Thermal diffusivity of upper chalk from Hampshire,England

The thermal diffusivity of Upper Chalk from the Micraster coranguinum zone had been calculated from 8 year temperature data obtained from depths between 30 cm and 21.34 m at Harestock, near Winchester, Hampshire.Amplitudes and phase lags were calculated from these data using Fourier analysis.Values of thermal diffusivity were calculated from the variation of amplitude with depth and phase lag with depth for the first harmonic using the Fourier heat flow equation.Agreement between the two methods was very good between 30 cm and 914 cm depth. An overall mean value is 0.004489 ± 0.00052cm^?2s^?1.Using appropriate values of porosity (47%) and density the mean thermal conductivity is 1.519W m^?1°C^?1± 0.326, for the water saturated state.