Chareidio

Study Shows Canyon Excavation in Three Days

In the summer of 2002, heavy rains in Central Texas caused a water reservoir to overflow its spillway and flood the adjacent area for several weeks. In the process, the raging waters excavated a 2.2-kilometer-long 7-meter-deep canyon in the bedrock, a process that took just three days according to Caltech research published this week in the journal Nature Geoscience. The traditional scientific view of deep river canyons, such as the Grand Canyon, is that they developed slowly over time by the rush of water eroding rock. But this is not always the case, according to lead scientist Michael Lamb, who explains that large canyons have been cut and chiseled by catastrophic flood events, that leave few telltale signs to distinguish them from slower processes. Using aerial photographs of the region, taken before and after the flood, the team applied an empirical model of the sediment-carrying capacity of the flood- that is, the amount of soil, rocks, boulders and other debris carried by the flood to produce the canyon. The analysis revealed that the rate of canyon erosion was so rapid that it was limited only by the amount of sediment the floodwaters could carry. The gushing water was able to pluck massive boulders from the fractured bedrock, producing waterfalls, channels, terraces, sculpted walls, plunge pools and islands of sediment.
June 21, 2010