The Cretaceous-aged Pebble porphyry Cu-Au-Mo deposit is a world-class mineralized system.

This work investigates the magmatic-hydrothermal fluid evolution using fluid inclusions and stable isotopic data.

A magmatic intermediate-density parental fluid underwent phase separation during cooling and depressurization.

Two brines of different salinity plus vapor are related to two variably mineralized hydrothermal alteration assemblages.

A second pulse of magmatic fluid formed an advanced argillic alteration overprint and a zone of high grade mineralization.