The dynamics of flowing, subsurface salt sheets: observational constraints and theoretical models

The dynamics of flowing, subsurface salt sheets: observational constraints and theoretical models

What is the viscosity of salt as it deforms at depth in the crust? Is it Newtonian? What are the effects of the layer geometry? How do fluids move through the salt and what are their effects?

Thick deposits of crystalline salt form when saline waters evaporate at the surface of the Earth.  These deposits can be buried by sediment to depths of tens of kilometres.  The low density and low viscosity of solid salt makes these layers unstable and easily deformable.  They are inferred to become detachment surfaces that cause large-scale motion of the overlying sediments. However, in such systems the kinematics and dynamics of the salt layer cannot be observed directly. Seismic surveying is useful, but it is difficult to image salt bodies because of their low seismic velocity.  Recently, seismic images of the Levant Basin salt formation have been shown to contain kinematic indicators of the salt deformation. These observations provide a rare opportunity to constrain detailed dynamical models.

Aims of the Project

The aim of the project is to develop theoretical and computational models that incorporate the observed  geometry of the Levant Basin salt formation. These models will be used to explore the dynamics of the salt under various assumptions about the rheology and forcing. Results will be compared with observations of the kinematics to place constraints on key in situ dynamical quantities, including flow laws.

Methods to be used

Mathematical modelling; partial differential equations for fluid dynamics; code development for numerical solutions; statistical analysis

Any specialised skills the student will need

The prospective student should have a training in geodynamics, applied mathematics or physics.

If interested please contact Richard Katz richard.katz@earth.ox.ac.uk , Joe Cartwright joe.cartwright@earth.ox.ac.uk and Christopher MacMinn christopher.macminn@eng.ox.ac.uk

 

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