The largest of several erratics on the north shore of Seattle's Discovery Park. Photo provided by Sandy Bowman.

A new field trip to visit some erratics on the north shore of Discovery Park is here. These were measured and photographed by Sandy Bowman and Consuela Larrabee. I confess I’ve been sitting on this report for months and months. This trip requires a hike on the North Beach Trail, and provides a nice excuse to get outside for a partial day’s outing.

Thanks to Wendy Bowlin for sending this along.

I’ll have an entire chapter about the Mima mounds and the many hypotheses concerning their formation in my book, Geology Underfoot in Western Washington. While you are breathlessly waiting for me to finish writing and get published, read Dan McShane’s discussion of the mounds on his website, Washington Landscapes.

In a related note, the Washington State Department of Natural Resources is seeking public comment on a proposal to expand the boundaries of the Mima Mound Natural Reserve. Read about it here.

Snip from Rochelle's video at Granite Falls, 2010.

Rapid snow melt is anticipated over the next couple of days in the region, bringing potential for high water and landslides. Rochelle Parry has posted a great comparison video contrasting December 2010′s 18 foot flood on the South Fork Stilliguamish at Granite Falls Washington with normal winter water level of 6 feet. Click to watch her comparison video on YouTube. Go here to see her entire video from December 2010. If you have the ability, this weekend might be a good time make a film (ooops! Who does that anymore?) video of your own favorite rambunctious stream.

A request for assistance is highlighted below in red.

The Lake Stevens Monster's high side. Keith Kemplin (top) and Bob Mooers for scale. Full width can not be appreciated in this view. Click to enlarge.

I have previously stated that the Lake Stevens erratic (“Lake Stevens Monster”) may be the largest in the USA, larger than the apparent reigning champ, the granitic Madison Boulder, near the town of Madison in New Hampshire. According to a brochure by the New Hampshire Division of Parks and Recreation, this is the “(l)argest known glacial erratic in North America and a National Natural Landmark”.

Looking across a portion of the 54' width on top of the Monster. Click to enlarge.

The Lake Stevens erratic was measured this past summer by Craig Valvick and Matt McCourt. However, an additional measurement, width, was needed to allow better comparison with the Madison erratic. This has now been made, and the comparison follows.

“Lake Stevens Monster” (serpentinized greenstone) 78 feet (23.77 m) in length 34 feet (10.36 m) tall and 54 feet (16.46 m) in width (widest point). The circumference is 210 feet (64 m). No mass has yet been calculated.

8th graders at the Madison Boulder.

“Madison Boulder” (granitic, no further detail known) 83 feet (25 m) in length, 23 feet (7.0 m) tall, and 37 feet (11 m) in width. No circumference is available, but assuming it is a square as it looks, this would be around 240 feet (length x 2 + width x 2). It weighs upwards of 5,000 tons.

Given the small difference in length (78 vs 83 feet) the large difference in height (34 vs 23 feet), and the large difference in width (54 vs 37), the Lake Stevens erratic is bigger, and is the largest measured erratic in the USA known to me. Further, while the base of Madison Boulder is reportedly buried “probably by a depth of ten to twelve feet” (see below), there is little doubt that at least a similar amount of the Lake Stevens erratic is buried. No mass has been calculated for the visible, above ground portion of “The Monster”. A 12-inch-wide chunk that had fallen off will be used to calculate density via weight and displacement of a volume of water. Once a rough volume for the entire erratic is calculated, mass can be estimated. Volume will be a tough nut, given the extremely irregular dimensions. Suggestions for a method of doing this are requested. Lake Stevens is smaller than the quartzite Okotoks erratic in Alberta (near Calgary), the accepted record holder for North America, but not by that much, really.

Does anyone have suggestions for how to measure volume of the “Monster”? It has an irregular shape. Would ground-based LiDAR do the job? How deeply buried is it? Would ground-penetrating radar be a tool to determine this?

The Wikipedia webpage for Madison, New Hampshire says: “The town is home to the Madison Boulder (43°55′52″N 71°10′04″W), the largest known glacial erratic in New England, and among the largest in the world. Madison Boulder is a huge granite rock measuring 83 feet (25 m) in length, 23 feet (7.0 m) in height above the ground, and 37 feet (11 m) in width. It weighs upwards of 5,000 tons. A part of this roughly rectangular block is buried, probably to a depth of ten to twelve feet. It is located at a state park in the northwest part of town.”

Mount Baker steam plume. January 9, 2010. Photo provided by Steven Trinkhaus. Click to enlarge.

Talks on the eruptive history and hazards of Mount Baker will be presented by Mount Baker Volcano Research Center director Dave Tucker at several venues this winter. We will have the famous MBVRC fundraiser t-shirts on hand as long as they last. We pass the hat for donations at these events to support Mount Baker volcano research.

We are looking for sponsoring organizations elsewhere in the region- Mount Vernon, Everett, Seattle, Richmond, Ferndale, Concrete, Glacier. . . if you have suggestions or wish to invite a presentation, please contact MBVRC via email: Vancouver:

January 10 (Tuesday) 7:30 P.M.- British Columbia Mountaineering Club, Vancouver, B.C.:  Floral Hall, Van Dusen Gardens, New Visitor Center, Vancouver, B.C.  Free and open to the public.

January 24 (Tuesday ) Alpine Club of Canada, Vancouver B.C. Details TBA.

Port Townsend:

January 14 (Saturday) 4 P.M. Port Townsend, Jefferson County Land Trust Geology Group: Quimper Unitarian Universalist Foundation, 2333 San Juan Ave. $5 donation

Bellingham:

February 16 (Thursday) Whatcom Museum, Bellingham.  Free event. Details TBA.

Anacortes:

April 13 Skagit County Beach Watchers and Friends of Skagit Beaches, Anacortes Library rotunda, 1220 10th, 7:00 PM

As soon as new presentations are scheduled, they are posted on the MBVRC blog. For more information on Baker research and activity, visit the primary MBVRC website.

Seattle’s downtown center uphill-downhill street names (from south to north, the direction of the field trip) are Jefferson, James, Cherry, Columbia, Marion, Madison, Spring, Seneca, University, Union, Pike, Pine. The time-tested mnemonic is “Jesus Christ Made Seattle Under Protest (alternate: “Pressure”)” (JCMSUP; note this doesn’t help with the order of the streets in each pair. Which is further south, Jefferson or James? Seneca or Spring?)

The decision was a tough one. After consulting BOTH my cats, and settling a heated argument between them, the winner is:

“Juan de Fuca Crashing Mighty Slowly Under People” by Peg Ferm.

Thank you, Peg. You will receive a free book when it comes out.

Snow & Spire, by John Scurlock

John  Scurlock, author of Snow and Spire, was interviewed Thursday for KING-5 TV’s Day Northwest . Here is the link to  watch the 8 minute interview. Includes photos, and a small part of the story behind the photography.

Glacial scours in bedrock at Songhees Point. Looking south across the narrow entrance to the Inner Harbo(u)r. B. Hardwick photo.

Bud Hardwick’s second article on geologic features in the Victoria area has been published on Northwest Geology Field Trips. This trip takes a stroll along the waterfront promenade of Westsong Way, focusing on glacial erosion features. He also tells us a bit about the native traditions at Songhee Point along the way. Read Bud’s article here.

The Harling Point erratic. This is a panoramio photo on Google Earth by crobinso2010. http://www.panoramio.com/photo/56782186

Bud Hardwick of Bellingham sent us a report on geology (and the Chinese cemetery) at Harling Point on Vancouver Island, in the Victoria-Oak Bay area. Read it here. The trip features a landmark erratic, and migmatite bedrock. This is the first in a pair of articles Bud sent. The next will be to Songhees Point on the west shore of Victoria Harbor. Stay tuned, it will appear on Northwest Geology Field Trips later this week I hope.

A portion of the Chinese cemetery at Harling Point. There may be as many as 1000 burials here. Bud Hardwick photo.

Looking north at landslide topography at White Bluffs. From "Washngton Landscapes Blog"

Happy New Year, everyone.

Dan McShane publishes occasional geology field trip-style posts on his Washington Landscapes blog. His recent post on landslides in the Hanford Reach of the Columbia River (link here) is worth keeping in mind for next time you are in the area looking for some geo-scenes to visit. Dan describes irrigation-induced landslides along the Columbia River’s Hanford Reach at White Bluffs, and also a much larger, and older, bedrock slide.