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    Northwest Geology Field Trips, by Dave Tucker, is licensed under a Creative Commons Attribution-Noncommercial- Share Alike 3.0 United States License. You can use what you find here, repost it with attribution to the author, "remix" it for your own purposes, but may not use it with the intent of making money off of it.

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Fidalgo ophiolite field trip, Part II- Mount Erie

Gabbro at Stop 1. Note the pale vertical dikes near the yellow hammer. Click any image to enlarge.

Gabbro at Stop 1. Note the pale vertical dikes near the yellow hammer. Click any image to enlarge.

A self-guided geology field trip to the second part of the Fidalgo ophiolite (oceanic crust section) is posted here. This field trip visits intrusive and sedimentary rocks on Fidalgo Island, including Mount Erie. This is the second installment in the ophiolite series, which started at the chunk of the mantle at Washington Park.

The April 12th guided geology field trip sponsored by Mount Baker Volcano Research Center will visit some of these rocks. Registration information is on the MBVRC website. If you have been waffling, time to be decisive- the trip is nearly full!

The view south from Stop 2 at Mount Erie.

The view south from Stop 2 at Mount Erie. Here we see an island in Lake Campbell, on Fidalgo Island. Skagit Bay stretches off to the south.

A bit of the mantle: Washington Park, Fidalgo Island, Washington

The 'snake-skin' texture of serpentinite lends its name to 'ophiolite'. This is a nice example near the foot of the stairs.

The ‘snake-skin’ texture of serpentinite lends its name to ‘ophiolite’. This is a nice example near the foot of the stairs.

A geology guide to ultramafic rock at Washington Park, near Anacortes, is now available on Northwest Geology Field Trips. Click here to go straight to the field trip! The rock is the metamorphic rock serpentinite, and was originally in the earth’s mantle below oceanic crust. Exposures are found along the dramatic rocky shore and on bare rocky knobs above the coastal cliffs. A single essential outcrop is highlighted in this quick self-guided field trip. The description explains what ‘ophiolite’ is and points out spectacular glacial polish at the same outcrop.

Coming soon:

  • Mount Erie- Fidalgo ophiolite Part 2
  • Finlayson Point, Victoria
  • Rock Trail, Larrabee State Park
  • ?????

Do you have field trips to share? Please do. Let’s branch out to places in southern and eastern Washington. I’m happy to help you write your guide . Contact me via comment or email:

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