Carbonate burial/preservation

As predicted by the classical equation, intervals when organic carbon burial exceeds sedimentary organic carbon erosion (i.e. when/, > (pk) would have higher 5 C values preserved in carbonate minerals. The prediction goes further, however. Assuming/, and (Pk are equal, intervals where Ab > Aw would also have elevated 5 C values preserved in carbonate minerals according to the expression ... 

On average about 20% of the BSi arriving at the sediment-water interfece dissolves prior to burial. Thus, only 3 to 5% of the surface production survives to become buried in the sediments. At some locations, where the BSi rain rate is high, a larger percentage (around 30%) is preserved. In comparison, 90% of the POC that rains onto the sediments is remineralized by the benthos, leaving sediment concentrations on the order of 1% w/w organic carbon. 

Wagner P.D. and Matthews R.K. (1982) Porosity preservation in the upper Smackover (Jurassic) carbonate grainstone. Walker Creek field, Arkansas Response of Paleophreatic lenses to burial processes. J. Sediment. Petrol. 52, 3-18. 

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