Concentrations of metal grains in stream sediment that develop when rocks containing native metals erode and create a mixture of sand grains and metal fragments; the moving water of the stream carries away lighter mineral grains.
(die) Seife Placers or placer deposits are deposits of secondary origin. Through wheathering and mechanical (fluvial) transportation ores can be congregated and enriched. Concentrations of ores are usually higher than in the original rocks. Typical ores of placers would be those of tin, gold, platinum, niobium, tantalum, titanium, zirconium. Diamonds are also to be found in placers. (EDWARDS, R. & K. ATKINSON 1986, S.175ff).
A deposit of a mineral formed by a concentration of heavy minerals in flowing water, such as by a stream or waves.
A mass of stream sediment that contains an economically significant concentration of mineral particles. This accumulation of mineral particles is a result of their being of high specific gravity or resistant to abrasion. Gold, magnetite, and diamonds can be found in placer deposits.
A deposit of heavy or durable minerals, such as gold or diamonds, typically found where the flow of water abruptly slows.
a concentration of a natural material that has accumulated in unconsolidated sediments of a stream bed, beach, or residual deposit
A deposit of sand or gravel that contains particles of gold, gemstones, or other heavy minerals of value. The common types are stream gravels and beach sands.
a glacial or alluvial deposit of sand or gravel containing eroded particles of valuable minerals.
In geology, a placer deposit or placer is an accumulation of alluvium or eluvium containing valuable minerals which is formed by deposition of dense mineral phases in a trap site. The name is from the Spanish word placer, meaning "sand bank".