OCCURRENCES OF DENDRITIC GOLD AT THE MCLAUGHLIN MINE HOT-SPRING GOLD DEPOSIT

Two styles of gold dendrites are variably developed at the McLaughlin Mine. The most abundant occurrence is hosted by amber-coloured hydroca rbon-rich opal. Silica likely precipitated from a boiling hydrothermal fluid and complexed with immiscible hydrocarbons forming an amorphous hydrocarbon-silica phase. This phase likely scavenged particulate gol d by electrostatic attraction to the hydrocarbon-silica phase. The den dritic nature of the gold is secondary and is the result of dewatering of the amorphous hydrocarbon-silica phase and crystallization of gold into syneresis fractures. The second style of dendritic gold is hoste d within vein swarms that focused large volumes of fluid flow. The den drites occur along with hydrocarbon-rich silica al the upper contact o f the vein margins which isolated the dendrites allowing sufficient ti me for them to grow. In a manner similar to the amber-coloured opal, t he dendrites may have formed by scavenging particulate gold by electro static attraction to the hydrocarbon-silica phase.