The Floods of 1993 and 2008 reveal the immense power of water. These floods carried a fraction of this power compared to the water that shaped our world in glacial times. The layers and weight of ice, the outflow of glacial meltwater, and the erosive rains that interspersed the time periods must have been incredible. Today's evidence includes the river valleys with their "underfit" streams, bluffs along rivers, bedrock with glacial grooves running east and west, fossils embedded in the limestone layers below the spillway at Coralville, and the highly eroded bank further down the Devonian Gorge.
The theory of the jostling of the plates as South America shoved into North America is evident with the bending of the rock layers. A prominent fracture running NE to SW across the Gorge demonstrates how water flows and the karst development of the dolomite.
Questions: Looking at the pools teeming with life, can this be an example of how mudstone formed and the fine layerings of sediments? (Provided that no other flooding or water release were to happen, which is unlikely.) Where did the peat come from? How thick was the loess soil that rested on top of the rock and peat?
Directions: From I-80 take exit 244, take Dubuque Street north 3 miles to West Overlook Road turn east and proceed 1/4 mile to the park entrance. Follow the signs once in the park to the desired area.
No comments:
Post a Comment