Pegmatite samples from Bynoe harbour area, NT, Australia
Hang Gong and Greenbushes workings
Cassiterite and tantalite have been produced from several
pegmatite mines in this region.
Samples from the Bynoe Harbour area show intense low temperature
decrepitation caused by abundant CO2 rich fluid
inclusions in most samples. There are interesting variations in
decrepitation between 350 and 550 C in these samples, but it was
not possible to interpret the cause of these variations.
Distal samples still show modest levels of CO2 rich fluids, perhaps as part of an extensive halo of fluid alteration in the vicinity of the main economically mineralized zone.
Cassiterite and tantalite show weak decrepitation, with traces of CO2 rich fluids in the inclusions within cassiterite.
Intense low temperature decrepitation caused by CO2
rich fluids, particularly in sample 327600C (blue).
Interesting variation in peaks near 450 C as well as CO2
These distal samples are assumed to be barren, but still show CO2 rich fluids, perhaps as an extensive halo around the economic centre of the deposit.
Cassiterite and tantalite also show decrepitation, albeit only at low intensity and with just a trace of CO2 rich fluids in the cassiterite sample 327705A (green).