Sedimentary Facies of Scabland Deposits

Touchet Beds - Burlingame Canyon near Lowden, WA. Sand-silt 'slackwater' beds with minor gravel at the base of some. O.P. Jenkins photo.

Touchet Beds - Willow Creek Valley at Cecil, OR.

Touchet Beds lie atop Bonneville Flood gravel at Lewiston, ID.

Touchet Beds - Sand-gravel bottoms and silt-sand slackwater tops. Abundant angular clasts in larger size fractions remobilized from local hillslopes (reworked colluvium). Latah Creek at Qualchan Golf Course west of Spokane, WA.

Energetic boulder gravel with many angular clasts capped by lower-energy sand-silt beds. Starbuck, WA.

Laminated sands variant. Latah Creek at Qualchan Golf Course/High Drive, west Spokane, WA.

Laminated sands variant. Smith Coulee near Eltopia, WA.

Laminated sands with and without a silty matrix. Smith Coulee near Eltopia, WA

Laminated sands variant. Rock Creek west of Sundale, WA (tributary to Columbia River).

Reworked colluvium with a sheeted clastic dike. Columbia Gorge downstream of Wallula Gap at Alder Ridge, WA.

Lake-flood rhythmites variant. Upper Columbia River shoreline bluff across from Grand Coulee Dam (Lake Roosevelt at Spring Canyon).

Lake-flood rhythmites variant. Flood sands punctuate lakebed deposition. Landslide scarp exposure in Sanpoil River Valley, WA.

Lake-flood rhythmites variant. Repeated, energetic subaqueous flows with flow-deformed beds on the meter scale. Lake Roosevelt at Wilmont Creek, WA.

Ancient flood gravels variant with calcrete rip-ups and exotic clasts (non-basaltic). Pre-late Wisconsin age deposit exposed at White Bluffs Overlook, WA.

Ancient flood gravel grading upward to silt-pebble diamict (upper portion of flood deposit). Railcut at Marengo, WA.

Touchet Bed-like rhythmites with lower portions composed of angular, locally-derived basalt (reworked talus/hillslope colluvium) and upper portions composed of silt-sand. Alder Ridge, WA off Hwy 14.

Angular basaltic clasts (reworked colluvium) and more rounded non-basaltic clasts embedded in repeated beds with sandy and silty matrixes, where grainsize reflects waxing and waning flood energy. Deposits like these are common in side canyons of the Columbia Gorge both above Grand Coulee and below Wallula. Jump Canyon, WA.

Coarse flood sands contain angular chunks of basalt and Miocene interbeds, swept up from nearby outcrops in Blalock Canyon, a tributary to the Columbia Gorge.

Lake-flood rhythmites variant of Glacial Lake Columbia. Exposures numerous in shoreline bluffs of Lake Roosevelt and Sanpoil River.

Lake-flood rhythmites variant - Repetitively-deformed lakebeds along the Sanpoil River. Pulses of flood sand load and remobilize the soupy, sticky, clayey lake beds, creating spectacular dike-sill structures (t-shaped mud squirts) and roll-ups. Cross cutting relationships show the deformation is entirely related to forces imparted by floods entering from the Columbia.

Touchet Beds variant - Rhythmites with laminar sand bases and light colored silt caps that appear to be inter-flood alluvium. Columbia Gorge at Old Lady Canyon, WA.

A stack of thin, sandy Touchet Beds are locally oxidized, bioturbated, and weekly cemented. Location is near the northern margin of Lake Lewis. Canal cuts south of Quincy, WA in Quincy Basin.