, a lode is a deposit of metalliferous ore
that fills or is embedded in a fissure
(or crack) in a rock
formation or a vein
of ore that is deposited or embedded between layers of rock.
The current meaning (ore vein) dates from the 17th century, being an expansion of an earlier sense
of a "channel, watercourse" in late Middle English
, which in turn is from the 11th-century meaning of ''lode'' as a ‘course, way’.
The generally accepted hydrothermal model
of lode deposition posits that metals dissolved in hydrothermal solutions (hot spring fluids) deposit the gold or other metallic minerals inside the fissures in the pre-existing rocks. Lode deposits are distinguished primarily from placer deposit
s, where the ore has been eroded out from its original depositional environment
and redeposited by sedimentation
. A third process for ore deposition is as an evaporite
A stringer lode is one in which the rock is so permeated by small veinlets that rather than mining the veins, the entire mass of ore and the enveined country rock
is mined. It is so named because of the irregular branching of the veins into many anastomosing
stringers, so that the ore is not separable from the country rock.
One of largest silver lodes was the Comstock Lode
in Nevada, although it is overshadowed by the more recently discovered Cannington Lode
in Queensland, Australia. The largest gold lode in the United States was the Homestake Lode
. The Broken Hill Lode
in South Australia is the largest lead-zinc lode ever discovered.
, known just as ''lode'' in the 16th and 17th centuries.
[The ''New Oxford American Dictionary'' (''NOAD''), 3rd edition.] [
*Mother lode, the principal vein