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

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

“…Subsequent to the 100 m sea-level fall, the Fringing Reef Unit recovered and continued to grow and its further progradation was finally abruptly interrupted in an ascending phase (Braga and Martín, 1996). The Fringing Reef Unit does not, therefore, descend step-by-step in its final stages, as suggested by Fortuin et al (2000) (Fig. 1). …”

“…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.…”

“…However, Fortuin et al (2000) state: "onlap … implies a general transgressive trend, whereas the overall tendency of the Yesares is shallowing up". Although it is difficult to ascertain, it is certainly possible that the Yesares gypsum shallows-up, but this does not mean that it did not also have an onlapping relationship.…”

“…This is a significant observation because, of the many remaining questions concerning the Salinity Crisis, one of them is stillsurprisingly-whether the Mediterranean really desiccated and, if so, by how much. Fortuin et al (2000) make four principal comments: (i) the surface that we recognize below the Yesares gypsum is not erosional; (ii) the Sorbas Member overlying the Yesares gypsum was deposited under conditions of raised salinity, not near-normal marine salinity as we deduced; (iii) the most likely horizon representing the Salinity Crisis erosion surface in the Sorbas sequence occurs higher in the Messinian, Member which we suggest represents "Salinity Crisis" sea-level fall (after Riding et al, 1999). Fortuin et al infer a late Abad sea-level fall of about 100 m affecting the Fringing Reef.…”

“…Fortuin et al, (2000) dispute this on the grounds that: (a) the erosion surface cannot be traced from basin margin to basin centre; (b) in the Hueli area the contact between the Yesares gypsum and the underlying Abad Marls and Bioherm Unit is complicated by dissolution effects; (c) the number of cycles in the Abad Marls below the gypsum appears to be constant at basin centre locations; (d) erosional features below the gypsum, for example near El Tesoro, can be better explained by local faulting and mass wasting effects; (e) at Los Yesos, west of Sorbas, the Yesares-Abad contact appears conformable; (f) the erosion surface above the Fringing Reef Unit is due to interregional sea-level fall "in the order of 100m".…”