See more from this Division: Topical Sessions
See more from this Session: Coastal and Aeolian Geomorphology Processes and Landforms
Abstract:
Detailed examination of exposures on Eleuthera, San Salvador and Providenciales, reveal that MIS 5e eolianites were deposited rapidly, as evidenced by an overall lack of rhizomorphs and the burial of trees and palm fronds in growth position at several localities. Also, in contrast to eolianites from other highstands, MIS 5e eolianites are dominated by fine-scale, top- and back-set bedding, suggesting limited lateral migration. Finally, fenestrae (keystone vugs) can be found within MIS 5e eolianites, in some cases up to 43m above sea-level. Though typically associated with beach facies, outcrop evidence shows these eolian fenestrae formed as storm waves ran over, ran up, and ran out on coastal dunes.
Facies stacking patterns, fossil reefs, and emergent bioeroded notches in the Bahamas all indicate that sea-level fluctuated dramatically during the latter half of the last interglacial. As climate destabilized, ooidal platform sediments were rapidly remobilized into voluminous eolian ridges. At the end of the last interglacial period, tropical storms intensified throughout the platform due to the onset of glacial conditions and the compression of global wind belts. The more frequent storms reworked lowland dunes into storm-beach ridges with tabular, fenestrae-rich bedding and few original eolian structures. At moderate elevations, storm waves scoured the dunes leaving meter-thick fenestral zones, while in the highest eolian ridges waves and wave spray formed wispy, discontinuous fenestrae beds. These dramatic climate events recorded by the MIS 5e eolianites serve as a sobering bellwether for the future stability of the current interglacial.
See more from this Division: Topical Sessions
See more from this Session: Coastal and Aeolian Geomorphology Processes and Landforms