DOI: 10.25921/vc7s-6549
title: NOAA/WDS Paleoclimatology - Prydz Bay, East Antarctica 36-33ma Biomarker Data and Climate Reconstructions

description: The Eocene-Oligocene Transition (EOT) marks the onset of Antarctic glaciation at 33.7 Ma. Although the benthic d18O record defines the major continental ice sheet expansion, recent sedimentary and geochemical evidence suggests the presence of earlier ephemeral ice sheets. Sediment cores from Ocean Drilling Program (ODP) Legs 119 and 188 in Prydz Bay provide an archive of conditions in a major drainage system of East Antarctica. We study biomarker and microfossil evidence to discern how the vegetation and climate shifted between 36-33 Ma. Pollen were dominated by reworked Permian Glossopterid gymnosperms; however, penecontemporaneous Eocene pollen assemblages indicate that vegetation such as moss, ferns, southern beech and podocarp trees grew in the region and survived the glacial advances suggesting some non-glaciated land. At the EOT, brGDGT soil biomarkers indicate abrupt cooling from 13-8C and soil pH increases from 6.0 to 6.7, suggesting drying. The biomarker proxies record cooling in under 50 ka, compared to the gradual trend detected by weathering proxies. Plant wax dD and d13C show further evidence for drying with shifts of 20 per mil and 1.1 per mil respectively across the EOT. Although the terrestrial soil biomarker influx mostly precludes use of TEX86, a few determinations find sea surface temperatures of 12C in the late Eocene cooling to 8C at the EOT. Marine productivity undergoes a sustained increase after the glacial advance, whether promoted by glacial nutrient flux and/or enhanced overturning circulation. Between the two glacial surge events of the Priabonian Oxygen Maximum (PrOM) at 37.3 Ma and the EOT at 33.7 Ma, we observe three warm events at 35.8, 34.9 and 34.7 Ma with a rise in temperature of 2-5C and increases in penecontemporaneous pollen and enhanced marine productivity, capturing the last flickers of Antarctic warmth before almost complete glaciation at the EOT.
description: Biomarker and pollen data from 4 ODP cores collected in Prydz Bay, East Antarctica, for 36-33 million years BP,
        plus SST and air temperature reconstructions.
         Provided Keywords: Ocean Drilling Program; Expedition 119; Site 739; Site 742; Expedition 188; Site 1166; biomarkers

 Sample List for Pollen Samples (working half of core).
 Composite depth based on Passchier et al. 2017.

 site  hole    core    type    sect    top     bottom  depth_m mcd_m   age_ma  IODP_ID
 739   C       28      R       2       35      36      204.365 204.365 32.926  119-739C-28R-2-W 35/36-TIBBETT
 739   C       29      R       3       63      64      215.835 215.835 33.004  119-739C-29R-3-W 63/64-TIBBETT
 739   C       30      R       5       5       6       227.855 227.855 33.085  119-739C-30R-5-W 5/6-TIBBETT
 739   C       31      R       3       73      74      235.135 235.135 33.135  119-739C-31R-3-W 73/74-TIBBETT
 739   C       33      R       2       60      61      252.805 252.805 33.255  119-739C-33R-2-W 60/61-TIBBETT
 739   C       33      R       6       73      74      258.935 258.935 33.297  119-739C-33R-6-W 73/74-TIBBETT
 739   C       34      R       3       84      85      264.245 264.245 33.333  119-739C-34R-3-W 84/85-TIBBETT
 739   C       35      R       3       4       5       273.045 273.045 33.393  119-739C-35R-3-W 4/5-TIBBETT
 739   C       36      R       2       52      53      281.725 281.725 33.452  119-739C-36R-2-W 52/53-TIBBETT
 739   C       36      R       5       62      63      286.325 286.325 33.483  119-739C-36R-5-W 62/63-TIBBETT
 739   C       38      R       3       109     110     302.995 302.995 33.596  119-739C-38R-3-W 109/110-TIBBETT
 739   C       39      R       1       117     118     309.775 309.775 33.642  119-739C-39R-1-W 117/118-TIBBETT
 739   C       40      R       1       133     134     319.535 319.535 33.709  119-739C-40R-1-W 133/134-TIBBETT
 739   C       41      R       3       18      19      330.985 330.985 33.787  119-739C-41R-3-W 18/19-TIBBETT
 739   C       42      R       2       117     118     340.175 340.175 33.849  119-739C-42R-2-W 117/118-TIBBETT
 739   C       46      R       2       4       5       377.745 377.745 34.105  119-739C-46R-2-W 4/5-TIBBETT
 739   C       47      R       1       45      46      386.355 386.355 34.163  119-739C-47R-1-W 45/46-TIBBETT
 739   C       48      R       1       125     126     396.855 396.855 34.235  119-739C-48R-1-W 125/126-TIBBETT
 739   C       51      R       1       66      67      425.165 425.165 34.427  119-739C-51R-1-W 66/67-TIBBETT
 739   C       56      R       1       25      26      453.755 453.755 34.622  119-739C-56R-1-W 25/26-TIBBETT
 739   C       58      R       2       61      62      465.315 465.315 34.700  119-739C-58R-2-W 61/62-TIBBETT
 739   C       60      R       1       32      33      473.225 473.225 34.754  119-739C-60R-1-W 32/33-TIBBETT
 742   A       20      R       1       119     120     172.495 483.925 34.827  119-742A-20R-1-W 119/120-TIBBETT
 742   A       20      R       2       68      69      173.485 484.915 34.833  119-742A-20R-2-W 68/69-TIBBETT
 742   A       21      R       1       18      19      181.185 492.615 34.886  119-742A-21R-1-W 18/19-TIBBETT
 742   A       21      R       3       45      46      184.455 495.885 34.908  119-742A-21R-3-W 45/46-TIBBETT
 742   A       22      R       1       122     123     191.925 503.355 34.959  119-742A-22R-1-W 122/123-TIBBETT
 742   A       26      R       1       37      38      229.575 541.005 35.215  119-742A-26R-1-W 37/38-TIBBETT
 742   A       27      R       7       44      45      248.245 559.675 35.342  119-742A-27R-7-W 44/45-TIBBETT
 742   A       29      R       6       78      79      266.385 577.815 35.465  119-742A-29R-6-W 78/79-TIBBETT
 742   A       32      R       4       107     108     292.675 604.105 35.644  119-742A-32R-4-W 107/108-TIBBETT
 742   A       33      R       6       48      49      304.685 616.115 35.726  119-742A-33R-6-W 48/49-TIBBETT
 742   A       34      R       1       33      34      306.635 618.065 35.739  119-742A-34R-1-W 33/34-TIBBETT
 1166  A       15      R       5       44      45      138.995 618.985 35.731  188-1166A-15R-5-W 44/45-TIBBETT
 1166  A       16      R       2       86      87      144.565 624.555 35.740  188-1166A-16R-2-W 86/87-TIBBETT
 1166  A       16      R       3       29      30      145.495 625.485 35.741  188-1166A-16R-3-W 29/30-TIBBETT
 1166  A       17      R       1       13      14      151.535 631.525 35.750  188-1166A-17R-1-W 13/14-TIBBETT
 1166  A       17      R       3       114     115     155.545 635.535 35.756  188-1166A-17R-3-W 114/115-TIBBETT
1166  A       18      R       1       11      12      161.115 641.105 35.765  188-1166A-18R-1-W 11/12-TIBBETT