During the flood basalt eruptions before the sediments were laid down, the Columbia River followed a different route than it does today, taking it near the present-day sites of Yakima and Goldendale. North-to-south compression of the Columbia Plateau caused anticline folds like Rattlesnake Mountain and the Horse Heaven Hills to rise. These ridges provided geographic barriers, rerouting the river eastward toward the Tri-Cities with it eventually flowing through Wallula Gap. The Ringold Formation is the sediment laid down after this course change took place. Some of the sediments found as part of the formation may have been sourced from ancestral versions of other Pacific Northwest rivers like the Clearwater and Pend Oreille. Layers of volcanic ash can also be found, with thicknesses ranging from being barely noticeable to thick.
s along the Columbia River have increased in recent years due to irrigation around Basin City and Othello. Irrigation water enters and flows through the groundwater system toward the river easily through deposits left by the Missoula Floods. This destabilizes Ringold Formation features like the White Bluffs, causing the landslides. Landslides did not occur frequently before 1960. Rapid changes in river flow caused by the Priest Rapids Dam upstream may also contribute to slope destabilization. The largest landslide in the White Bluffs portion of the formation is adjacent to Locke Island. This complex, initiated in the 1970s, has rerouted the Columbia River. As a result of the change, critical salmon spawning habitat has been destroyed. The landslide restricts the flow of the river on the east side of the river and as a result, large portions of Locke Island are being removed by the Columbia River. Movement of this landslide is ongoing, but the primary factor behind the continued movement is destabilization by the Columbia River eroding the fallen material. Blown sand from this landslide is the primary source material for sand dunes atop the bluffs near the island. The Locke Island slide is the northernmost slide along the White Bluffs. There are at least five other major slides into the Columbia River, with the southernmost one being across the river from Pacific Northwest National Laboratory in north Richland, which occurred in 2008. At least one slide has occurred in nearby coulees.
Paleontology
The sediments include fossils from the Miocene. Along the Columbia River, fossilized remains of rhinoceros and salmonoid fish. The largest diversity of remains have been found among the White Bluffs, which are an exposed portion of the uppermost part of the formation. In addition to those that were discovered along the river, there are 27 additional species. These include smaller animals such as frogs and lizards as well as larger ones like horses, mastodons, and camels. Petrified wood can be found nearby. Several unique specimens have been found in the formation. An excavation done for a basement near Badger Mountain in Richland unearthed the northwesternmost example found thus far of Aphelops. This is also the only confirmed specimen of Aphelops in Washington.
