>Dear list-members
>
>We are interested in the range of values for 18O/16O in
>commercially-available bottled CO2 supplies  and wondered
>if anyone had made measurements on their supply.


In Australia, there are two sources of CO2 that I know of.  On the east
coast we get our CO2 from the furnace stacks in Wollongong.  There are also
some volcanic wells near Mt Gambier in SA.  The well supply generally
doesn't come to the east coast unless there is a production shortage.


Approximate values

                  Wollongong                   Mt Gambier
                Industrial stacks             volcanic wells

18O[smow]           +21.5                         +19
13C[pdb]            -28                           - 4


Gases with greater depletion of carbon are possible if the gas is produced
from methane burns or other hydrocarbon plant combustion products.

We've obtained volcanic gas in the past by getting a bleed straight off the
well head.  This volcanic gas is in a particularly inconvenient form (ie
40cc @ 800 ATM pressure).

Joe Cali


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Joseph A. Cali                    |                               |
Environmental Geochemistry Group  |                               |
Research School of Earth Sciences | Phone :  +61 2 6249 3246      |
Australian National University    |   Fax :  +61 2 6249 3683      |
Canberra, Australia,  0200        | Email :  [log in to unmask]  |
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