Ar-kan-saw to ar-KAN-zes: THE ROAD TO WICHITA

The annual convention of the Rocky Mountain Federation of Mineralogical Societies (April 22, 23, 24 2016) was hosted by the Wichita Gem and Mineral Society at their 62^nd Annual Show.  Thursday the 22^nd was designated as “student day” and over 600 students “field tripped” to the Show and were treated to a variety of student-orientated activities.  I was quite impressed with the sheer numbers of children attending the three-day show and their fascination with the “touch & feel,” “rock pile,” “gem wheel,” and “grab bags.”  What a tremendous way to help create future rockhounds.  I also noticed that several dealers had colorful specimens priced so that children could afford to purchase their “very own” mineral or fossil.

The route of US 50 paralleling the Arkansas River from Pueblo to the Kansas state line.

Portion of the geological map of Colorado showing route of the Arkansas River cutting through rocks of Cretaceous age.  The city of Los Animas is about the position of the A on Arkansas.

In wandering to Wichita, I wanted to stay away from the Interstate System, especially I-70 from Limon, Colorado, on east to Hays, Kansas.  It seems as though I have traveled that stretch a thousand times; therefore, I often just wander through the countryside.  On this trip I traveled south from Colorado Springs to Pueblo on I-25 on the far western reaches of the Colorado Piedmont Physiographic Province (mostly through the Pierre Shale).  At Pueblo I picked up U.S. 50 and the Arkansas River and headed east to Kansas.  The entire ride to the boundary of my home state was in the lowlands where the Arkansas River has excavated a major channel through the Cretaceous Rocks of the Colorado Piedmont.

Physiographic regions of Colorado.  Map courtesy of Colorado Geological Survey.

Topographic elevation map of area around Salida/Poncha Springs, Colorado.  At one time the upper Arkansas River flowed south into the San Luis Basin in the Rio Grande Rift Valley.  Map courtesy Colorado Geological Survey.

The Arkansas River in Colorado is an amazing and diverse river.  Heading near Leadville between the Sawatch and Mosquito ranges, the stream flows south in the Rio Grande Rift Zone, an extensional feature (spreading) extending from Mexico through west Texas, central New Mexico, into the San Luis Valley of Colorado and finally north to Leadville and beyond.  However, near Salida the River abruptly turns east cutting major canyons, such as the Royal Gorge, before emerging near Pueblo.  What happened?  As I understand the situation, the Arkansas once continued south flowing into, and through, the San Luis Valley (in the Rift Zone).  But, a major extrusive eruption of volcanic rocks, maybe 3 Ma., blocked the river south of Salida/Poncha Springs and forced the stream to flow east.  Fascinating!  

  

At the state line I continued along U.S 50 and the River in what Kansas calls the Arkansas River Lowlands where the excavation has been in the Tertiary and Cretaceous rocks of the High Plains Physiographic Province. About four miles into Kansas I was greeting by flashing red lights and first thought Wichita Gem and Mineral Society had sent a welcoming committee. Alas, it was just a friendly member of the Kansas Highway Patrol questioning my need for speed in heading to Wichita!

Physiographic regions of Kansas showing route of the Arkansas River and the resulting lowlands.  Map courtesy Kansas Geological Survey.

Route of US 50 through western Kansas following the Arkansas River.  Map courtesy of RoadTripUSA.com.

The River flows east through Garden City and Dodge City and then does a “strange” thing---it makes a large turn to the northeast, the “Great Bend” of the Arkansas River.”  This feature was noted by Europeans as early as 1541 when that Spanish treasure hunter, Francisco Vázquez de Coronado y Luján, tromped through the area.  After traveling about 70 miles to the northeast, the River does a “strange” thing and turns back to the southeast and heads 70 miles to Wichita.  There it flows south into Oklahoma and ultimately east to its final destination, the Mississippi River in southeastern Arkansas. 

The upper and middle stretches of the Arkansas River from Colorado through Kansas.  Public Domain map.

At 1469 miles, the River is the 6^th longest in the U.S. As for the “Great Bend,” I was unable to find a concrete answer as to “why.” In my graduate school days, many years ago, we speculated that some sort of feature in the basement Precambrian rocks was responsible for the Bend.  I suppose that may be as good an answer as any!
 

Geologic map of Kansas with X indicating Dodge City and W for Wichita.  US 54 cuts across the "Great Bend" of the River while the previous road, US 50 continues to flow the River northeast from Dodge City. Map courtesy of Kansas Geological Survey.

In cutting across the “Great Bend” of the River I traveled on U.S 54 across some nondescript parts of the High Plains including Quaternary loess deposits, lowlands of the Ninnescah River, sand dunes, and a few Permian redbeds before reaching the lowlands of the Arkansas at Wichita.   

What a difference a day makes, as the old crooning goes!  The following photos are a day apart (of driving) and represent the extremes of river valleys.

And finally, growing up in Kansas we knew the river as the ar-KAN-zes.  Later in life I learned the rest of the world called it the AR-kan-saw!

Royal Gorge of the Arkansas River, Colorado.  Public Domain photo courtesy B. K. Thompson.

The Arkansas River at Wichita.  Public Domain photo courtesy Spacefem.