%0 Conference Proceedings %T The many impacts of building mountain belts on plate tectonics andmantle flow %+ Géosciences Rennes (GR) %+ Institut des Sciences de la Terre (ISTerre) %A Yamato, Philippe %A Husson, Laurent %< avec comité de lecture %( Geophysical Research Abstracts %B European Geoscience Union General Assembly 2015 %C Vienne, Austria %V 17 %P EGU2015-5836 %8 2015-04-12 %D 2015 %Z Sciences of the Universe [physics]/Earth SciencesConference papers %X During the Cenozoic, the number of orogens on Earth increased. This observation readily indicates that in the sametime, compression in the lithosphere became gradually more and more important. Such an increase of stresses inthe lithosphere can impact on plate tectonics and mantle dynamics.We show that mountain belts at plate boundaries increasingly obstruct plate tectonics, slowing down and reorientingtheir motions. In turn, this changes the dynamic and kinematic surface conditions of the underlying flowingmantle. Ultimately, this modifies the pattern of mantle flow. This forcing could explain many first order featuresof Cenozoic plate tectonics and mantle flow. Among these, one can cite the compression of passive margins, theimportant variations in the rates of spreading at oceanic ridges, or the initiation of subduction, the onset of obduction,for the lithosphere. In the mantle, such change in boundary condition redesigns the pattern of mantle flowand, consequently, the oceanic lithosphere cooling.In order to test this hypothesis we first present thermo-mechanical numerical models of mantle convection abovewhich a lithosphere rests. Our results show that when collision occurs, the mantle flow is highly modified, whichleads to (i) increasing shear stresses below the lithosphere and (ii) to a modification of the convection style. Inturn, the transition between a “free” convection (mobile lid) and an “upset” convection (stagnant –or sluggish- lid)highly impacts the dynamics of the lithosphere at the surface of the Earth. Thereby, on the basis of these modelsand a variety of real examples, we show that on the other side of a collision zone, passive margins become squeezedand can undergo compression, which may ultimately evolve into subduction or obduction.We also show that muchfurther, due to the blocking of the lithosphere, spreading rates decrease at the ridge, a fact that may explain a varietyof features such as the low magmatism of ultraslow spreading ridges or the departure of slow spreading ridges fromthe half-space cooling model. %G English %L insu-01137645 %U https://insu.hal.science/insu-01137645 %~ INSU %~ UNIV-SAVOIE %~ UNIV-RENNES1 %~ UGA %~ UR2-HB %~ CNRS %~ UNIV-GRENOBLE1 %~ OSUG %~ GR %~ OSUR %~ ISTERRE %~ UR1-HAL %~ UR1-SDLM %~ UR1-SDLMJONCH %~ GR-3T %~ UNIV-RENNES2 %~ TEST-UNIV-RENNES %~ TEST-UR-CSS %~ UNIV-RENNES %~ INRAE %~ USMB-COMUE %~ UR1-ENV %~ GR-DEMO