IODP EXP. 313 SEA-LEVEL RECONSTRUCTIONS FROM PALYNOLOGY (DISTANCE-TO-SHORELINE ESTIMATES) AND BENTHIC FORAMINIFERA (WATER-DEPTH ESTIMATES): INSIGHTS INTO CONTROLS ON THE ARCHITECTURE OF THE NJ MARGIN

Integrated Ocean Drilling Program (IODP) Expedition 313 is the inner continental shelf portion of a linked set of boreholes ( “New Jersey/Mid-Atlantic Transect” (NJ/MAT)) that extends from the NJ coastal plain to the continental slope, designed to unravel the complex relationships between eustatic change and margin sedimentation. Previous drilling provided dates for the major sequence boundaries on the outermost shelf and upper slope (Ocean Drilling Program [ODP] Legs 150 & 174A); the onshore coastal plain portion provided great detail of facies successions (ODP Legs 150X & 174AX). Exp. 313 boreholes fill the critical intervening gap in the NJ/MAT, and contain a strong imprint of sea-level change. Microfossils are a critical tool in deciphering the sea-level record. The ratio of terrestrially-derived palynomorphs (pollen & plant spores, “P“) vs. the cysts of marine algae (dinoflagellate cysts & acritarchs, “D“) has been used as a proxy for distance from the shoreline. The D:P, together with dinocyst assemblages and qualitative descriptions of palynofacies, allowed late Cenozoic sea level to be reconstructed at two sites on the NJ continental shelf: IODP EXP 313 Hole M0029A on the inner shelf and ODP Leg 174A Hole 1072A on the outer shelf. In general, paleobathymetric changes derived from benthic foraminifera show close agreement with the paleosea-level estimates derived from the palynomorphs. The combination of these independent micropaleontological datasets provides greater confidence in reconstructions of sea-level change, and assists in understanding the impact of sea level on the architecture of the NJ margin.