Transgression Regression in the Grand Canyon


One of the most difficult problems in addressing questions is overcoming preconceived notions. This is true of the biologist who considers only evolutionary mechanisms, the sedimentologist who considers only present-day rates of erosion and deposition, or the Flood geologist who adheres only to one Flood model. Far too often, the most difficult part of dealing with any data is to let it speak for itself. This problem is illustrated by the relationship between the Tapeats Sandstone (Barnhart, 2012) and the transgression/regression of the Flood. The Tapeats is a widespread, flatlying sandstone deposited on the surface of the angular Great Unconformity in Arizona, and is thus the lowermost Paleozoic stratum in the Grand Canyon sequence (Figure 1). McKee (1945) proposed that it was deposited by a transgressive sea moving inland from the southwest, with sand being brought to the marine front by rivers flowing from the northeast. This basic concept was reiterated by Hereford (1977) and Rose (2006). Berthault (2004) took a slightly different view when he suggested an erosional transgressive invasion of water from the southwest, followed by deposition by the regressing current (analogous to a wave running up the shoreline and then receding).