Breccia and vein mineralization of the Balatoc Diatreme, Acupan gold deposit, Baguio Mineral District: An example of a diatreme-hosted epithermal deposit in the Philippines

•The Balatoc Diatreme significantly influenced fluid flow and ore precipitation in Acupan.•Veins represent early-stage precious metal mineralization while the GW orebodies record late-stage base-metal deposition.•Fluid inclusion and sulfur isotope data suggest prevalence of meteoric water input in reduced environments.•Fluid mixing is an important process in diatreme-hosted mineral deposits such as Acupan.