We have conducted a palaeomagnetic study of a Permian red sandstone layer intruded by a 70 cm wide Plio-Pleistocene basaltic dike, with the ultimate goal of estimating the flow duration of the magma before its solidification. Thirty-one samples were collected at various distances from the dike/sandstone interface and were thermally demagnetized. An apparent palaeotemperature profile and two corrected ones were thus deduced from the samples in which the dike emplacement produced no crystallization of new magnetic minerals. These profiles were compared with the calculations of a new conductive thermal model. Good fits with the experimental data are obtained for a flowing width consistent with field observations and when the latent heat is taken into account, in the two following cases. First, when k is temperature dependent in the basalt and in the sandstone, which implies a magma flow duration of 5 days. Second, when a limited convection process is assumed in the sandstone only; here, a flowing time of only 1 day is required. -from Authors