Oklahoma Rocks Part 1

Admittedly, I am one of those strange creatures that like both 

Texas and Oklahoma and I wish that I could spend more time in each state.  As I am not a football fan, I don't care about those rivalries (I know that makes me a heretic).  

Texas is important because that is where I lived for 14 years, I got my Master's Degree, I got married the first time there, I haven't yet seen the Spring Bluebonnet season, I haven't been able to stop and hunt for Topaz yet, and well, there is just so much more nature to see and photograph.

As for Oklahoma, my first wife was born in Ellis County, Northwest Oklahoma, and during visits with various in-laws, it was hard to "break away" to go rockhounding.  Her hometown happens to be in an area where the geology is "subtle".  Most of the area is covered with a mantle of Tertiary/Quaternary surficial deposits and there have been scattered Pleistocene mammal fossils found sporadically, usually in gravel pits.  

I hadn't been able to do the preparatory work in seeking locality information and permission to search for mammal fossils, as visits were usually for just a few days and we had to return either to El Paso or after 1990, Atlanta.  So Oklahoma was always "in-between".

My first introduction to Oklahoma Geology was during our 1973 family vacation.  My Dad had a passing interest in Geology after taking a course at Georgia Tech in the 1930s and he wanted me to do well with my chosen field.  We found and briefly visited the Oklahoma Geological Survey (Oklahoma City/Norman area) to ask about rockhounding and we were directed to an area south of Lake Thunderbird, where Barite "desert roses" could be found.  

After traveling the short distance to the locality, we found quite a few lightly- to moderately-weathered "roses", and I was quite satisfied.  The other personally-notable Oklahoma finds were connected with in-law visits.  

The first one was by accident.  We had gone from my wife's hometown to the southern part of the county to visit Lake Vincent, where her family had gone on picnics.  Just below the dam, I noticed some outcrops of red shales and mudstones (Figure 1), with a few scattered thin slabs of sandstone (Figure 2).  

Figure 1.

Figure 2.

These were part of the Permian Cloudchief Formation, (as I learned while later doing some internet follow-up study).  [Additional info is here.]  Upon examining some of the sandstone slabs, I noticed some unfamiliar trace fossils.  I took a few of the slabs by the Oklahoma Geological Survey and they said they were probably arthropod tracks (Figure 3).   [Their most-appropriate invertebrate paleontologist was out in the field and unavailable.]  

Figure 3.

At the time I labeled Figure 1, I had not yet learned that these were "Arthropleurid" tracks.  Upon further internet searches, I learned that Arthropleurids were Pennsylvanian/Permian terrestrial/semi-aquatic arthropods found in present-day North America and Europe.  At lengths of up to 6 feet, they are amongst the largest arthropods, a distinction probably due to higher atmospheric oxygen contents and the apparent lack of terrestrial predators.

On my 2015 Arizona Trip #2, I spent part of the morning of Day 3 going back to Lake Vincent one more time, as I hoped to find a slab with "paired tracks", (to be able to estimate a length extrapolated from the monster's width), but was unsuccessful in finding one.  

[Aside from getting a number of wildflower photos, my journey from I-40 to Lake Vincent wasted at least a good hour (my goal that day was Palo Duro Canyon State Park).  I was unaware of Google Maps not yet having good coverage of the rural Oklahoma countryside, and my "dead-reckoning" was faulty, with the normal E-W grid-pattern of the county roads interrupted by streams and ravines of the Red River drainage system.]

[The second notable Oklahoma specimen will be shown in the next Oklahoma post, scheduled for 11/15/2020.]