• Your EMAIL ADDRESS is never used for ANY purpose except to send you updates. EVER!!!!!!

    Join 987 other followers

  • MOUNT BAKER: Eruptive history, hazards, research.

    Visit Mount Baker Volcano Research Center websites Main website and the blog
  • Most recent posts

  • This website first appeared December 6, 2009

    • 612,595 hits
  • Feel free to use the material on these pages.

    Creative Commons License
    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

  • Advertisements

Another southern Jackass erratic sighting

Jackass conglomerate erratic tucked among logs on Camano Island. Photo courtesy Carl Johansen and Frank Alishio. Click to enlarge.

Website subscriber Carl Johansen sends these photos of erratics from the Jackass Formation conglomerate on the beach on the east shore of Camano Island. Unfortunately, the beach is private. Earlier this winter, I asked people to keep their eyes open for any of these distinctive erratics south or west of Whatcom County. This is relevant, as they have been associated only with the last gasp of Pleistocene glacier readvance (the Sumas advance) which barely reached Bellingham and was entirely on land- no glaciomarine component is recognized, so they didn’t flow to their current resting places in calved icebergs. The presence of these distinctive boulders to the south or west negates that theory, put forth by Dr. Don Easterbrook of WWU. Thanks to the reports sent to this website, it looks like these rocks can not be used to delineate the extent of the Sumas readvance.

I’m still hoping for photos of a reported Jackass erratic way down south in Des Moines.

Verified Jackass erratics. Red line marks approx terminus of Sumas readvance.

A smaller Jackass erratic, north of the first. Photo courtesy C. Johansen and F. Alishio.


Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

%d bloggers like this: