Passive margins getting squeezed in the mantle convection vice - INSU - Institut national des sciences de l'Univers Access content directly
Journal Articles Tectonics Year : 2013

Passive margins getting squeezed in the mantle convection vice

Abstract

Passive margins often exhibit uplift, exhumation, and tectonic inversion. We speculate that the compression in the lithosphere gradually increased during the Cenozoic, as seen in the number of mountain belts found at active margins during that period. Less clear is how that compression increase affects passive margins. In order to address this issue, we design a 2-D viscous numerical model wherein a lithospheric plate rests above a weaker mantle. It is driven by a mantle conveyor belt, alternatively excited by a lateral downwelling on one side, an upwelling on the other side, or both simultaneously. The lateral edges of the plate are either free or fixed, representing the cases of free convergence, and collision (or slab anchoring), respectively. This distinction changes the upper mechanical boundary condition for mantle circulation and thus, the stress field. Between these two regimes, the flow pattern transiently evolves from a free-slip convection mode toward a no-slip boundary condition above the upper mantle. In the second case, the lithosphere is highly stressed horizontally and deforms. For a constant total driving force, compression increases drastically at passive margins if upwellings are active. Conversely, if downwellings alone are activated, compression occurs at short distances from the trench and extension prevails elsewhere. These results are supported by Earth-like models that reveal the same pattern, where active upwellings are required to excite passive margins compression. Our results substantiate the idea that compression at passive margins is in response to the underlying mantle flow that is increasingly resisted by the Cenozoic collisions.
Fichier principal
Vignette du fichier
Yamato_et_al_2013_Tectonics.pdf (3.78 Mo) Télécharger le fichier
Origin Publisher files allowed on an open archive
Loading...

Dates and versions

insu-00945535 , version 1 (13-02-2014)

Identifiers

Cite

Philippe Yamato, Laurent Husson, Thorsten W. Becker, Kevin Pedoja. Passive margins getting squeezed in the mantle convection vice. Tectonics, 2013, 32 (6), pp.1559-1570. ⟨10.1002/2013TC003375⟩. ⟨insu-00945535⟩
236 View
300 Download

Altmetric

Share

Gmail Mastodon Facebook X LinkedIn More