Crust-mantle decoupling by flexure of continental lithosphere

Rayleigh-wave dispersion reveals crust-mantle decoupling beneath eastern Tibet

The Tibetan Plateau results from the collision of the Indian and Eurasian Plates during the Cenozoic, which produced at least 2,000 km of convergence. Its tectonics is dominated by an eastward extrusion of crustal material that has been explained by models implying either a mechanical decoupling between the crust and the lithosphere, or lithospheric deformation. Discriminating between these end...

Chemical differentiation of the Earth: the relationship between mantle, continental crust, and oceanic crust

The average chemical compositions of the continental crust and the oceanic crust (represented by MORB), normalized to primitive mantle values and plotted as functions of the apparent bulk partition coefficient of each element, form surprisingly simple, complementary concentration patterns. In the continental crust, the maximum concentrations are on the order of 50 to 100 times the primitive-man...

Global Decoupling of Crust and Mantle: Implications for Topography, Geoid and Mantle Viscosity on Venus

The surface of Venus is so hot that the lower crust may be weak enough to allow decoupling of mantle and crust. An analytic model of such decoupling assumes that the shallow mande forms the top boundary layers of large scale mantle convection cells. Crustal flow is driven by the motion of the marie and by topographically induced pressure gradients. The model predicts that the lowest lowlands ar...

Isostasy and Flexure of the Lithosphere

A tensile, flexural model for the initiation of subduction

S U M M A R Y We argue that subduction may be initiated at passive continental margins without shortening the lithosphere. Overcoming the lithosphere’s high compressive strength requires special circumstances, and these make it difficult to explain the nearly complete recycling of old sea-floor. Instead, we present a model that predicts tensile decoupling of the continental and oceanic lithosph...