 Picture taken from location slightly above the location of Fort Nez Percés as seen in 2006, looking to the south toward the Walulla Gap.  Looking to the North from about the midway point within the Walulla Gap.  Looking from the Northern end toward the South within the Walulla Gap.  Looking to the West across the Walulla Gap.
 The Sisters: a scabland residual of the Missoula Floods on the east bank of the Columbia River in the Wallula Gap. Wallula Gap is a large water gap through basalt anticlines in the Columbia River basin just south of the confluence of the Walla Walla River and the Columbia River. Image File history File links Download high-resolution version (1339x1786, 716 KB) Wallula Gap, Washington state, USA. The Sisters: a scab residual of the Missoula Floods on the east bank of the Columbia Rivenr in the Wallula Gap. ...
Image File history File links Download high-resolution version (1339x1786, 716 KB) Wallula Gap, Washington state, USA. The Sisters: a scab residual of the Missoula Floods on the east bank of the Columbia Rivenr in the Wallula Gap. ...
Water gap is a term geologists use to describe a notch which flowing water has carved into a mountain. ...
Anticline with syncline visible at far right- USGS In structural geology, an anticline is a Fold (geology) that is convex to the youngest beds—youngest sediments are on back of hand, older under the palm. ...
Columbia River Gorge, Washington or North side The Columbia River (French: fleuve Columbia) is a river situated in British Columbia and the Pacific Northwest of the United States. ...
The Walla Walla River is a tributary of the Columbia River located in northeastern Oregon and southeastern Washington in the United States. ...
The Wallula Gap was formed by the historic flow of the Salmon-Snake and Columbia Rivers combined with the glacial waters that poured across the Channeled Scablands during the Missoula Floods. The Wallula Gap constrained the flow such that less than 1/5th of the 800 km³ of water per day entering could be discharged. As a result, the floods filled the Pasco Basin and formed, for a short period, Lake Lewis. The large volumes of flood water passing through the gap contributed substantially to the errosion of the gap, as is evidenced by the shear walls and by scab-features such as "The Sisters" (photo below).[1] (Coordinates: 46°00′00″N, 118°56′00″W) DrumHeller Channels The Channeled Scablands are unique geological erosion features in the U.S. state of Washington. ...
Geology
Flood basalts In southeastern Washington, eastern Oregon, and southern Idaho, flood basalt flows of extremely fluid basaltic lava spread in all directions from long fissures, building broad fields of gently sloping lava that spread widely over great distances. Along the Snake River in Idaho, and the Columbia River in Washington and Oregon, these lava flows have been extensively exposed by errosion (with extensive displays of columnar basalt) and measure almost 2 km in total thickness.[2] A flood basalt is a giant volcanic eruption that coats large stretches of land with basalt lava. ...
Basalt Columnar basalt at Sheepeater Cliff in Yellowstone Basalt (IPA: ) is a common gray to black volcanic rock. ...
Basalt Columnar basalt at Sheepeater Cliff in Yellowstone Basalt (IPA: ) is a common gray to black volcanic rock. ...
The basalts flows which are visible in the Wallula Gap were laid down during the Miocene Era, about 17 million years ago. They are part of the massive fissure flood basalts of the Columbia River Basalt Group. During the basalt eruptions, the southern & western Columbia Plateau, which included the current locaiton of the Wallula Gap, began to fold along the . The bending (Geological shear) of the ancient lava flows is clearly visible in the folded layers of basalt exposed in the steep walls of the gap.[3][4] The Miocene Epoch is a period of time that extends from about 24-5 million years before the present. ...
The Columbia River Basalt Group encompasses portions of 3 states. ...
The Washington towns of Spokane, Vantage, Yakima and Pasco, and the Oregon town of Pendleton, lie on the Columbia River Plateau. ...
Study of geological shear is related to the study of structural geology, rock microstructure or rock texture and fault mechanics. ...
Creation of the Wallula Gap Early in the history of folding, the ridge crest at Wallula Gap must have been the lowest along the ridge. The ancient Salmon-Clearwater River began to flow across the ridge over this low point, cutting a channel. As the ridge continued to fold upward, erosion cut through and the water gap was formed. Until about 10 million years ago, the Salmon-Clearwater River flowed through the Wallula Gap alone. As the flood plane in the Columbia Basin continued to tilt, the Columbia River was forced eastward and joined the Salmon-Clearwater River about 6 million years ago. About 2.5 million years ago, the Snake River was forced northward by the Blue Mountain uplift and was captured by the Salmon-Clearwater River near the Idaho-Oregon border.[3][4] Blue Mountain may refer to the communities: Blue Mountain, Alabama Blue Mountain, Arkansas Blue Mountain, Mississippi or to the geographical features: Blue Mountain Peak in the Blue Mountains of Jamaica. ...
Missoula Floods During the Missoula Floods water backed up in the Pasco Basin because of the narrow opening of the Wallula Gap. The floods were so large in volume that they could not rapidly discharge through the gap, even though it is 2 km (1 mile) wide. Maximum flood waters reached elevations of about 380 meters. The hydraulic head required to drive the flood waters through the gap, combined with the elevated levels downstream of the constriction resulted in a head of about 250 meters. The peak flow is estimated to have been about 10 million cubic meters per second. Glacial Lake Columbia (west) and Glacial Lake Missoula (east) are shown south of Cordilleran Ice Sheet. ...
It has been suggested that Hydraulic head (hydrology) and Head (hydraulic) be merged into this article or section. ...
History
Lewis & Clark Lewis and Clark first saw the Wallula Gap on October 18, 1805, as they headed downstream from their camp on the confluence of the Columbia & Snake rivers. The Corps camped near Spring Gulch Creek on the night of October 18, 1805 and proceeded through Wallula Gap the next day.[5]
External links
References - ^ Wallula Gap - National Natural Landmark
- ^ USGS Material on shield-volcano eruptions
- ^ a b Channeled Scabland of Eastern Washington:The Geologic Story of the Spokane Flood; U.S. Government Printing Office; 1982.
- ^ a b Carson, Robert J. and Pogue, Kevin R. (1996). Flood Basalts and Glacier Floods:Roadside Geology of Parts of Walla Walla, Franklin, and Columibia Counties, Washington. Washington State Department of Natural Resources (Washington Division of Geology and Earth Resources Information Circular 90). ISBN none.
- ^ Moulton, Gary E. (1991). The Journals of the Lewis & Clark Expedition: March 23—June 9, 1806. University of Nebraska Press, Lincoln, Nebraska. ISBN 0-8032-2898-8.
| Glacial Lake Missoula | Missoula Floods | Channeled scablands | Grand Coulee | Dry Falls | Drumheller Channels | Columbia River Plateau | Wallula Gap | Touchet Formation | Lake Lewis | Columbia River Gorge | Columbia River Basalt Group | Palouse Falls | Sims Corner Eskers and Kames | Moses Coulee | Withrow Moraine Image File history File links Download high-resolution version (1339x1786, 716 KB) Wallula Gap, Washington state, USA. The Sisters: a scab residual of the Missoula Floods on the east bank of the Columbia Rivenr in the Wallula Gap. ...
The Pacific Northwest from space This page is about the region that includes parts of Canada and the US. For the US only region, see Northwestern United States The Pacific Northwest (abbreviated PNW, or PacNW) or Cascadia is a region in the northwest of North America. ...
Glacial Lake Missoula was a prehistoric proglacial lake in western Montana that existed periodically at the end of the last ice age between 15,000 and 13,000 years ago. ...
Glacial Lake Columbia (west) and Glacial Lake Missoula (east) are shown south of Cordilleran Ice Sheet. ...
DrumHeller Channels The Channeled Scablands are unique geological erosion features in the U.S. state of Washington. ...
The Grand Coulee The Grand Coulee is an ancient river bed in the U.S. state of Washington. ...
In Central Washington at the opposite side of the Grand Coulee from the Columbia River resides a three and a half mile crescent shaped precipice known as Dry Falls. ...
Drumheller Channels Drumheller Channels National Natural Landmark showcases the Drumheller Channels, which are the most significant example in the Columbia Plateau of basalt butte-and-basin channeled scablands. ...
The Washington towns of Spokane, Vantage, Yakima and Pasco, and the Oregon town of Pendleton, lie on the Columbia River Plateau. ...
Touchet beds in the Little Grand Canyon near Lowden in the Walla Walla valley. ...
// Lake Lewis formed as a result of the restricted flow of waters[1] from cataclysmic floods from Glacial Lake Missoula, pluvial Lake Bonneville, and perhaps from subglacial outbursts through the constriction of the Wallula Gap in the Horse Heaven Hills (southern Washington state). ...
The Columbia River Gorge is a spectacular canyon of the Columbia River in the Pacific Northwest of the United States. ...
The Columbia River Basalt Group encompasses portions of 3 states. ...
Palouse Falls on the Palouse River. ...
A Glacial erratic called Yeager Rock, Waterville Plateau, Washington, USA The Sims Corner Eskers and Kames National Natural Landmark includes excellent examples of Pleistocene ice stagnation landforms including numerous Glacial erratics terminal moraines, eskers and kames. ...
Three Devils grade in Moses Coulee, Washington. ...
The Withrow Moraine erratic on glacial till at the terminus of the Okanogan lobe. ...
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