Port Ludlow :: a Master Planned Resort Community for All Ages :: Birding, Boating, Golfing, Hiking, & More

Port Ludlow is located around Port Ludlow Bay on the Olympic Peninsula in Washington State.

The Olympic Peninsula is a unique region in the Pacific Northwest. Although it is part of the ring of fire around the Pacific, the mountains are not former volcanos. Almost all the mountain ranges on the Pacific coast were created by vulcanism (i.e., volcanos, not aliens with pointy ears, sorry, couldn't resist :)). Some of the mountains in the Cascades, such as Mount St. Helens and Mount Rainier, are still active volcanos.

The Olympics were created by plate tectonics when the Olympics terrane collided with North American (Cascade) terrane and the San Juan terrane, "causing the new arrival to be literally stood up and slivered against itself like a deck of cards pushed up against a wall, with slices of repeated units of rock sliding up past each other" (from The Natural History of Puget Sound Country).

Because of their origin, the rocks in the Olympic Mountains are very different than the rocks on the mainland. the Olympic Mountains are primarily basalts and sedimentary rock, and do not contain any granite except that transported south from the Canadian Cascades by glaciers during the ice age.

The Port Townsend Marine Science Center's Natural History Exhibit has a fascinating interactive exhibit called the "Washington Geo-Puzzle" that illustrates the formation of present day Puget Sound. You visualize the effects of the different plate tectonic actions and post-glacial floods by moving sheets of plexiglass.

Port Ludlow Bay, and the topography of Puget Sound as we know it, was shaped by glaciers, in particular the Puget lobe of the Vashon Glacier, the last glacier in the Fraser Glaciation. From about 2.2 million years ago until about 11,000 years ago waves of massive continental glaciers periodically covered the hills and lowlands between the Cascades, the Olympics, and the Vancouver Island ranges, extending south of present day Olympic and out to the Pacific Ocean.

The Vashon Glacier gouged out the deep canyons which later filled with water and became the Strait of Juan de Fuca, Admiralty Inlet, and Puget Sound, also known as the Salish Sea (in conjunction with parts of British Columbia).

When the massive glaciers of the ice age finally retreated, they left deposits behind. The top layer of soil in most areas of Port Ludlow is what is called "glacial till", which is a bouldar-clay mix.

The Vashon Glacier also left huge deposits of gravel which are the subject of controversy in the Port Ludlow and Hood Canal area because of commercial interests which want to mine them. For more information see the Hood Canal Coalition website.

For additional information on glaciers and terranes, see the following links:

• National Park Service pages
  • Olympic Mountains Geologial Features
  • Glaciers in Olympic National Park
  • Olympic Mountains
• UW Dept of Atmospheric Sciences - the Frasier Glaciation
• Geology of the Puget Sound Field Guide and Road Log (PDF) for Whidbey Island, a particularly interesting area for geologists.
• The Restless Earth: A Geologic Primer from the Burke Museum