Caves, arches, and stacks - The Juan de Fuca Trail

Nothing on Earth can survive the physical and chemical power of water. As a liquid, it dissolves solids, suspends minerals, and both weathers and erodes all rocks regardless of size or durability. As a solid, it forces cracks apart, plucks boulders from bedrock, and scours its way across the land as if it were a sanding block held by the hand of God. There are many examples of its destructive capabilities.

The famous statue of David created by the genius Michaelangelo was created from a single block of marble. He created the sculpture by removing pieces of the rock and leaving behind what people would be in awe of. Water works in much the same way, although the genius behind it is physics and chemistry.

Starting with a cliff face against a sea, rolling waves are dashed against its surface. With each strike, the water removes tiny particles of the substrate, some as solute and others as sand. When a pocket is formed trapped air is compressed as a wave strikes and the hydro-pneumatic action works its way into the tiny cracks and crevices and causes mini-explosions that further degrade the rock. A hole is formed, which enlarges over time, the action of water and air drilling into its depths.

Eventually, a sea-cave is formed. A giant hole gouged into a vertical surface; rounded debris is strewn about its entrance and across its floor. These boulders were once sharp and jagged as they were ripped away from the mother overburden, but the endless action of the sea has softened their corners. As time marches on, so does the endless scouring of the elements as the sea-cave bends under the strain. Sometimes, depending on the thickness of the rock affected and the direction the forming cavern crawls, an opening to the air may occur. The sea-cave has now become a sea-arch.

Sea-arches tend to be visually stunning. The most famous one in Canada is probably Perce Rock off the shores of Quebec. The one I photographed (right inset) is located near the town of Pacific City in Oregon. At low tide, it is possible to walk through some of them. Of course, it doesn't end there; the process of weathering and erosion continues and the sides of the newly formed arch become increasingly thinner. The overburden can no longer be supported as the columns get further apart, the arch collapses becoming so much rubble.

A stack is left in its wake. The spire, now isolated from the mainland, stands proud and erect as if to say it is not yet beaten. In spite of its resistance to the everbearing action of wave and wind, it too will come to an end. It seems that time is not on its side. Eventually, it will be just a memory, just as the sea-cave and arch that came before it.

Thanks for reading.     Ericspix     Eric Svendsen