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Mineral Resources Tasmania

Scamander and Lily-Lagoon 3D models

Mineral Resources Tasmania continues to develop regional 3D geological and geophysical models for prospective terranes at a range of scales and extents as part of its suite of precompetitive geoscience products. 3D models are used as a vehicle for the better synthesis and understanding of controls on ore-forming processes and prospectivity.

The Scamander and Lily-Lagoon 3D geological models express a synthesis based on geological mapping by MRT geologists together with geophysical and structural interpretations. The models are constrained by 3D geophysical modelling using MRT's high-quality gravity and magnetic survey data coupled with drilling and rock physical property databases. This information has been used to derive uncertainty estimates for each element in the model volume. The model files also include nominal density and magnetic susceptibility estimates obtained for each voxel, thus incorporating intra-unit variations.

The Scamander geological model was constructed explicitly using the GOCAD® Mining Suite from Mira Geoscience, with initial geophysical inversions using the VPmg code. Further geophysical modelling and uncertainty characterisation was carried out with the GeoModellerTM software from Intrepid Geophysics.

The Lily-Lagoon 3D geological model was constructed in GeoModellerTM and built entirely by implicit means, whereby surfaces bounding unit volumes were interpolated from geological observations (stratigraphic and fault contacts, dips, and strikes) via prior geological knowledge encoded in a matrix of rules defining the relative timing of all model components. As a useful model can thus be constructed with far fewer user-entered points than explicit modelling, this makes it much easier to modify the model in response to indications from subsequent geophysical modelling or emergent 3D geometric plausibility.

These 3D models are being distributed primarily as a Geoscience ANALYST project. Geoscience ANALYST is visualisation and communication software for GoCAD® 3D models, made freely available by Mira Geoscience. Explanatory notes and model data are provided here for both Scamander and Lily-Lagoon.