Spatial Patterns of Mineral Deposits in the Mount Isa RegionQueensland, Australia

PowerPoint 6-8

All images and text are Copyright © 2005 by Larry Robinson

Prepared as part of:

The Spatial and Temporal Distribution of theMetal Mineralisation in Eastern Australia

and the Relationship of the Observed Patternsto Giant Ore Deposits

byLarry Robinson

A thesis submitted for the degree of

PhD

2006

Mt Isa Regional Geology with Mineral Deposits1

Detail of Mt Isa Area showing structural complexity

Pattern Recognition using a Clustering Algorithm

The AUTOCLUST AlgorithmThe approach automatically extracts boundaries based on Voronoi modellingand Delaunay Diagrams.

Parameters are not specified by users in the automatic clustering.

All clustering operations takes place on the Delaunay Diagram where data points become vertices and edges connect pairs of points to model spatial proximity.

Estivill-Castro & Lee (2000)2

The AUTOCLUST Algorithm

The m value shown in the following slides designates the lengths of edges, in units of the standard deviation away from the Global Mean, which are included in a single cluster. The Global Mean is determined from edges in the entire data set.

The noise index of a point (p) is the ratio - Local Mean / Global Mean - where, Local Mean is determined from the mean of points with edges incident to that point (p). The noise index is a measure of the deviation of any single point from proximal points. The mean of edges incident to noise tends to be significantly greater than the Global Mean.

The Spatial Distribution of All Mineral Deposit Types in the Mt Isa Region3, 4, 5

Mt Isa Regionm = 1.3, noise 2%,Cu Deposits Only.

Voronoi (without deposits)

Mt Isa Regionm = 1.3, noise 2%,Cu Deposits Only.

Voronoi and Delaunay

Mt Isa Regionm = 1.3, noise 2%,Cu Deposits Only.

Delaunay

Mt Isa Regionm = 1.3, noise 2%,Cu Deposits Only.

Cluster

Mt Isa Regionm = 1.3, noise 2%,Cu Deposits Only.

Boundary

Mt Isa Regionm = 1.3, noise 2%,Cu Deposits Only.

Polygonization

Mt Isa Regionm = 1.3, noise 2%,Cu Deposits Only.

Polygonization withradial trends

"The Mount Isa region is a good example of a geological system which exhibits considerable complexity in both space and time." (p. 1)

Upton and Ord (1996)6

This spatial and temporal complexity may explain the unique relationship of the Mount Isa Deposit with the radial pattern.

See PowerPoint 6-9 Macro-Scale Patterns in Eastern Australia using Binary Slices of Magnetic Data for a model that explains the cause of this complexity.

Thank You

The End

References

1. Raymond, O. L., and Needham, R. S., 1993, Metallogeny of the Mount Isa Inlier and Environs – Queensland and Northern Territory, AGSO Record 1992/66.

2. Estivill-Castro, V. and I. Lee, 2000, AUTOCLUST: Automatic Clustering via Boundary Extraction for Massive Point-data Sets. In Proceedings of the 5th International Conference on Geocomputation, 2000. to appear. Extended version is available at http://www.cs.newcastle.edu.au/Dept/techrep.html as a technical report.

3. Ewers, G.R., Ryburn, R.J., Hazell, M., Sedgmen, A., Bastrakov, E. & Black, J.,2000. OZMIN Documentation – National Mineral Deposits Dataset (Version 3). Australian Geological Survey Organisation, Record 2000/18.

4. OZMIN, 2000, National Mineral Deposits Dataset (Version 3). Australian Geological Survey Organisation.

5. MINERALIS, Minerals Resources And Locations Information System, Minloc 1999/1, Data Guide, (version 1.01), Geoscience Australia.

6. Upton, P., and Ord, A., 1996, Coupled Mechanical/Fluid Flow Numerical Modelling: Modelling as a Tool for Understanding the Development of the Orebodies at Mount Isa: A Synthesis of Current Research in the Mount Isa Inlier, AGCRC, Monash University, 18-19 November 1996, Monash University, Victoria, Australia, 1996, p. 1-4.