Click here to go to the UNF website
Project GEO

Geotechnical Engineering
Earth Science Outreach

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

Spring 2004 Term Projects

The Formation of Clay Smears
Last Updated: May 15th, 2004
Hola neighborinos! We're April and Kiara, and the project we're doing here at UNF is on clay smears. We know, we know... "clay smears"... sounds pretty boring, right?  But really, clay smears affect many important things, such as the way we drill oil and retrieve groundwater.  Clay in soil provides a barrier for liquids to get through, and sometimes this clay even makes little compartments where oil or water can be trapped.  Our job in these experiments is to see how the hardness of clay effects fluid flow, and to observe the smear that is created when pressure on the clay is applied to only one side.  If you want to see some of our results, scroll down to the pictures of our first (and softest) clay specimen.

Any questions? Please email Dr. Hudyma or Mr. Smith .

                                                                      These are the 'Clay Smears' girls
April Urroz on the left and Kiara Toti on the right

Image Gallery of Our Project

Saturday, March 27th


Dr. Hudyma tells us that the clay specimens we're making have two 10 mm layers of clay, and the rest we fill up with blue sand.

April, "The Best Clay Cutter in The World", is cutting a layer of clay to use as a base for our specimen.

Kiara is adding water to the sand so that it will be more compact.

April is tapping the side of our specimen to get the air bubbles out of the wet sand.

We have added the second clay layer, and are now pouring in the final amount of sand.

TA-DA!!! Our creature is complete MWAHAHAHA...

The next step is to place the specimen in a special machine (which puts pressure on one side of the specimen to shear it), but before we do this, we have to screw the specimen in a metal container.

Here we are, still screwing the final bolts down, into a contraption that costs about $1000!
Oops!  We put the specimen in the wrong way.. uhhh..heh heh.. But luckily, it's Dr. Hudyma to the RESCUE!!!!! 
(da na na na na na na na  HUDYMA!)

We're now putting the specimen in the shearing machine, which will apply pressure at a speed of 2 mm per minute.

Still waiting....
The clay has now been sheared, and the line forming down the break of the clay is called the fault zone.
We took the clay specimen out of it's container, and now we're disecting the sand to see if the clay smear is continous all the way through. 
It turns out that with the softest clay, the clay smear is a continous thin line that doesn't crack, and goes all the way down.

Two Saturdays in  April

This is the 2nd clay specimen, which we had already made beforehand the previous week. We had to wait until two weeks later, though, to test it in the shearing machine, because the equipment had to be altered first. 

While we were waiting for the second specimen to be sheared, we made our third specimen (made with the hardest clay).

This was the result of our second clay specimen after shearing.  The smear is continuous like the first, yet the thickness varies throughout.

This was the reult of our third clay specimen.  This time, the clay smear is flaky and not all the way contiuous.  Like the second specimen, it also has varrying thicknesses and has a sort of step-ladder pattern to the smear.

This is the container which had to be altered in order to finish our experiment; the mechanism would not allow the clay to be sheared without the clear box crushing (the one that held in the clay).

To the left is the second specimen, with just the sand disected away from the clay.  To the right of that is the third spcimen.  As you can see, the third specimen has broken in a few places. 

Here is a better view of the smear itself... and an even better view of Kiara'a hand nyuk nyuk nyuk...