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Geologic Trip, The Mother
Lode Columbia State Historic
Park Placer deposits of gold
were discovered at Columbia in 1850, and Columbia rapidly became one of the most famous placer mining towns along the entire
Mother Lode. The central part of the town became a State Park in
1945. Many historic buildings in the town have been restored, and provide
good insight into life in an 1850’s mining town. The city lies in a flat
valley underlain by a bed of marble that lies within the Calaveras Complex.
During the long Eocene erosion period, the marble had weathered to form a
highly irregular karst surface that
was pitted by numerous
deep potholes and cavities. At the time of the gold rush, this irregular
limestone surface was covered by about ten feet of rich gold-bearing gravel.
The gold was concentrated in the potholes and cavities in the marble. The
town was built on this gold-bearing gravel, and the buildings and streets of
the town were continually under siege by ambitious miners. You can see the
results of their efforts to get at the gold-bearing gravel at many places in
and around the town, such as at the miner’s cabin and the Donnell and Parsons
Building site. Exterior Websites California State Parks: _____ |