Physical Volcanology, Hydrothermal Alteration and Massive ...

Stop F-1: High Level Lake Ash Flow Tuff And MesobrecciaAt this location (Figure 7), approximately 300 meters southwest of the F-Group pit,intensely altered High Level Lake ash flow tuff and mesobreccia deposits crop out. TheHigh Level Lake ash flow tuff deposits are the host rocks for the F-Group massive sulphideorebody. These rocks vary in colour from grey-green to greyish-pink and contain 5-20%1 mm quartz phenocrysts in a quartz-rich, locally chlorite-bearing recrystallized ash matrix.Light grey pumice fragments, from 3-20 mm in diameter, are subrounded to oval in shape,and are composed primarily of recrystallized quartz. These fragments typically contain 30­50%