Horizontal stress in planetary lithospheres from vertical processes

Abstract

Understanding the stress states in a lithosphere is of fundamental importance for planetary geophysics. It is closely linked to the processes which form and modify tectonic features on the surface and reflects the behavior of the planet's interior, providing a constraint for the difficult problem of determining interior structure and processes. The tectonics on many extraterrestrial bodies (Moon, Mars, and most of the outer planet satellites) appears to be mostly vertical, and the horizontal stresses induced by vertical motions and loads are expected to dominate the deformation of their lithospheres. Herein, only changes are examined in the state of stress induced by processes such as sedimentary and volcanic deposition, erosional denudation, and changes in the thermal gradient that induce uplift or subsidence. This analysis is important both for evaluating stresses for specific regions in which the vertical stress history can be estimated, as well as for applying the proper loading conditions to global stress models. All references to lithosphere herein should be understood to refer to the elastic lithosphere, that layer which deforms elastically or brittlely when subjected to geologically scaled stresses.