The entire Blue Heron property (and the bulk of the Nancy Creek watershed) is located in what is called the “Buttton Schist” formation. What it means is that this rock is highly metamorphosed, not from the Pangaean Orogeny, but from the effects of motion on the Brevard Fault Zone that runs right through Atlanta.
When rock is subjected to long-term stress in faults it results in unique characters that are unmistakable to the trained eye.
The primary characteristic is of the rock being metamorphosed to the schist level and the schist having a “button” or “fish-scale” texture of the micas.
We search for mica textures during Outdoor Education programs at the Preserve, and at surrounding schools. Kids love seeing the sparkle of the micas within the rock!