The Thermo-Chemical State and Thermo-Tectonic Evolution of Cratons and Deep Cratonic Lithosphere

William Marsh Rice University, Houston TX

Investigators

Abstract

Adrian Lenardic A continental craton is a region that has remained tectonically stable for on the order of a billion years. Many cratons are also associated with thick lithosphere that has been isolated from mantle recycling for an equally long period of time. Understanding the factors that provide for the stability of cratons and for the longevity of deep cratonic lithosphere are related issues that bridge the gap between studies of continental tectonics and of mantle dynamics. To address these issues, the investigators will constrain the present day thermo-chemical structure and explore the thermo-tectonic evolution of the crust and mantle lithosphere below several cratons. They will work with collaborators from Montreal and Australia to collect and compile data constraints for thermal models of the cratonic lithosphere in the Canadian Shield and in Western Australia. They will then develop data constrained models for the present day thermo-chemical structure of cratonic lithosphere within these regions. The heat that comes from the convecting mantle will be treated in a fully self-consistent way and both vertical and lateral variations in lithospheric structure will be explored. The researchers will also work directly with data oriented colleagues to collect, analyse, and synthesize all the data that can constrain the evolution of target cratons. They will then explore models of coupled mantle convection and continental tectonics to isolate the factors that allow for the longevity of deep cratonic lithosphere and the stability of cratonic crust. This will be accomplished using a powerful new numerical simulation tool that has been designed to bridge the gap between mantle convection modeling and continental tectonics modeling. The advanced modeling methodology, together with the data that will be brought to bear on the problem at hand, will allow this team to develop rigorous and testable models that address the cratonization of continental crust and the longevity of cratonic lithosphere in a self-consistent manner.