WERE SUPERSTORMS THE NORM? FENESTRAL POROSITY IN BAHAMIAN EOLIANITES AS EVIDENCE OF EXTREME STORMS DURING THE LAST INTERGLACIAL
Throughout the Bahamas, facies stacking patterns, emergent bio-eroded notches and fossil reefs record a series of rapid sea-level fluctuations toward the end of MIS 5e. As climate destabilized, global wind belts likely compressed and tropical storms intensified. In low-lying areas, storm waves regularly ran over coastal dunes, obliterating their eolian structures and reworking them into storm-beach ridges dominated by thick, tabular, fenestrae-rich beds. At moderate elevations and further from shore, storm waves ran up the dunes, forming zones of discrete, fenestrae-rich beds, often with evidence of scour. In the highest and most inland eolianites, where the effects of storm waves ran out, fenestrae formed in wispy, discontinuous beds, on the windward side of the dunes.
At several localities on multiple islands, fenestral beds in MIS 5e eolianites occur in separate horizons, signifying repeated inundation. Furthermore, with increasing elevation and distance from shore, the character of fenestrae-rich bedding changes as does the abundance and geometry of fenestral pores. This suggests a storm-wave origin to these structures, rather than rainstorms or a single event, and vividly illustrates the sobering potential for extreme storms at the end of an interglacial.