Lateritic Gold Deposits
Lateritic or saprolitic gold deposits occur in some parts of the world, mainly where the environment and time vector that facilitates lateritization transects and ultra basic rocks with a small content of gold, supergene concentration of gold is done by this process. The deposit is developed by the attack of solvents picked up by meteoric water on a mass of weakly mineralized primary material. The solvent or fluids in the vadose water react with the rock matrix changing its composition and transferring the precious metals to a lower horizon where they are precipitated to form a secondary enriched zone. Removal of the precious metals from the surface results in a surficial zone with almost total impoverishment, but with a concentration of iron oxides which is an index to the amount of by supergene agencies.
The elevation and migration of the water table during the leaching period is a critical influence on the depth and volume of enrichment of gold. The barren capping of a supergene gold deposit corresponds to the unaltered ultrabasic rock which contains a small amount of gold locked in the ferromagnesian silicates. Between he metore and the protore zone is the zone of secondary enrichment, which may be ore. Occasionally in gold deposits the protore is of commercial grade, particularly during the period of high demand and price for gold. The oxidation and enrichment of leaching and transference of gold downward effecting a concentration of gold is influenced by the rock type.
The surficial geologic appearance of gold deposits does not vary greatly, but they vary widely in ultimate economic aspect, according to the stage, at which concentration was arrested, and the type and extent of modification succeeding concentration. In spite of local variations, supergene gold deposits show a common rhythmic consistency in the redistribution and concentration of gold. This is a function of the process of lateritization. In exploring these deposits, once the type of deposit is established, certain prognostication almost invariably hold true. Some examples of lateritic deposits are: Boddington, Mt. Gibson, Edna May, Western Australia; Akaiwang, Arakaka, Guyana; Lumpkin and White Counties, Georgia.
Profile of lateritic gold deposit
- Lateritization of Gold Deposits
- Transitional Products of Lateritic Gold Deposits
- Formation of Lateritic Gold Deposits
- Effect of Climate on the Lateritization Process
- Effect of Physiography on the Lateritization Process
- Source of Gold in Lateritic Deposits
- Chemical Environment of Lateritic Gold Deposits
- Development of Lateritic Gold Deposits