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A study of the paleoenvironmental evolution of the middle Eocene platforms recognized in the westernmost Tethys has been carried out in the well exposed middle Eocene succession from Sierra Espuña-Mula basin (Betic Cordillera, S Spain). Eight microfacies (Mf1 to Mf8) have been recognized, based mainly on fossil assemblages (principally larger benthic foraminifera), and rock texture and fabric. The fossiliferous assemblage can be asigned to the ‘subtropical’ heterozoan association or to the low-latitude ‘foralgal facies’, which are dominated by non-framework building, light-dependent biota such as perforate larger benthic foraminifera, coralline algae, and sometimes green algae and solitary corals. Larger benthic foraminifer assemblages, corresponding from euphotic to oligophotic conditions and the large surface showed, suggest a progressive marine ramp under essentially oligotrophic conditions. Eventually, supply of detrital sediments from the continent and/or upwelling currents increasse the nutrients of marine waters. Comparision with other Tethyan sectors allows stating that coral-reef buildups (z-corals) were widespread on shallow platforms of the central and eastern Tethys Ocean, but that these were neither of great dimensions nor dominant because of the much more dominant presence of larger benthic foraminifera. Moreover, these coral constructions were completely absents in the westernmost Tethys. The dominance of larger benthic foraminifera and the absence of z-corals in the westernmost Tethys is explained by particular paleogeographic features due to the occurrence of a narrow and deep oceanic branch (i.e., the Maghrebian Flysch Basin) connecting the Tethys with the Atlantic Ocean. The various issues regarding the morphological characters and evolution of larger benthic foraminifera in the study area, such as sizes of tests, specific diversity and/or intraspecific variability, number of appearances and last occurrences during the middle Eocene are analyzed a

A study of the paleoenvironmental evolution of the middle Eocene platforms recognized in the westernmost Tethys has been carried out in the well exposed middle Eocene succession from Sierra Espuña-Mula basin (Betic Cordillera, S Spain). Eight microfacies (Mf1 to Mf8) have been recognized, based mainly on fossil assemblages (principally larger benthic foraminifera), and rock texture and fabric. The fossiliferous assemblage can be asigned to the ‘subtropical’ heterozoan association or to the low-latitude ‘foralgal facies’, which are dominated by non-framework building, light-dependent biota such as perforate larger benthic foraminifera, coralline algae, and sometimes green algae and solitary corals. Larger benthic foraminifer assemblages, corresponding from euphotic to oligophotic conditions and the large surface showed, suggest a progressive marine ramp under essentially oligotrophic conditions. Eventually, supply of detrital sediments from the continent and/or upwelling currents increasse the nutrients of marine waters. Comparision with other Tethyan sectors allows stating that coral-reef buildups (z-corals) were widespread on shallow platforms of the central and eastern Tethys Ocean, but that these were neither of great dimensions nor dominant because of the much more dominant presence of larger benthic foraminifera. Moreover, these coral constructions were completely absents in the westernmost Tethys. The dominance of larger benthic foraminifera and the absence of z-corals in the westernmost Tethys is explained by particular paleogeographic features due to the occurrence of a narrow and deep oceanic branch (i.e., the Maghrebian Flysch Basin) connecting the Tethys with the Atlantic Ocean. The various issues regarding the morphological characters and evolution of larger benthic foraminifera in the study area, such as sizes of tests, specific diversity and/or intraspecific variability, number of appearances and last occurrences during the middle Eocene are analyzed a

The likelihood that extensive dissolution of aragonite (and high magnesian calcite) takes place during very early burial, even in relatively shallow tropical settings, has wide implications for interpreting and modelling ancient limestones. Some low energy environments may constitute net sinks (¿black holes¿) for carbonates. If this is the case attempts to model sediment budgets and develop depth-productivity profiles for carbonate systems require as yet unavailable quantitative data on the effects of these processes. We query whether the established trends of diminishing carbonate productivity with depth could, for some settings such as ramps, be in part an artifact of selective, offshore dissolution more than simply due to reduced benthic production. Many fossil assemblages from low energy settings may be limited to refractory (residual) skeletal elements, which limits our ability to make palaeoenvironmental determinations: some important carbonate grain producers such as the green algae may have been especially prone to early dissolution. The possibility exists that what is now mud-grade carbonate in low energy deposits may not represent original material deposited from suspension but could represent transformed aragonite from in situ production by the skeletal fauna. The selective removal of labile aragonitic (and high Mg calcite) components could produce sediments that appear to have had the composition of cool water types, and the reduced diagenetic potential of many Palaeozoic and cool water carbonates could be a consequence of the effects of early aragonite dissolution rather than due to differences in primary (depositional) composition.

The likelihood that extensive dissolution of aragonite (and high magnesian calcite) takes place during very early burial, even in relatively shallow tropical settings, has wide implications for interpreting and modelling ancient limestones. Some low energy environments may constitute net sinks (¿black holes¿) for carbonates. If this is the case attempts to model sediment budgets and develop depth-productivity profiles for carbonate systems require as yet unavailable quantitative data on the effects of these processes. We query whether the established trends of diminishing carbonate productivity with depth could, for some settings such as ramps, be in part an artifact of selective, offshore dissolution more than simply due to reduced benthic production. Many fossil assemblages from low energy settings may be limited to refractory (residual) skeletal elements, which limits our ability to make palaeoenvironmental determinations: some important carbonate grain producers such as the green algae may have been especially prone to early dissolution. The possibility exists that what is now mud-grade carbonate in low energy deposits may not represent original material deposited from suspension but could represent transformed aragonite from in situ production by the skeletal fauna. The selective removal of labile aragonitic (and high Mg calcite) components could produce sediments that appear to have had the composition of cool water types, and the reduced diagenetic potential of many Palaeozoic and cool water carbonates could be a consequence of the effects of early aragonite dissolution rather than due to differences in primary (depositional) composition.

Brief description of Devonian algal microflora observed in open marine, semi-restricted and restricted environments compared with the French-Belgian Devonian. The abundance and fair preservation of the Sphaerocodiaceans permit erection of two new genera (Pseudosphaerocodium et Sphaerocodiella) and three new species (Sphaerocodium tortuosum, Pseudosphaerocodium halysiformis, Sphaerocodiella punctata)., SCOPUS: ar.j, info:eu-repo/semantics/published

Brief description of Devonian algal microflora observed in open marine, semi-restricted and restricted environments compared with the French-Belgian Devonian. The abundance and fair preservation of the Sphaerocodiaceans permit erection of two new genera (Pseudosphaerocodium et Sphaerocodiella) and three new species (Sphaerocodium tortuosum, Pseudosphaerocodium halysiformis, Sphaerocodiella punctata)., SCOPUS: ar.j, info:eu-repo/semantics/published