Permeability in the amphibolite is moderate. In the unsheared gneiss, soil radon concentration is moderate to low as is the indoor radon concentration. Amphibolite A small body of hornblende amphibolite flanks the mylonite zone to the northeast. Hornblende, biotite, quartz, and sodic plagioclase are the principal minerals present. Abundant titanite, zircon, and magnetite occur as accessories.
Permeability is slow in soil derived from the amphibolite.
Soil radon is low to moderate and indoor radon is low. Uranium concentration in the rocks varies between 1 to 3 ppm. Magnetite Ore Three abandoned magnetite pits are located along the northern edge of the mylonite zone. The magnetite ore is made up of magnetite and pyrrhotite interlayered with sillimanite and quartz gangue. Uranium concentration varies from 2 to 5 ppm in the magnetite ore, and radon concentrations over the ore were low to moderate.