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

Mountain range

A mountain range is a single, large mass consisting of a succession of mountains or narrowly spaced mountain ridges, with or without peaks, closely related in position, direction, formation, and age; a component part of a mountain system or of a mountain chain...

, in the historic Gold Country

Gold Country

Gold Country is a region in the central and northeastern part of California, United States. It is famed for the mineral deposits and gold mines that attracted waves of immigrants, known as the 49ers, during the 1849 California Gold Rush.-Geography:State Route 49 was built through the Gold Country,...

 in eastern California

California

California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...

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Gold

Its eastern margin is the Rescue Lineament-Bear Mountains fault zone

Rescue Lineament-Bear Mountains fault zone

The Rescue Lineament-Bear Mountains fault zone, in eastern California, is a series of co-axial faults located in the foothills of the Sierra Nevada mountain range....

, and generally defines the gold-bearing veins range of the Mother Lode

Mother Lode

Mother lode is a principal vein or zone of veins of gold or silver ore. The term probably came from a literal translation of the Spanish veta madre, a term common in old Mexican mining...

, important in the history of the California Gold Rush

California Gold Rush

The California Gold Rush began on January 24, 1848, when gold was found by James W. Marshall at Sutter's Mill in Coloma, California. The first to hear confirmed information of the gold rush were the people in Oregon, the Sandwich Islands , and Latin America, who were the first to start flocking to...

. It is named for the small Gold Rush town of Smartsville in Yuba County

Yuba County, California

Yuba County is a county located in the U.S. state of California's Central Valley, north of Sacramento, along the Feather River. As of the 2010 census, its population was 72,155. The county seat is Marysville. Yuba County is part of the Greater Sacramento area.-History:Yuba County was one of the...

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Geology

The Smartville Block is thought to be a geologic terrane

Terrane

A terrane in geology is short-hand term for a tectonostratigraphic terrane, which is a fragment of crustal material formed on, or broken off from, one tectonic plate and accreted or "sutured" to crust lying on another plate...

, a piece of crust, probably an island arc, which accreted to the North America

North America

North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...

n continent in the Jurassic Period

Jurassic

The Jurassic is a geologic period and system that extends from about Mya to  Mya, that is, from the end of the Triassic to the beginning of the Cretaceous. The Jurassic constitutes the middle period of the Mesozoic era, also known as the age of reptiles. The start of the period is marked by...

, 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

Gold

Gold is a chemical element with the symbol Au and an atomic number of 79. Gold is a dense, soft, shiny, malleable and ductile metal. Pure gold has a bright yellow color and luster traditionally considered attractive, which it maintains without oxidizing in air or water. Chemically, gold is a...

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