Friday, December 2, 2011

Driftless

On my return from points east I got a nice, if not a bit of a fuzzy, view of the Driftless Area of northeast Iowa as well as adjoining states. The area was not glaciated during the last few glacial periods. The continental ice sheets instead wrapped around the area. It was, at least for a time, an island in a sea of ice along the southern margin of the ice sheets. The term driftless refers to the lack of glacial drift desposits in the area.

As such the area has not been rubbed smooth by glacial ice like other areas on all sides of the driftless area. And the soils, topography and ecology of the area is markedly different than glaciated areas that surround the driftless area. Note in the photograph the generally incised stream valleys that this older surface of land has compared to the smooth plains that begin at the bottom of the photograph.

Driftless Area, northeast Iowa

Image from University of Minnesota Extension

I enjoyed the view of this area as Will and I drove across this area in August. While driving across northern Iowa, Will took a long 1.5 hour nap and when he woke joked that I was driving in circles as we were still driving through miles of gentle plains with corn and soy. The scenery changed abruptly upon entering the driftless area. Compared to the plains that surround this area the area is rugged with steep hills. And after days on the plains very scenic. 

Another aspect of the view I enjoyed was just the week before I had written up a couple of sections on a paper I am working on that included a description of a driftless areas in southwest Washington State. The same deeply incised stream channel network and different soils. An ancient landscape compared to the glaciated and Missoula flood landscapes that cover much but not all of Washington State.

2 comments:

DaveOnFidalgo said...

I never knew this. I got my M.S. at the University of Iowa and lived in the Iowa City area during the 1970's. In SW Wisconsin is a tourist spot called "House on the Rock." It's a house on a pinnacle next to a sheer cliff. I always thought this terrain seemed out of place in the Midwest, more appropriate to Utah. Now I know why.

Doug Clark said...

Funny thing, I never visited the driftless area when I taught in Indiana. Definitely an interesting anomaly.