Guest lecture: Robert Moucha

Guest lecture: Robert Moucha (Department of Earth and Environmental Sciences, Syracuse University)

Investigating the role of inherited structures in continental rifting using coupled geodynamic and landscape evolution models

Abstract

Continental rifting is a fundamental process of plate tectonics and the Wilson Cycle where weak zones within the continental lithosphere are exploited by both past far-field and near-field forces to break-up the continental lithosphere These pre-existing weak-zones are remnants of past tectonic deformation, delineated by shear zones, faults, and/or mobile belts. Reactivation of such inherited structures from previous tectonic phases has been attributed to several continental rift systems, for example, the Rhine graben, Rio Grande rift, Main Ethiopian Rift, Malawi Rift, and the Red Sea. In geodynamic modeling of continental rifts, these weak zones are often approximated by lithospheric thermal perturbation or a weak seed/fault to facilitate strain localization and initiate rifting in response to uniform stretching of the lithosphere. Here, we adopt a different approach. To implement the inherited structures, we start with a geodynamic simulation of continental collision and orogenesis or a failed extension prior to a period of quiescence that is followed by extension. We include the effect of temperature-dependent strain healing in the mantle based on grain-size evolution and time dependent plastic strain healing in the crust. We use a 2D geodynamic model coupled to a landscape evolution model, to explore the parameter space to understand the longevity of weak zones and their implications for rift initiation.

GFÚ Lecture hall / 9 April / 3:30 PM