Magnetostrategraphy and rock-magnetism of the Mead Stream section (Late Cretaceous - mid Eocene), New Zealand

• Applicant: Professor Dr. Valerian Bachtadse
• Subject Area: Geophysics ; Palaeontology
• Term: from 2012 to 2018
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 213849507

• Final Report Year: 2017

Final Report Abstract

The Cretaceousearly Cenozoic world was dominated by warm conditions and the general absence of ice sheets. During the late PaleoceneEarly Eocene, the Earth witnessed an extreme global warming which culminated in the Early Eocene climatic optimum (EECO), lasting from ∼53 to 50Ma. The EECO was followed by a long-term cooling trend that continued over the ensuing Middle to late Eocene, interrupted at ∼41.5Ma by the ∼600kyr-long middle Eocene climatic optimum (MECO). Pacific sedimentary records and their inventory are particularly important for understanding the evolution of global climate during early Paleogene, since 80% of the heat transport occurred here. Within the framework of this project we collected samples from the Early to Middle Eocene part of the Mead Stream section (Clarence Valley, South Island, New Zealand) as well as from the Early-Middle Eocene Mid-Waipara River section (North Canterbury, South Island, New Zealand).Magnetostratigraphic results indicate that the Mid-Waipara River section extends in stratigraphic continuity from Chron C23n to Chron C21n (from ∼51.5 to 47Ma), with an average sedimentation rate of 9.9 m/Myr. These data have been integrated with a revised interpretation of the magnetic polarity stratigraphy of IODP Site U1356 (Wilkes Land Margin, Antarctica) resulting for the first time in a robust magnetostratigraphy for the latest Paleoce-Eocene. The Mead Stream section ranges from Chron C24r to C18n (from ∼55 to 39Ma), with an average sedimentation rate of 22.3 m/Myr. Short term increases in sedimentation rates, observed at Mead Stream as well as at mid Waipara can be linked to several EECO events and reflect increased erosional processes on the continents during elevated temperatures. Preliminary data from coeval and slightly older marine deposits from New Caledonia support this interpretation. The identification of Chrone C20r and calcareous nannofossil Zone CNE10 is coinciding with the transition from pelagic to turbiditic sedimentation and thus represents the first magneto-biostratigraphic calibrated age of the compression inception in northern Zealandia, which likely to be related to the Tonga-Kermadec subduction initiation.

Publications

• (2018) Magneto-biostratigraphic constraints of the Eocene micrite–calciturbidite transition in New Caledonia: tectonic implications. New Zealand Journal of Geology and Geophysics 61 (2) 145–163
  Dallanave, Edoardo; Agnini, Claudia; Pascher, Kristina M.; Maurizot, Pierre; Bachtadse, Valerian; Hollis, Christopher J.; Dickens, Gerald R.; Collot, Julien; Monesi, Edoardo
  
• (2012), Early-middle Eocene chronology of the Southern Ocean :Magnetostratigraphic data from the South Island of New Zealand. Abstract GP12A- 03 In: AGU Fall Meeting 2012, 3-7 December, San Francisco California : abstracts. Washington, DC: American Geophysical Union
  Dallanave, E., Bachtadse, V., Agnini, C., Muttoni, G., Hollis, C.J., Morgans, H.E.G., Crampton, J.S.
  
• (2014), Early to middle Eocene magnetobiochronology of the southwest Pacific Ocean and climate influence on sedimentation : new data from the Mead Stream section (Marlborough, New Zealand). Abstract GP23B-3681 In: AGU Fall Meeting, San Francisco, 15-19 December 2014. American Geophysical Union
  Dallanave, E., Agnini, C., Bachtadse, V., Muttoni, G., Crampton, J.S., Strong, C.P., Hines, B., Hollis, C.J., Slotnick, B.
  
• (2014), Early-middle Eocene magneto-biochronology of the Southern Pacific Ocean : new data from the South Island of New Zealand. p. 50-51. In: Dickens, G.R.; Luciani, V. (ed) Climatic and Biotic Events of the Paleogene 2014, CBEP 2014 : selected short notes and abstracts : Ferrara, Italy, July 1-6, 2014. Rome: Societa Geologica Italiana. Rendiconti Online 31
  Dallanave, E., Bachtadse, V., Agnini, C., Muttoni, G., Hollis, C.J., Hines, B.R., Morgans, H.E.G., Strong, C.P., Tauxe, L., Crampton, J.S.
  
• (2015), Early to Middle Eocene chronology of Zealandia: Magnetostratigraphic data from New Zealand and New Caledonia. p. 26-27 In: Hannah, M. (convener) Zealandia in space and time: Geosciences 2015, Geoscience Society of New Zealand, 25th-27th November 2015: abstract volume. Wellington, N.Z.: Geoscience Society of New Zealand. Geoscience Society of New Zealand miscellaneous publication 143a
  Dallanave, E., Bachtadse, V., Hollis, C.J.,Maurizot, P., Collot, J., Strogen, D.P., Crouch, E.M.,Morgans, H.E.G., Shepherd, C.L., Dickens, G.R.
  
• (2015), Early to middle Eocene Magneto-biochronology of the southwest Pacific Ocean and climate influence on sedimentation: Insights from the Mead Stream section, New Zealand, Geological Society of America Bulletin, 127(5/6), 643-660
  Dallanave, Edoardo, Claudia Agnini, Valerian Bachtadse, Giovanni Muttoni, James S. Crampton, C. Percy Strong, Benjamin R. Hines, Christopher J. Hollis, and Benjamin S. Slotnick
  
• (2016), Constraining early to middle Eocene climate evolution of the Southwest Pacific and Southern Ocean, Earth and Planetary Science Letters, 433, 380-392
  Dallanave, Edoardo, Valerian Bachtadse, Erica M. Crouch, Lisa Tauxe, Claire L. Shepher, Hugh E. Morgans, Christopher J. Hollis, Benjamin R. Hines, and Saiko Sugisaki