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Ellipsis Modelling
Scott DyksterhuisDietmar Müller, Louis Moresi and Patrice Rey
University of Sydney
Geodynamics
Combined mantle convection and plate kinematic modelling Palaeostress modelling
Dynamic basin modelling(mantle convection, lithos-pheric thinning, sedimentation/erosion)
Basin history
Put constraints on tectonic/thermalhistory of deep sedimentary sections
Constrain timing of fault reactivation bycombining palaeo-stress modelling withobservations from seismic data
Seismic and well data integration and interpretation
LithologiesPhysical propertiesBiostratigraphyBasin geometryFaulting through time
Geological modeling is associated with a different set of requirements:
• Very large deformation of solid materials including• accurate tracking of material (compositional) interfaces –
melt?• accurate tracking of history variables • evolution of oriented structure• etc…
• Only want a tool to fit data/concepts (geometry, thermal history, potential field)
• Easy use and implement
Ellipsis
• A particle-in-cell finite element code that solves 2D and 3D fluid mechanics problems with & w/o heat transfer, e.g.,– Mantle convection– Lithospheric deformation– subduction
• Ellipsis works with a multigrid solver, which allows quite rapid solutions (but does constrain allowable mesh geometry)
• Solid-like materials can be given higher viscosities than fluid-like materials, or material properties can depend on temperature, depth, pressure, strain, strain rates, etc.
Ellipsis GUI
• Java based GUI for easy interaction with existing models or for creating new ones
• Allows for more complicated geometries – can even use drawings (based on seismic, reconstructions etc) to create models
• Handles all scaling automatically so user can do as much/little as they want
Interactive Inversion - Nimrod
• NIMROD, NIMROD/G manage the distribution of parameter-space studies on clusters / grids
– robust job distribution
– secure
– visual feedback / portal
• NIMROD/O contains a number of objective inversion algorithms to reduce the number of models evaluated
– Models are cached
– Multiple inversions to help avoid local minima
Conclusions
• Initial constrains extremely important– temperature– rheology
• Modelling not ready for applied examples?
• Accessibility of code important – get the geologist using the modelling software
A student’s perspective…
• Need to have some kind of online materials (rheology) database – Initial conditions
• A permanent web presence/meeting point (wiki site):– Codes, manuals, (benchmark) results (corner store)– community collaboration and “sounding ground”– centralised location for groups to benchmark
codes/results – location for observationalists to pose “challenges”– data