Microbial Biomineralization in Biotic Crusts from a Pleistocene Marine Cave (NW Sicily, Italy)

ABSTRACT

Biotic crusts occurring in the Early Pleistocene Rumena Cave, in NW Sicily, have been analyzed from a geomicrobiological point of view. The crusts consist largely of scleractinians and of subordinate bryozoans and serpuloideans, all typical of submarine cave biota. Encrustations document a blind cave in a shadowed setting, or possibly below the fair weather swell zone. Autochthonous and, subordinately, detrital fractions were observed within the skeletal framework of biotic crusts. The syndepositional lithified fraction occurs mainly as very fine-grained laminations. Clotted peloidal and aphanitic (structureless) textures occur in the micrites as well. Autochthonous micrite is always associated with a significant amount of organic matter remains. In caves from the Plemmirio area in SE Sicily, the autochthonous microbial micrite, occurring in the bioconstructions, contains bacterial lipid biomarkers, including abundant compounds derived from sulfate-reducing bacteria. It is likely that a similar microbial mediation was involved in the formation of the autochthonous micrite present in the biotic crusts of the Rumena Cave.

KEYWORDS:

• Biotic crusts
• cave
• microbialites
• Pleistocene
• Sicily

Acknowledgments

The authors wish to express their gratitude to the reviewers and the editors for comments and suggestions. Rosario Ruggeri (CIRS Ragusa) is thanked for allowing visitation of the cave.

Funding

This research has been supported by grants MIUR (ex 60% 2015 A. Mastandrea, University of Calabria) and grants by the University of Catania to Antonietta Rosso and Rossana Sanfilippo. Catania Palaeoecological Research Group: contribution n. 424.