Peru Margin ODP1228D Holocene Organic Geochemical Data Makou, M.C.; Eglinton, T.I.; Oppo, D.W.; Hughen, K.A. Makou, M.C. Eglinton, T.I. Oppo, D.W. Hughen, K.A. ENSO earth science/paleoclimate/paleoceanography (dinosterol,null,null,parts per million,null,paleoceanography,null,null,N,null) earth science/paleoclimate/paleoceanography (age,null,null,calendar kiloyear before present,null,paleoceanography,null,null,N,null) earth science/paleoclimate/paleoceanography (cholesterol,null,null,parts per million,null,paleoceanography,null,null,N,null) earth science/paleoclimate/paleoceanography (depth,null,null,centimeter,null,paleoceanography,null,null,N,null) earth science/paleoclimate/paleocean (ODP1228D>LATITUDE -11.0667>LONGITUDE -78.0833) Paleoclimate reconstructions suggest distinctive changes in the El Niño-Southern Oscillation (ENSO), the dominant mode of tropical climate variability, over the last glacial cycle and throughout the Holocene. However, to the best of our knowledge, no studies provide parallel reconstructions of warm (El Niño) and cold (La Niña) phase variability, thus precluding distinction between variations in ENSO activity and the mean state of the tropical Pacific. Here we provide the first such records, generated using molecular organic geochemical proxies in a sediment core from the Peru margin region. The opposing influences of El Niño and La Niña on coastal upwelling and phytoplankton community structure produce distinct sedimentary sterol records describing the evolution of each ENSO phase. We document changes in surface ocean productivity on the Peru margin over the past 16 ka that indicate enhanced La Niña–like conditions alone during deglaciation, but concomitant increases in both El Niño and La Niña activity during the past 2 ka. We propose that the preponderance of La Niña–like conditions prior to 11.5 ka reflects the influence of waning glacial boundary conditions. By contrast, warm and cold phase covariability during the late Holocene suggests centennial-scale changes in ENSO activity, rather than the Pacific mean state, driven by tropical insolation. STUDY NOTES: Stratigraphic records of cholesterol and dinosterol abundance for ODP 1228D. All results are normalized to organic carbon (OC) abundance and are reported as micrograms/gram OC. A full description of analytical methods and age scale development is presented in Makou et al. 2010. Radiocarbon dates are provided for both bulk OC and compound- specific (alkenone) measurements, both of which include a constant 700 yr reservoir age correction. Bulk OC dates were used to construct the published age scale. For the readers convenience, dates from this core by Higginson and Altabet (2004) are also included and are denoted in the cited publication. NCDC-Paleoclimatology https://www.ncdc.noaa.gov/data-access/paleoclimatology-data - Bauer Bruce Investigator : Makou, M.C. Investigator : Eglinton, T.I. Investigator : Oppo, D.W. Investigator : Hughen, K.A. 2011-02-10 ONLINE Files online, ASCII https://www.ncdc.noaa.gov/paleo/study/10530 https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/makou2010/makou2010.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/makou2010/makou2010.xls https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/makou2010/makou2010.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/makou2010/makou2010.xls English https://www.ncdc.noaa.gov/paleo/study/10530 https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/makou2010/makou2010.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/makou2010/makou2010.xls Makou, M.C., T.I. Eglinton, D.W. Oppo, and K.A. Hughen. 2010. Postglacial changes in El Niño and La Niña behavior. Geology, Vol. 38, No. 1, pp. 43-46, January 2010. doi: 10.1130/G30366.1 START YEAR: 15928 cal yr BP * END YEAR: 494 cal yr BP -78.0833 -11.0667 -78.0833 -11.0667