Physics of the Earth and Planetary Interiors 164 (2007) 2–20 Effects of latent heat release at phase boundaries on flow in the Earth’s mantle, phase boundary topography and dynamic topography at the Earth’s surface Bernhard Steinberger a,b,∗ a Bayerisches Geoinstitut, Universit¨ at Bayreuth, D-95440 Bayreuth, Germany b Center for Geodynamics, NGU, N-7491 Trondheim, Norway Received 17 August 2005; received in revised form 16 April 2007; accepted 23 April 2007 Abstract Mantle flow models that do not consider the effects of latent heat on phase boundaries typically predict dynamic surface topography too large to be compatible with observations. Here these effects were implemented in a mantle flow model and resulting changes in dynamic topography and topography of phase boundaries were computed. Inclusion of these effects was found to reduce the rms amplitude of dynamic topography by about 50–60 m, still leaving a substantial misfit from observations in most cases considered. Generally, it also leads to a slight improvement of correlation with dynamic surface and phase boundary topography constrained by observations. Results thus indicate that the model implemented here is applicable to the Earth, but that other effects need to be considered as well in order to fully explain phase boundary and dynamic surface topographies. © 2007 Elsevier B.V. All rights reserved. Keywords: Latent heat; Phase boundary topography; Mantle flow; Dynamic topography 1. Introduction Lateral variations of density in the Earth’s mantle cause solid-state flow, which is the underlying cause for motion of tectonic plates. This flow field can be com- puted (e.g. Hager and O’Connell, 1979, 1981) based on various assumptions about the density field, rheol- ogy, etc. In order to assess how realistic the computed flow field is, certain quantities that can be compared to observations can be derived from the flow field. One of those quantities is dynamic topography: The sur- ∗ Correspondence address: Center for Geodynamics, NGU, N-7491 Trondheim, Norway. E-mail address: bernhard.steinberger@ngu.no. URL: www.geodynamics.no/steinberger/. face will be uplifted above upwellings and depressed above downwellings. It is not straightforward to com- pare dynamic topography with observations, because topography isostatically compensated in the crust and topography due to ocean floor cooling both need to be subtracted from observed topography, and the “resid- ual topography” obtained after these two subtractions is considerably uncertain. A number of efforts to com- pare dynamic topography with observations, and/or to use dynamic topography as a constraint to improve models of mantle density and flow have been made over recent years (Lithgow-Bertelloni and Silver, 1998; Kaban et al., 1999; Pari and Peltier, 2000; Panasyuk and Hager, 2000a,b; Steinberger et al., 2001; ˇ Cadek and Fleitout, 2003). While the results of the various studies are discrepant to a certain degree, because of different 0031-9201/$ – see front matter © 2007 Elsevier B.V. All rights reserved. doi:10.1016/j.pepi.2007.04.021