student blog post by Kelsey C.
There is truth to the old adage “you learn something new everyday.” Today was a day for learning about soil (and making a new friend!).
As my partner and I began yet another shovel test in Area F, we did not expect anything to be really different from what we had seen in other areas — basic brown soils with some possible chunky chert inclusions. Once we reached below 25 cmbs (centimeters below surface) we noticed a distinct mottling of soil colors. The shovel test terminated at 60 cmbs, and by this depth the soil was a complete gley (interestingly, if you Google search “gley” most of the sites that are listed are from England, Scotland, and Wales — is that really any surprise?).
What is gley? Gley is a soil layer that is formed by the layering out of silicates from the upper clay layer. The gley is an aneorbic environment, and a dark grey green in color. In non-technical terms: gley is a lot like cool damp Play-doh.
These different layers tell us about the moisture patterns of the soils. As in the 26-40 cmbs layer (Bt2), there is mostly clay, but as water rises and falls underground, there is a redox reaction within the soil. The iron and manganese that are in the soil are being eroded and can be seen in darker (black/dark orange) clusters. The gley is also being drawn into this layer (from below) through the rise and fall of the water. The deepest layer we encountered was a solid gley and registered a Gley Chart 1 3/1 (dark greenish gray on the Munsell Soil Chart).
This particular shovel test had the most diverse layering that we have seen thus far in our survey. To see these distinctive layers and to learn about how they formed and what the mean was really very cool!