The following session will be held at AGU (PP10).  We have four top 
invited speakers who have agreed to present.  Should be an exciting session.

The Meaning Changes of the Carbon Isotope Values in the Sedimentary Record

Conveners Martin Kennedy, Paul Knauth, Peter Swart

The standard method of tracking changes in the global carbon cycle 
throughout geological time has been the use of the stable isotopes of 
carbon in both organic and inorganic materials. Generally speaking 
increases in the carbon isotopic ratio of carbonates implies an 
increased burial of organic carbon, while decreases are believed to 
reflect increased oxidation of organic carbon. However, while changes 
in the carbon isotopic composition undoubtedly reflect variations in 
the global carbon cycle, this paradigm is increasingly questioned and 
some of the changes are now believed to reflect (i) variations in the 
source of the carbonate materials, (ii) changes in the restricted and 
open nature of the environment, and (iii) diagenetic alteration. This 
session invites contributions from true believers and skeptics which 
discuss mechanisms explaining global change in the carbon isotopic 
composition of the geological record.