gsminmag Mineralogical Magazine Mineralogical Magazine 0026-461X Mineralogical Society 10.1180/minmag.1998.62A.3.155 Factors Governing the Preservation of Insoluble Soil Organic Matter van Bergen P. F. Nott C. J. Bull I. D. Evershed R. P. Organic Geochemistry Unit, School of Chemistry, University of Bristol, Bristol BS8 1TS, UK Poulton P. R. Soil Science Department, IACR-Rothamsted, Harpenden, Herts. AL5 2JQ, UK 1998 62A 3 1567 1568 Copyright © 1998, The Mineralogical Society 1998