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    This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States License.
    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.

    EDUCATORS: Please feel free to use anything you find here that is useful to your mission educating people about Earth science. E-mail me if it would help to have a larger or higher-resolution version of any of the images. tuckerd at geol dot wwu dot edu

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Geology Underfoot in Western Washington- order copies from your bookstore.

Dear friends,

Geology Underfoot in Western Washington should be available in late April or early May. Order copies from your favorite bookstore now. You have the title; the ISBN is 978-0-87842-640-9. It is being published by Mountain Press Publishing. The store won’t have heard of it yet. Get the word to the store now and they will place their orders with the publisher or with their distributors.

Cover art by Eric Knight

Cover art by Eric Knight

Two presentations are scheduled:

May 12th, 7 PM, Whatcom Museum in Bellingham, sponsored by Village Books and the Museum.

May 13th, University Bookstore [Seattle’s U-District] at 7.

I will be signing copies at each of these talks.

Feel free to ask a bookstore or group to sponsor a presentation. They can contact me via my email:

email address to send reports and photos. I'll credit you.

email address.


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:

send email here

send email here

Welcome new subscribers

January 1, 2014. Happy New Year!

A nice sight in the gloom of a NW winter. Franks Beach on Lummi Island.

A nice sight in the gloom of a NW winter. West Beach on Lummi Island.

Many thanks and a big welcome to the 154 people who have subscribed to this website in the past year. There are now 538 subscribers. Posts have not been very frequent because I put most of my writing energy this year into finishing my book, Geology Underfoot in Western Washington. But, the book has gone to the editor at Mountain Press Publishing (Missoula), and should be out in Fall of 2014. You’ll certainly get the good news as the publication date nears. While I’m waiting for the editor to get back to me, I continue to write another, with the working title of  Road and Trail Guide to Mount Baker Geology. But, I promise to add more field trips to the blog in 2014.

Readers are encouraged to send in their own geology field trip guides, or suggest good places for me to visit in Washington and British Columbia- perhaps in your company. Send a comment to the blog, or an email directly to me. Winter has arrived in the high country, so let’s focus on the lowlands for now. A Victoria, BC field trip submitted by Gerri McEwen will be posted in the next few days. If you know of a place in the mountains, go ahead and let me know why it seems interesting (with your photos) and I’ll try to get to it next summer. Even better, you write it up! Also, if you come across any good field trip guides, send the info so I can add it to the “Guides, Books and Maps” page.

email address to send reports and photos. I'll credit you.

email address to send reports and photos. I’ll credit you. This is not a link.

There were 85,000 visits to the website in 2013. The most popular page on the website in 2013 was a tutorial on sedimentary structure (strike and dip of beds). That one had over 4200 hits. I think many students find it in the course of school projects. And many people checked out the trip guide to the Nooksack ‘Gold Mine’ near Sumas, in Whatcom County. The most popular topic of all time on this website remains the story of Diatryma, the giant flightless bird whose 10-inch footprints were found in the Chuckanut Formation in 2009, and put on display at WWU’s geology museum in 2010. (Over 10,100 site visits to date).

A request- when you take one of the field trips on the blog, please drop me a note via comment and let me know how it turned out. Especially let me know if road or trail names have been changed or are labeled differently, if trails are washed out or rerouted, if you couldn’t find what I tried to direct you toward, if my description was inaccurate. I’ll do my best to update things.  But, please, at minimum, tell me you went.

MBVRC field trip to Baker Lake during draw down.

MBVRC field trip to Baker Lake during drawdown. Great geology!

So enjoy the next year’s ramblings from your scribe. Visit two other blogs I moderate: the Mount Baker Volcano Research Center’s is http://mbvrc.wordpress.com. MBVRC occasionally offers fundraiser geology field trips oriented toward folks just like you. The best way to stay posted is to subscribe to the blog. And, a blog for die-hard cross-country skiers in the Chuckanut hills: http://chuckanutcrosscountryskiing.wordpress.com/


Geology Field Trip gift certificates from MBVRC

Cross country trip to Schreibers Cinder Cone.

Cross-country trip to Schreibers Cinder Cone.

Mount Baker Volcano Research Center is offering gift certificates for geology field trips.  These make great gifts for your geophile friends and relatives. The cost  is $75 (the usual cost of a one day guided trip, including van transport) and can be applied to any field trip offered by MBVRC. This year there are plans to offer  trips to lowland sites in Northwest Washington in the late winter/early spring. In the summer, trips will go to locations around Mount Baker , and a multi-day trip to Mount St. Helens is in the early planning stages.

To purchase a gift certificate, send an email or letter to MBVRC. Include  the name of the person the certificate is for, as well as your mailing address. You may send payment via check payable to ‘MBVRC’ to  708 13th St, Bellingham, or use the MBVRC PayPal account – the account code is this email address:

this is not a link

You will receive a nicely printed gift certificate in the mail. Field trip fees beyond expenses go to the MBVRC research and education fund. To see brief descriptions of some  past geology field trips, scroll down here: http://mbvrc.wordpress.com/field-trips/

Guided geology trip to Ptarmigan Ridge, Mount Baker

Mount Baker and Rainbow Glacier from Ptarmigan Glacier.

Mount Baker and Rainbow Glacier from Ptarmigan Glacier.

There are three spaces left on North Cascade Institute’s guided geology hike [led by yours truly] to the volcanic wonders along the Ptarmigan Ridge trail. This traverses the high country between Mount Baker and Artist’s Point at the end of the Baker Highway.

Sunday, September 29 Rendezvous in Glacier at 8 AM. An all day hike, about 6 miles round trip, 500′ elevation gain/loss. $95 includes bus from Glacier.

Sign up info here:


Here’s the NCI blurb:

Experience time travel by foot on the Ptarmigan Ridge trail in Mount Baker’s radiant late-summer high country. Our field excursion will begin above tree line at Artist’s Point at the end of the Mount Baker Highway before venturing out toward the simmering, glaciated volcano herself. Along the way, we’ll travel over ancient records of volcanism as we traverse the 1-million-year-old Kulshan caldera, a giant volcano that erupted cataclysmically through a continental ice sheet long before Mount Baker built itself from stacks of lava.

As we hike past lava domes that erupted shortly after the caldera collapsed, we’ll lay hands on much younger columnar andesite that still predates Mount Baker, discuss the origin of the eroded table at Table Mountain, and examine layers of volcanic ash preserved in the soil, including the famous Mount Mazama/Crater Lake layer.

Dave is a leading geological expert on the Mount Baker region and will share his intimate knowledge of the natural and cultural history of the area. He’ll interpret the story of this landscape as evidenced in its rocks and ash.

Geology field trips offered by North Cascades Institute

I will be leading three field courses on behalf of North Cascades Institute in late summer of 2013.Also, my friend David Williams will lead an urban geology tour in Seattle.

Migmatite in the Diablo Overlook road cut? What's 'maigmatite'? Sign up to find out!

Migmatite in the Diablo Overlook road cut. What’s ‘migmatite’? Sign up to find out!

August 9-11: GEOLOGY OF THE NORTH CASCADES: CROSS SECTION THROUGH THE CRUST. This course will be based out of the NCI Environmental Learning Center at Diablo Lake. Over three days we will examine different sites along Highway 20 from Sedro Woolley to Washington Pass. Meals and lodging at the Learning Center.

Kuslhan caldera, Mount Baker, and Table Mountain volcanics can all be examined along the Ptarmigan Trail.

Kulshan caldera, Mount Baker, and Table Mountain volcanics can all be examined along the Ptarmigan Trail.

September 28 and repeated on September 29: MOUNT BAKER: THE STORY OF VOLCANOES I AND II. I will lead a one day hike along Ptarmigan Ridge on the east flank of Mount Baker.We will look at volcanic deposits from the Kulshan caldera, pre-Mount Baker andesite volcanoes, and young Baker itself. These two hikes will fill up VERY QUICKLY so register right now if you are interested.

In downtown Seattle, see 3.5 billion year old Morton gneiss, probably the oldest building stone in the world!

In downtown Seattle, see 3.5 billion year old Morton gneiss, probably the oldest building stone in the world!

Also on September 28, David Williams leads ‘Street Smart Naturalist’. This will be a walking tour of downtown geology. highly regarded and a must for Seattle residents interested in geology.

Registration and descriptions for all these programs begins at the NCI geology webpage.