Antarctic Geochemistry Data and Mean Annual Temperature Reconstruction through the Eocene-Oligocene transition Passchier, S.; Ciarletta, D.J.; Miriagos, T.E. Passchier, S. Ciarletta, D.J. Miriagos, T.E. Air Temperature Reconstruction earth science/paleoclimate/climate reconstructions|paleoceanography (depth,null,null,meter,null,climate reconstructions|paleoceanography,null,null,N,sample top below seafloor) earth science/paleoclimate/climate reconstructions|paleoceanography (depth,null,null,meter,null,climate reconstructions|paleoceanography,null,null,N,Meter composite depth top) earth science/paleoclimate/paleoceanography (inorganic compound index,sediment,null,dimensionless,null,paleoceanography,null,null,N,"chemical index of alteration: 100 times the molar ratio of Al2O3 and the sum of Al2O3, CaO, Na2O and K2O (Nesbitt and Young 1982)") earth science/paleoclimate/climate reconstructions|paleoceanography (sample identification,null,null,null,null,climate reconstructions|paleoceanography,null,null,C,null) earth science/paleoclimate/climate reconstructions|paleoceanography (age,null,null,million years ago,null,climate reconstructions|paleoceanography,null,null,N,GTS2012 timescale) earth science/paleoclimate/paleoceanography (iron oxide,sediment,null,weight percent,null,paleoceanography,normalized,inductively-coupled plasma atomic emission spectroscopy,N,null) earth science/paleoclimate/paleoceanography (inorganic compound index,sediment,null,dimensionless,null,paleoceanography,null,null,N,S index: molar ratio of Na2O and K2O to Al2O3 (Sheldon et al 2002)) earth science/paleoclimate/paleoceanography (aluminum oxide,sediment,null,weight percent,null,paleoceanography,normalized,inductively-coupled plasma atomic emission spectroscopy,N,null) earth science/paleoclimate/paleoceanography (sodium oxide,sediment,null,weight percent,null,paleoceanography,normalized,inductively-coupled plasma atomic emission spectroscopy,N,null) earth science/paleoclimate/paleoceanography (potassium oxide,sediment,null,weight percent,null,paleoceanography,normalized,inductively-coupled plasma atomic emission spectroscopy,N,null) earth science/paleoclimate/paleoceanography (phosphorus pentoxide,sediment,null,weight percent,null,paleoceanography,normalized,inductively-coupled plasma atomic emission spectroscopy,N,null) earth science/paleoclimate/paleoceanography (titanium dioxide,sediment,null,weight percent,null,paleoceanography,normalized,inductively-coupled plasma atomic emission spectroscopy,N,null) earth science/paleoclimate/paleoceanography (magnesium oxide,sediment,null,weight percent,null,paleoceanography,normalized,inductively-coupled plasma atomic emission spectroscopy,N,null) earth science/paleoclimate/paleoceanography (calcium oxide,sediment,null,weight percent,null,paleoceanography,normalized,inductively-coupled plasma atomic emission spectroscopy,N,null) earth science/paleoclimate/climate reconstructions|paleoceanography (temperature,null,null,degree Celsius,annual,climate reconstructions|paleoceanography,null,null,N,calibraton of Sheldon et al. 2004) earth science/paleoclimate/paleoceanography (silicon dioxide,sediment,null,weight percent,null,paleoceanography,normalized,inductively-coupled plasma atomic emission spectroscopy,N,null) earth science/paleoclimate/paleoceanography (manganese oxide,sediment,null,weight percent,null,paleoceanography,normalized,inductively-coupled plasma atomic emission spectroscopy,N,null) earth science/paleoclimate/paleocean earth science/paleoclimate/paleocean (ODP 739>LATITUDE -67.276167>LONGITUDE 75.081833) (ODP 742>LATITUDE -67.549667>LONGITUDE 75.4045) (ODP 1166>LATITUDE -67.696167>LONGITUDE 74.787) Earth’s current icehouse phase began ~34 m.y. ago with the onset of major Antarctic glaciation at the Eocene-Oligocene transition. Changes in ocean circulation and a decline in atmospheric greenhouse gas levels were associated with stepwise cooling and ice growth at southern high latitudes. The Antarctic cryosphere plays a critical role in the ocean-atmosphere system, but its early evolution is still poorly known. With a near-field record from Prydz Bay, Antarctica, we demonstrate that Antarctic ice growth was stepwise and had an earlier onset than previously suggested. Prydz Bay lies downstream of a major East Antarctic Ice Sheet drainage system, and its sedimentary records uniquely constrain the timing of ice-sheet advance onto the continental shelf. We investigated a detrital record extracted from three Ocean Drilling Program drill holes within a new depositional and chronological framework spanning the late Eocene to early Oligocene (ca. 36–33 Ma). The chemical index of alteration (CIA) and the S index, calculated from the major-element geochemistry of bulk samples, yielded estimates of chemical weathering intensities and mean annual temperature on the East Antarctic continent. We document evidence for late Eocene mountain glaciation along with transient warm events at 35.8–34.8 Ma. From 34.4 Ma, associated with the Eocene-Oligocene transition precursor d18O excursion, glaciers advanced into Prydz Bay, coincident with a decline in chemical weathering and temperature. We conclude that Antarctic continental ice growth commenced with the Eocene-Oligocene transition “precursor” glaciation, during a time of Subantarctic surface ocean cooling and a decline in atmospheric pCO2. These results call for dynamic high-latitude feedbacks that are currently poorly represented in Earth system models and emphasize the need for additional near-field glacio-sedimentological, high-latitude sea-surface temperature and pCO2 records across the Eocene-Oligocene transition. STUDY NOTES: ODP Sites 739 (-67.276167 S, 75.081833 E, -412.4 m), 742 (-67.549667 S, 75.4045 E, -415.7 m) and 1166 (-67.696167 S, 74.787 E, -475.4 m) together encompass a composite record; the standard error on the MAT is 3.6 degrees Celsius Provided Keywords: Antarctica, chemical index of alteration, Eocene NCDC-Paleoclimatology https://www.ncdc.noaa.gov/data-access/paleoclimatology-data - Bauer Bruce Investigator : Passchier, S. Investigator : Ciarletta, D.J. Investigator : Miriagos, T.E. 2017-03-23 ONLINE Files online, ASCII https://www.ncdc.noaa.gov/paleo/study/21770 https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/passchier2017/passchier2017-ODP739_742_1166.xlsm https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/passchier2017/passchier2017.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/passchier2017/passchier2017-ODP739_742_1166.xlsm https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/passchier2017/passchier2017.txt English https://www.ncdc.noaa.gov/paleo/study/21770 https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/passchier2017/passchier2017-ODP739_742_1166.xlsm https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/passchier2017/passchier2017.txt Passchier, S., Ciarletta, D.J., Miriagos, T.E., Bijl, P.K., and Bohaty, S.M.2017An Antarctic stratigraphic record of stepwise ice growth through the Eocene-Oligocene transitionGeological Society of America Bulletin1293-4318-33010.1130/B31482.1 START YEAR: 35850000 cal yr BP * END YEAR: 32910000 cal yr BP 74.787 -67.696167 75.4045 -67.276167