Mineralogy
The California Ranges had a high production of mercury following the discovery of gold in the Sierra Nevada. In the Cache Creek Basin, Cenozoic cinnabar deposits near Clear Lake are the northernmost of a group of similar deposits associated with volcanism and migration of a transform fault system. During 1877, these deposits hit their peak production of mercury, producing approximately 2,776 metric tons. These abandoned mines are still a source of mine waste runoff in Cache Creek and other downstream bodies of water.
Read more about this topic: California Coast Ranges