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Departamento de Estratigrafı´a y Paleontologı´a, Universidad de Granada, Campus Fuentenueva s/n, 18002, Granada
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- PublicationRestrictedPalaeoceanographic controls on reef deposition: the Messinian Cariatiz reef (Sorbas Basin, Almería, SE Spain)(2007)
; ; ; ; ; ;Sánchez-Almazo, I. M.; Departamento de Estratigrafı´a y Paleontologı´a, Universidad de Granada, Campus Fuentenueva s/n, 18002, Granada ;Braga, J. C.; Departamento de Estratigrafı´a y Paleontologı´a, Universidad de Granada, Campus Fuentenueva s/n, 18002, Granada ;Dinarès-Turell, J.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia ;Martín, J. M.; Departamento de Estratigrafı´a y Paleontologı´a, Universidad de Granada, Campus Fuentenueva s/n, 18002, Granada ;Spiro, B.; Department of Mineralogy, The Natural History Museum, Cromwell Road, London SW7 5BD, UK; ; ; ; The Cariatiz section lies at the toe of the palaeoslope of the Messinian Cariatiz fringing reef, at the northern margin of the Neogene Sorbas Basin in SE Spain. Distal-slope reef deposits in the upper part of the section can be traced laterally to the reef core of the last episodes of reef progradation. The underlying deposits are alternating diatomitic marl, marl and silty marl that intercalate with sandstone beds. Combined lithological changes, variations in proportions of warm-water planktic foraminifera and d18O values suggest that at least seven, probably precessional, cycles are recorded throughout the Cariatiz section. The correlation of seven cycles in the pelagic deposits to seven reef progradation cycles, and associated vertical shifts in reef facies, indicates relative sea-level oscillations of several tens of metres. Biostratigraphic and palaeomagnetic data suggest that both the Cariatiz section and the fringing reef formed during the reverse polarity Chron C3r. Surface-water temperatures seem to be the major factor controlling carbonate production in the reef system. Deposition of bioclastic calcirudite and calcarenite, with no active coral growth, took place at the lowest sea-level within each reef cycle during temperature minima within each precessional cycle. Porites framework and reef-slope deposits with Halimeda gravel, in contrast, formed during temperature rises and thermal maxima within precessional cycles.163 28 - PublicationRestrictedTesting models for the Messinian salinity crisis: The Messinian record in Almería, SE Spain(2006-06-15)
; ; ; ; ; ; ;Braga, J. C.; Departamento de Estratigrafía y Paleontología, Facultad de Ciencias, Campus de Fuentenueva s.n., Universidad de Granada, 18002 Granada, Spain ;Martín, J. M.; Departamento de Estratigrafía y Paleontología, Facultad de Ciencias, Campus de Fuentenueva s.n., Universidad de Granada, 18002 Granada, Spain ;Riding, R.; School of Earth, Ocean and Planetary Sciences, Cardiff University, Cardiff, CF10 3YE, United Kingdom ;Aguirre, J.; Departamento de Estratigrafía y Paleontología, Facultad de Ciencias, Campus de Fuentenueva s.n., Universidad de Granada, 18002 Granada, Spain ;Sánchez-Almazo, I. M.; Departamento de Estratigrafía y Paleontología, Facultad de Ciencias, Campus de Fuentenueva s.n., Universidad de Granada, 18002 Granada, Spain ;Dinarès-Turell, J.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; ; ; ; ; Neogene intermontane basins in Almería Province, SE Spain, display excellent exposures of Messinian (Late Miocene) sequences. The Sorbas, Almería-Níjar and Vera basins maintained connection with the Mediterranean throughout the Messinian, except during the major desiccation phase leading to the formation of salt in the deep centre of the Western Mediterranean. These basins were part of the Western Mediterranean with no separate link to the Atlantic Ocean. The presence of normal marine sediments in these basins reflects the Western Mediterranean watermass. Messinian pre-evaporitic sediments in the basins of southeastern Almería do not show gradual change towards evaporite deposits. Instead they contain stenohaline invertebrates right up to a major erosion surface that separates them from overlying gypsum deposits. This contradicts suggestion of progressive salinity increase in this part of the Western Mediterranean prior to the Messinian Salinity Crisis (MSC); it also indicates that initiation of evaporite precipitation was not synchronous throughout the Mediterranean Basin. There is no major erosion surface within or at the top of the evaporites in these Almería basins, and the gypsum beds exhibit upward transition to siliciclastic and carbonate deposits. This is inconsistent with a model of Messinian Mediterranean evaporite formation whereby deposition of marginal evaporites was followed by their erosion during drawdown that resulted in formation of evaporites in the centre of the Western Mediterranean. The presence of stenohaline biotas in siliciclastic deposits interbedded with the gypsum and in the Messinian post-evaporitic sediments, challenges the view that a long-standing large body of brackish water (the Lago Mare) filled the Western Mediterranean following the MSC and prior to Early Pliocene flooding. It also contradicts the concept of many relatively small brackish basins spread across an otherwise desiccated Western Mediterranean basin. The basins of southeastern Almería record normal marine Early Messinian sedimentation that was abruptly interrupted by sealevel fall. This drawdown most likely resulted in precipitation of evaporites in the central deep Western Mediterranean basin. Following this episode, final marine reflooding of the Western Mediterranean took place during the Late Messinian, and the Mediterranean Sea rose to a level similar to, or higher than, that preceding the Salinity Crisis.353 48