Thermal analysis techniques were utilized to investigate the thermal properties of two soils and a lignite coal obtained from the International Humic Substances Society (IHSS), and sediment obtained from The Netherlands. Differential scanning calorimetry (DSC) revealed glass transition behavior of each sample at temperatures ranging from 52 degrees C for Pahokee peat (euic, hyperthermic Lithic Medisaprists), 55 degrees C for a Netherlands (B8) sediment, 64 degrees C for Elliott loam (fine, illitic, mesic Aquic Arguidolls), to 70 degrees C for Gascoyne leonardite. Temperature-modulated differential scanning calorimetry (TMDSC) revealed glass transition behavior at similar temperatures, and quantified constant-pressure specific heat capacity (Cp) at 0 degrees C from 0.6 J g(-1) degrees C(-1) for Elliott loam and 0.8 J g(-1) degrees C(-1) for the leonardite, to 1.0 J g(-1) degrees C(-1) for the peat and the sediment. Glass transition behavior showed no distinct correlation to elemental composition, although Gascoyne Leonardite and Pahokee peat each demonstrated glass transition behavior similar to that reported for humic acids derived from these materials. Thermomechanical analysis (TMA) revealed a large thermal expansion followed by a matrix collapse for each sample between 20 and 30 degrees C, suggesting the occurrence of transition behavior of unknown origin. Thermal transitions occurring at higher temperatures more representative of glass transition behavior were revealed for the sediment and the peat.