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Middle Miocene environmental change in the eastern Atlantic Ocean at the Porcupine Basin (IODP Leg 307) : results from an integrated palynological and biogeochemical study

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Abstract
The relatively warm climate of the Miocene reached peak values during the middle Miocene Climatic Optimum (MMCO; 17-14.5 Ma). After the MMCO, the global climate started cooling. This happened through several short-lived cooling events, represented by positive oxygen isotope excursions: the Mi-events. These disturbances can be associated with growth of the East Antarctic Ice Sheet and potentially Northern Hemisphere ice expansion. The causes and consequences of the Mi-events are not well constrained. For this reason we want to examine the role of the Gulf Stream in the cooling and subsequent warming of the Mi-events, since it is a possible mechanism to amplify regional changes in northwestern Europe. Integrated Ocean Drilling Program (IODP) Leg 307 recovered a high resolution record from the middle Miocene of the Porcupine Basin, offshore southwestern Ireland and therefore under the influence of the Gulf Stream. We have extracted well-preserved palynomorphs (mainly organic-walled dinoflagellate cysts, acritarchs, some pollen) and organic molecules for paleothermometry (e.g. TEX86 and UK'37) from core 1318B. With these proxies the development of the Mi-3 and Mi-4 events are reconstructed on high resolution, by assessing e.g. temperature, sea level, thermocline depth and productivity. First results indicate a pronounced cooling as recorded simultaneously in TEX86, Uk'37 and dinoflagellate cyst assemblages during Mi-4. The presented results will focus in detail on the phasing and rates of change in the reconstructed Mi-events.

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MLA
Quaijtaal, Willemijn, Stefan Schouten, Timme Donders, et al. “Middle Miocene Environmental Change in the Eastern Atlantic Ocean at the Porcupine Basin (IODP Leg 307) : Results from an Integrated Palynological and Biogeochemical Study.” Proceedings of the 34th International Geological Congress 2012. Brisbane, QLD, Australia: Australian Geosciences Council, 2012. Print.
APA
Quaijtaal, W., Schouten, S., Donders, T., & Louwye, S. (2012). Middle Miocene environmental change in the eastern Atlantic Ocean at the Porcupine Basin (IODP Leg 307) : results from an integrated palynological and biogeochemical study. Proceedings of the 34th International Geological Congress 2012. Presented at the 34th International Geological Conference (IGC), Brisbane, QLD, Australia: Australian Geosciences Council.
Chicago author-date
Quaijtaal, Willemijn, Stefan Schouten, Timme Donders, and Stephen Louwye. 2012. “Middle Miocene Environmental Change in the Eastern Atlantic Ocean at the Porcupine Basin (IODP Leg 307) : Results from an Integrated Palynological and Biogeochemical Study.” In Proceedings of the 34th International Geological Congress 2012. Brisbane, QLD, Australia: Australian Geosciences Council.
Chicago author-date (all authors)
Quaijtaal, Willemijn, Stefan Schouten, Timme Donders, and Stephen Louwye. 2012. “Middle Miocene Environmental Change in the Eastern Atlantic Ocean at the Porcupine Basin (IODP Leg 307) : Results from an Integrated Palynological and Biogeochemical Study.” In Proceedings of the 34th International Geological Congress 2012. Brisbane, QLD, Australia: Australian Geosciences Council.
Vancouver
1.
Quaijtaal W, Schouten S, Donders T, Louwye S. Middle Miocene environmental change in the eastern Atlantic Ocean at the Porcupine Basin (IODP Leg 307) : results from an integrated palynological and biogeochemical study. Proceedings of the 34th International Geological Congress 2012. Brisbane, QLD, Australia: Australian Geosciences Council; 2012.
IEEE
[1]
W. Quaijtaal, S. Schouten, T. Donders, and S. Louwye, “Middle Miocene environmental change in the eastern Atlantic Ocean at the Porcupine Basin (IODP Leg 307) : results from an integrated palynological and biogeochemical study,” in Proceedings of the 34th International Geological Congress 2012, Brisbane, QLD, Australia, 2012.
@inproceedings{4414521,
  abstract     = {The relatively warm climate of the Miocene reached peak values during the middle Miocene Climatic Optimum (MMCO; 17-14.5 Ma). After the MMCO, the global climate started cooling. This happened through several short-lived cooling events, represented by positive oxygen isotope excursions: the Mi-events. These disturbances can be associated with growth of the East Antarctic Ice Sheet and potentially Northern Hemisphere ice expansion. The causes and consequences of the Mi-events are not well constrained. For this reason we want to examine the role of the Gulf Stream in the cooling and subsequent warming of the Mi-events, since it is a possible mechanism to amplify regional changes in northwestern Europe. Integrated Ocean Drilling Program (IODP) Leg 307 recovered a high resolution record from the middle Miocene of the Porcupine Basin, offshore southwestern Ireland and therefore under the influence of the Gulf Stream. We have extracted well-preserved palynomorphs (mainly organic-walled dinoflagellate cysts, acritarchs, some pollen) and organic molecules for paleothermometry (e.g. TEX86 and UK'37) from core 1318B. With these proxies the development of the Mi-3 and Mi-4 events are reconstructed on high resolution, by assessing e.g. temperature, sea level, thermocline depth and productivity. First results indicate a pronounced cooling as recorded simultaneously in TEX86, Uk'37 and dinoflagellate cyst assemblages during Mi-4. The presented results will focus in detail on the phasing and rates of change in the reconstructed Mi-events.},
  author       = {Quaijtaal, Willemijn and Schouten, Stefan and Donders, Timme and Louwye, Stephen},
  booktitle    = {Proceedings of the 34th International Geological Congress 2012},
  isbn         = {9780646578002},
  language     = {eng},
  location     = {Brisbane, QLD, Australia},
  publisher    = {Australian Geosciences Council},
  title        = {Middle Miocene environmental change in the eastern Atlantic Ocean at the Porcupine Basin (IODP Leg 307) : results from an integrated palynological and biogeochemical study},
  year         = {2012},
}