WESTWATER, UTAH: A QUATERNARY ICE-DAM LAKE ON THE COLORADO RIVER?

The existence of standing water on the Colorado River at Westwater, Utah during the Quaternary is supported by several separate bodies of evidence: (1) the presence of mudflat and delta deposits in the major tributaries to the Westwater area north of the river; (2) delta deposits along the south side of the Colorado River channel at the mouth of Westwater Canyon derived from a catchment basin from the south, and; (3) several feet of laminated silt overlying up to two feet of well sorted and unconsolidated sand resting upon Colorado River gravels at the Westwater Flatbottom.

As there is no evidence of landslide, slumping or other collapse below the Westwater Flatbottom it is suggested that the damming of the Colorado River occurred as a result of an ice-dam blocking the river channel in Westwater Canyon. The ice-dam that developed raised the level of the river approximately three hundred feet in elevation from the mouth of Westwater Canyon, stilled the water, and resulted in the deposition of numerous perched mudflats, slackwater deposits, deltas and lake bottom laminated sediments.