Uniting brittle and ductile deformation in extensional basins

Albert de Montserrat Navarro, Jason Morgan, Robert Hall & Lloyd White

Background

The Earth has an amazingly flexible rheology, with brittle fault-like deformation predominating near the surface, and ductile deformation dominating in hotter deeper rocks. Fault zones are thought to deform by brittle and ductile modes of deformation occurring at different spatial locations within the deforming lithosphere. Typically, numerical modelling studies of extension processes have used techniques that work well for idealizing brittle deformation (e.g. discrete element techniques), or ductile deformation (e.g. finite element techniques), but not both simultaneously.

Aims

This project will involve the development of a 2D numerical model that simultaneously includes both discrete element and finite element subdomains. To test this hybrid deformation code we will compare its predictions for the evolution of an extensional basinal system with previous analogue experiments and numerical models. Coding will be done using MATLAB and parallel-MATLAB, which allows us to combine these new deformation codetools with previous finite element codetools developed to model heat transport and melting processes. The resulting code will be used to model the evolution of extensional processes in one or more basins associated with Indonesian back-arc and within-arc regions that are currently being explored by the SE Asia Research Group.

Recent Papers –

Max Webb et al., 2020. Isotopic mapping reveals the location of crustal fragments along a long-lived convergent plate boundary. Lithos.

https://doi.org/10.1016/j.lithos.2020.105687

Max Webb et al., 2020. The history of Cenozoic magmatism and collision in NW New Guinea – New insights into the tectonic evolution of the northernmost margin of the Australian Plate. Gondwana Research.

https://doi.org/10.1016/j.gr.2019.12.010

Amy Gough et al., 2020. Mid-Cenozoic fluvio-deltaic to marine environments of the Salin Sub-basin, Central Myanmar. Journal of Asian Earth Sciences.

https://doi.org/10.1016/j.jseaes.2019.104143

Recent News –

Amy Gough and Max Webb attended the Restech 2.0 Virtual Reservoir Conference. Amy Gough presented new SEARG research on the pitfalls of light mineral studies for sedimentary provenance in tropical climates.

Amy Gough was awarded an honorary research fellowship of the British Geological Survey and continues to foster collaborative relationships between SEARG and the BGS.