Geo-pic of the week: Ozark Plateaus

If you live in Arkansas, chances are you’ve heard of the Ozark Mountains.  Actually, the correct geologic term is Ozark Plateaus.  Unlike typical mountains in which the bedrock has been squashed and folded, the Ozarks are one broad dome-like structure made up of flat-lying sedimentary bedrock.  The hills and valleys of the Ozark topography are the result of rivers carving into this dome, rather than compression or deformation.  

The picture above was taken overlooking the Buffalo River.  The various hills, from the foreground to the distance, are roughly the same height.  Of course they are!  If not for this and other rivers, the landscape pictured here would be one solid flat surface, as tall as the highest peaks in the picture, stretching to the horizon.  

Early map of Bathhouse Row, Hot Springs, Arkansas

(Click map to see large high-resolution version)

(Click picture to see large high-resolution version)

 

At top is a scan of a hand-drawn map of downtown Hot Springs Arkansas ca. 1859.  It was drawn By Dr. David Dale Owen, the first State Geologist of Arkansas.   It shows Bathhouse Row, the area renowned for its hot mineral-water springs (a photo of the area depicted on the left side of the map is included for comparison).  Bathhouse Row remains a popular attraction today, though a lot has changed since 1859. 

Hot Spring Creek, which displays across the bottom of the map north to south (note that north is to the left here), now flows underneath Central Avenue in downtown Hot Springs.  Central Avenue is the street at the bottom of the photograph (see photo).  In 1860, there was no Central Avenue and people crossed Hot Spring Creek on wooden bridges (see map).  The bluff east of the creek from which the hot springs flow is now Hot Springs National Park.

This map was included in the second of two geological reconnaissance reports published by Dr. David Dale Owen concerning Arkansas geology.  During the field work for that publication in 1859, Dr. Owen, only fifty three years old, contracted malaria.  He died a short time later.  In the introduction to the final volume of that publication, Dr. Owen’s brother writes that David was dictating the report, from bed, until 3 days before his death.