IRIS – Institutional Research Information System

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 nongeniculate Corallinales (calcareous red algae). Therefore, these bioconstructions represent a rare fossil example of corallige`ne 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 corallige`ne by wellsorted shoreface bioclastic sands. Optimal and extensive growth of the coralligène took place during the highstand systems tract (HST).

Nalin, R., Basso, D., & Massari, F. (2006). Pleistocene coralline algal build-ups (coralligène de plateau) and associated bioclastic deposits in the sedimentary cover of Cutro marine terrace (Calabria, Southern Italy). In H.M. Pedley, & G. Carannante (a cura di), Cool-Water Carbonates: Depositional Systems and Palaeoenvironmental Controls (pp. 11-22). London : Geological Society Publishing House.

Powered by IRIS-about IRIS-Utilizzo dei cookie-Privacy

 Copyright © 2022