History & Geology
Rock and Formations of the Mother Lode Gold Belt
October 2015 by Chris Ralph
The faulting, folding and shearing that occurred in the Mother Lode belt has created zones of structurally weak rocks or contacts between different types of rock, which has been favorable for the deposition of gold bearing ores.
Benches and Fossil Placers
Unfortunately for us mortal humans, we have a poor perspective on geologic time. When we look at a landscape such as a stream valley, we see it only in two, or at the most, three dimensions. We have poor comprehension of the valley’s fourth and most important dimension—time.
The Ely Copper-Gold District of Nevada
The main ore deposits of the Ely district are associated with an east-west belt of altered and mineralized rocks measuring about one mile wide that extends 8 miles westward from Ely.
Jadeite in California
...two jadeite locations in California have been thoroughly researched by geologists. There are no doubt others that lie in wait.
Las Médulas—The Gem of the Roman Gold Mines
This mine was a real wonder of engineering, and the water supply and drifts had to be carefully managed to keep it in operation. In fact, it didn’t close due to lack of gold, but instead closed with the fall of the Roman Empire.
The Tombstone Silver-Lead District, Arizona
In 1877, a prospector named Ed Schieffelin discovered silver in “the middle of nowhere” and staked two claims: “Tumbstone” and “Graveyard.” Soon a town and mining district were organized and acquired the name “Tombstone” after making a spelling correction.
Ask The Experts
Sulfides and oxides—what's the difference between the two?
Exploring Iron Oxide Copper Gold Deposits
The excitement over IOCG deposits began with the discovery of a monster deposit at Olympic Dam in Australia in 1976. The discovery was accidental as the operator was searching for strata-bound copper deposits.
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