Lava Dam Remnant in Grand Canyon. Kayakers on the Colorado River in Grand Canyon rest in an eddy at the foot of Lava Falls. This rapid is one of the largest in the whole 277 miles of river in the canyon and formed when a debris flow delivered large boulders to the river channel from Prospect Canyon on the south (right). The thick black lava flows seen on the far wall above the rapid are the remnants of a former lava dam that once blocked the Colorado River, likely between about 830,000 and 400,000 years ago (Pleistocene). At least 13 different lava dams are documented as having formed across the river, some may have been as high as 2,000 feet. The lavas are part of the Uinkaret Volcanic Field, located mainly on the rim above the canyon to the north. (Photo and caption by Wayne Ranney)
Photographer: Wayne Ranney
Photo Date: circa 2010
Photo Location Accuracy: Known Location
Photo Tags: Grand Canyon, Uinkaret volcanic field, lava dam, Colorado River, geotourism, geologic hazard, Pleistocene 
