Gold deposits are on the surface or deep in the ground.
Gold deposits are regions with rich concentrations of gold. Finding gold deposits allows mining companies to extract the gold for commercial use. Gold deposits, according to the Science Education Resource Center at Carleton College, are found in geological locations around the world -- from Connecticut to South Africa -- making the characteristics of gold deposits multitudinous.
Epithermal Vein Deposits
Epithermal vein deposits are gold deposits that are 1 km to 2 km underneath Earth's crust due to volcanic activity. The volcanic activity enables minerals to mix and oxidize, chemically altering the elements. This natural occurrence allows gold to form. As the result of all the volcanic activity deep in the crust, the gold tends to accumulate up toward the surface, allowing gold companies or government contractors to extract the gold. An example of this is gold found in or around Yellowstone National Park, where the gold comes to the surface thanks to the volcanic hot springs.
Greenstone-Hosted Deposits
Greenstone-hosted deposits are regions of surface crust where large amounts of greenstone, a type of metamorphic rock, accumulates along fault lines. These network of fault lines allow many types of metamorphic rocks and minerals to form, including quartz carbonate. The gold that forms in these fault lines is slowly created and accumulated over millions of years of fault line activity. Many of these greenstone-hosted deposits are also the home of large silver deposits as well. According to the Geological Survey of Canada, many of Canada's gold deposits come exclusively from these fault lines.
Skarn Deposits
Skarn is a metamorphic rock with a large amount of silicate. Typically, these deposits have tungsten and copper, but the deposits occasionally hold large amounts of gold deposits. Typically, a skarn is formed when carbon rich igneous rock is covered over by volcanic magma, especially under the ocean. This allows a high amount of chemicals to enter into the rock formation chemistry and may sometimes create gold deposits. Many skarn deposits are found in canyons or mountain ranges that used to be covered in ocean millions of years ago. Over that time span, the waters dissipated and eroded the rocks in these mountains and canyon ranges.
General Characteristics
Many, if not all, gold deposits seem to take millions of years to develop. Most gold deposits, whether they are deep in the earth crust or near the surface, tend to have developed as a result of metamorphic rock activity. This means that ocean water sedimentary deposits and volcanic activity helps chemically alter enough elements to create the gold deposits seen today. Most of these gold deposits are still found either near the volcanic activity that helps create them, such as near hot springs, or placed in old regions where volcanic, seismic, or erosion activities were commonplace.
Tags: gold deposits, volcanic activity, fault lines, metamorphic rock, millions years, create gold, create gold deposits
