Explore Geology
geology fieldnotes title


National Park


cover of park brochure

park geology subheading
Mountains and lake
Olympic National Park, Washington

The Olympic Mountains are not very high--Mount Olympus, the highest, is just under 8,000 feet--but they rise almost from the water's edge and intercept moisture-rich air masses that move in from the Pacific. As this air is forced over the mountains, it cools and releases moisture in the form of rain or snow. At lower elevations rain nurtures the forests while at higher elevations snow adds to glacial masses that relentlessly carve the landscape. The mountains wring precipitation out of the air so effectively that areas on the northeast corner of the peninsula experience a rain shadow and get very little rain. The town of Sequim gets only 17 inches a year, while less than 30 miles away Mount Olympus receives some 200 inches falling mostly as snow. mountains and glacial flow

These mountains have arisen from the sea. For eons, wind and rain washed sediments from the land into the ocean. Over time these sediments were compressed into shale and sandstone. Meanwhile, vents and fissures opened under the water and lava flowed forth, creating huge underwater mountains and ranges called seamounts. The plate(s) that formed the ocean floor inched toward North America about 35 million years ago and most of the sea floor went beneath the continental land mass. Some of the sea floor, however, was scraped off and jammed against the mainland, creating the dome that was the forerunner of today's Olympics. Powerful forces fractured, folded, and over-turned rock formations, which helps explain the jumbled appearance of the Olympics. Radiating out from the center of the dome, streams, and later a series of glaciers, carved peaks and valleys, creating the beautiful, craggy landscape we know today. Ice Age glacial sheets from the north carved out the Strait of Juan Fuca and Puget Sound, isolating the Olympics from nearby landmasses.

Surrounded on three sides by water and still crowned by alpine glaciers, the Olympics retain the distinctive character that developed from their isolation. Several plants and animals are unique to the Olympics--examples of how genetic diversification occurs when geographical isolation exists. The most striking example is the Olympic marmot, with its distinct chromosonal and behavioral patterns. Others included Flett's violet, Piper's bellflower, Olympic Mountain synthyris, Olympic chipmunk, Olympic snow mole, and Beardslee and Cresceti trout, as well as others.

The Coast
the coastSome 57 miles of Pacific Ocean coastline form a vital component of Olympic National Park. This coastline has remained little changed except for the impact of the pounding surf and storms. It looks much as it did when American Indians built their first villages thousands of years before European explorers arrived.

The coast is where the land meets the sea, vibrating with life and energy. Drift logs cast high on the beach; sculptured arches and sea stacks; the roar of crashing waves; the calls of gulls, bald eagles, and black oystercatchers; dramatic sunsets; the sheer vastness of the ocean and a myriad of other elements impress themselves upon you.

Scooping up a handful of sand, you discover that it is virtually impossible for you to count the shades of colors or to classify shapes, so varied are the grains. At low tide you can walk toward the surf stopping at tidepools along the way. If you squat down and spend some time just looking, you will be amazed at what you see as your eyes start ferreting out objects that look like rocks, but which in fact are small sea animals. Slowly extending your horizon, you may see some raccoons feeding on shellfish that are reachable now that the tide is out and the danger of the surf is withdrawn. You are likely to find the footprints of shore birds all over the beach, but you will also find those of bear, deer, raccoons, river otters, and a host of other creatures.

The sheer quantity of flotsam and jetsam cast upon the beach is astonishing. Probably the most exotic are the glass floats that Japanese fishermen use to support their nets. It takes the ocean currents about one year to carry the floats across the Pacific to the Washington coast. Among the debris cast upon the shores are huge trees felled from inland stream bank sites by rushing rivers and washed out to sea. They are repeatedly thrown and banged against sand and rock. Limbs are removed and trunks are sanded smooth by the action of the waves. Finally a great storm may toss them high on the beach to join many others.

The Olympic coast is a wild place, a place for endless exploration.

Superlatives about the trees abound, for several specimens reach record sizes. In some locations, the forest canopy is so thick that falling snow is caught in the trees and never reaches the ground.

There are four basic types of forests on the Olympic peninsula:

  1. temperate rain forest
  2. lowland
  3. montane, and
  4. subalpine.
Temperate rain forest is found at low elevations along the Pacific Ocean coast and in the western-facing valleys of the peninsula where lots of rain, moderate temperatures, and summer fogs exist. Sitka spruce is the dominant tree, but trees typical of the lowland forest also grow here, including western red-cedar.

The lowland forest grows further inland from the coast, and above the rain forest valleys. You will not find Sitka spruce here, but you may see grand fir. Western hemlock will probably be the most common tree, although stands of Douglas-fir may prevail where fire or drier conditions caused by the rain shadow give these trees an advantage. Western redcedar is never an abundant tree, but its gradual disappearance is a true indicator that the upper limits of this zone have been reached.

Gradually the lowland forest gives way to the montane forest. Unless you are an expert you may have difficulty recognizing when the change occurs. If silver fir is present you know that you have moved into the montane zone, but in drier parts of the park, the montane zone may look much like the lowland forest, with the exception that the western redcedar will no longer be present.

As elevation increases, temperatures cool and more moisture falls as snow; growing seasons get shorter and the subalpine zone takes over. Silver fir grows here as well as in the montane zone, and in the western portion of the park may be prevalent. The presence of subalpine fir, mountain hemlock, or Alaska cedar groves assure you that this is the subalpine zone. The lower portion of the subalpine zone consists of continuous forest, but in the upper part of this zone the forest thins out. Delightful alpine meadows graced with wildflowers and glacial lakes often intermingle with stands of firs. Subalpine fir is especially well adapted to the heavy snows and cold temperatures experienced here. Its spire-like shape sheds snow. It also extends its lower branches under the snow, often putting down roots from them where they touch the ground. When the snow melts the trees may be surrounded by skirt-like arrangements of longer, lower branches. forests

Increasing elevation causes even more severe climatic conditions. Trees become fewer, shorter, and more misshapen. Trees may be mere shadows of their cousins living lower down the mountain. Here a 100-year-old tree may be only three feet tall. Eventually tree line is reached, beyond which trees do not grow, but a profusion of wildflowers often rewards your eye in a vivid display that is an effective foil to the scenery below, now visible because the trees no longer block the view.

From seashore to mountaintop Olympic is blessed with an incredibly rich plant community created by varying environments.

park maps subheading

The General park map handed out at the visitor center is available on the park's map webpage.

For information about topographic maps, geologic maps, and geologic data sets, please see the geologic maps page.

photo album subheading

A general photo album for this park can he found here.

For information on other photo collections featuring National Park geology, please see the Image Sources page.

books, videos, cds subheading

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.

Please visit the Geology Books and Media webpage for additional sources such as text books, theme books, CD ROMs, and technical reports.

Parks and Plates: The Geology of Our National Parks, Monuments & Seashores.
Lillie, Robert J., 2005.
W.W. Norton and Company.
ISBN 0-393-92407-6
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.

geologic research subheading


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.

selected links subheading

NPS Geology and Soils Partners

NRCS logoAssociation of American State Geologists
NRCS logoGeological Society of America
NRCS logoNatural Resource Conservation Service - Soils
USGS logo U.S. Geological Survey

teacher feature subheading

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.
updated on 01/04/2005  I   http://www.nature.nps.gov/geology/parks/olym/index.cfm   I  Email: Webmaster
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