Juske: Yes and no. As I stated, the dissolution of carbonate will likely cause a modification of the stable isotope ratios if for instance there are admixtures of different minerals and one is preferentially dissolved. Molluscs are a good example of calcite and argonite. The Geology paper on "coral roasting" deals with stable isotope ratios. I think this was written by a fellow from LSU and the discussion by Peter Swart...I could be wrong. One could also conduct the experiment on their own with similar reagents and techniques. It is interesting to note that we have been conducting isotope analyses of organic matter in things like calcareous algae and have found that chlorox treatments only get the surface coating of organic matter...We have pre-treated with dilute chlorox and not and measured the d13C values of the organic matter with no observable difference in either the carbonate or organic matter. We roast aragonite samples in vacuo at 200 degrees C prior to analysis. When we did this discussion a year ago - nobody said anything about the interaction of the water and CO2 inclusions with organic matter during roasting. Perhaps this is a good experiment for someone. I hope this has helped in some way, Scott Juske Horita wrote: > Dear Scott and others: > References Scott mentioned are about the effect of > pretreatment on > mineralogy and trace elements, not on stable isotopes; am I right?. > I'm, > like Reed, very interested in how to pretreat organic-rich carbonate > samples > for isotope analysis; vacuum roast vs. bleaching vs. plasma ashing or > some > other methods? What happen, if no treatment? > Any comments are appreciated. > ***************************************** > Juske Horita > Chemical and Analytical Sciences Division > Oak Ridge National Laboratory > P.O.Box 2008, MS6110 > Oak Ridge, TN 37831-6110 > (423) 576-2750 > Fax: (423) 574-4961 > e-mail: [log in to unmask] > ***************************************** -- ************************************************************************ Scott J. Carpenter Assistant Professor Phone: (972) 883-2481 FAX: (972) 883-2537 Laboratory: (972) 883-2632 U.S. Mail: UPS/Federal Express: Department of Geosciences Department of Geosciences The University of Texas at Dallas The University of Texas at Dallas P.O. Box 830688 2601 N. Floyd Road Richardson, TX 75083-0688 Richardson, TX 75080 *************************************************************************