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Reconstructing middle Miocene tectonic boundary conditions. Nicholas Herold, Seton, M., Müller , R. D. and You., J. University of Cambridge 11 th August, 2008. This talk. Part 1. Reconstructing the oceans Part 2. Reconstructing topography
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Reconstructing middle Miocene tectonic boundary conditions Nicholas Herold, Seton, M., Müller, R. D. and You., J. University of Cambridge 11th August, 2008
This talk... Part 1. Reconstructing the oceans Part 2. Reconstructing topography Part 3. Reconstructing middle Miocene palaeogeography – is it worth it? Part 4. Combining palaeogeography with other model boundary conditions
Why the Miocene? Miocene Climatic Optimum (MCO) TIME (Ma) Zachos et al. (2001)
Sediment thickness Global modern sediment thickness: http://www.ngdc.noaa.gov/mgg/sedthick/sedthick.html
Large igneous provinces (LIPs) With surrounding seafloor Without surrounding seafloor
Bathymetric reconstruction Age converted depth Age Sediment thickness LIPS
Topography/bathymetry MIOCENE MODERN
Adjustments for climate models Narrow gateways Marginal seas
General Circulation Model • NCAR Community Atmosphere Model and Community Land Model. • ~3.75° x 3.75° horizontal resolution, 26 atmospheric layers. atm lnd ice cpl ocn
Combining palaeogeography with other boundary conditions • Other boundary conditions • - Greenhouse gases • - Orbital parameters • Solar constant • River Transport
Model-data temperature discrepancies Mean discrepancy: -1.7°C
Model-data precipitation discrepancies Mean discrepancy: -172 mm/year
In summary • New Miocene palaeogeography. • Preliminary results of a Miocene climate simulation: too cool and arid compared to proxy data. • Need to run coupled climate simulations using new palaeogeography in order to better resolve and understand proxy-model discrepancies.
Thanks... • Müller, R.D., Sdrolias, M., Gaina, C. and Roest, W.R., 2008. Age, spreading rates and spreading asymmetry of the world's ocean crust. Geochemistry, Geophysics, Geosystems.: Q04006. • Müller, R.D., Sdrolias, M., Gaina C., Steinberger B. and C., H., 2008. Long-Term Sea-Level Fluctuations Driven by Ocean Basin Dynamics. Science, 319(5868): 1357-1362.
References • Stampfli, G.M. and Borel, G.D., 2002. A plate tectonic model for the Paleozoic and Mesozoic constrained by dynamic plate boundaries and restored synthetic oceanic isochrons. Earth and Planetary Science Letters, 196(1-2): 17-33.