The petrology and palaeoenvironment of the Sortino Group (Miocene) of SE Sicily: evidence for periodic emergence

Abstract

The Sortino Group of carbonates consists of three formations which developed on a shallow marine shelf during Tortonian and lower Messinian times. The two lower formations contain three bioherms and are intercalated with thick volcaniclastic sequences. The youngest formation is dominated by shoal water, lagoonal and peri-tidal carbonates. Early submarine lithification is well-developed within the bioherms and consists of construction by both algae and invertebrates, the development of peloidal micrites and isopachous fringe growth. Superimposed upon these are a series of both meteoric phreatic and vadose textures related to episodic emergence of the bioherms. These features include bladed cements showing cathodoluminescence, pendent cements, brecciation, alveolar texture and palaeosols. The Sicilian strata may be directly correlated with the Maltese Islands sequence, and collectively exhibit the effects of fluctuating Mediterranean sea levels at an early stage in the late Miocene salinity crisis.