Late Miocene Mediterranean desiccation: topography and significance of the 'Salinity Crisis' erosion surface on-land in southeast Spain: Reply

Abstract

We welcome this opportunity to amplify the results of our studies of the Late Miocene Messinian sequence in the Sorbas Basin of southeast Spain. The Salinity Crisis concept has captured geological imagination and found its way into textbooks, but scrutiny reveals its details to be disturbingly elusive. Our approach has been to read the history of this important episode in Neogene history in well-exposed on-land sections at Sorbas, Almería, near the western end of the Mediterranean. The Salinity Crisis concept, as it was first proposed (Hsü et al., 1973, 1977) and has largely survived (Cita, 1991), is of deep-desiccation and reflooding of the Mediterranean near the close of the Miocene. Marine downdraw resulted in marginal erosion; evaporites accumulated in depressions; and final marine reflooding completed the cycle. Our rationale is that if these principal tenets of the concept are correct, then one or more of their effects should be recorded throughout the region, both on the deep Mediterranean floor and in marginal basins that were contemporaneously connected to the Mediterranean, including the Sorbas Basin. This emphasis on the widespread effects of the Salinity Crisis does not exclude the possibility that they were overprinted by local conditions, which probably differed considerably over a region as extensive and diverse as the Mediterranean basins. Indeed, we have interpreted the evaporites of the Sorbas Basin to be local products of basin barring, related to the Salinity Crisis but not coeval with deep Mediterranean evaporites. At the same time, we have taken the view that the regional result of the Salinity Crisis in all marginal basins should be an erosion surface on the scale of the massive sea-level fall implied by the concept. It is our recognition of this erosion surface in the Sorbas Basin that has drawn most criticism from Fortuin et al. (2000). Here we provide further details of critical localities so that our observations can be accurately assessed.