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Saturday, April 5, 2014

The Wilcox Formation - Boulders & Red River levee along Clyde Fant Parkway, Shreveport, LA


 The other day there was an article in the paper (Shreveport Times Friday March 28, 2014 'History lives here, just under our feet' by John Andrew Prime about the Veterans park along Clyde Fant Parkway in Shreveport Louisiana.   I read it with interest because not too long ago I had said to my husband I really wanted to get out and look at some of those rocks that can be seen from the parkway.  When I first moved to the city that area had more water around it and was difficult to get to and look at the rocks. But I did it anyway and from what I could tell they were mostly sandstones (at the time to me boring and I didn't think much about them or spend too much time looking at them.).  Then over the years, especially the last five years, we've had some droughts going on and the area stopped being so inundated with water and easier to get to since the water level had dropped so much.  A lot more of the rocks were now exposed and were interesting to  pass by.  For years I kept on passing by thinking I really must go look at those rocks again.  They don't look as boring as I first thought they were.  For one thing you could tell some of them were  well rounded rocks and I wondered  whether they could possibly be concretions ( since they did look like some I've seen before in textbooks?
    The article was written by a Historian and the main part of the article was about how the area used to have a lignite seem running through it as seen in on a  1836 map and the early settlers had mined it to fuel there homes.  The seam had been stopped being mined a long time ago but recently as they were developing the area to build homes they came across remanents of the seam and the article had a picture of a piece that was obtain from that excavation.  After reading that article some of it then made sense to me because when I first moved to the area a city dump was there and I used to have to drive by it every day to go to work.  It was obvious they had made a big hole there and they were just filling it back up (which I thought was really dumb since it was so close to the river).  It also help make me realize why the area had gone undeveloped for so long.  I used to think it was because an oil refinery used to be in the area and people were concerned about the possible pollution but the article didn't go into that at all.  It did make sense to build an refinery in that location it does not make sense now to turn it into a housing project. How easily people forget things.
     One of the things the city did do that seemed to make sense to me was they turned it into a city park/ recreation area.  I do feel like that is good utilization of the land.  I also figured with the Red River being there it should not be developed for a select few but should be for the enjoyment of all, especially since its prone to flooding.
    In the article he mentions an article that was mentioned in 1920 about there being the coal seam and caves under the city and also some natural springs.  That made sense to me since one of the street names is Spring street and its obvious there had to be a spring near it for it to have that name.  I also found out that the lake that was in the area was Silver lake.  We had always called it the Railroad lake since the railroad yard is on the other side of it.  I always thought that the lake was the result of the big log jam that had occurred in area and was how the city got formed where it was when Captain Shreve was able to break up the long jam back in the 1830's.(here's the section on Shreveport as found in Wikipedia,_Louisiana   )  The article didn't go into that much but did mentioned that the spring are now under the city in pipes.

   Then the article go really interesting to me because he starts to talk about the rock formations that can be seen along the parkway.  I thought he would get it right since the picture that headed the article "History lives here, just under our feet' by John Andrew Prime had this to say about the boulders:  "These boulders alongside Clyde Fant Memorial Parkway in Shreveport are part of the Wilcox Formation of sandstone, dated from the Paleocene geologic epoch, which lasted from about 66 million to 56 million years ago.  The pond likely was formed by the shifting Red River."  From my years of working in the oil field industry I knew this was correct and he had done his research.
But later in the article he writes (and I choked on it)  "people driving just north of the railroad bridge near Veterans Park can see rock formations that most think are decorative and were brought  there for landscaping.   Think again. Glaciers moved those stones here ages ago. The exposed rock is part of an upward thrusting of sandstone known as the Wilcox Formation.  Dating from the Paleocene geologic epoch that lasted from about 66 million to 56 million years ago, it holds peats from the ancient delta plain that became dehydrated and carbonized over time and turned into the Lignite that Loschen saw and that warmed Shreveporters more than 150 years ago.'  
     I couldn't believe he had put in that Glaciers had moved those rocks there.  Where on earth did he ever get that silly notion?  To me it was so obvious that the rocks had broken off from the Wilcox Formation that still outcrops in the area.  I figured the river had been there at one point and undermined the formation with those big pieces falling into the river and then rounded them off.  Then as the river shifted they were left along the banks of the river.

     After reading that article I was more determined than ever to go look at those rocks and figure out what was going on here.  I could agree with some of the stuff of it being Wilcox in age and that the Wilcox formed in a deltaic setting.  But Glaciers? - I'm like urgh??? Come on lets get real.  Glaciers have never been reported this far south - where's the evidence to support glaciers?  How can I've missed that for all of these years?
    I grew up in a glaciated area and there is always telltale signs of them having been there like the scouring of rock formation faces.  Also the rounded more resistant rocks the sizes of boulders, and cobbles.  Not to mention the diversity of the rocks that are present since they come from such distant places.   I've lived in this area for a long time and haven't come across any of these type of things?
       So now I'm really curious how he could be saying glaciers? What was his bases for it - except big round rocks and maybe someone else's research? 
       There was no doubt about it I just had to go and look.

       The next day was Saturday and it was an absolutely gorgeous day with nothing on the calendar.  My husband and I thought it would be a perfect day to go for a walk.  We also decided to take the puppies with us.  At first we thought about the Rose Gardens since we used to like taking our other dogs walking there.  So we drove to it only to find it closed for the weekends.  We still wanted to go for a walk with the dogs and decided maybe today would be a good day to walk in Veterans park.  It had rained heavily the night before and had ruled it out previously thinking it may be too wet but decided if we stayed on the paths we'd be okay.  Once we got there we decided it really wasn't that bad after all.

So now here's some of the images I took with my cellphone as we were walking.  I did wished I had brought my camera but wasn't expecting to take pictures.   I figured these are better than nothing.

 The first thing I noticed as I was walking along the path was the cliff (and I use the word loosely) was looking like.  I notice how steep it was.  Immediately I thought I've seen this before                      (  ).  It's loess deposits. (  )

 Okay that's probably where someone got the glacial idea.  They read that loess are glacial deposits. What they failed to realize - its the result of being blown by the wind.  The glaciers don't transport it but the wind does.  The boulders are just to big to be wind transported.  Also if you have loess that is usually a good indication the glaciers didn't get that far south.    I felt that solved one thing.

    Here was the first boulder that I was able to walk up to and examine. It was very typical of what I remembered seeing before. The one thing I noticed was it was very sand in appearance - it looked friable.  You could see the layering in it.  Also you see some red with it too.  All of this is consistent with what a rock deposited in a deltaic environment would look like.  Since its been so rounded I can only assumed it had been weathered out of the Wilcox formation and that the Red river is what had done the rounding of it.
    To me I'd say how it got there it's simply GRAVITY, or better yet a landslide.  Then once it was in the water the water rounded the edges off. Its easier for me to believe something that's more basic as that than glaciation which means the boulder had to be transported a long way to get there.  Also if you look at how friable it is I just couldn't image it lasting long in a glacier.
 Here was another piece that almost looked like a log.  Reminded me a lot of the petrified forest.  but the rock was not very silicious  and so it wouldn't be considered  petrified wood.
 Here's another boulder that I saw.  It looked like there was some limestone with this one.
 Then I came across this one that was really fascinating to look at.  The next three images are of the same rock. 

 And here's it with a penny on it for scale. 
  More boulders that were closer to the cliffs and looked more like they had eroded down.
 We got to the area that used to be in water and thus the reason why I felt it was the river that rounded them.
 I did think they were interesting to see and you could see the layering that was around them.  The more I looked at them the more I thought of concretions.
 This one you could see where the water level had been and how it had been resting on sand that was later eroded away but because the more resistant rock was above it -it was kept from being eroded away too.
 The one thing that I did noticed was how these boulders all seemed to be lined up.  That's what helped me to believe that at one point this was the edge of the river and they had fallen down into the river and just stayed there.
 Here you can see them actually being in Silver Lake.  This is more how it was when I first saw them in this area.  To look at them you had to go through water. 
 This is an good example of how much the lake has decreased in size.
 This is looking back toward the cliff area and the one thing that was notable was how much more angular these boulders appeared to be, further leading me to believe that most of them were in-suto and had not been transported very far.
 Some more interesting ones.

 This was taken so you could get a sense of scale as to how big they are.

 Here was one that was more rounded than some of the others.  When I looked at it - it seemed to have more limestone in it.
 Here's another picture of it with another one that was more of a sandstone. Also you can get a feel for where the lake used to be. This is looking south. 
 While this was looking north.  You can see how the boulders seem to be in a line.
 Here's another view so you can get a sense of how it was when there was a lake in the area and this would have been its bottom.
 Walking back we did come across this section were they were doing some excavation.  I was wondering if this is where  the piece of lignite came from.

 Another picture of the lake that was there.  I don't know if this is offically Silver lake or the other pond is.
 As you can tell it was such a pretty day and I was glad we could get out and walk around and enjoy it.
    This is a picture looking east towards the Red River and the Veterans park area.  If you look closely you can see why its called Veterans park.
 Here it is blown up.  What you see is the eagle dedicated to the veterans.  Also you see some wooded structures.  During the Civil war the Confederates built structures like these and then they also had logs painted black.  So when the Union spies were looking at Shreveport they thought it was a well fortified city and there never was a battle here.
 Here is another image of the cliffs where it looks like loess deposits to me.
  I just thought this was s pretty tree, but the puppy was pulling on the leash as I took it and it didn't turn out as I thought it would.  The building in the background that is on top of the cliffs is the VA Hospital.
 Here you can see the levee and how high it is and the cliff with the VA hospital on top.
 The reason we were walking.
 The one thing about these puppies they don't like to be apart and it amazes me how they can walk so close to each other.
 I thought this was a good picture where you could see the levee  (  ). And the one thing I cringe about is how they cut it down to put that path through it to get to the park on the other side.  Don't they know that levee is there for a reason?  To prevent the Red River from flooding the city.
 Another view so you can see the levee cut and the bridge on top.
 We didn't take the path down but decided to walk along the top of the levee.
 And you can see how there are pools of water that had accumulated from the rain we had the night before. 
 We needed to go home so I didn't get to take some pictures that I wanted to about the rocks that outcrop just around the corner on Stoner Avenue.
    They are near the VA Hospital and its a no trespassing area. So I just had to walk along the fence line on the sidewalk and hoped to get some good shots of The Wilcox formation.

 Here you can see this resistant ledge in the Wilcox and how it's probably the source rock for the boulders and how I feel like they just eroded down and were not transported by glaciers.


While I was walking I did pick up two pieces that had come off of one of the boulders.  When I got home I was able to look at them more closely.  The one piece was calcite.

And the other was more massive and I could tell that it had limestone and also a red outer layer that suggested to me that part of the time it was in an areal environment.

What struck me the most was how you could see the rounding associated with these rocks.  Got me curious as to what would cause it.  The more I looked at them I did feel more confident in thinking that these may truly be some concretions.  Now I wished I knew more about concretions since I've never studied them much before.

This is some of the information I've gathered on the Wilcox.
***The rocks are of the Wilcox formation and here's a link to an image showing were they outcrop:

The Wilcox is late Paleocene to Eocene in age.  I know this is about it in Texas but in the North East corner it continues into Louisiana.  Caddo parish boarders Texas and the city of Shreveport is only 25 miles away from Texas.

There is  set of diagrams for the deposition of the Wilcox that comes to you when you do an image search.  I should note this is for the Wilcox aquifer.   Here's the image search..;_ylt=A0LEV0u7L2lTll4ADtRXNyoA;_ylc=X1MDMjc2NjY3OQRfcgMyBGJjawM0YTNmYTFkOWxhb3ExJTI2YiUzRDQlMjZkJTNEdS4wTTBVcHBZRUl2T21nU05jQ1pNdHppd0c2amc1eTVNSGFJbXctLSUyNnMlM0RyZCUyNmklM0R3Q1VrQmxDMHg3NXlYeEcuZWFSawRmcgNtb3ozNQRncHJpZAN2bXMuWG1nVFNibU5ORndIdXg5d2JBBG10ZXN0aWQDTE9ORyUzRERGRDYEbl9yc2x0AzEwBG5fc3VnZwMxMARvcmlnaW4Dc2VhcmNoLnlhaG9vLmNvbQRwb3MDMARwcXN0cgMEcHFzdHJsAwRxc3RybAMxNwRxdWVyeQN3aWxjb3ggZm9ybWF0aW9uIAR0X3N0bXADMTM5OTQwOTk5NTQ5MQR2dGVzdGlkA0RGRDY-?gprid=vms.XmgTSbmNNFwHux9wbA&pvid=ohNFkjk4LjFFDeoLU1VjQQtbNTAuMVNpL7v_pIZY&p=wilcox+formation+&fr2=sb-top&fr=moz35
 When I click on the one I can read it but it wont let me create a link to it without paying for it. It's with World Oil  and look for this caption under it:

fig 1 paleogeographic map of drawdown climax with residual gulf of ...

500 x

If you click on this image it may take you to the article that is really good about the Wilcox formation and the depositional model for it.  It's too complicated to explain here but if you're into geology its worth looking at. 

I still want to do more research on  the Wilcox and concretions and if I do I may add to this post at a later date.

I'm getting interest in this post.  The one thing I would like to add is that I did take a graduate level course on Glacial Geology at Ohio U. under Goeffery Smith.  And the one thing about Dr Smith if you got a passing grade from him you really had to know your stuff. I do feel like I am qualified in recognizing glacial features when I do see them.