What are placer deposits 

Placer deposits are valuable mineral deposits that have been separated by gravity. As a result of the weathering process, dense and stable minerals are separated from the matrix and slowly flow into the downhill stream. This enables the stream to swiftly wash the light flux away. Ore deposits are created when heavy minerals collect in streams, beaches, and leftover gravel. Denser and chemically weather-resistant minerals make up the soap deposits. They are stable and enduring. Gold, platinum, cassiterite, magnetite, chromite, ilmenite, rutile, natural copper, zircon, monazite, and different jewels are a few minerals that can be discovered in placer deposits. These deposits are thick and challenging to weather since they are produced on steep slopes.

Minerals have a higher density than sand-making quartz. The alluvium is the Spanish term for placer. Option C is the right response, thus. minerals discovered in the sand at the valley bottom as alluvial deposits. Minerals that are resistant to water corrosion are typically present in these deposits.

Placer deposits are natural collections of heavy minerals brought about by the gravitational pull of moving particles. When weathering releases heavy, stable minerals from their matrix, they are gently carried into streams, which quickly winnow the lighter matrix. As a result, viable metal deposits and heavy minerals are concentrated in rivers, streams, beaches, and lag (debris) gravels. The minerals that make up placer deposits have a high specific gravity, are robust and are resistant to weathering chemically.

In addition to magnetite, ilmenite, chromite, cassiterite, rutile, and native monazite, placer deposits can also include valuable metals including gold, platinum, copper, zircon, and different gemstones.

Hence, the correct answer is option C.