CHARACTERIZATION OF HYPERTHERMAL ETM-2 (LOWER EOCENE) FROM THE SANDTOWN, DELAWARE CORE

Hyperthermals were short-lived global warming events linked to the release of isotopically light carbon. These events can be compared to today's human-caused emissions and may offer insights into future climate change impacts. Although significant research has centered on the Paleocene–Eocene Thermal Maximum (PETM), smaller-scale hyperthermals can also be studied to understand climatic responses to varying levels of forcing. These hyperthermals can be identified by negative excursions in δ¹⁸O and δ¹³C, smaller than at the PETM, which are associated with the release of ¹³C-depleted carbon into Earth’s ocean-climate system. In this study, we are assessing the global hyperthermal ETM-2/H1, or Elmo, from the recently drilled Sandtown core (Kb33-26) in Delaware that recovered an expanded lower Eocene sequence E2 (~53-54 Ma; Zone NP11) from the Manasquan Formation. This study combines biostratigraphy, bulk carbonate isotopes, elemental composition from Minalyzer core scans, gamma log, calcareous nannofossils, and benthic and planktonic foraminiferal assemblages. The ETM-2 hyperthermal event is identified as a distinct excursion event at Sandtown with δ¹³C and δ¹⁸O excursions of -1.9‰ and -2.9‰, respectively, within calcareous nannofossil Zone NP11. This ETM-2 interval shows laminated, rapidly deposited (~5 cm/kyr or greater) clays with little glauconite and silt sediment characteristics similar to the Marlboro Clay found elsewhere. The cores were analyzed on a pass-through XRF to detect changes in elemental composition in the core to try to understand changes in environmental conditions at the time of deposition. The Ca data are well correlated with the hyperthermal and likely reflect dilution from increased input of terrigenous mud. Iron does not show the low values that are associated with the Marlboro, but otherwise the similarities of ETM-2 with the Marlboro Clay suggest similar high sediment input and pulses of fluid mud deposition. Gamma log data show ETM-2 as a minimum (despite its peak mud content) bracketed by peaks. Ongoing analyses of benthic and planktonic foraminifera are expected to provide insight into timing, duration, and faunal response to this warming event.