Dear colleagues:

Is there anything known about the temperature dependence of the equilibrium
isotope exchange between oxygen in water and oxygen in siderite (FeCO3)? I
consulted Friedman & O'Neil (1977) without success.

Background: I have recently analyzed the carbon and oxygen isotope ratios of
siderites from laminated lake sediments of early Holocene age. The siderites
are believed to be a primary formation under reducing conditions at the
water/sediment interface of a Fe-rich, Ca-poor freshwater lake. The shifts
in carbon isotope ratios of the siderites from the lake sediment sequence
agree nicely with known climatic and paleoenvironmental changes at the time.
However, the oxygen isotope ratios in the siderites do not.

Any suggestions would be welcome.

Cheers,

Bernhard

Bernhard Mayer
Associate Professor
University of Calgary
Departments of Physics and Astronomy
and Geology and Geophysics
2500 University Drive NW
Calgary, Alberta
Canada T2N 1N4
phone (403) 220-5389
fax (403) 220-7773
e-mail: [log in to unmask]