Mid-Pliocene sea level and continental ice volume based on coupled benthic Mg/Ca palaeotemperatures and oxygen isotopes.
Ostracode magnesium/calcium (Mg/Ca)-based bottom-water temperatures were combined with benthic foraminiferal oxygen isotopes in order to quantify the oxygen isotopic composition of seawater, and estimate continental ice volume and sea-level variability during the Mid-Pliocene warm period, ca 3.3-3.0Ma. Results indicate that, following a low stand of approximately 65m below present at marine isotope stage (MIS) M2 (ca 3.3Ma), sea level generally fluctuated by 20-30m above and below a mean value similar to present-day sea level. In addition to the low-stand event at MIS M2, significant low stands occurred at MIS KM2 (-40 m), G22 (-40m) and G16 (-60m). Six high stands of +10m or more above present day were also observed; four events (+10, +25,+15 and +30 m) from MIS M1 to KM3, a high stand of +15m at MIS K1, and a high stand of +25m at MIS G17. These results indicate that continental ice volume varied significantly during the Mid-Pliocene warm period and that at times there were considerable reductions of Antarctic ice.
Division of Earth and Ocean Sciences, Nicholas School of the Environment, Duke University, Durham, NC 27708, USA. gary.dwywer@duke.edu
Gary S
GS
Dwyer
Mark A
MA
Chandler