Summary: 22. G. J. Demaison, E. T. Moore, Am. Assoc. Petrol. Geol.
Bull. 8, 1179 (1980).
23. Sediments were demineralized with mixtures of HCl
(1N) and hydrofluoric acid (10%). Acid-soluble OM
was recovered after removal of paramagnetic metals
and desalting as described [Y. GeŽlinas, J. A. Baldock,
J. I. Hedges, Org. Geochem. 32, 677 (2001)].
24. Solid-state 13
C NMR is well suited for probing the
bulk composition of sedimentary OM. When rigor-
ous care is taken with spectral acquisition tech-
niques [P. Kinchesh, D. S. Powlson, E. W. Randall,
Eur. J. Soil Sci. 46, 125 (1995)], 13
C NMR can
provide a representative estimate of all OC forms
in a sample.
25. P. N. Nelson, J. A. Baldock, P. Clarke, J. M. Oades, G. J.
Churchman, Aust. J. Soil Res. 37, 289 (1999). Bio-
chemical compositions and an application of the
model can be found in Hedges et al. [Nature 409, 801