Time, Change and Travels
Northeast Washington Geology Trip
October 13, 2001
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The landscape and rocks of Northeast Washington are records of change that reach back more than a half billion years. The products of those changes influence how we move about and have lived our lives.
The plan for this trip would take us to higher than 5,700 feet elevation. In case of snow we will take an alternate trip, that stays under 4,000 feet. If the weather is very adverse. We may re-trace one of the lower elevation trips, that have been done before. The meeting point stays the same: Cookie’s Café, in Colville, 8:30AM.
Start driving south on Main street at First Avenue.
1.6 Stop to get a close look at part of the Metaline Formation. This rock is the thick bedded and massive limestone that form the upper part of the unit. The Metaline represents a long time span. Trilobite fossils, in the lowest beds, are Early Middle Cambrian (545Ma). Graptolites that are inter-bedded with the top of this unit are latest Early Ordovician (485Ma).
2.2 Where the Colville River is closest to the highway it is seventeen miles. along the channel, to the mouth (river mile 17). The distance is 14.2 miles along the valley (sinuosity 1.2). The river falls only 40 feet in the 11.9 river miles to Meyers Falls (0.0006 gradient). The drop, below the falls, was 160 feet (0.005 gradient). We can talk about why that makes a difference, at the next stop.
3.5 Stop to look at the Colville River Channel and the wetland mitigation area. The ponds were constructed in 1989, to mitigate the loss of other wetlands by highway construction. The rock in the cut-slopes is Ledbetter Slate Formation. The Ledbetter overlaps, in age, during the Lower Ordovician, with the Metaline. The estimates of thickness are poor, because of faulting, folding, variation and lack of exposure. It is likely that the Metaline is about 1,600 meters thick and that the Ledbetter is near 1,000 meters thick. By comparison, the Grand Canyon exposes 1,700 meters of strata, including sixteen formations plus the Vishnu Schist Group.
3.7 Orin-Rice Road
4.2 Turn left and park on the Old Highway Road. The same Metaline and Ledbetter rocks look very different here. This is the result of contact metamorphism by heat and fluids from the freezing magma of the Starvation Flat Quartz Monzonite. That pluton entered and cooled very nearly to 100 million years ago.
4.8 Outcrops of Starvation Flat Quartz Monzonite are on both sides of the road.
6.0 This small swale is a Holocene distributary channel of the Little Pend Oreille River. This shallow cone of alluvial material formed after the draining of Glacial Lake Colville.
6.2 Crossing the Little Pend Oreille River
6.3 Turn right on Arden-Brooks Road.
6.4 Stop to look at the channel of the Little Pend Oreille River. This channel was dredged in the late 1940's so that sediment would not be washed down to refill the dredged channel of the Colville River.
6.5 Continue, across Highway 395, onto Arden Hill Road.
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6.8 Cross the Colville River. As part of the original dredging project, an artificial channel was cut, to move the river to the west, developing more agricultural land. The river meandered, in response to the increased gradient. The channel was re-dredged in 1979 to prevent it from flooding into its original course.
7.0 Bear right on the Townsend-Sackman Road. This route follows the toe of a terrace that is about 400 feet high, 2 miles wide and 6 miles long. The terrace is what remains of an area where deeply weathered quartz monzonite was removed by the last advance of the continental glagier.
8.8 The meandering swales in the valley floor are the former channel of the Colville River. The dredging operation moved the river to the east side of the valley, and this area was drained by a ditch to the north.
11.2 Turn left on Twelve Mile Road. Stop for a look at the Colville River and the Twelve Mile Water Gap. This was one of the few places where the Colville Valley was not spanned by fens and swamps, at the time of European contact. That makes it the most likely place where the Salish Road crossed from the west to the east side of the river.
11.7 Turn left (north) on Highway 395.
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J).12.0 Notice that the east edges of the road fill are collapsing. The fill failures are related to the popcorn texture that is visible in the fill slopes. The silt that was deposited in the glacial lake and blown into this area, after the lakes drained, contains large amounts of montmorillonite. Volcanic ash decomposed in the waters of the lakes to form this clay, that swells and shrinks by ten times as it absorbs and loses water between the layers of the crystals. After it has been disturbed, the clayey soil does not have enough cohesion to support its own weight on the fill slope.
15.3 Turn right on Arden-Brooks Road.
15.6 Turn left on Old Highway.
16.1 Turn right on Artman-Gibson Road. The upland habitats are mostly hot, dry Ponderosa pine types.
19.4 Park in the gravel pit area. There are good exposures of Starvation Flat just to the southwest. There is a wealth of information about late glacial conditions in the gravel exposure.
20.0 Turn right on Kitt-Narcisse Road.
21.1 This is one of the many exposures of the Starvation Flat that were scoured by the Cordilleran Ice Sheet. The surface is sculpted by a combination of the flow direction of the ice (mostly south south-east) and the fracture pattern of the rock (south southwest by east south-east). Only the hardest parts are preserved in the hill top sheep’s backs ((roches mutone
22.3 Turn to the right, onto Bear Creek Road.
23.0 Cross Narcisse Creek. We will get chances to see the middle reaches and headwaters of this fifth field watershed. The area drained by the Little Pend Orielle is is at the fourth field level (hydrographic unit code 4, watershed). All of the drainage of the Colville River is HUC3 (sub-basin).
23.6 The more weathered rock is visible in places where erosion has removed the cover of glacial debris.
24.2 This is the outcrop that Joan Engels sampled for radiometric dating, in 1972. The potassium-argon ratios dated the freezing of biotite at 100Ma and hornblende at 99Ma.
26.0 Stop at the turn off to the homestead barn. We will walk down to the Little Pend Orielle River to look at the record of river terraces and the state of the channel and riparian zone.
29.7 Return to Kitt-Narcisse Road, and turn right. Above this elevation, the hot, dry Ponderosa pine habitat becomes warm, dry Douglas fir sites
31.8 The soils in these wet meadows are rich fen peat. The peat is fibrous remains of sedge and rush vegetation that grew in water, from run-off that carried mineral nutrients. The waters that were kept acid by organic acids, nitrogen and phosphate leached uranium from the granitic rocks. When cations were abundant, in dust of the early Holocene and volcanic ash, the uranium was precipitated in many of the wetlands.
33.2 Turn left, west, on Highway 20.
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33.6 Stop to examine the Granite of Narcisse Creek. The granite is a little more than four million years older than the Starvation Flat Pluton. Both rocks are probably parts of the same production generation of igneous material. All of these related rocks contain very little mantle or oceanic crust material, leading to a tectonic consensus that the oceanic lithosphere was being subducted at a very shallow angle.
34.6 The to the north is of the 1980 Narcisse Fire.
36.6 The elevation of Keogh and White Mud Lakes is 2,168 feet similar to Hatch Lake and Rocky Lake. With the elevation of the flats, nearby in the range of 2,200 to 2,260 feet they for a widespread terrace level. Remnants of that terrace level slope to the west and south, where it is at 2,010 feet at Rice and Springdale. It probably represents a late surge of glaciation, younger than the 2,480 feet maximum, at Deer Lake, and older than the 1,680 foot level of Kelly Hill and the Colville Valley. Mega-ripple marks on the terrace between Loon Lake and Deer Lake indicate that the Lake Missoula Floods occurred along with the local, glacial maximum.
37.8 The kilns of the Tulare Dolomite Quarry provided refractory for lining the Georgetown steel mill, in West Seattle, from 1914 to 1947.
38.5 Turn right on the Pouty Corners Loop.
39.0 Turn right on Old Dominion Road. The rocks in the outcrops are all within the Metaline Formation: however, this was named the Old Dominion Limestone be C. E. Weaver in the first geologic survey of Stevens County, 1920. Most of the calcite, here, is from hydrothermal alteration.
41.5 Park here to visit the Old Dominion Mine. This is the oldest, hard rock mine in Stevens County. The forty pound ore sacks were shipped to the railroad, at Spokane Falls by mule train. There are more than eight miles of workings, on eleven levels, extending up the mountain to the northeast. By 1947, the total production was 342,517 ounces silver, 744,400 pounds lead and 148,600 pounds of zinc.
41.8 Granodiorite of the Starvation Flat Pluton is in the road cut, here.
43.8 Old Dominion Road becomes Forest Road 9411. cool, mesic Grand fir habitat types occupy the north and northeast aspects beyond here.
45.7 The granitic sand here is glacial out wash, at 3,800 feet elevation.
46.9 Turn left on the 9411-130 Road to the Old Dominion Look-out.
47.1 Hornblende monzogranite of the Narcisse Creek Pluton is exposed here.
48.9 Addy Quartzite Formation with pyrite and magnetite in the cross-beds. Cool, mesic Douglas fir types, such as Douglas fir/ Big huckleberry, occur on these east facing slopes.
50.1 The quartzite is altered by regional metamorphism to quartz-muscovite schist. The severe conditions of these south and west facing slopes will only allow Douglas fir woodlands, not closed forest, in the Nine-bark shrublands and Pine grass grasslands.
51.8 Here is a granitic boulder, carried onto this quartzite mountain by the continental glacier. we are moving into Sub-alpine fir/ grouse huckleberry stands that are typical of the north and east aspects, down to 4,800 feet elevation.
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52.4 Summit of Old Dominion Mountain. The rocks on this mountain top have been folded and tipped up from mid-crust depths (about 20 kilometers). That was not deep enough to cause melting, but deep enough to deform plastically under shearing forces. The style of deformation, here, is similar to the style at the lower structural level of the Kettle and Okanogan Domes. The depositional age of the rock is roughly 600 million years ago. This is a fine vantage point to see the structural relationship of the various mountain ranges. Return to the 9411 Road.
57.8 Turn left on the 9411 Road.
58.6 Turn right on Road 9411-175.
59.9 The rock, in the road cuts and outcrops, is a dark phase of the Narcisse Creek Pluton. There is enough moisture and cold air ponding in this area to produce cold, mesic Western hemlock habitat types. These are some of Northeast Washington’s most productive timberlands.
61.4 Cross Hanson Creek.
61.9 The creek has cut down in Hanson Meadow. What once was a mix of sedges and wetland grasses has dried, and is dominated by Kentucky bluegrass.
62.3 Stop at the crossing of South Fork Mill Creek. This crossing is a good place to see the transition segment between a montane meadow reach, above, and a degradational valley reach.
62.4 Turn left on the South Fork Mill Creek Road.
64.0 Most of the creek is out of sight in riparian stands of Western red cedar, but it runs a nearly straight course in a valley that is has cut in glacial debris. The gradient is 0.027, steep enough to do a large amount of work with a bankfull flow of less than 20 cubic feet per second.
64.8 Stop at the crossing of South Fork Mill Creek. There is a falls on the north of the road.
65.8 These sands were deposited as a stream delta. Similar glacial drift mantles the slope to 800 feet above here. The dark ravines that show in the aerial photo are pre-historic landslides that delivered sediment to the stream.
66.6 The outcrops are of Maitlen Formation phyllite. These metamorphosed mud rocks are of intermediate age and position between the Addy and the Metaline.
66.9 Cross Mill Creek. The channel has cut downward about two meters below its pre-historic level. That is probably due to a combination being deprived of mass wasted sediment and faster run-off after large fires and intensive logging.
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67.0 Turn left on Aladdin Road.
71.0 Mill Creek formerly flowed over what is now a ridge to the south. Probably about the time that the mouth of the Colville River was cleared of its glacial blockage, a more energetic stream captured the drainage toward the west and north.
72.5 Turn right on Douglas Falls road.
75.7 Turn left, into Douglas Falls Park. We can park at the view point and walk to the Falls. Here is another close look at the Addy Quartzite. As you look up from the top of the falls there are minor terraces that record the history of Mill Creek. Return to the Douglas Falls Road.
76.0 Turn Left on Douglas Falls Road.
77.6 We are crossing the wedge of glacial outwash from the melting ice in the Echo arm of the Colville valley. The topsoil is a thin layer of Holocene dust and volcanic ash. The subsoil is gravely and severely drained.
78.4 Turn left on Williams Lake Road.
78.9 Cross Clugston Creek. We have descended to the aggradational wedge of Mill Creek. During most of the Holocene, Mill Creek meandered across the valley spreading out the sediment derived from stream capture, down cutting below the falls and landslides. The fine material was deposited over the banks, during floods. The soils are fertile and loamy throughout the subsoil.
80.5 Cross Mill Creek. This would probably have been one of the best places for the Salish Road to cross Mill Creek and the Echo arm.
82.3 The bottom land fields on the right are part of the main Colville Valley bottom. The lakebed soils are loamy muck that are difficult to till in the early planting season.
82.5 Turn left on Highway 395, to return to Colville. Thanks for sharing the day.