Gold is a solid, malleable and compliant metal that is a shiny, yellow colour. The element is formed inside solid crystalline rocks in deposits, also known as veins. Gold is found with telluride and sulphide minerals in a large, primary deposits (lodes). Wind or rain typically obliterates the minerals over time, leaving the gold behind. Gold comes in various sizes, with some being the size of specks and others the size of nuggets.
Soil consisting of solid volcanic rock compiled of compressed volcanic ash (tuffs) is where gold is typically found. The immediate zone is magnetic and can be found by using a metal detector. Gold located in veins is referred to as high-grade gold.
Hillside eluvial deposits are gold that has been deposited by water or wind into soil close to streams. This phenomena, along with changes of temperature or of the Earth's outer layer and vegetation development, can transfer gold from one location to another. When this happens, the soil components diminish the rocks to clay, sand, silt and gravel and release the gold. Deposits are often located close to a lopsided plane of a hillside underneath a mineral resource. Consequently, if looking for gold near a mineral quarry, look to the area beneath the quarry. Gold is also found where there is a blend of gravel, debris and boulders from a neighbouring hillside.
When gold is passed through the lode canal to a water table (groundwater) this process is called supergene enrichment. The region nearby the water table is where the gold is redeposited and augmented in lateritic (soil that is rich in aluminium and iron found in tropical regions) deposits. Prospectors needed lateritic deposits to make the smaller mines cost-effective. Gold is typically low-grade when found in lateritic deposits. However, the deposits are normally quite large, and are found close the exterior of the water table.
Streams and Canals
Rainstorms during the summer bring about streams, materialising rapidly. The streams then will move the gold throughout furrows and dry washes. Gold is pressed into washes by sand and other fragments when transported by milder rain. The collected resources can be carried further from the veins throughout the next downpour. Rain makes the development of gold unpredictable. Gold can be located in short-lived canals that were created at some point in the rainstorm. Wind can also disperse light rocks and sand to expose gold as well.
- SBS: Geology of Gold
- Encyclopedia of Alabama: Minerals of Alabama
- Mirasol Resources LTD: La Curva Project - Available for Joint Venture
- SpringerLink: Relationship Between Low-Grade Gold Disseminations and High-Grade Veins in the Quartz Mountain District
- Geologynet: Gold Prospecting
- Cochise College: Gold Mining