San Diego Natural History Museum--Your Nature Connection[BRCC San Diego Natural History Museum: Herpetology Department]



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Reptiles & Amphibians


Frequently Asked Questions about San Diego Geology

What kinds of rocks and minerals occur in our region?
What is the geologic history of the San Diego region?
What causes earthquakes?
Do we have any major faults in the region?


What kinds of rocks and minerals occur in our region?

San Diego County is about 900 square miles of very complex geology, from the high desert and mountains to the coast with lots of faulting all along the way. So a lot depends on where you are looking. Here is a list of many of the minerals known to occur in the county:

  Acmite, Albite, Allanite, Amblygonite, Andalusite, Apatite, Arsenopyrite, Azurite, Basalt, Bavenite, Bertrandite, Beryl, Biotite, Bismite, Bismuth, Bismuthinite, Bornite, Calcite (optical), Cassiterite, Celestite, Cerussite, Chalcocite, Chalcopyrite, Chrysotile, Clintonite, Cookeite, Corundum, Epidote, Erythite, Ferrimolybdite, Ferrisicklerite, Ferroaxinite, Fersmite, Fluorapatite, Francolite, Gabbro, Gahnite, Galena, Garnet, Glauconite, Gneiss, Gold, Granite, Graphite, Gypsum, Helvite, Heterosite, Heulandite, Hydromagnesite, Laumontite, Lawsonite, Leadhillite, Lepidolite, Limonite, Lithiophylite, Magnetite, Malachite, Manganite, Marcasite, Microcline, Molybdenite, Morenosite, Morinite, Muscovite, Nickel, Orthoclase, Pentlandite, Petalite, Plagioclase feldspar, Pollucite, Purpurite, Pyrite, Pyrophyllite, Pyrrhotite, Quartz, Rhodonite, Rutile, Rynersonite, Samarskite, Scheelite, Schist, Sicklerite, Silver, Sphalerite, Spinel, Spodumene, Stellerite, Stokesite, Tellurium, Tenorite, Thorogummite, Todorokite, Topaz, Tourmaline, Tremolite, Tridymite, Triphylite, Uranmicrolite, Uranophane, Violarite, Wollastonite, Zircon

What is the geologic history of the San Diego region?

To understand the history of our area, we must first unravel the present geologic picture. Although earthquakes and active faults are now a very recognizable part of life in southern California, they are a very recent addition to a much longer and more complex pattern of geologic activity. Part of this picture is hidden by geologically young sedimentary rocks on which much of metropolitan San Diego is built. As we travel eastward, however, into the less populated mountain and desert areas, the exposed rocks record a long history of plate collisions, volcanic activity, and crustal uplift. From 250 million-year-old sedimentary rocks, through 100 million-year-old granites and 18 million-year-old volcanic eruptions, to the faults that shake us into today’s reality, the San Diego area has been a very active place indeed. Learn more...