Smartville Block

The Smartville Block, also called the Smartville Complex or Smartville Intrusive Complex, in eastern California, is a geologic zone in the foothills of the Sierra Nevada mountain range.

Geology and gold

Its eastern margin is the Rescue Lineament-Bear Mountains fault zone, and generally defines the gold-bearing veins of the Mother Lode important in California's Gold Rush history. It is named for the small town of Smartsville in the Gold Country.

The Smartville Block is thought to be a geologic terrane, a piece of crust, probably an island arc, which accreted to the North American continent in the Jurassic Period, about 165 million years ago. The collision created sufficient crustal heating to drive mineral-laden water up through numerous fissures along the contact zone. When these cooled, among the precipitating minerals was gold.

References

• Assembling California, by John McPhee, published 1993 by Farrar, Straus and Giroux, New York. ISBN 0-374-52393-2