The invention is a method relating to the formation by simulation of a reference map of the spatial distribution of the sediment supply, according to the composition thereof, in a sedimentary basin during a sedimentary deposition sequence (during a given geologic time interval) and also allows obtaining the topography of the land surface of the basin at the beginning and at the end of this period. The available input data are a map of the thickness of the sedimentary layer studied, known by interpretation of seismic survey results, data relative to the location and to the composition of the sediment supply at the boundaries of the sedimentary basin being studied, obtained by interpretation of seismic surveys, measurements and observations, and physical parameters characterizing transportation of the sediments (diffusion coefficients in the marine environment and in the continental environment) during the period considered. An application is locating hydrocarbon reservoirs.