EXCEPTIONALLY PRESERVED CORAL BANK AND SEAGRASS MEADOW FROM THE LOWER PLEISTOCENE OF FAUGLIA (TUSCANY, ITALY).

Abstract

Near the Fauglia village (Tuscany, Italy), a Calabrian (lower Pleistocene) stratigraphic succession crops out in a sand quarry. This succession is comprised of an alternation of sands and silts featuring an exceptionally preserved Posidonia oceanica meadow (preserving in situ rhyzomes and loose leaves) and an abundant and diverse assemblage of fossil invertebrates that also includes the zooxanthellate coral Cladocora caespitosa. The latter forms a rare example of a Cladocora bank, exhibiting peculiar fossilization modes that range from compound molds to recrystallized corallites, overlain by an oyster reef. Paleoenvironmental considerations, based on a comparison with analogue environments from the present-day Mediterranean region, indicate a shallow-water, protected marine environment characterized through time by a seagrass meadow (ranging in water depth from 10 to 35 m), a subsequent coral bank (5 to 20 m water depth), and finally by an oyster reef in water shallower than 5-10 m. Throughout the 6-m-thick stratigraphic section, five taphofacies are recognized, showing different diagenetic signatures. Subsequent stages of aragonite dissolution and calcite re-precipitation are thus hypothesized, revealing a complex and unusual diagenetic history for this remarkable find of exceptionally preserved Pleistocene coral bank and seagrass meadow.