Sporomorph counts, diversity, DCA and climate estimate calculations from ODP Hole 113-696B

• Main Authors: Thompson, Nick, Salzmann, Ulrich, López-Quirós, Adrián, Bijl, Peter K, Hoem, Frida, Etourneau, Johan, Sicre, Marie-Alexandrine, Roignant, Sabine, Hocking, Emma, Amoo, Michael, Escutia, Carlota
• Format: Article in Journal/Newspaper
• Language: English
• Published: PANGAEA - Data Publisher for Earth & Environmental Science 2021
• Subjects: Antarctica; Drake Passage; Eocene-Oligocene Transition; palynology; Antarc*
• Online Access: https://dx.doi.org/10.1594/pangaea.936435; https://doi.pangaea.de/10.1594/PANGAEA.936435

A total of 35 samples from the late-middle Eocene to earliest Oligocene (643.73-520.88 mbsf) were analysed for their pollen and spore content. Slides were analysed using a Leica DM500 and Leica DM2000 transmitted light microscopes at 200x and 1000x magnification. Where possible, counts of 300 (excluding reworked grains) sporomorphs were made. Only samples containing 50 or more in situ sporomorphs were used for further analysis and evaluation. Sporomorph diversity was measured using both the Shannon–Wiener index and the observed number of taxa. A rarefaction method for sums of ≥50 and ≥100 grains was applied, so that the effect caused by differences in the sample size may be removed allowing the estimation of the number of sporomorph species at a constant sample size. Detrended Correspondence Analysis (DCA) was performed, with downweighting of rare species by removing pollen types whose representation is <5%. Estimates for terrestrial mean annual temperature (MAT), mean annual precipitation (MAP), warmest month mean temperature (WMMT) and coldest month mean temperature (CMMT) were obtained using the NLR approach in conjunction with the Probability Density Function (PDF) method.