Improved Planktonic, Benthic Foraminiferal and Nannofossil Biostratigraphy Aids the Interpretation of the Evolution at Hole U1468A: IODP Expedition 359, the Maldives

Extended shallow carbonate platform, pelagic, and drift deposits were drilled during International Ocean Discovery Program (IODP) Expedition 359 in the Inner Sea of Maldives. These sediments yield rich well-diversified benthic, planktonic foraminiferal nannofossil assemblages spanning from early Oligocene to Recent. We present here shore-based revised integrated biostratigraphy these microfossil groups at IODP Hole 359-U1468A together with paleobathymetric reconstruction. Our data suggests presence a late marked by shallowest water depths entire sequence around 80 m. This platform occurred 29 Ma, extrapolated minimum age estimate, least up 27.5 Ma possibly 25.4 Ma. Up sequence, similar production conditions until 22.5 across Oligocene–Miocene transition, equated 23.04 increased >120 Notably, time interval approximately 24 21.5 orbitally induced sapropel layers indicate change open restricted circulation. However, pelagic deposition distal slope sedimentation rates 3 cm/years. initially >350 m but gradually reached >500 m, which persisted 21.12 12.8 Sedimentation 10.5 cm/1000 years 450 below sea floor, marking initiation as identified seismic lines an estimate The is also drastic decrease preservation benthic foraminifera good very poor essentially continued day was interrupted two events: distinct shoals large hiatus. From shallowing upward bathymetry suggested occurrence that close 11.93 maximum depth shoal then prograded into basin 9.89 Basin exceeding 500 re-established upper part sedimentary succession after hiatus 9.83 2.39 implying renewed ocean Pliocene–Pleistocene record.