Land on the Move
Basalt is a dense and therefore heavy volcanic rock. The sea floor is composed of basalt in the form of pillow lavas. During the sea floor spreading process the ocean plates grow older and hence acculmulate thick layers of comparably lightweight sediments. The Juan de Fuca ocean plate subducts under the North American continent while being still young with only 10 million years of age. The lightweight deep-sea sediments get scraped of the heavy volcanic ocean floor during the subduction process. This causes the sediments to steeply tilt into a tectonic mélange, called flysch that is attached to the hence seaward growing continent. Former deep sea ocean sediments become land in a geological process called accretion. This explains why the coastline of the Olympic peninsula exhibits the youngest rocks with only 20 million years of age. The surf already erodes these former deep sea sediments that are now headlands into sea stacks.
August 2008
Canon 20D, Canon EF-S 10-22mm, f/22, 1 sec, ISO 100, tripod