Mother lode

Mother lode
For the band, see Motherlode (band). For the 1982 film, see Mother Lode (film). For the album by Sara Hickman, see Motherlode (album).
Crystalline gold specimen from the California Mother Lode, probably from Tuolumne County. Size: 5.3 x 2.7 x 2.4 cm.
Two typical water-worn gold nuggets from Tuolumne County, California. These would have been typical of the larger nuggets recovered by the early miners in the Mother Lode. Larger nugget is 1.6 x 1.1 x 0.3 cm.

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. Veta madre, for instance, is the name given to an 11-kilometre-long (6.8 mi) silver vein discovered in 1548 in Guanajuato, New Spain (modern-day Mexico).[1]

In the United States, Mother Lode is most famously the name given to the long alignment of hard-rock gold deposits stretching northwest to southeast in the Sierra Nevada of California. The California Mother Lode is a zone from 1.5 to 6 kilometres (0.93 to 3.7 mi) wide and 190 kilometres (120 mi) long, extending from Georgetown in El Dorado County on the north, through Amador, Calaveras, and Tuolumne counties, south to Mormon Bar in Mariposa County. It was discovered in the early 1850s, during the California gold rush. Following the elucidation of the theory of plate tectonics, the Mother Lode was found to coincide with the suture line of a terrane, the Smartville Block. The zone contains hundreds of mines and prospects, including some of the best-known historic mines of the gold-rush era. Individual gold deposits within the Mother Lode are gold-bearing quartz veins up to 15 metres (49 ft) thick and a few thousand feet long. The California Mother Lode was one of the most productive gold-producing districts in the United States. Now it is known as a destination for tourism.[2]

The California gold rush, as with most gold rushes, started with the discovery of placer gold in sands and gravels of streambeds, where the gold had eroded from the hard-rock vein deposits. Placer miners followed the gold-bearing sands upstream to discover the source in the bedrock. This source was the "mother" of the gold in the river and so was dubbed the "mother lode".

A popular misconception is that small veins of gold or silver ore in a mining district are necessarily branches of a single rich and massive mother lode deep in the ground. This idea is contrary to modern theories of ore deposits.

The term is also used metaphorically to refer to the origin of something valuable or in great abundance.


References

  1. ^ Alan M. Bateman (1942) Economic Mineral Deposits. New York: Wiley, p.465-466.
  2. ^ A.H. Koschman and M.H. Bergendahl (1968) Principal Gold-Producing Districts of the United States. US Geological Survey, Professional Paper 610, p.55

See also

 
Search Wikimedia Commons
    Wikimedia Commons has media related to:

Wikimedia Foundation. 2010.

Игры ⚽ Нужна курсовая?

Look at other dictionaries:

  • mother lode — moth|er|lode [ˈmʌðələud US ðərloud] n [C usually singular] AmE 1.) a mine that is full of gold, silver etc 2.) a place where you can find a lot of a particular type of object mother lode of ▪ The Sharper Image catalog is a mother lode of men s… …   Dictionary of contemporary English

  • mother lode — ☆ mother lode n. the main lode, or vein of ore, in a particular region or district …   English World dictionary

  • mother lode — noun the main vein of ore in a deposit • Syn: ↑champion lode • Hypernyms: ↑lode, ↑load * * * noun, pl ⋯ lodes [count] chiefly US : the place where the largest amount of gold, silver, etc., in a particular area can be found …   Useful english dictionary

  • Mother Lode — In diesem Artikel oder Abschnitt fehlen folgende wichtige Informationen: Vollständige Handlung Du kannst Wikipedia helfen, indem du sie recherchierst und einfügst …   Deutsch Wikipedia

  • mother lode — UK / US noun [countable] Word forms mother lode : singular mother lode plural mother lodes mainly American 1) a supply of something that you can use His vast experience gives him a mother lode of political stories to tell. 2) a very large amount… …   English dictionary

  • mother lode — noun a) A large or rich vein of gold or of another precious mineral from which other branches extend. Undeterred, reasoning from the coarseness of the gold that it had not traveled far, they had set out in search of the mother lode. b) Any source …   Wiktionary

  • mother lode — 1. Mining. a rich or important lode. 2. a major or profitable source or supply: New York City is a mother lode of actors. [1855 60] * * * …   Universalium

  • mother lode — noun (countable usually singular) AmE 1 a mine that is full of gold, silver etc 2 a place where you can find a lot of a particular type of object: The Sharper Image catalog has a mother lode of men s gadgets and toys …   Longman dictionary of contemporary English

  • Mother Lode Motel — (Placerville,США) Категория отеля: 2 звездочный отель Адрес: 1940 Broadway, Placer …   Каталог отелей

  • Mother Lode Lodge — (Марипоса,США) Категория отеля: 2 звездочный отель Адрес: 5051 Highway 140, Марипо …   Каталог отелей

Share the article and excerpts

Direct link
… Do a right-click on the link above
and select “Copy Link”