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Project GEO

Geotechnical Engineering
Earth Science Outreach

Dr. Nick Hudyma
The University of North Florida
Bo Smith
Terry Parker High School

Spring 2005 Term Projects

Laboratory Investigation of Ptygmatic Folding
  Last Updated: May 12th, 2005

 "The Ptygmatic Prognosticators"
Amanda Corbin (left) & Karen Thomas (right)

Ptygmatic Folding by Karen Thomas and Amanda Corbin (Ptygmatic Prognosticators)

Our project was based upon the folding of rock layers.
Our hypothesis was: If we apply pressure to our models, then new patterns will emerge and changes will occur. Each Saturday morning we would write down what we did that day in our composition book. We kept it as a journal. Also when we put the models on the machine to apply the pressure we recorded it so that we could look at it and observe the changes once more to help us with our project.
The goal was to show the patterns that occur when pressure is applied to rocks and we examined what takes place among the different layers when folding occurs. We did this by creating models out of clay and 'play doh' so that we could easily see each individual layer. We made two models. One was a model in which the layers were horizontal and the other modelsí layers were placed vertically. Each model had six layers with every other layer consisting of clay and each layer was measured 5 inches by 8 inches. The height was 2 inches.
We then placed the horizontal model on the machine, which applied the pressure we wanted (2mm per minute) to notice the changes. We watched the process that took 7 minutes. After this was done, we removed the model and cut into it to see the inside. The changes we noticed were exactly what we wanted. We saw anticlines and synclines. Also, we saw that the pressure of the clay on the 'play doh' was too much for the 'play doh' to bear and it began to ooze out the sides. If we looked closer, we could see little pieces of 'play doh' embedded in the clay.
Now we moved on to the vertical model. We did the same thing as we had done with the horizontal model, applied the same pressure, but for a longer period of time. The changes we noticed were much different than that of the horizontal model. The vertical layer continually leaned to the right throughout the whole process. After this, we removed the vertical model from the machine and cut into it. Again, there were anticlines and synclines. But this time, gaps began to form between each individual layer and the 'play doh' did not ooze out the sides.
In conclusion, our experiment proved to be successful. We noticed the anticlines and the synclines with both models and also we saw other new things in which we did not expect to see, such as the gaps in the layers and the oozing of the 'play doh'.

Image Gallery of Our Project


  Dr. Hudyma describing the procedures for our project

We are putting the clay down for our solid bottom layer

  We spread the messy goo 

   We cut up our model to make it just right

  measuring our final model before the big test.

  Dr Hudyma sets up the camera for the experiment

One last check to make sure the camera is set up just right


  Click on the image above to see a movie of of the horizontal setup


Our first attempt didn't  go as planned so we try once more..


Playing with play-doh is fun.

Is each layer just right?

Taping the horizontal layers 

Anything happen yet?

So... that's what's supposed to happen.
This is a picture of the horizontal layers after a successful experiment. As you can see, some major changes took place. The layers seem to be sliding horixontally apart. We also noticed some anitclines and semiclines in the middle of our whole model. 
This is a picture of our horizontal model before we cut it in half. As you can see, the play doh is oozing out of the sides. This is because the clay is harder and more firm than the play doh so the play doh could not take the pressure and oozed out. 

And now the vertical layers. No changes yet but click on the image to see a movie of the vertical setup...

Look at the model leaning towards the right. Also, gaps are beginning to form between the layers. 

This is after we applied the pressure. The whole model is leaning towards the right and gaps have formed between individual layers.
This is our vertical layer after we cut into it. You can see the anticlines and semiclines formed due to the hardness of the clay and the softness of the play doh. 


Now we must put our videos onto a disk. 

hmmm what does this button do??

That's All Folks!!

All this work makes Karen hungry! 

Karen's pimpin in her cool goggles and munchin on some rock layers.