Mother lode

For the California region commonly known as the Mother Lode, see Gold Country. For other uses, see Mother lode (disambiguation).
(Left) Two water-worn gold nuggets from Tuolumne County. They are typical of larger nuggets found by the early California gold rush placer miners (each ~1.6 x 1.1 x 0.3 cm). (Right) Crystalline gold specimen from the California Mother Lode, probably from Tuolumne County (5.3 x 2.7 x 2.4 cm).

Mother lode is a principal vein or zone of gold or silver ore. The term probably derives from a literal translation of the Spanish veta madre, a phrase common in old Mexican mining. It is also used colloquially to refer to the real or imaginary origin of something valuable or in great abundance.

In the United States, the California Mother Lode is a 190-kilometre-long (120 mi), 1.5-to-6-kilometre-wide (0.93 to 3.73 mi) alignment of hard-rock gold deposits in the Sierra Nevada of California, bounded on the east by the Melones Fault Zone. The deposits formed along the suture where the Smartville Block, a Jurassic oceanic terrane, accreted onto North America; hydrothermal fluids emplaced gold-bearing quartz veins during the Early Cretaceous. Discovered in the early 1850s during the California gold rush, the zone stretches from Georgetown in the north to Mormon Bar in the south and contains hundreds of mines. The Mother Lode district produced more than 13 million troy ounces of gold through 1959, making it one of the most productive gold-producing districts in the country.

The term has entered popular culture through films, video games, and other media. In mining terminology, the "mother lode" refers to the bedrock source from which placer gold erodes into streambeds.

This article is issued from Wikipedia. The text is available under Creative Commons Attribution-Share Alike 4.0 unless otherwise noted. Additional terms may apply for the media files.