Who doesn’t love the San Juan Islands? It’s a place to instantly fall in love with. Most people come to the island for the touristy side of things like shopping in town or the ever popular whale watching. As students here at FHL we know better and that there are much more complex things going on in the waters surrounding the island and on the land it’s self. Cruising up from Anacortes you are given the opportunity to view the islands and their natural beauty, the carved stone cliffs that plummet into the water, the small rocky coves here and there abounding in driftwood, and the tree lined rolling hills.
Geographically this region is a hot spot, the islands are being pushed and squeezed by continental plate shifting. There are at least 6 different terranes (fault line formed rock groupings) are present in the San Juan Islands. A geologically interesting area on San Juan Island is the limestone. Lime Kiln state park has one such area where they actually had 2 kilns for the extraction of the limestone. The limestone operation started in the 1860’s, the kilns were used to extract the lime from the rock. Because of the kiln operation much of the area was logged and developed, causing the old forested area to disappear. Much of the woods that you see hiking the trails there is newer growth. In 1984 the property was turned over to the state and one of the kilns was restored and you can see it today.
- Kiln doors
The limestone was created from magma that erupted underneath the seafloor 200 million years ago. This magma flowed over the sea-floor sediment and caused a volcanic chain to form. Not long after the magma started forming the islands pillow basalt started to form and it’s evident that it came from under water because it cooled quickly. After the basalt cooled a process know as sedimentation happened. This geologic formation was then pressed upward by shifting plate tectonics. The after affect can be see at Lime Kiln park where there are still limestone deposits.