Charles Wilkes and the Mima Mounds

Mima Prairie

Charles Wilkes headed the U.S. Exploration Expedition that included a lengthy expedition and survey of Oregon Territory in 1841. Wilkes sailed into Puget Sound and then traveled overland from Fort Nisqually to Fort Vancouver. As such Wilkes provides an early description of the southwest Washington prairies as well as other important early observations of the area at the very earliest stages of American and English settlement

Fort Nisqually and Fort Vancouver were Hudson Bay Company forts. Fort Niscually was located near present day Dupont on the slope above and east of the Nisqually River delta. Fort Vancouver was the main Hudson Bay post on the Columbia River at present day Vancouver, Washington. Wilkes described the prairies around Fort Nisqually in very positive terms. Being there in May he had the pleasure of seeing the prairies in fine bloom.

On his overland journey south he noted that at one location the prairie was "covered with strawberries so tempting we were induced to dismount and feast upon them."

Wilkes also provides an account of the Mima Mounds, "We soon reached Butte Prairies, which are extensive, and covered with tumuli or small mounds, at regular distances asunder. As far as I could learn, there is no tradition among the natives relative to them. They are conical mounds, thirty feet in diameter, about six to seven feet high above the level, and many thousands in number. Being anxious as to ascertain if they contained relics, I subsequently visited these prairies and opened three of the mounds, but nothing was found in them but a pavement of round stones."

Hence, Wilkes conducted the first documented scientific investigation of the mounds. Wilkes surmised the mounds had been made by the Indians. His idea of a man made origin was likely influenced by the fact that very similar sized mounds are located in the Midwest and are man made. 

Prairies and the Puget Ice Lobe

A few Washington State our prairies

Scattered around various parts of western Washington Sate are prairies. Early English and American explorers noted large prairie areas in the low lands of Western Washington. There are prairies on Whidbey Island and the San Juan Islands, but the big prairie areas are in southwest Washington with a fair number in what is now Thurston County south of Olympia. I labeled the satellite image above with some of the prairies that are designated on USGS topographic maps. Except for two Fort Lewis prairies named for military divisions, all the above labeled prairies are in Thurston County. 

These Thurston County prairies are associated with glacial outwash from the Puget ice lobe. Large rivers of water flowed across these areas depositing gravel as the rivers flowed toward what is now the Chehalis River valley. Consider all the rivers coming off the west side of the Cascade range, all the rivers coming off the east side of the Olympic Range, and all the ice melt from the Puget ice lobe itself - that is a lot of water. The Geologic Map of the Maytown 7-5-minute Quadrangle, Thurston County, Washington (Logan, Walsh, Stanton and Sarikan, 2009) has a spectacular side map to help sort all the various water routes out - and that map only contains some of them channels.

Goldstein, Pringle and Futornick have noted that some of these water routes are associated with huge floods that are associated with volcanic mudflows coming off of Mount Rainier along some of the outwash channels http://www.centralia.edu/academics/earthscience/pringle/pubs/Tanwax_NWSA_poster2010.pdf.

I started thinking more about this area of our state when I had a project in the Black Hills southwest of Olympia and realized the outflow routes were a lot more complicated than I had realized. Lots of geologists have been working on figuring this area out and as can be seen LiDAR has clarified some of the water routes or pehaps made us realize how complicated the outwash channels that developed as the ice lob retreated from the area approximatley 17,000 years ago.

There are a lot to these prairie landscapes of southwest Washington State. The geology is a big part of the story for some of the prairies. But there is a lot more that I will be posting on over the next few weeks or months depending on my own interest and whims. In the meantime here is one of the prairie's from above and one of my favorite prairie songs.

Mima Prairie

  

Erratic Bloggers

A bit of an inside joke. Given Dave Tucker has been the Erratic Guru http://nwgeology.wordpress.com/the-fieldtrips/glacial-erratic-field-trips/seattle-area-glacial-erratics/ I got a kick out of the prolific blogger Paul Krugman's latest post
http://krugman.blogs.nytimes.com/2012/01/29/erratic-blogging-ahead/.

Don't worry Dave, Krugman is not taking over your mantle as the Erratic Guru - I think your stuck with it.

Chilly Day in the Field

I headed out into the field today. Typically I do not like to have snow obscure my views of the ground. But given the time constraints on the project and expected weather for the site, better now than later and the snow cover was just thin enough that I was able to figure out the ground once I got into the evergreen stands. Just wish the sleet had held off and then there was also an unexpected detour.

Traversing through the red alder forest

This beaver dam caused a bit of a detour

This steep slope is a result of a river down cutting into a huge landslide deposit.

Soils were full of angular chunks of rock

Memories of Short Sand Beach

Short Sands Beach, Oregon

Seeking aerial images of the sand burial site at Waldport, Oregon I posted on yesterday caused me to meander around and look at some other images of the Oregon coast. (Yes, this is not the Washington Landscape, but Washington used to be part of the same territory as Oregon up to 1853 and geologically we share with Oregon living on the same plate boundary with the Juan de Fucca Plate subducting beneath us.) 

One site I checked out was Short Sands Beach. I have visited this beach three times. All three times were in the winter and all three times were semi epic. The above picture is clearly taken in the summer - a nice wide sandy beach.

My first venture to this beach involved traversing the beach from south to north to check out the headlands to the north. On the return I noted a very large wave at the head of the small bay. Not sure why it caught my attention and I did not yet know the term rogue wave, but I suggested running for the woods would be a very good idea. My companion did not share my concern and decided that escaping the water could be accomplished by scrambling up onto a 6-foot diameter driftwood log at the top of the beach versus smashing through the jungle at the top of the beach. I turned around just in time to see the recognition on my companion's face that the wave was high enough that it was floating the log. A brief lumberjack act ensued before my friend tumbled off the log fortunately in the right direction as the wave began to pull back and rolled the entire massive log down the beach and into the sea with my friend not far behind. Another wave rolled in. The water was full of logs and the cobbles under foot were all rolling so foot purchase was minimal. I had tossed the backpack and went into this mess to try to assist and we stumbled back up into the woods out of reach of the waves and logs. A bit of a chilly hike out after our unexpected soak.

My second trip had a different result. I decided to camp along the coast during the winter despite the freezing rain as cold arctic air was pouring out of the Columbia River Gorge and reaching all the way to the coast during one of the coldest winters in Pacific Northwest history. But the real trouble was after setting up camp and realizing that a particularly virulent strain of the Asian flu that had been sweeping the nation had found me. By the time I hiked out, I gained an understanding of fever induced delirium I would prefer not to repeat anytime soon.

My third trip is still told with great enhancement by my brother Mike. We were staying a bit to the north at Cannon Beach and I suggested that Short Sands Beach was nice day hike. Being leery of the rogue wave issue we stuck to the forest trail. Only problem was that a major windstorm sometime since my last visit had obliterated the trail with downed massive trees. Hence we were compelled to climb and crawl over lots of large downed wood. Upon arrival at the headlands, none of my companions were impressed with the condition of what I had described as a trail on the exposed headland. A wave of cold rain and wind began to wrack us. On the trek back Lisa and Mike came up with the idea that I could start a tour group company called Odysseus Travels implying that survival was not part of the package. 

All said, Short Sands Beach looks like a great place. It has been a long time since I have been there; perhaps I will give it another try in the summer versus the middle of winter.    

Sand Burial in Waldport

I routinely assess geology hazards: landslides, erosion, debris flows, channel migration, tsunami, soil liquefaction and even avalanches. Here's a geology hazard I have not dealt with: sand burial. This via Cliff Mass via Brad Smull and picture by Jason Durret.

The location is on the coast of Oregon at Waldport.

Not a particularly safe home site area on a sand spit. Throw in the tsunami risk, subduction quake subsidence risk and the long term prospects for these homes is not good. But in the short term a very wonderful sandy beach to live by - perhaps a little too much sand.

Nice Day on Orcas

I really appreciate the National Weather Service. The challenge of determining where and how much snow and freezing rain caused the forecasters a tough time last week. But the big picture was accurate and the forecast nailed Monday (yesterday) very well. A nice break in the weather that I took advantage of scheduling field work. Lovey day with sun and even a bit of warmth. Much better than today with wind and rain. So thumbs up to the National Weather Service for making my life so easy.

My field day was out on Orcas Island. First was looking at joint and fractures on a cliff slope.

Fractures and joints in Constitution Formation, Orcas Island

Had some nice early morning views on this project.

View down East Sound

Turtleback Mountain on Orcas Island from East Sound

I also came across my current favorite native tree - Gary Oak.

There were three oaks growing in the talus along the route I took. A few lonely outliers. I am sure there may be other oaks in the area, but these were the first I had seen on this part of Orcas Island. There is an extensive oak forest area on the southwest side of Turtleback Mountain that extends down to West Sound. This small group of oaks are taking advantage of the rocky dry slope. I noted that the Douglas fir on the same slope had burn marks from past fires and many had broken tops as this can be a very windy spot.