EXPLORATION STRATEGY FOR HOT-SPRING PRECIOUS-METAL DEPOSITS.

The discovery of economic precious-metal deposits related to physical-chemical processes in the near-surface portions of high-temperature hot-spring systems has led to intensive exploration efforts for this deposit type. To increase the probability of success, these exploration programs should (1) be based on the most important visually recognizable or readily measurable deposit-model criteria; (2) be able to identify specific targets within the best search areas; and (3) be able to rank the order of priority among the targets. We propose a process-recognition exploration strategy for hot-spring deposits that has been developed from data from precious-metal occurrences at several localities in the western United States. The exploration model is based on the degree to which recognizable geologic and geochemical criteria are favorable or unfavorable to the occurrence of an economic deposit, either through their presence or absence.