BACK TO BASICS
TWENTIETH FALL GEOLOGY TRIP
OCTOBER 12, 2002

 Northeast Washington is a rich environment for teaching and learning geology.  Nearly all of the basic principles can be seen in examples. Even though we cannot visit active glaciers or volcanoes, we may examine the evidence of past activity. We can only investigate a significant portion of the menu that is presented. There is simply too much for one day. We will try to cram in all that we can. That makes for a tightly scheduled day, so I ask that we keep to two or three questions at each stop. I will try to answer as many questions as possible, as I ride with different groups.

Mileage

0.0 Start going west on First Street at Main, Colville. Between Wynne Street and Lincoln Street we are going down the face of deltas, formed in a glacial lake.

0.2 Proceed west on Oakshot Road.

1.3 Cross theColville River, where it has been confined to straight ditch, bounded by levees.  The first project of the Steven County Conservation district, in 1948, was to straighten the river and drain land for farming. The small channel to the west is the native course.

1.7 Turn right on Valley West Side Road.

1.8 Stop for Quarry in Sanpoil Volcanic Formation. The dome shape of these outcrops, as seen    best from Colville, is a clue to their similarity to the lava dome in the Mount St. Helens crater. This andesite is about 51 million years old (51MA), and part of the same set of volcanic events as similar rock occurring from Newportto Tonasket.

1.9 Continue south on Valley West Side Road. Looking to the left we can see the complexly meandering channel of the pre-drainage Colville River.

3.8 Turn left on Mantz-Rickey Road.

4.8 Cross the Colville River.

5.1 Cross a drained channel.

5.2 Stop for outcrops of Metaline Formation. This is the massive limestone that constitutes the upper member of the unit. This is the host for silver-lead ore at the Old Dominion Mine and for Zinc-lead ore deposits near Metaline Falls. The age of this member is as young as 520MA, Lower Ordovician (Llandvirinian).

5.4 The road cuts display more of the Upper Metaline Formation. The southern most extension of the formation is near Hunters, where the whole unit is much thinner, resembles this thick bedded limestone and rests directly on the Addy quartzite.

5.7 Pull off to the left for a quick look at the Ledbetter Formation. Being bleached by hydrothermal alteration, this is not typical of the Ledbetter. The type section is near Ledbetter Lake, north of Metaline. Here, it is slate, as it breaks easily along surfaces at an angle to the original bedding.

7.0 Take note of how the gravel bars (bankfull level) of the river are nearly two meters below the valley floor. This is the result of channelization above and below this reach.

8.1 Turn left on Old Arden Road, and park. From here it is a short walk, along and across the roads, to see the rock units of the last two stops as they were altered by heat and fluids from the Starvation Flat Quartz Monzonite. The Metaline has been re-crystallized to a coarse grained, mottled marble. The micas and feldspar, of the Ledbetter, have been chemically recombined as different minerals in association with pyroxene. Continue south on 395.

9.8 Cross the Little Pend Oreille River.

11.6 The rounded outcrops, to the east, are characteristic of the Starvation Flat Pluton, and felsic rocks in general. Plutonic rocks cool along a network of fractures, where fluid carries heat away. The result is a sort of three dimensional mud crack pattern, usually inverted.

13.7 The silty sand exposed in the road cuts has a popcorn texture. Volcanic ash fell in a glacial lake, then was moved here by wind, after the lake drained. The glassy ash weathered to clay that expands by a factor of eight between dry and wet states.

14.7 The ridge of gravel that nearly spans the valley is a set of deltas. Streams flowing from what are now Twelvemile Creek and Slide Creek were small additions to melt water along both sides of the valley ice tongue. The break in slope, between the cross ridge and Erickson Ridge, to the west and 300 feet above us, was the shore line of the lake.

15.5 Blocky outcrops, on the left are Addy Formation Quartzite. The Addy is nearly all quartzite, and generally grades from massive, at the bottom, to thinly bedded, at the top.

16.9 The railroad cut, serving northwest Alloys, exposes the bedded dolomite, Middle Member of the Metaline Formation.

17.4 Turn right on Mill Street, Addy.

17.5 Turn left on Main Street.

17.6 Turn left on Addy-Gifford Road.

17.7 Cross the Colville River and park in the entrance to River Cliff Park. The inter-bedded quartzite and siltite are near the top of the Addy Formation. A borrow pit, on the far side of the hill, is the original locality for Nevadaella addyensis, a Lower Cambrian trilobite. Return to 395 on the Addy-Gifford road.

18.1 Turn right on 395. A rock pit, south east of the intersection exploits talus of Addy quartzite for construction rock.

18.6 The Buckskin Quarry was active from 1977 to 1981. It provided silica ore from massive quartzite. The ore was shipped to Vancouver, Washington for making silicon carbide.

19.2 Blue-green rock showing in the road cuts is greenstone of the Huckleberry Formation. The rock was originally basalt lava. The age of the flows has been obscured by several episodes of alteration, but is between 734MA and 862MA.

21.1 The cliff and cut at Blue Creek expose Huckleberry. The formation is correlated with the Leola Volcanic Formation, in the Metaline District, and the Irene Formation, in British Columbia. All of those are part of the Windermere Group.

21.7 This mine has produced magnesite from the Stensgar Formation, for both refractory production and decorative stone.

23.2 Park near the white marble gate post. We will climb up the bluff to see glacial striations on the Addy Quartzite.

25.5 The cliffs, east of Chewelah, are steeply dipping Addy Formation. The rocks beyond the cliffs are dismembered parts of a great sequence. From the youngest: Striped Peak Formation, part of the Missoula Group; Wallace Formation; and Burke Formation, part of the Ravalli Group. They are all silica rich, fine grained, thin-bedded, meta-sedimentary rocks. Together they are part of the Belt Super-group, ranging in age from 1,100MA to 1,500MA.

26.3 Cross Chewelah Creek.

26.9 Northwest Marble produces stone products including: stucco flocking, decorative stone, filler for plastics, reagents for sugar refining, steel making flux, and livestock feed additives.

27.5 Cross the Colville River.

27.8 Ruins and tailings are all that is left of the Northwest Magnesite plant. In its time, it was the world’s largest producer of magnesite refractory products. Mg(CO₃) was separated from the ground dolomite by the difference in density. The heat of coal fired kilns drove out CO₂ to leave MgO. The oxide was used to line steel making furnaces. Demand for the product declined as acid process, using silica lining, replaced basic process steel. The final blow was the end of sanctions imposed by the Treaty of Rome, ending World War I with Turkey. Magnesite could be produced more cheaply from the deposits at Magnesia. The last of the sanctions prohibited production of light metals. Those expired in 1998, adding to the economic problems of Northwest Alloys.

30.4 Cross the Colville River.

31.3 Another kame terrace lies to the left of the highway, with its surface rolling between 2,200 and 2,600 feet elevation.

33.5 These road cuts are in McHale Slate Formation. The rock was intensely sheared and mineralized with iron and magnesium as it was thrust along a major fault. That may explain why geologists originally misidentified it as Huckleberry Greenstone.

34.4 We are crossing the trace of the Jump-off Joe Fault. It was active from the Devonian until the Eocene, about 330 million years. The displacement was mostly by thrusting, but changed to extension, as the tectonic forces changed. For the next few miles, the rocks under the fault are Addy Formation.

34.7 The depression, right of the road, is a kettle. As a large block of ice melted, under the glacial outwash gravels, the surface of the terrace sank. The water level in the kettle is dependant on the height of the water table.

37.0 Turn left on Roitz Road. Do a drive by identification of the rocks that line the driveway on the left.

37.6 Turn right on Solokar Road.

38.2 Cross Grouse Creek, as it flows through a willow and cattail wetland.  The willows suggest recent disturbance, and cattails out compete rush and sedge communities where nutrient levels are high. The elevations of meadows, near 2,400 feet. were controlled  by the margins of the ice tongue.

38.6 Park along either shoulder, at the top of the grade. Red argillite of the Striped Peak Formation was quarried for flagstone, and barite was shipped for testing. Several sedimentary structures are preserved in this rock. It can be eerie to see familiar patterns of ripples and mud cracks, and know that the events happened more than a billion years ago. Return to 395, and continue south.

40.9 The streaks of dark rubble, in the road cuts are dikes of Columbia River Basalt.

46.3 Turn left on Garden Spot Road.

46.7 Park near the PUD Enclosures. We will step to the south to get a view of the giant ripples that were constructed as the flood coursed through the Sacheen gap and into Glacial Lake Columbia. Return to 395, and continue south.

49.3 Park on the shoulder, opposite the sandy textured road cuts. The sandy grus retains many of the igneous structures of the Silver Point Quartz Monzonite. This area was beyond the farthest extent of the Pleistocene glaciers. It takes time, on the order of millions of years, to weather rocks to this depth. Continue south on 395.

52.5 Turn left onto Swenson Road, and park. The Latah Formation consists of sedimentary rocks that were deposited around the eastern margin of the Columbia River Basalt flows. The source of sediment was low gradient rivers that drained low mountains, weathered for 40 million years. The result was wetlands filled with silt and clay. The clay from Clayton provided the brick and terra cotta that rebuilt Spokane, after the 1889 fire. Return to the north on 395.

58.0 Turn left on Highway 291, toward Springdale.

59.9 Cross Sheep Creek.  This was an insignificant branch, until a canal was dug from Loon Lake, some time before 1918. The lake formerly drained to the south, down Beaver and Dragoon Creeks, to the Little Spokane River. The canal lowered the lake, so that sedge peat wetlands could be farmed.

60.3 Park on the shoulder, in the middle of the large through-cut. The south side of the cut exposes a contact between two plutonic rocks, a monzo-granite and a grano-diorite separated in age by about 50 million years. The subtle distinctions make it hard to map granitoid rocks.

64.5 Park in the rock pit area, on the left. The Grand Rhonde Basalt Formation comprises 90% of the volume of the Columbia River Basalt Group. The volcanic fissures were centered the mouth of the Grand Rhonde River. This flow extended, north to Valley. Other flows covered St Maries, Idaho, Madras, Oregon, and reached the ocean near Astoria.

64.8 Turn right to follow Highway 231 through Springdale. The ridge, south and west of Springdale, arcs across the valley. It is the Springdale Moraine, marking the farthest advance of the Colville sub-lobe of the Cordilleran Ice Sheet.

65.0 Cross Sheep Creek. The moraine turns Sheep Creek to the north, just as it turns Chamokane Creek to the south.

69.0 Turn left on Deer Creek Road. As we go down the grade, look to the south to se landslides. The most recent slides, active in 1998, are alcoves of bare soil. Older slumps are grown up in hawthorn and choke cherry brush.

69.5 Cross Sheep Creek. At the head of the Colville Valley lies a complex of recessional moraines and pro-glacial lake beds.

69.8 Cross Deer Creek. Deer Creek and Sheep Creek join to form the Colville River, about 600M northeast of here.

69.9 Turn right on Long Prairie Road.

70.8 Turn right on Betteridge Road. The rim rock of The Island, to our left, is Grand Rhonde Basalt. The columnar cooling joints are the outstanding feature of thick basalt flows.

73.3 Cross the Colville River. From here to the highway you can see a few buildings and many-colored dumps of NANOME Aggregates. The plant formerly produced a variety of colored, decorative stone products.

73.7 Turn left on Highway 231.

76.1 The industry, on the left, is Lane Mountain Silica. The mine is in a fractured zone of the Addy Quartzite, on the west side of Lane Mountain, about nine road miles west of here. Most of the sand is produced for abrasive, with lesser amounts for glass, flux, filtration, or catalyst. A minor product is bagged, traction sand, for the local market.

77.7 Turn left on Waitts Lake Road.

80.0 Cross the Colville River. The flat surface is the bed of a glacial lake, bounded by the Springdale Moraine and the glacier, first at Twelve Mile, then at Kettle Falls. In seven miles, we have descended 350 feet from Springdale, 500 feet from the top of the moraine. The Colville River only falls 162 feet in 45 miles, to Meyers Falls.

82.6 Waitts Lake would have been a very shallow bay in the latest Pleistocene lake.

84.6 The Carr copper mine is visible, on the right. Very little ore was produced. Marv Carr had a big loader, so he dug a big tunnel to use it.

84.7 Bear slightly to the left onto Red Marble Road. We are now going up the headwaters of Cedar Creek

87.1 We are now crossing the North Fork of Deer Creek. If it looks like the creek directions and grades reverse, at random, it is a result of stream capture. All of the drainage that converged here, at one time flowed down Cedar Creek. The glacier blocked Cedar Creek and melt water excavated Deer Creek. That outlet captured Cedar Creek’s old headwaters.

87.2 Stop at the small rock pit for the first of a set of structure mapping observations.

87.6 The next observation is at the borrow pit with prominent, slaty fractures. That the McHale Slate has fracture parallel to the bedding indicates the limb of a very tight fold.

87.8 Note the brick red soil color in the new logging road. The Edna Dolomite has few natural exposures. Campbell and Loofbourow mapped most of the formation on the basis of this soil color.

89.1 The blocky outcrop on the inside of the right hand curve is McHale Formation again.

89.6 Just beyond the hairpin turn, stop in the road for a brief look at meter  scale folding in the McHale Slate.

89.8 The craggy, pitted surface of these outcrops is indicative of carbonate rock. They are fairly well exposed, and the soil is gray brown, so it must be Stenger Formation.

90.9 The foundations, above the road, were for the crusher building. The concrete, below the road, supported the loading bins, and was the anchor for the cable tramway. The ropeway carried buckets of ore 7.2 miles to the Finch Quarry. The rock was transferred to a second cableway for a 4.9 mile trip to the Magnesite plant.

91.2 Park in the haul road, on the right. We will walk into the  upper area of the Red Marble Quarry. Several notable features are displayed in the bench walls. It is a good spot to map and discuss the repetition patterns, which we noted on the way up. This mine had a pioneering start, by using trucks, rather than rail way for ore and waste hauling. The only subsequent advances that the company adopted were diesel power and blasting agents replacing high explosives. By the end, it was an antique, still using churn drills and wagon drills. The same company that built the original tramway, BRECOL (British Ropeway Engineering Company Ltd.) built the gondolas at Spokane Falls and Kellog-Silver Mountain.