Video: Density of Dikes at Willow Creek, OR
Most geologists are familiar with the Touchet Beds of the Walla Walla Valley and Pasco Basin that formed upstream of Wallula Gap in slackwater Lake Lewis. This video provides a quick look at one roadcut along Hwy 74 near Cecil, OR. Here, Touchet-equivalent deposits were laid down in a similar slackwater setting, but in Lake Condon which formed upstream of a constriction near The Dalles. Missoula flood rhythmites are exposed in roadcuts for several miles along the rural, two-lane Heppner Highway. About 15 sand-silt beds that host the dikes are exposed in the Willow Creek area. The location is 55 miles southwest (downstream) of Wallula Gap and 12 miles as-the-crow-flies from the Columbia River. The Willow Creek drainage is part of the larger Umatilla Basin. Same dikes, same deposits, same floods, different lake basin.
Check out my other videos on Clastic Dikes on my YouTube Channel: Skye Cooley.