PLEISTOCENE SHALLOWING-UPWARD SEQUENCES IN NEW-PROVIDENCE, BAHAMAS - SIGNATURE OF HIGH-FREQUENCY SEA-LEVEL FLUCTUATIONS IN SHALLOW CARBONATE PLATFORMS

Examination of several closely spaced cores from western New Providenc e, Bahamas, shows a classic shoaling-upward progression of facies. Ref ined age constraints from magnetostratigraphy indicate that since the Brunhes/Matuyama boundary (0.78 Ma), only three sea-level highstands h ave flooded this part of the platform. The reefal-skeletal-oolitic-pel oidal facies sequence, probably representing deposition during fourth- order highstands, show lateral facies changes and perhaps regional cli matic influences. This skeletal-to-nonskeletal transition is common in other Bahamian platform records, and appears to be youngest near the edges of the platform. Estimates of sea level during the reversed-pola rity Matuyama, without subsidence corrections, show that it reached wi thin about 10 m below present sea level. During the Brunhes chron, at least one highstand came to within 6-7 m of present mean sea level. Th e uppermost part of a core, containing beach facies, is now about 6 m above sea level and is thought torepresent the 0.13 Ma sea-level event .