The Ups and Downs of Geologic Faults
May 2011 by Chris RalphFaults are fractures, breaks and broken zones in the Earth’s crust where one side of the break has moved relative to the other, and they come in many different varieties.
It also happens sometimes that glaciers will bury valuable placer deposits. This occurs when the glacier goes over the top of an existing placer deposit.
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.
Most gold-bearing veins in this region are controlled by fractures associated with the Melones Fault, a late Cretaceous structure that is 108 to 127 million years old.
I get a lot of questions from prospectors about garnets, their value and what they tell us about the geology of some types of mineral deposits. So I thought it would be a good idea to take a closer look at the lowly garnet and learn a bit more about it.
In the summer of 1854, John Selkirk, a discouraged placer miner who was down on his luck and ready to go back to Massachusetts, tied his mule up in a gulch north of what is now downtown Angel's Camp.
...these nuggets have not traveled far from the lode because the golden wire lattices would have been torn apart or flattened during weathering of rock and deposition by violent stream action.
Sulfides and oxides—what's the difference between the two?
The Bawl Mill • Why Haven't They Mined This Claim? • Ask The Experts—Where can I find information on the Abby mine? • Ask The Experts—Is it possible for a mountain range to have good lode gold deposits and yet the area streams not carrying like deposits of gold? • Ask The Experts—How do you amend a placer claim? • Ask The Experts—What happened to the BLM web site geocommunicator.gov? • Fountain of Youth Gold • Legislative and Regulatory Update • Suction Dredging Update for California & Idaho • The Disappearance of State Mining Departments • The Golden Streams of Butte County, California • Melman on Gold & Silver • Mining Stock Quotes & Mineral and Metal Prices