Acton sits in a small valley created partially by the Santa Clara River and its tributaries. The geology here is of a fairly wide variety in ages. The Sierra Pelona Mountains to the north and the San Gabriel Mountains to the south are composed mostly of Precambrian granites and schists. The lower hills surrounding the valley are mostly composed of the Oligocene Vasquez Formation and some stream terraces of Pleistocene age. Gold, copper, and titanium ore have been mined here. At the Mount Emma Mine near Parker Mountain, a large copper deposit was mined. Veins of green chrysocolla and low grade malachite can be seen near the western junction of Soledad Canyon Road and Crown Valley Road. The Red Rover and Governor Mines were first mined back in the late 1800’s and were gold mines. Currently, there is very little mining being done in the Acton area.
Rivers and Drainage
All the streams in this area drain into the Santa Clara River. None of the streams empty into the adjacent Antelope Valley but may have at one point through Soledad Pass, according to one theory. The Santa Clara River originates in Aliso Canyon near Mill Creek Summit and flows out into Soledad Canyon and onward to the Santa Clarita Valley.
Faults and Folds
Many faults and folds exist here but few pose much danger to people. The San Andreas Fault runs about 5-10 miles north of the Acton area on the north side of the Sierra Pelona Mountains. The Soledad Fault runs along Soledad Canyon giving the canyon its somewhat linear appearance. This is not from movement along the fault but from a weakening of the rock along the fault zone allowing for easier erosion of the material.
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