Wednesday, November 28, 2012

A Peek Under Iowa's Topsoil


Near the fringe landscape between rolling farmland and northeast Iowa's driftless area, where the most recent glaciers missed scouring the land, there lies a variety of topography. An example is just north of Fayette, Iowa where this limestone quarry operation carves out some small hills. Notice the relatively thin soil supporting the meadow vegetation. Most of the Hawkeye state is built on sedimentary layers like these from ancient shallow ocean deposits. This is the source of many shell, coral and marine bottom creature fossils found throughout the state. Today this solidified mud and ooze from shallow seas makes great gravel (once ground to size) used for rural roads and paved road shoulders. Take a drive on Iowa roads and you'll now think about where the source material is found.