How do sedimentary processes create mineral deposits?

Sedimentary processes create mineral deposits primarily through the concentration of minerals via physical or chemical mechanisms. These processes generally fall into two categories:1

Physical Concentration: Placer Deposits

Placer deposits form when gravity acts on moving particles. As weathering releases stable, heavy minerals from their parent rock, they are transported by water or wind. Because the ability of a medium to transport material depends on its velocity, heavy minerals settle and concentrate in areas where the flow slows down, such as in stream beds, beaches, or lag gravels.2

Chemical Precipitation

Many sedimentary mineral deposits form through the chemical precipitation of minerals from solutions, such as groundwater or seawater.1
* Evaporites: These form when water evaporates from brines, leaving behind concentrated layers of minerals like halite, gypsum, and sylvite.3
* Chemical Sediments: Minerals can precipitate directly from water due to changes in chemical conditions, such as oxidation. For example, manganese and iron can precipitate when soluble compounds encounter oxidizing environments.45