Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) are thermal analyses techniques, which can give vital information about a material's properties and phase transitions when exposed to heating. This study utilised a combined TGA-DSC approach to determine how exposure to varying temperatures and different heating regimes affect the decomposition of skeletal hard tissue. It was found that an accelerated heating rate causes the onset of phase changes in the bone matrix to be delayed to higher temperatures. The progression of matrix changes within a certain phase is also highly dependent on the rate of heating. Longer exposure times or slower heating rates increase progression of decomposition within a certain phase, progression to a different material phase however will only occur after a key "activation temperature" is reached. These findings have important implications for the subsequent analytical investigations of burnt bone.