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FOP 2023 Planning

Camping Options

- Potholes State Park group site at MarDon.

Field Stops

Here's what I'm thinking as far as potential stops. My focus is on calcrete-cemented sediments that reflect low-relief, alluvial settings and that define a paleosurface since warped by uplift of the Yakima Folds. I may add a stop at Smyrna Bench and north side of Frenchman Hills.

Study area map. Three of Washington's geomorphic domains overlap here: Palouse (wind), Yakima Fold Belt (active tectonics), and Channeled Scablands (flooding).

Map of potential field stops in Saddle Mountains area. Stops arranged below in no particular order.

Line across the mountain. Calcrete as seen from Crab Creek/Royal Slope.

Compiled timeline. Events relevant to tectonic uplift of Cascade Range and evidence for rainshadow conditions to the east. Thick, pedogenic calcretes at Saddle Mountains post-date the Elephant Mtn basalt, post-date the unconformity at the top of the Ringold (drainage of last Ringold lake), and interfinger with Plio-Pleistocene sediments (low angle alluvial fans, old loess). Calcrete caps pre-Wisconsin flood gravels at George, Othello, White Bluffs, Old Maid Coulee, Harder Road, Fancher, and other locations.

Redraw and correlation of Lindsey's columns. Ringold stratigraphy at White Bluffs, paleosols (lake shoalings), cemented zones, diatomite beds (overprinted ash), oxidization, wood fragments, ash, flooding surfaces, and soft sed deformation. Cementation in middle Ringold (fluvial) expresses differently from that in upper Ringold (lacustrine). Soils in the floodplain formed in patches of slightly drier, slightly elevated sediment (overbank areas). Soil formation in the lake basin require lowering of the shoreline (drainage) and a dusting of loess. Weak soil development, mostly just diatomite shows, occured after drainage/lowering of Lake #1, indicating incomplete drainage or a relatively brief lowstand period. Stronger soil development occured following the lowering/drainage of Lake #2. Soil development following final drainage of Lake Ringold (Lake #3) is substantial. Thick pedogenic calcrete - a set of welded horizons commonly separated by thin sediment intervals - armors the post-Ringold unconformity. The abandoned lakebed and shoreline surface was left dry, but not that high. Most of the topographic relief in the study area was created by Scabland floods, which removed the armoring calcrete from larger coulees.

Hanford subsurface boreholes. Three geologic units were identified in borehole cores from Hanford's 200 Area by Slate (1996, 2000). Units include the Pliocene upper Ringold Fm, the Plio-Pleistocene unit (fanglomerate-loess-calcrete-paleosol complex), and late Wisconsin Missoula flood deposits ('Hanford Fm'). Yellow brick pattern is calcrete (CP). Other paleosols are colored yellow (labeled P) or light green (groundwater-influenced, GW). Slate identified GW zones a cemented horizons with morphologies suggestive of formation in the capillary fringe, the 'groundwater' or 'phreatic' calcretes described by others (Malde, 1955; Birkeland, 1999; Budd et al., 2002; Moore, 2003; Alonso-Zarza and Tanner, 2006; Wright, 2007). I've redrawn her columns here to clarify and make comparisons . Packer and Johnston (1979) sampled DH-6 and DH-11 for paleomag. They also sampled DH-7, DH-13, DH-17, DH-9b.

Pre-Wisconsin deposits capped by calcrete. Bjornstad et al. (2001) described and sampled several sites in the Channeled Scablands where ancient flood gravels are capped by thick petrocalcic horizons. I've redrawn his stratigraphic columns here for clarity.


1.) Saddle Mts Crest Hike (SM)

Drive Rd R from Mattawa to Sentinel Pk radio towers. Hike out-and-back fairly over easy ground (6 miles roundtrip). Excellent exposures of pedogenic and groundwater calcrete, Ringold Fm stratigraphy, fan gravels, 'early Palouse' loess, faulting and north escarpment, flood-scoured Crab Creek valley below, Elephant Mtn basalt, Cougar Pt Tuff, Priest Rapids basalt, older units below.

Time: Most of one day.


2.) Cougar Point Tuff (CPT)

Ten meters of 11.8 Ma Cougar Point Tuff exposed in pumicite quarry near Mattawa. Currently working on getting us access. A cool place to see, if not directly related to trip. Short hike from landowner's driveway. Is diatomite found here?

Time: 2 hours.


3.) White Bluffs Overlook (WBO)

Exotic-bearing calcrete flood gravel (ancient flood deposit?), deltaic sands, anomalous massive sand beds (homogenite? distal fan?), soft sed deformation features, cemented loess paleosols representing shoalings of Lake Ringold, Lindsey's strat columns, old and active landslides, damming of Lake Ringold by Simcoe volcanics, post-Ringold unconformity, seismites(?), excellent views of Hanford reactors. 45 minute drive from Othello. Short, easy hikes along old road and along bluff top. May get shot at by black helicopters if we linger too long.

Time: 2 hours at outcrop.


4.) Herman Railcut (HRC)

Boulder gravel deposited by ancient scabland flood beneath two calcrete ledges. New discovery. Undeformed section reflects low elevation setting located far from Saddle Mts and Frenchman Hills anticlines. Calcretes and parent materials strongly resemble those along Saddle Mts crest. Outcrop is short, easy hike from roadside pullouts a few miles north of Othello.

Time: Less than 1 hour at outcrop.


5.) Hendricks Road (HR)

Alluvial beds with Bk horizons and cicada burrows rest atop Elephant Mtn basalt. Brown beds are identical to those exposed atop Elephant Mtn flow (base of Ringold section) along the crest of Saddle Mts 1000' higher. Beds here are remarkably well preserved given their position just downstream of cataracts within a major scabland flume (Eagle Lakes-Ringold Coulee scabland). This exposure provides some new evidence for a broad, formerly low-relief paleosurface, now folded. Roadside stop. Hendricks Rd crosses Eagle Lake scabland. Access south of Othello near Connell exit off Hwy 17 or from Hwy 24 and Sagemore Rd east of White Bluffs Overlook.

Time: 30 minutes at outcrop.


6.) Ringold Road Bluffs Hike (RR)

Deformed upper Ringold lakebeds truncated by flood-laid(?) calcrete gravel. Lithified clastic dikes intrude Ringold. Spectacular active landslide features along trail. Moderately steep hike about 1 mile long. Can be hot. Ringold Road is rough, dusty. Runs north from Ringold Fish Hatchery near mouth of Ringold Coulee, several miles west of Basin City.

Time: 2 hours hiking out and back.


7.) Offramp Site (OFF)

You need both copius amounts of water to evapotranspire, a steady influx of Ca2+ from dust, and CO2 from rain. Dry and dusty alone can't make meter-thick calcretes in less than 1.8 million years. Stacked, very thick calcretes in two different parents. The upper, a sandy loess parent - proximal sand sheet of Sweeney(?) or flood-reworked seds of Medley and Burns(?). Abundant soil features, burrows, root casts. The lower, Ringold lakebeds visible at base of the exposure. CaCO3-inflation along bedding planes (displacive fabric). Easy hike from cars near Othello. Intersection of Hwy 17, Hwy 26, and canal wasteway at hay storage area.

Time: 1 hour at outcrop.


8.) Booker Road Canal

Interfingering of Palouse loess and calcrete highlights transition between two geomorphic domains (loess hills vs. undulaing alluvial plain). Perspective on Palouse hills 'caliche' (high sedimentation competes with soil development) and Columbia Basin 'calcrete' (stable lowland setting, nearer water table). Farm road pullout off Booker Rd at canal.

TIme: 30 minutes at outcrop.


9.) O'Sullivan Dam & Reservoir / Lind Coulee Fault (OD)

Location of paleoseismic trenching by M.W. West in the 1980s. Exposed Quaternary fault places Palouse loess over Roza basalt. Corestones in top of Roza below fault plane (repeated section). Excellent alluvial stratigraphy exposed in nearby bluffs if water level permits access. Easy hike. Discovery Pass may be needed. WDFW parking off Hwy 262 or free parking at Rd M SE bridge.

2 hours at outcrop.


10.) Taunton Powerhouse

Thick fluvial sands of ancestral Columbia-Snake punctuate upper Ringold lakebeds and are truncated by Corfu Landslide deposits. Flood-cut terraces in vicinity. Where is river with respect to Crab Creek Valley, Drumheller Channels, and Quincy Basin? Danielson Rd/Taunton Heights Rd.

1 hour at outcrop.

Breached anticlines and geomorphic surfaces. Modern rivers and Ice Age floods had no respect for bedrock folds. Did all younger channels follow ancient drainages established after cessation of CRBG eruptive activity? What is the relative timing of gap cutting and ridge uplift? Can we see (and map) remnants of the post-basalt surface with its ancient channels today? Five geomorphic units can be identified with respect to a post-basalt, pre-floods 'remnant Pliocene surface', 1.) Scabland scoured bedrock-Pliocene surface completely eroded away, 2.) Loess hills-Pliocene surface buried if present, 3.) Flood deposits-Pliocene surface buried, 4.) Flooded but not eroded-remnant Pliocene surface w/ calcrete armor and ancient channels, 5.) Bedrock highlands-Pliocene surface mostly stripped away by uplift. Unit 4 is the interesting one.


RIngold section is well exposed in gullies at Smyrna Bench.

Calcrete-cemented fan gravels cap bench.

Savage Island lake shoreline appears to be exposed.

Micaceous fluvial sands interrupts lake beds section.

Thick lowland paleosols closely resemble those along the Saddle Mountains crest near Maughan Ranch.

Thick paleosol sections in Ringold.

Elephant Mountain basalt crops out low on bench, often faulted, tilted, mass wasted. Vesicular flow top is often seen, indicating no loss to erosion since eruption.

Fan gravels invade the loess-paleosol unit near top of Ringold section. Same unit occurs at Saddle Mts crest 25km to the west.

At least 20 red conglomerate beds (fan gravels) rest atop 10.5 Ma Elephant Mountain basalt (base of Ringold Fm). Between each gravel bed is a soil. Low in the unit green-gray lowland soils dominate. Higher up, loess soils containing abundant cicada burrows and root casts dominate (Pliocene loess, Bk horizons). Age of red conglomerate is likely older than 5 Ma. Change in nature of soils seems to indicate lowland to upland transition as fan thickened. Fan deposition ends with cessation of tectonic pulse? Returns later, after 2nd lake section. Very little angular discordance between gravels and soils. Everything is low angle, a valley setting typical of alluvial fan.

Calcrete-fan gravel-loess complex. Sharp erosional surface where gravel truncates soil that appear to have formed in a wet swale. Minimal angular discordance between gravel and soil.

Lake bed sections are locally very sandy and interfingered with thick, crossbedded micaceous sand. Similar relationship as seen at White Bluffs, but here sand is thicker and singular. There, sands occur as many thin beds.


Thick calcrete ledge developed in loess overlies a complex mix of Ringold alluvium, gleyed paleosols, thin sand-gravel beds, and older loess - all constituents of the ancestral Crab Creek's floodplain. The bedrock here is not involved in folding of Saddle Mountains or Frenchman Hills; its essentially flatlying and has not be raised. Similar sediments and paleosols are found at several other sites in the area with calcrete. The armored surface corresponding with the top of the 2m-thick calcrete (Paradise Flats) was scoured by late Wisconsin Missoula floods. A few small wedge-shaped, sheeted clastic dikes descend from above and cut the section.

Overbank sediments and related paleosols comprise most of the section.

Upstream a short distance, Missoula flood deposits are found. Floods moving down Lind Coulee scoured the top of the calcrete ledge, ripping up and transporting clasts of calcrete.

Touchet Beds deposits mark slackwater deposition during each of 4-5 flood events. Some of the beds are deformed (flow-drag and loading structures). Deformation occurred either during south-moving overland flow or during energetic backflooding. Rhythmites contain basaltic clasts, non-basaltic clasts, rip-ups of cemented Ringold sediment and calcrete, maybe some Vantage sandstone, too.

A crossbedded gravel (basaltic) lies at the base of the exposed section (2-3m below calcrete). Gravel invades cemented, cicada-burrowed loess. Cemented burrows behave as clasts in the gravel.

Packer and Johnston (1979) sampled sediments exposed here for paleomag. They called it their "Moses Lake" site.

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