TECTONIC FEEDBACK AND THE ORDERING OF HEAT PRODUCING ELEMENTS WITHIN THE CONTINENTAL LITHOSPHERE

Abstract

The distribution of the heat producing elements within the lithosphere provides an important control on continental thermal regimes and the mechanical strength of the lithosphere. Moreover, the strong temperature dependence of lithospheric rheology suggests the possibility of an important feedback between deformation and the distribution of heat producing elements. Simple models for lithospheric rheology are used to illustrate how such feedback might serve as an important control on both the characteristic abundance of, and spatial variation in, the heat production elements in the crust. These models also imply that the organisation of heat producing elements is essential for the long-term tectonic stabilisation of the continental crust. This is particularly relevant to the evolution of cratons in early Earth history, wherein lies the most dramatic evidence for the role played by tectonic processes in achieving a stable ordering of the heat producing elements.