Redeposits

Rede deposits, in geological and mining contexts, are ore or mineral deposits that form when minerals dissolved in fluids are redeposited in a new location or form, rather than being preserved in their original ore body. Redeposits can occur as secondary accumulations created by weathering, groundwater movement, or changes in chemical conditions that cause minerals to precipitate from solution or melt.

Formation mechanisms include supergene or secondary enrichment in weathered zones, where oxidized ore minerals are dissolved and transported downward or laterally and then precipitated as new minerals in more reduced environments. Redeposition can also occur along fractures, faults, or cavities as hydrothermal fluids cool or react with surrounding rock. Placer or alluvial redeposits, produced by physical reworking of eroded material, represent another common form, concentrating valuable minerals in stream beds or coastal environments.

Rede deposits are important in economic geology because they can concentrate minerals beyond the grades found in the primary ore body, sometimes creating profitable mining opportunities even when the original deposit is poor. They also affect exploration strategies, guiding geologists to look for geochemical anomalies, alteration halos, and mineral assemblages indicative of secondary processes.

Distinctions are often made between primary (hypogene) ore deposits and secondary (redeposited) deposits, with the latter typically associated with weathering, groundwater flow, and supergene processes. See also ore deposit, secondary enrichment, supergene processes, and placer deposits.