Looking at the Walls
- Is there more tufa or rock in the wall section?
- What is the size of the stones in the wall?
- Is there more tufa or rock?
- Would the western waves hit the wall from the side or the ends?
- How did the Quartzite in the wall weather (color, shape, gaps)?
- Add a photo of you from the location or of an identifiable item (paper with trackable name). Posting a photo pulled from the internet, or photoshopped will result in instant deletion.
The Wall
The wall is what I call a short stretch of what appears to be a cemented wall. Many rocks are deposited at this outcropping and cemented together by Tufa (Calcium Carbonate) You can see more about the formation of this by the other Earthcache down by the lake.
Tufa walls, and stone is formed at locations where the waves and the concentration is high enough to allow it to form. If you think of a cave and the formation of a stalactite, every drop of water brings a few molecules of material to allow it to form. Over extended periods this allows those stalactites to form large columns or flowstones.
In lake environments like this the waves are bringing the calcium carbonate to the location in an arid location. Ideally it splashes against the rock, then falls back. Som evaporation may occur and a few molecules attach to the sides of the rocks, or between them.
Locations of Tufa
Most of the Tufa stones appear at two locations. If you look to the hill to the west you can see the Provo shoreline, and the Stansbury shorelines. Lake Bonneville held at those altitudes for many years. At the Provo one because that was the level the lake drained. Later at the Stansbury level, it reached a point of equilibrium (same amount coming in as evaporation) for many years. During those periods there are growths of Tufa at those altitudes. This allowed them to grow. In some places the tufa is 20+ feet thick (though that is rare). Most of those are either solid tufa, or use the gravel to help bond the calcium carbonate together.
However at most other levels the conditions were not right for the creation of tufa. More than just a few mm on the rocks that would have eroded off quickly. However here you find an exception.
Tufa at this outcropping
A rock outcropping exists at this point. It is the location where a vertical outcrop of quartzite. Here that outcrop would have been like a small reef. The waves from the storms splashing against the quartzite and evaporating quicker than against the side of the hill. So there are few other locations around the island that have tufa at this lake level. The reef of quarzite shattered and broke under the constant weathering, and the tufa forming in those cracks.
As the lake rose and receded over and under this level it allowed it to grow. Drop higher and the reef was gone, drop much lower and the waves were hitting the sides. So the ideal level for this wall to form was gone.