Chemical change in rock caused by the same fluids that carried the metal — the fingerprint a mineralising system leaves behind.
Chemical and physical changes to rock caused by hydrothermal fluids, often associated with mineralization. Alteration patterns help geologists identify potential ore zones and understand the processes that formed a deposit.
Alteration extends far beyond the ore itself, which makes it the main tool for vectoring toward a deposit. Recognising a specific alteration assemblage tells a geologist which part of a system they are standing in and which direction to drill.
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