Snohomish and Tacoma Geology Underfoot Book talks

A reminder that I will be in Snohomish this Saturday, Feb. 20, and in Tacoma next Thursday, Feb. 25, to talk about Geology Underfoot in Western Washington.

SNOHOMISH Saturday February 20th, 2 PM, Sno-Isle Public Library, 311 Maple Ave., Snohomish, WA

TACOMA Thursday February 25 Kings Book Store, 218 St Helens Ave Tacoma, WA. 7 PM http://www.kingsbookstore.com/event/2016-02

 

New Geology hiking guide published on this website: Ridley Creek Trail, Mount Baker

Link to Ridley Creek Trail geology guide:

https://nwgeology.wordpress.com/the-fieldtrips/ridley-creek-trail-geology-guide/

Foot bridge over the Middle Fork

Ridley Creek Trail begins at the end of the Middle Fork Nooksack Road on the southwest flank of Mount Baker. The trail accesses the heather meadows of Mazama Park and on to Park Butte Lookout. Along the way see forested latest Pleistocene moraines, glacial till from Canada complete with quartzite pebbles from the Rocky Mountains, limestone, lahar and ash deposits, a close up of the Cathedral Crag lava that predates Mount Baker, and finally, great views of Baker, the Black Buttes, and that enigmatic slice of the mantle, the Twin Sisters Range. Read the geology guide here.  Enjoy!

Dave Tucker

Citizen geology- new page added to Northwest Geology Field Trips

This new page directs readers to projects they can participate in, usually as volunteers with a minimum of geologic experience. Go to the Citizen Geology page.

Glacial erratic inventory website open for business

White Rock, Hood Canal. Not in the inventory yet. Many of the erratics on the Northwest Geology Field Trips website aren’t listed (yet). Maybe that is your job!

The Washington Glacial Erratics website has re-opened for business. Managed by the undergraduate GeoClub within the Earth and Space Sciences Department at the University of Washington, it is an inventory database and map showing “significant erratics (i.e., large, diameter >8-10 feet , or has a unique composition or features)” in Washington State. Anyone can add their favorite glacial erratics including photos and a description. You will need to know coordinates (UTM or Lat/Long). Visit the website at http://waglacialerratics.ess.washington.edu/ At present (February 9, 2014) there are 12 erratics shown. Get busy!

Dave Tucker

Rock Trail, Larrabee State Park

Thin beds in the Chuckanut Formation along the Rock Trail.

I will post a full geologic guide to the new Rock Trail when the trail is formally opened on April 26th. An email subscription to this blog will deliver the news to you directly. In the meantime, please enjoy other Chuckanut area geology descriptions on my blog.

Fragrance Lake

Raptor Ridge

Oyster Dome

Clayton Beach– a layer of volcanic ash preserved in the Chuckanut Formation

A full listing of localities I describe is here. For a primer on Chuckanut geology, visit this page.

Dave Tucker

Washington Erratics website temporarily down

Dear friends,

The new Washington Erratics website is temporarily down while a glitch is dealt with. Please do not send in new material until further notice. Anticipated reopening date is November 1. I’ll send out a post when the webmaster there gives me the thumbs up. http://waglacialerratics.ess.washington.edu/

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 ‘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.

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!

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.

Fragrance Lake addendum: Where quartzite in the till comes from

Broken surface of quartzite.

I’ve been asked about the source for the quartzite clasts in Puget Lowland glacial till. They are diagnostic of a British Columbian provenance for the Puget Lobe of the Vashon advance, and the great glaciations that preceeded that one. Go to the quartzite page, where I discuss the source for these pebbles, and attempt to confuse everyone because there are two kinds of quartzite.

Pillows in the Middle Fork Nooksack

Stacked pillows. Stolen from a commercial website. So, sue me.

(Click HERE to go straight to the page about the pillows along the road.)

No, pillow lava, silly!

Cross-sectioned basalt lava pillow in the Elbow Lake Formation, Middle Fork Nooksack Road. Click to enlarge.

I planned a XC ski trip up the Porter Creek Road or elsewhere off the Middle Fork Road today, but it was raining and 41 degrees. Indulging my secret identity as a geologist, I instead poked around in a roadside quarry, looking at pillow lava in the Elbow Lake Formation. A rewarding outing from Bellingham if you have a 2-3 hours on your hands and a deeply felt need to look at some exotic, unusual, and (admittedly) not too beautiful rocks. The saving grace is the lava pillows, and a cup of coffee on the way and on the way back. As an added bonus, there is access to Twin Sisters dunite nearby.

P.S. There ARE some nice roads to ski up and back down off the Middle Fork.

Geology guide to Fragrance Lake Trail (Larrabee State Park)

The Christmas Girls had just finished decorating all the sign posts as I pulled into the parking lot. Very festive! Click to enlarge.

I’ve written up a geology guide to the popular Fragrance Lake trail. You’ll find it here. Even if the hike is mostly in glacial till, there are interesting stones in it, and the Chuckanut cliffs are always worth a peak. I do some armwaving about the origin of the big cliffs above the lake, too.