Adakite and Tamanowas Rock (Chimacum Rock)

Adakite at Tamanowas Rock

Adakite is stretching my knowledge of volcanic rocks. Magmatists like using more than three names for lava and have moved well beyond the simple basalt-andesite-rhyolite terminology those less versed in lava use. Magmatists are like Eskimos talking about snow when it comes to magma.

David Tucker sent me an abstract by Hahn and others (2004) regarding adakite at Chimacum Rock. Before I proceed I will note that I will call Chimacum Rock Tamanowas Rock for the rest of the post. Tamanowas Rock is located just west of Chimacum on the ridge between Chimacum and Anderson Lake. Tamanowas Rock is a sacred place to the S’Klallam Tribe. Out of respect, please refrain from hammering chunks of rock off of the formation. The property is open to the public, but ownership requests a "leave no trace" ethos.

I was vaguely aware that Tamanowas Rock was not the more typical basalt one sees on the Olympic Peninsula as part of the Eocene Crescent Formation. I had even stumble across some unmapped notably non basalt outcrops on the forested slopes above the southeast end of Discovery Bay. Schasse and Slaughter (2005) and Whetten and others (1988) both indicate on their maps the presence of dacites and associated sediments near the southeast part of Discovery Bay and link those rocks as being the same as that at Tamanowas Rock area. The nuances of lava were not my primary concern as I was mostly focused on some tricky slope stability problems in the area.

I had never stopped to gander at the bedrock exposed along the Anderson Lake Road south of Tamanowas Rock or ventured to Tamanowas Rock itself, a cliff rising up out of the forest west of the town of Chimacum. So earlier this week, I took a little non work geology field trip to take a look.

Site can be accessed via trials out of Anderson Lake State Park

 or at the close road indicated on the Google image

Analytical work by Hahn and others (2004) (See Here) indicate that the Tamanowas Rock has adakite like traits and point out that the presence of adakite at Tamanowas Rock may be used to have a better understanding of how the ocean plates off of Washington were subducted during the Eocene as this was a period when North America was overriding an ocean spreading ridge. The presence of adakite may be related to the location of the mid-ocean Kula-Farallon spreading ridge at the time. The significance of adakite is that it is very unlikely that Tamanowas Rock is associated with lava segregation associated with the Crescent basalts. At least that is what I think the magma folks are saying. A summary/overview of adakite melt formation by Castillo (2006) can be found HERE.

Regardless of how well versed you are on adakite, a short hike to Tamanowas Rock provides a fantastic exposure of the adakite lava and volcanic breccia. I was a bit pressed for time so I did not take in all the rock exposures, but I also did enjoy the great view from the summit.

Volcanic breccia consisting of adakite blocks

Breccia exposure

View from the summit to the northeast and Admiralty Inlet

The crane is at the naval base on Indian Island

The grassy slopes of the west shore of Whidbey Island are in the distance

While on the summit of Tamanowas Rock it is easy to see that this would be a place of pilgrimage for not only people to today, but would be a special place for First Nations peoples. The S’Klallam Tribe considers the site sacred. According to tribal elders, travelers from great distance would make a pilgrimage to the summit with nothing but a supply of water and fast for three days seeking inspiration.

Use of the site is currently in flux. The back, west side of the ridge abuts Anderson Lake State Park and can be accessed via a foot path that leaves the park to reach the summit of the rock. The property has been in private ownership for many years. Zoning and lots are such that up to a dozen homes could be built on the slopes around the rock including homes on the summit area itself. Property in the immediate vicinity of the Rock was bought by the S’Klallam Tribe. The Tribe hopes to sell the land with a permanent conservation easement that would preclude development of the property. The Rock itself and the land to the east, a total of approximately 60 acres were purchased this year using a loan from the Bullit Foundation to the Jefferson Land Trust combined with private donations and contributions from the S’Klallam Tribe. The loan is to be paid back in two years and is currently being held by the Land Trust.

All together there are a number of players involved: The Jefferson Land Trust, The S’Klallam Tribe (Jamestown), Washington State Parks and Jefferson County. At this point in time final exact ownership is uncertain and as well as management. It will be an interesting management plan to transition from a private land that was routinely used by recreationist including rock climbers to a property managed with public access consistent with the significance of the sacredness of the site and the goals and policies of the entities involved in preserving this landscape feature.

Orcas on the Port Townsend to Keystone Ferry Run

Two Orcas with Whidbey Island in background

I had a good two day trip to the northwest side of the Olympic Peninsula. Besides the good fortune of the Olympic Mountain rain shadow that allowed for dry work and even sun despite the rain most everywhere else in western Washington, the work was good and I even did a little non work geology trip I'll write up on another day.

Had a special treat on the ferry run from Port Townsend to Keystone. A pod of Orcas were crossing our path. It appeared there were at least a dozen. The ferry had to slow for a bit to let them pass as they were in our direct path. I ride Washington Ferry boats all the time, at least two or three times a month. This is the first time I have seen Orcas while from the a ferry. It got everyone out on deck.

Olympic Rain Shadow

I spent the day on the northwest portion of the Olympic Peninsula. Had a bit of dread given the storm off the coast and it was dumping all the way till I got to the Hood Canal Bridge. Then a peak of blue sky and no rain. I ate my lunch sitting in the sun! A great Olympic Mountains rain shadow experience.

Telford Scabland, Highway 2 between Creston and Davenport

Telford Scabland, a tough place for driving fence posts.

Large tracts of Washington’s landscape were shaped by the Missoula Floods. One prominent feature found along the flood route is scabland topography. Scablands are areas where all of the soil was stripped from the bedrock and the bedrock was ripped up leaving a scabland landscape. With most of the bedrock consisting of dark basalt lava rock the term scabland is very apt.

The Telford scabland is crossed by US Highway 2 between Creston and Davenport west of Spokane. It is easy to be locked into driving the straight stretches of highway heading east towards Spokane or west from Spokane and not fully appreciate this landscape unless you’re versed in the Missoula Floods. The surge of water from the rapidly draining Lake Missoula flowed into Washington State and Glacial Lake Columbia. Glacial Lake Columbia overflowed at multiple locations including a broad swath north of the Telford scabland.

Missoula Flood way paths

Telford Scabland

The scabland is mostly brown with rectangular fields on

the elevated areas where the flood waters did not pass.

Note the large number of lakes within the scabland area.

Not all of the local bedrock is basalt. If you are alert or not driving in the dark, you might notice an outcrop of much older granitic rocks east of the town of Creston. These rocks are part of the Lincoln Metamorphic Core Complex, one of a series of metamorphic core complexes that are located across the northern tier of Washington State. A little side trip to take in the view from Creston Butte a mile south of Creston is to take a trip back into deep geology time as the butte is underlain by possible Precambrian quartzite. The Columbia River Basalts are thinner here and the much older rocks that dominate the metamorphic complexes of the Okanogan Highlands and mountains north of the Columbia River crop out on through the basalt in a few places on this high plateau.

Though rocky scabland, this area is not a desert. The area is full of lakes and in areas where soils are thicker there are stands of ponderosa pine and thickets of brush. The ponderosa pine forest can be seen along stretches of Highway 2 and occasionally a small lake can be glimpsed from the highway. The elevation of the area traversed by Highway 2 is just below 2,500 feet hence the somewhat wetter conditions. The Telford scabland becomes drier to the southwest as elevation lessens.

Scub steppe scabland with ponderosa forest

Kolk or pothole pond in scabland

Although not pristine, the area has been used for grazing for many years, this part of Washington is a big area of wild land. Significant blocks of this area are within public ownership. Bureau of Land Management (BLM) owns an approximately 30 square miles of contiguous land southwest of Highway 2. I believe this may be the largest contiguous BLM block land in Washington State. The BLM owns an additional approximately 8 square miles adjacent to Highway 2 and approximately 20 square miles west and northwest of Odessa. In addition the 21,000-acre Swanson Lakes Wildlife Area managed by Washington State Fish and Wildlife abuts the BLM land. The area also contains roughly 18 square miles of Federally granted trust lands granted to Washington State in 1889 some of which abut the Swanson Lakes Wildlife Area and the BLM land.

The Swanson Lakes Wildlife Area is the result of wildlife mitigation by the Bonneville Power Administration for Lake Roosevelt wildlife loss due to Grande Coulee Dam. The lands were acquired in the mid 1990s. Washington Fish and Wildlife has been introducing both Columbia sharp tailed grouse and sage grouse to the wildlife area. These birds had been extirpated from the area by the late 1980s.

Despite the term scabland, this is land has great fishing, hunting and just solitude with wide views. I spent a nearly full moon night on the BLM land a few miles south of the highway last summer. Woke in the early light to coyotes calling out to each other, brewed a pot of coffee and headed to Spokane feeling very refreshed.

The scabland area is surrounded by soft rolling hills of eolian silt covered with wheat fields on the high ground untouched by the great floods. A few peaks rising above the wind deposited sediment are ancient rocks of the metamorphic core complexes and Precambrian rocks of the ancient continental margin.

Wheat on eolian silts with buttes of Precambrian rocks in the distance

Geology and Public Policy - a Few Examples

Debris flows and homes, South Fork Nooksak River Valley, January 2009

I am working on reports as well as doing some research on the land use policy and Mars comparisons on the Telford Scablands west of Spokane. In the meantime I came across a couple of geology and policy articles. As some readers of this blog know I spent some time in the public policy arena and geology came up more often than I ever thought it would. My all time favorite quote as an elected official was after telling fellow Council members that it was not moral to vote for a project until they actually went up and looked at a landslide, I stated "It is slicker than snot." Not a technical geologic term, but descriptive of the conditions above Canyon Creek in the Northwest Cascades where a large slope failure within a ultramafite lined fault posed a threat to a housing development on the alluvial fan below.

The first article is from the New York Times regarding construction of barrier islands off the coast of Louisiana. I'll leave it to the reader to assess if this is a good use of money. Article HERE

The second article is about earthquake drills in California. I kind of liked this because I once lived in Alamo. Article HERE

Finally a local Whatcom County blog that covers politics had a clip of a radio debate between two county council candidates when Swift Creek came up HERE   I have posted a few times on Swift Creek and will do some more in the future. Swift Creek posts are Whatcom County's Desert and Floods and Urban Landscapes

View of Swift Creek from the slope of Sumas Mountain. Dredged sediment can be seen lining the creek banks as it flows across the low lands towards the Sumas River.

A few notes on Fall Color

I did get a few fall color treats while travelling across Wyoming and northern Colorado as well as seeing this patch of aspen in northern Utah.

Aspen in northern Wasatch Range

A great fall show in the low land forest of western Washington is partially limited due to the trees we have. Of course the conifers don't provide any color, but we do have plenty of deciduous trees. However, most perform poorly on the fall color front. Red alders seem to drop their leaves even before the leaves yellow. The cottonwoods are not much better. Low land aspens and paper bark birch found north of Everett particularly around Whatcom County's aptly named Birch Bay behave a lot like the alders.

The one tree that has the best potential for putting on a great show is the big leaf maple. The big leaf maple is common and and in some areas is the dominant stand of mature trees. This is particularly true on portions of the northeast Olympic Peninsula. I would describe the big leaf's fall show ability as a bit sensitive. The leaves turn brilliant yellow but are easily knocked off by storms. Hence a long sunny spell with no wind like this past week are helpful. Perhaps I will be surprised next week when I head over to the Olympic Range and foot hills. Last year and the year before the weather not only in the fall by the summer led to great colors and the big leaf maples even developed some red tones.

Highway 101 north of Quilcene, October 20, 2009

Big leaf maple as a dominant stand.

Stand of big leaf maples behind farm on recessional morainal area along Highway 101

A few other trees put on a good show as well. Wild cherry has great color under the right conditions and happens to more common on the northeast side of the Olympic Peninsula. Vine maple almost always does a good show, but it is low growing tree and typically most of its color show is in August well before the other trees.

For consistent great color the high alpine meadows of the North Casades with vast fields of wild blue berry and mountain ash are a guarantee good show, but it is a little late for that show. In the more easterly North Cascades mountain larch are present in the high meadows growing at the extreme edge of the tree line in one of the few areas we have a true tree line. Larch are a conifer that looses its needles and turns gold in September. Further to the east in the high mountains of north central Washington, western larch is a dominant species particularly in the Kettle Range. I have always wanted to make the drive over Sherman Pass or Boulder Pass across the Kettles between Republic and the Columbia River during the western larch showing. I have never timed it right though.

A final Washington State trivia note: Sherman and Boulder Passes over the Kettle Range are the highest paved passes in Washington State.

Across the Columbia Crest from Prosser (Part III and Final)

After crossing the crest of the Horse Heaven Hills just south of Prosser on Highway 221 one enters the Horse Heaven Vinticultural Area. Unless you live in the immediate area there are two reasons fro driving this road: 1) an alternative route to take a few miles off of a trip to northeast Oregon or 2) as part of a wine quest. So after enjoying the view HERE and the Ellensburg Formation HERE one heads south into the Horse Heaven Hills Vinticultural Area. The upper area may not appear very promising as a wine growing area, but as one heads south down the gentle side of the Horse Heaven anticline towards the Columbia River, the agriculture changes from dry land winter wheat to large scale irrigated farm land with a variety of crops including grapes and wineries. (of course if your heading north everything is reversed)

As noted in an earlier Blog, the Horse Heaven Hills also contain a large population of wild horses. However, do not expect to see any wild horses in this area as the horses live well to the west in a large but remote area of the Yakima Indian Reservation. Besides the sign welcoming travelers to the Horse Heaven Vinticultural Area another nearby sign celebrates the wheat land production of the initial farm land.

This year's winter wheat appears to be off to a good start. In this area the fields are left fallow for a year. This allows for the stubble to break down and the field to be worked prior to seeding and moisture buildup may play a role as well. The fields are generally seeded in September and early fall rains are a great help as it allows for some good growth going before cold weather. Some wet weather has already arrived in late September and additional rain arrived the last time I drove through on October 8. Hence the new crop is off to a good start. 

Across the Columbia Crest from Prosser (Part II)

Besides the views of the Yakima Valley, possible exploration of the old landslides and a great sense of the geometry of the Horse Heaven Hills anticline there is a great exposure of the underlying formations along the crest of the fold along the highway just below (north side) the crest of the hill.

Geology exposure along Highway 221 south of Prosser, Washington.

The units are clay, diatomite, and sandstone with a minor offset.

Elephant Mountain member basalt capping a member of the Ellensburg Formation

The Ellensburg Formation are the non basalt basalt units in between the various Columbia River Basalt Group lava flows. In this case the exposed outcrop is capped by the Elephant Mountain member of the Saddle Mountains Basalts - one of the youngest lava flows of the Columbia River Basalt Group. The member designations of the Ellensburg Formation are derived from the age of the basalt flows above and below them. On this basis the unit would be the Rattlesnake Ridge member. Laval (1956) mapped this area and proposed Prosser member for a unit containing diatomite. 

A number of distinct units can be seen within the Ellensburg Formation at this site: 1) a green-gray clay that likely highly altered volcanic ash, 2) bright white layers of diatomite, 3) cross bedded sands and silts with a mix of diatomite and volcanic ash and 4) a volcanic ash or tuff deposit.

Diatomite layers over clay and under sands. Diatomite is formed by the accumulation of diatoms, a single-celled organism with a silica structure. Diatomite signifies a quiet lake environment will little sediment input as it takes a long time for the diatoms to accumulate.

Volcanic ash overlaid by basalt of the Elephant Mountain member

 

Across the Columbia Crest from Prosser (Part I)

A drive south up over the Horse Heaven Hills south of Prosser on State Highway 221 provides great views of the Yakima Valley, a short cut for those driving on Interstate 82 towards Oregon, and a direct route from the Yakima Valley, Rattlesnake Hills, Red Mountain and Snipes Mountain Viticultural Areas to the Horse Heaven Hills Viticultural Area. Just below the crest of the steep north facing anticline is an outstanding geology exposure (a future post) in the road cut as well as a great view. There is also a nice pull out just beyond the road cut if your heading south or just before the cut if your heading north.

Highway 221 heading south of Prosser, Washington

View from the crest of the ridge towards Prosser and the Yakima Valley

The lumpy area in the foreground is a old landslide feature.

Old landslides are a common feature along the steep north facing slopes of this ridge. There are several reasons: 1) the slope is steep often over 45 degrees, 2) The north steep side of the anticlines on the Yakima fold belt are tightly folded and fractured with some minor faulting thus creating lots of fractured broken rock blocks, 3) Basalt is the predominant rock type and vertical columnar jointing provides weak plains in the rock and allows water to readily infiltrate, 4) sedimentary units between some of the basalt flows are clay rich and some of the more fractured basalt has altered to clay, and 5) the lower portion of the slope was rapidly eroded during the Missoula Floods - flood waters reached an elevation of approximately 1,250 feet well up the sides of the lower slopes.

The highway curves around this old landslide feature and cuts across the steep slope just above the slide area. Other possible slide areas are easily observed along Interstate 82 below the slope or from above by continuing along a gravel road along the crest of the ridge or by a tour of Google earth. I suspect that most of the lumpy topography is the result of old landslides; however, secondary folds, faults and aseismic deformation features are present in these areas as well (Reidel and Fecht, 1994 and Reidel, Campbell, Fecht and Lindsey, 1994) and some of the lumpiness may be a combination of these features along with slide areas.

Lumpy areas outlined in red are potential old landslide areas.

It Does Not Take an Eruption to Wipe Out a Village

Mount Baker from Penn Cove

A number of years ago I was working on an environmental impact statement where I put in a few lines about the impacts of mud flows on flooding on a river system and that the mud flows very often take place without an eruption. This information was a bit of a shock to some folks. If your a Bellingham person or want to visit Bellingham Thursday you can find out a lot more about mud flows and Mount Baker by going to a talk on Mount Baker by David Tucker Thursday evening October 14 at the Whatcom Museum - see nwgeology.

In 1983 I did some mapping work with Chuck Ziegler east of Mount Baker. Our interest was in much older metamorphic rocks of the Northwest Cascades Complex and Mount Baker was in the way. Lava flows and eruptive centers covering up the metamorphic rocks. But we did see some interesting volcanics and Dave Tucker will explain it all (mostly).

Gates of Lodore and My First Snow Storm of the Fall

I have returned from a week and half in the east part of the western U.S. My route back from the high plains took me through northwest Colorado where I ventured to the gates of Lodore and Brown's Hole. The Gates of Lodore is a narrow canyon where the Green River cuts through a high anticline. The canyon is located within Dinosaur National Monument. The name of the canyon was coined in 1869 by Andrew Hall a member of John Wesley Powell's expedition that traveled down the Green River and is from the poem the Cataract of Lodore by Robert Southey.

Green River flowing towards the Gates of Lodore

The Gates of Lodore marks the south end of Brown's Hole. Holes in this context are relatively lower areas in the terrain within the mountains. Holes in the mountains. Jackson Hole being the most famous and one people are most familiar with. These areas were areas to hunker down in the winter as they tend to be drier and milder relative to the surrounding high country. First Nation people used them and cattle herders and sheep herders used them later. They were also a place where outlaws would lay low. Brown's Hole was frequented by Butch Cassidy. The Columbia Basin in Washington State can be thought of as an especially large hole in the mountains as it is surrounded by mountains and was used in a similar manner.   

Brown's Hole now more commonly called Brown's Park is made up of a National Wildlife Refuge, Bureau of Land Management lands, a scattering of ranches and a few National Historic Landmarks in an effort to protect some of the historic structures. 

Old cabin and morning fog in Brown's Hole

I was really struck by this grave marker at the small cemetery. It appeared many graves were unmarked and at least half of the marked graves had no birth year.

I also ventured into the north Wasatch Range in Utah. My timing could have been better as the weather took a rather abrupt turn as can be seen by the view I had of the approaching cold front that brought my first snow fall experience of the fall.

Approaching cold front

This storm would have launched my tent if I had not stayed in it and gave me a great noise and light show that lasted a good five hours. And it made for a chilly hike the next day over the 9,000 foot plus summit ridge.

Summit ridge on the way back to the trail head. The bedrock is limestone.

Tricky footing and route finding

  

R&R at a Different Latitude and Altitude

I am having some R&R in Fort Collins, Colorado. I have been struck by the trees not having turned yet with the exception of a few with just a hint of yellow. This despite the fact that I am at over 5,000 feet. The difference of a few degrees of latitude and a more continental climate. In Bellingham with a north Pacific marine climate and more northern latitude, many trees including the maples behind my office have lost leaves. But it will not be long before it gets colder here than western Washington.

The other impressive difference is the tree line in the mountains. Yesterday I was at 10,000 feet and still in forest. The tree line in western Washington is not straight forward. The shear volume of snow limits tree growth versus the cold that creates a sharp tree line in the Rockies of Colorado. The only area in Washington State with a true tree line is the northeast portion of the North Cascades with a tree line around 8,000 feet. Given the lack of area above 8,000 feet it amounts to a small area.

My other note worthy observation is the take over of the Estes Park golf course (a town) by herds of elk. I find the adjustments animals make to human induced habitat change fascinating. And of course humans have made adjustments as well. A little less late season golfing. 

Riding the High Plains

I have spent the last few days riding my red stallion (1991 tercel) on the high plains. Cool rocks, my favorite animal (pronghorns) and my usual odd observations - It appears that stimulus money was used to shore up a lot of snow fences along the highways.
In regards to the Washington landscape I figured out one can drive over Snoqualmie Pass without being on the interstate. A very nice detour from the usual. Exit at Denny Creek and drive in the woods including some old growth.