Mathematics – Logic
Scientific paper
Sep 2002
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2002e%26psl.202..303m&link_type=abstract
Earth and Planetary Science Letters, Volume 202, Issue 2, p. 303-320.
Mathematics
Logic
13
Scientific paper
Removal or delamination of the lithospheric mantle in a late stage of mountain building is a process often invoked to explain syn orogenic extension, high temperature metamorphism, magmatism and uplift. One mechanism that could explain the lithospheric root detachment is the development of convective instabilities within the peridotitic lithosphere due to its high density. This mechanism is studied by two-dimensional convective numerical simulations in the simple case of a strongly temperature dependent viscous rheology appropriate for upper mantle rocks. We neglect here the weakening effect of a brittle rheology and of a crustal layer, and therefore we did not model tectonic deformations. Depending on the upper mantle viscosity and activation energy, a 300 km thick root can be inferred to be either indefinitely stable or to thicken with time or to thin with time. When the lithosphere is initially thicker than its equilibrium thickness, the convective flow at the base and on the sides of the lithospheric root is strong enough to cancel downwards heat conduction and to progressively remove the root. This flow is due to the finite density perturbations induced by the topography of the isotherms on the base and at the sides of the root. We derive two general parameterizations of the convective removal duration as a function of the equilibrium thickness, the thickening factor, the root width, and the rheological temperature scale. Using these relationships, and assuming that the lithospheric equilibrium thickness is about 100 km, the removal duration of a 250 km thick root ranges from 55 to 750 Myr depending on the root width. It is too small to explain the long term stability of cratonic lithospheric root, but too long to explain any sudden change in the stress and strain states in mountain belts development.
Doin Marie-Pierre
Dumoulin Caroline
Morency Christina
No associations
LandOfFree
Convective destabilization of a thickened continental lithosphere does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Convective destabilization of a thickened continental lithosphere, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Convective destabilization of a thickened continental lithosphere will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1045976