Upper Miocene sediments of a proximal basin-margin facies association were deposited on the eastern edge of the Sierra Espuña mountains of the Betic Cordillera, SE Spain. These are interpreted as having been deposited along an active, basin-bounding fault. The sequence is composed of mixed marine carbonate and clastic sediments with conglomerates and calcarenites containing coralgal detritus passing distally into finer-grained sediments. Laterally along the faulted margin there are marked variations in facies and clast composition over very short distances. Clastic conglomerates interfinger both laterally and upwards with algal and coral reefs. Sedimentary facies analysis and provenance data are used to infer that mass flows coming off the steep basin margin fed talus cones. Laterally to the talus cones a fan delta coexisted with active algal and coral reefs.