Importance of clay, glacier and
the hydrothermal system
Clay mineralogy: smectite,
quartz-feldspar, kaolinite and cristobalite
suggests a former very active hytrotermal system
Clay ---- good conditions
for water saturation (pore water),
increases porosity but reduces permeability
in the hydrothermal system
Hydrothermal alteration:
a) degasing and
ascent of H2O, CO2, H2S, SO2 and HCL
b) combine with water &
atmopheric O ------------sulfur acid
c) descent of acidic fluids
acid sulfate leaching
------------ adds sulfate
removing mobile elements
foms clay, silica, sulfate
min.
Glacier:
- Erosion----expose deeper
altered zones/steep slopes
- Enhance
alteration-----------slow reservoir of water as a constant
supply of water
in contrast, heavy rain may
dilute the fluids
