Teodora Blaj (teodora@geo.su.se) Department of Geology and Geochemistry

1. Late Eocene through Oligocene calcareous nannofossils from the paleo-equatorial Pacific OceanTaxonomy, preservation , biochronology and evolution Teodora Blaj (teodora@geo.su.se) Department of Geology and Geochemistry

2. OUTLINE METHODS Blaj, T., Henderiks, J., 2007. Smear and spray preparation techniques put to the test (II): reproducibility and accuracy of calcareous nannofossil assemblage counts.Journal of Nannoplankton Research 29, 92-100 Blaj, T., Backman, J., Raffi, I. 2009. Late Eocene to Oligocene preservation history and biochronology of calcareous nannofossils from paleo-equatorial Pacific Ocean sediments.Revista Italiana di Paleontologia e Stratigrafia 151/1, 67-85 Blaj, T., Henderiks, J., Young, J., Rehnberg, E., in review. On the nature of the Oligocene Sphenolithus evolutionary lineage: insights from the paleo-equatorial Pacific Ocean. Submitted to Journal of Micropalaeontology. Blaj, T., Young, J., in review. A new Oligocene Triquetrorhabdulus species: Triquetrorhabdulus longus sp. nov. Submitted to Journal of Nannoplankton Research. Blaj, T. manuscript to be submitted to Marine Micropaleontology. Abundance and diversity changes among calcareous nannofossil assemblages across the early/late Oligocene boundary in the paleo-equatorial Pacific Ocean. BIOCHRONOLOGY EVOLUTION TAXONOMY PALEOECOLOGY

3. WHO?Coccolithophores ("round-stone-bearers")Haptophytae Algae Coccoliths = Coccosphere + Wilson & Groom1999 Blaj 2008

4. WHERE?Pacific Ocean WHEN?Oligocene * Site 1218 http://jan.ucc.nau.edu/~rcb7/RCB.html Blaj et al., Paper III

5. WHY?Aims of study • decipher the calcareous nannofossils response to the Oligocene climate changes • detailed analysis of taxonomy, biostratigraphy, evolution, preservation and abundance/diversity fluctuations of the Oligocene nannofossils assemblage

6. HOW? Material Methods • ODP Leg 199 Site 1218 • 1484 samples – Late Eocene to Late Oligocene 35-24.4 Ma (11.6 Myrs) - biochronology • 76 samples – dissolution pattern • 522 samples – mid-Oligocene assemblage study – 30-26.5 Ma • high sample resolution: 10 cm (< 8 kyrs) • smear slide technique • astronomically calibrated timescale(Pälike et. al., 2006) • LO (lowest) and HO (highest) occurances • N/mm2 method (Backman & Shackleton, 1983) • 300 specimens/sample • morphometry: 20 samples: 100 specimens/sample • Leica DMLP & Zeiss LM • Phillips XL30 SEM – NHM, London

7. Accuracy & Reproducibility of Methods TEST: Smear vs. Spray (Blaj & Henderiks, 2007)

8. Biochronologic framework (11.6 Myrs) Triquetrorhabdulus longus sp. nov Sphenolithus evolution Nannofossils diversity (3.6 Myr) Reticulofenestra umbilicus-hillae Calcium Carbonate & nannos (1 Myr) Blaj et al., 2009

9. Fluctuating Carbonate Compensation Depth Carbonate contents & nannofossils abundances 1 million year interval across the E/O transition (34.63 – 33.63 Ma) IV III II I Blaj et al., 2009

10. Calcareous nannofossils Morphometry –Case study: (1) Reticulofenestra spp. Blaj et al., 2009

11. (2) Oligocene Sphenolithus lineage dissolution interval Blaj et al., 2009 Blaj et al., Paper III

12. Sphenolithus morphometry Blaj et al., Paper III

13. (3) Two Triquetrorhabdulus morphotypes Blaj & Young, Paper IV

14. Nannofossils diversity in the mid-Oligocene temperature/ice volume productivity/nutrients Blaj, T. Paper V

15. Cyclical variations in Nannofossils Abundance & Diversity & Other proxies

16. 3 things to remember... 1.Late Eocene and E/O interval all complete/all broken nannofossils closely reflects the changes in carbonate content 2. nannofossil morphometry – a powerfull tool 3. Mid-Oligocene nannofossil assemblages show cyclicity in composition and diversity; However, it is difficult to linearly correlate these changes with changes in temperature and/or productivity conditions

17. Thank you!