Pleistocene coralline algal build-ups (coralligène de plateau) and associated bioclastic deposits in the sedimentary cover of Cutro marine terrace (Calabria, southern Italy)
Published:January 01, 2006
R. Nalin, D. Basso, F. Massari, 2006. "Pleistocene coralline algal build-ups (coralligène de plateau) and associated bioclastic deposits in the sedimentary cover of Cutro marine terrace (Calabria, southern Italy)", Cool-Water Carbonates: Depositional Systems and Palaeoenvironmental Controls, H. M. Pedley, G. Carannante
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Carbonate build-ups mainly constructed by encrusting coralline red algae are currently developing on Mediterranean soft bottoms, at depths ranging from 20 m to 160 m. They are usually referred to as 'coralligène de plateau'. Few fossil examples of these bioconstructions have been described in the literature and their evolution in the context of a stratigraphic cycle has never been modelled in detail. Cutro marine terrace (Calabria, southern Italy) preserves mid-Pleistocene deposits assigned to Marine Isotope Stage (MIS) 7 or MIS 9. Extensive algal build-ups representing the deepest unit of the succession occur in the outer and central portion of the terrace, interpreted as the most distal setting from the palaeo-shoreline. Two studied sections, Vrica and Telegrafo, showed that the solid biogenic framework grew over a basal rhodolithic layer, which was stabilized by the binding activity and overgrowth of non-geniculate Corallinales (calcareous red algae). Therefore, these bioconstructions represent a rare fossil example of coralligène de plateau. At the Telegrafo section, Titanoderma pustulatum has been identified as the major rhodolith component. The build-ups are dominated by T. pustulatum, associated mainly with Mesophyllum spp. and locally with Lithophyllum stictaeforme. Rhodalgal bioclastic deposits are found in lateral contact with the build-ups. The two facies developed together under a hydrodynamic regime where phases of sedimentation from storm-driven currents alternated with phases of calm conditions. They were deposited during a single stratigraphic cycle beginning with the generation of a ravinement surface during the transgressive systems tract (TST) and ending with the burial of the coralligène by well-sorted shoreface bioclastic sands. Optimal and extensive growth of the coralligène took place during the highstand systems tract (HST).
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Cool-Water Carbonates: Depositional Systems and Palaeoenvironmental Controls
During the past decade, work on cool water carbonates has expanded to become a mainstream research area. Studies on modern and Quaternary deposits will continue to be important; however, there is increasing momentum towards unravelling sediment processes, biota-sediment interactions and diagenetic products in Cenozoic and older cool-water carbonates.
Many contributions in this book document Cenozoic and Quaternary carbonates from landlocked (microtidal) water-bodies. These carbonates display important differences in biota and fabric distributions when compared with world ocean examples. Consequently, the scientific community is now better placed to reinterpret pre-Tertiary carbonates where there is a suspicion that they have developed under microtidal conditions. Some papers in the book provide new approaches to interpreting environmental change within macrotidal regimes and others lay firm foundations for future cool-water carbonate diagenetic research
The aim of the book is to illustrate recent international contributions to cool-water carbonates research, with an emphasis on Neogene and Recent case studies. Contributions are divided into three sections: microtidal carbonates from the Mediterranean realm; macrotidal examples from New Zealand, Australia and Mexico; and early diagenetic fabrics.