The story of Point Reyes is a study in motion - slow, continental transformations and sudden, violent jolts that shake the Earth; the rhythmic play of sea-spray along the coast; wings of birds flashing in flight; drifting shrouds of mist and fog; grazing deer who occasionally follow your movements with soft eyes; migrating whales offshore; and the ebb and flow of Pacific tides. Point Reyes is also the story of the Coast Miwok Indians, English and Spanish explorers, the Mexican "lords of Point Reyes," and 20th-century dairy farmers. The land and its inhabitants have created a legacy for all.
Land and Sea
The Point Reyes Peninsula has long baffled geologists. Why should the rocks of this craggy coast match those of the Tehachapi Mountains, more than 310 miles to the south?
The answer lies in plate tectonics: the constant motion of the Earth's crust. The peninsula rides high on the eastern edge of the Pacific Plate, which creeps northwestward about two inches a year. The slower-moving North American plate travels westward. In Olema Valley, near park headquarters, the North American and Pacific plates grind together along the San Andreas Fault Zone. This fault zone contains many large and small faults running parallel and at odd angles to one another. Because each plate cannot move freely, tremendous pressures build up. From time to time this pressure becomes too great, the underlying rock breaks loose, and the surface actually moves. This is what happened in the San Francisco Earthquake of 1906 when the peninsula leaped 20 feet northwestward.
As if to accent the geological separation along the San Andreas Fault, the weather may vary quite markedly on both sides of Inverness Ridge. A succession of summer days on the east side may be warm and sunny, while on the ocean side, a chilling fog may hide the sun.
geologic maps page.
A geology photo album for this park can be found here.For information on other photo collections featuring National Park geology, please see the Image Sources page.
Currently, we do not have a listing for a park-specific geoscience book. The park's geology may be described in regional or state geology texts.
Parks and Plates: The Geology of Our National Parks, Monuments & Seashores.
Lillie, Robert J., 2005.
W.W. Norton and Company.
9" x 10.75", paperback, 550 pages, full color throughout
The spectacular geology in our national parks provides the answers to many questions about the Earth. The answers can be appreciated through plate tectonics, an exciting way to understand the ongoing natural processes that sculpt our landscape. Parks and Plates is a visual and scientific voyage of discovery!
Ordering from your National Park Cooperative Associations' bookstores helps to support programs in the parks. Please visit the bookstore locator for park books and much more.
The San Francisco Bay Area Network of National Parks has established the Pacific Coast Science and Learning Center at Point Reyes National Seashore. The learning center will provide office space, housing, data, reports, coordination and logistical support for researchers performing projects within Bay Area parks.
Information about the park's research program is available on the park's research webpage.
For information about permits that are required for conducting geologic research activities in National Parks, see the Permits Information page.
The NPS maintains a searchable data base of research needs that have been identified by parks.
A bibliography of geologic references is being prepared for each park through the Geologic Resources Evaluation Program (GRE). Please see the GRE website for more information and contacts.
NPS Geology and Soils PartnersAssociation of American State Geologists
Geological Society of America
Natural Resource Conservation Service - Soils
U.S. Geological Survey
General information about the park's education and intrepretive programs is available on the park's education webpage.For resources and information on teaching geology using National Park examples, see the Students & Teachers pages.