Global patterns of Earth's dynamic topography since the Jurassic
Michael Rubey1, Sascha Brune2, Christian Heine3, David Rhodri Davies4, Simon E. Williams1, and Ralph Dietmar Müller11Earthbyte Group, School of Geosciences, The University of Sydney, Australia 2Helmholtz Centre Potsdam, GFZ German Research Centre for Geosciences, Potsdam, Germany 3Shell International Exploration & Production B.V., The Hague, Netherlands 4Research School of Earth Sciences, The Australian National University, Canberra, Australia
Received: 05 Mar 2017 – Accepted for review: 12 Mar 2017 – Discussion started: 23 Mar 2017
Abstract. We evaluate the spatial and temporal evolution of Earth’s long-wavelength surface dynamic topography since the Jurassic, using a series of high-resolution global mantle convection models. These models are Earth-like in terms of convective vigour, thermal structure, surface heat-flux and the geographic distribution of heterogeneity. The models generate a degree-2 dominated spectrum of dynamic topography, with negative amplitudes above subducted slabs (i.e. circum-Pacific regions and southern Eurasia) and positive amplitudes elsewhere (i.e. Africa, north-west Eurasia and the central Pacific). Model predictions are compared with published observations and subsidence patterns from well data, both globally and for the Australian and South African regions. We find that our models reproduce the long-wavelength component of these observations, although observed smaller-scale variations are not reproduced. We subsequently define “geodynamic rules” for how different surface tectonic settings are affected by mantle processes: (i) locations in the vicinity of a subduction zone show large negative dynamic topography amplitudes; (ii) regions far away from convergent margins feature long-term positive dynamic topography; (iii) rapid variations in dynamic support occur along the margins of overriding plates (e.g. Western US) and at points located on a plate that rapidly approaches a subduction zone (e.g. India and Arabia). Our models provide a predictive quantitative framework linking mantle convection with plate tectonics and sedimentary basin evolution, thus improving our understanding of how subduction and mantle convection affect the spatio-temporal evolution of basin architecture.
Rubey, M., Brune, S., Heine, C., Davies, D. R., Williams, S. E., and Müller, R. D.: Global patterns of Earth's dynamic topography since the Jurassic, Solid Earth Discuss., doi:10.5194/se-2017-26, in review, 2017.