Gold Deposit Types

Gold Deposit Types

Gold can be deposited in several locations, all the way from its source, or mother rock, right the way down to the Sea. During this journey which would take gold millions of years to do (depending on the river system) it will go through several transformations. These transformations from one type of gold deposit to another need to be examined in order to understand where the gold will be at certain points during this long journey. I will start from the mother rock/ mother lode and work all the way down to the sea and explain each gold deposit type which is formed as the gold transforms.

 

Gold Deposit Type 1 – The Mother Lode

Gold Deposits of this type contain the vast majority of gold. It will usually be a Quartz rock with gold intertwined within. If you find a piece of Quartz with gold in it you are probably very near to the mother lode, although it will most likely have been eroded by the forces of nature. This Quartz vein would have been forced up through a weak point, or fissure in the earths crust while it was molten, the gold would also have been in its molten state, both would then have cooled and solidified into their solid states over a short period of time. Most Geologists think that the vast majority of Earths gold deposits were laid down almost all at the same time during a period of intense geological activity several tens of millions of years ago. This is the reason why mother lodes are buried several tens of feet and sometimes hundreds and even thousands of feet underground –  the relentless geological forces of earth have worked and reworked the land which we stand on, constantly shifting, burying, breaking, smashing and eroding everything that was once at the earths surface. Mining for the mother lode is called hard rock mining or reef mining for those of you down under, you need some serious equipment and money to undertake this sort of mining.

Gold deposit types - The Mother Lode

Gold deposit types – The Mother Lode

 

Gold Deposit Type 2 – Placer Gold

This is the Gold Deposit type that most gold prospectors live for. It is easier to find and  to recover than the hard rock mining mentioned above. Placer gold is created by the weathering and destroying of the mother rock or mother lode by the forces of nature. Gold is virtually indestructible (all gold on planet earth was created in the heart of a dying star several billion years ago) , as a result the original Quartz vein may be all but annihilated yet the gold that was trapped within it can still be found. When a reef vein is broken down the gold will eventually find its way into a river system, this river system will then do the job of carrying the gold downstream and eventually take some of it out to Sea, as we all know – “all rivers lead to the Ocean”.  However, the vast majority of the gold will get trapped somewhere along the river system and remain there for millions and millions of years, sitting there waiting to be sluiced and panned from the river gravels :).

Placer gold can be further broken down into three separate categories before our gold reaches the Sea –

Gold Deposit Type 3 –  Residual Deposit

The Residual Gold deposit is the gold that has broken away from the mother lode in the immediate vicinity. This can be large and coarse gold and is sometimes found with the Quartz still attached –

Residual Gold - Quartz Gold

gold deposit type 2a – Residual Gold

 Gold Deposit Type 4 – Alluvial Gold

The gold deposit type is the next stage in the transformation of the gold. This has been taken away from the immediate vicinity of the source rock and eventually found its way into a river system. Once there it will settle itself into various bends, fissures and various other obstructions in the river system.

gold deposit types - alluvial gold

gold deposit type 2b – alluvial gold

 Gold Deposit Type 5 — Bench Placer

This Gold deposit type is formed when a river cuts through a mountainside through the action of the water eroding the hills away. This type of gold placer can be very profitable if found a it most likely has not been prospected before. Read more here

gold deposit type 2c - bench placer

gold deposit type 2c – bench placer

UA-29172388-1