features
  • Petrology of igneous, sedimentary, and metamorphic rocks with in-depth descriptions of the three major classes of rocks. Although some of these links are under construction, the sites contain a wealth of detailed information about how geologists describe and interpret rocks. Also navigate to a description of petrology (the origin and genesis of rocks, based on analysis of their properties and setting)
  • An interactive discussion of the Rock Cycle with links (most under construction) to geologic processes and products
  • The Houghton Mifflin Company (College Division) has a Geolink that is a gateway to several different information resources. These include its Online Glossary and Inside Geology, a gateway to numerous online resources about various geologic topics
  • The Newfoundland and Labrador Geological Survey has an online Geological Features Collection that has brief discussions of geological features accompanied by excellent photographs. Some of the links take a while to load, so be patient. Especially look at the Rocks and Minerals Discussion and its Rock Cycle Diagram for a clear summary of how the three main classes of rocks (Igneous, Sedimentary, Metamorphic) relate to each other and to geologic structures like folds and faults
  • Geoscience departments at some universities maintain online archives of photographs of rocks as observed in thin sections (wafers of rock sliced so thinly that light can be passed through the slices and the textural and mineralogical properties of the rock observed through a microscope-the study of petrography). For starters, check out the Atlas of Igneous and Metamorphic Rocks, Minerals, & Textures put up by the Geology Department at the University of North Carolina, Petrography maintained by the Geology Department at California State University, Humboldt (navigate to the contents at the bottom of the petrography page), and Minerals in Thin Section maintained by the Department of Earth and Ocean Sciences at the University of British Columbia

Where can I find online definitions of geologic terms?

Geologic terminology can be incomprehensible to those not familiar with the jargon. Online geologic glossaries that can make your life a little easier include:


  • The Online Glossary at the Geologic Basics website developed by the National Park Service and the U.S. Geological Survey. This glossary is nice because it has interactive links that expand on the initial glossary entry.
    • For example: In the glossary, look for "fault" in the "F" section. There, a link to "more detail" takes you to a clearly-written discussion of earthquake faults, with graphics showing different kinds of faults and how they respond to different kinds of stress in the Earth's crust. When used in conjunction with the Geologic Basics website discussion of geologic strain, you can prepare yourself for SCAMP's discussion of Major Faults in Southern California
  • The University of British Columbia maintains an online search tool for finding definitions of geologic terms. This resource allows you to type in a geologic term you are interested in, and the data-base engine will retrieve one or more definitions and (or) related terms, accompanied in many cases by graphics

USGS General Interest Geologic Publications

Online general-interest publications produced by the U.S. Geological Survey, include:

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