EVIDENCE FOR DYNAMIC PALEOSHELF MUD DEPOSITION IN PALEOCENE-EOCENE THERMAL MAXIMUM SEDIMENTS AT WILSON LAKE, NJ

The Marlboro Clay is an almost exclusively fine-grained and highly kaolinitic formation in the Mid-Atlantic Coastal Plain. The Marlboro Clay at Wilson Lake, NJ provides an expanded record (15 m) of the carbon isotope excursion (CIE) that defines the Paleocene-Eocene boundary in a middle shelf environment. However, rapid sedimentation rates (>23 cm/kyr) for the Marlboro Clay are inconsistent with a siliciclastic starved ramp or prodelta influenced shelf where muds are commonly found in the coastal plain. Recent work on the Marlboro Clay has identified the continental shelf that is adjacent to the Amazon River as a possible analog for the New Jersey paleoshelf, and cyclicity in high resolution oxygen isotopes as being indicative of annual layering at the CIE onset. I report lithologic and clay mineralogic data and interpret the sedimentary processes of the Amazon shelf to be consistent analogs for the depositional environment and characteristic bedding of the Marlboro Clay. Analysis of the bedding distribution, fine and coarse fraction grain sizes, and quantified clay mineralology at Wilson Lake indicate a subtle progression from a highly kaolinitic and rhythmically laminated facies to a decreasingly kaolinitic and non-laminated one. This lithologic change is consistent with an aggrading clinoform shelf configuration with rapid foreset deposition and reworked topset beds. Furthermore, sediment gravity flows that dominate Amazon shelf deposition are consistent with the homogenous looking beds of the Marlboro Clay. Fluid mud deposition can explain the regularity of bedding where clay diagenesis is lowest, and the lack of distinct beds when alteration increases. This depositional model supports the rapid onset to the carbon isotope excursion that has been proposed in the shallow marine environment.