Plio-Pleistocene Seawater Mg/Ca Variability Data and SST Reconstruction Medina-Elizalde, M.; Lea, D.W.; Fantle, M.S. Medina-Elizalde, M. Lea, D.W. Fantle, M.S. Sea Surface Temperature Reconstruction earth science/paleoclimate/climate reconstructions|paleoceanography (sea surface temperature,magnesium/calcium,null,degree Celsius,null,climate reconstructions|paleoceanography,null,null,N,null) earth science/paleoclimate/paleoceanography (age,null,null,radiocarbon year before present,null,paleoceanography,null,null,N,null) earth science/paleoclimate/paleoceanography (magnesium/calcium,Trilobatus sacculifer,null,millimole per mole,null,paleoceanography,null,null,N,null) earth science/paleoclimate/climate reconstructions|paleoceanography (sea surface temperature,magnesium/calcium,null,degree Celsius,null,climate reconstructions|paleoceanography,null,null,N,adjusted for Mg/Ca variation) earth science/paleoclimate/paleoceanography (depth,null,null,centimeter,null,paleoceanography,null,null,N,null) earth science/paleoclimate/paleocean earth science/paleoclimate/paleocean earth science/paleoclimate/paleocean (ODP 806B>LATITUDE .32>LONGITUDE 159.35) (ODP 847>LATITUDE .2>LONGITUDE -95.32) Recent reconstructions of Mg and Ca concentrations of seawater indicate that seawater Mg/Ca changed significantly over the last 5 million years (Ma). Tropical sea surface temperature (SST) records for the last 5 Ma based on foraminiferal Mg/Ca paleothermometry assume constant seawater Mg/Ca. These SST records suggest that average equatorial Pacific SSTs remained thermally stable from 5 to 2 Ma, after which significant cooling occurred only in the eastern equatorial Pacific. This study examines the implications of adjusting available equatorial Pacific SST records based on Mg/Ca paleothermometry to account for the inferred past variations of seawater Mg/Ca. The results suggest that both the cold and the warm regions of the equatorial Pacific were much warmer during the early Pliocene (30-31 °C), and that both regions experienced a marked cooling from ~4 Ma to ~1 Ma. This new interpretation of foraminiferal Mg/Ca creates a discrepancy with alkenone unsaturation-based SST records from the eastern equatorial Pacific, which might be due to either overestimation of changes in past seawater Mg/Ca or to factors affecting the interpretation of the UK'37 index. The adjusted SST records are consistent with the hypothesis that higher levels of greenhouse gases maintained the warmth of the early Pliocene. NCDC-Paleoclimatology https://www.ncdc.noaa.gov/data-access/paleoclimatology-data - Bauer Bruce Investigator : Medina-Elizalde, M. Investigator : Lea, D.W. Investigator : Fantle, M.S. 2008-01-01 ONLINE Files online, ASCII https://www.ncdc.noaa.gov/paleo/study/9037 https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/medina-elizalde2008 https://www1.ncdc.noaa.gov/pub/data/paleo/paleocean/sediment_files/complete/odp847-tab.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleocean/sediment_files/complete/o806b-mm-tab.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/medina-elizalde2008 https://www1.ncdc.noaa.gov/pub/data/paleo/paleocean/sediment_files/complete/odp847-tab.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleocean/sediment_files/complete/o806b-mm-tab.txt English https://www.ncdc.noaa.gov/paleo/study/9037 https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/medina-elizalde2008 https://www1.ncdc.noaa.gov/pub/data/paleo/paleocean/sediment_files/complete/odp847-tab.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleocean/sediment_files/complete/o806b-mm-tab.txt Medina-Elizalde, M., D.W. Lea, and M.S. Fantle. 2008. Implications of seawater Mg/Ca variability for Plio-Pleistocene tropical climate reconstruction. Earth and Planetary Science Letters, 269(3-4), 585-595. START YEAR: 5220000 14C yr BP * END YEAR: 0 14C yr BP -95.32 .2 159.35 .32