Spatial Patterns of Mineral Deposits in the Broken Hill Region
New South Wales, Australia
All images and text are Copyright © 2005 by Larry Robinson
PowerPoint 6-6
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
New South Wales Topography1
The High Temperature Type Deposits
The Broken Hill TypePredominantly stratiform disseminations or pods of galena-sphalerite quartz gahnite lode.
The Giant Broken Hill Deposits
The three giant ore deposits beneath and immediately south of the city contained"over 200 million tonnes of high gradelead-silver-zinc ore".
Barnes (1980)2
The Minor Broken Hill Deposits
The production from the 525 minor deposits was "only a few thousand tonnes of ore"from each deposit.
Barnes (1980)2
The Giant and Minor Broken Hill Deposits
Pattern Recognition by Clustering theBroken Hill Type Deposits
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)3
Area Clustered
Delaunay Diagram, m = 0.8, noise = 0%
Voronoi Tesselation (without deposits)
Voronoi Tesselation and Clusters
Voronoi Tesselation and Boundaries
Voronoi Tesselation and Polygonization
Polygonization
Polygonization with Giant Deposits
Polygonization with Radial Trends
The Lower Temperature Type Deposits
Thackaringa Type*Mount Robe Type*Gold Vein Type*Iron Duke Pyrite TypeEttlewood TypeSilver King TypeWaukeroo TypeVein Pyrite TypeGreat Eastern TypeVein Cu Type
*These reveal the pattern adequately.
New South Wales mineral exploration data package, 2004New South Wales Department of Mineral Resources, CD-ROM
Thackaringa Type Deposits
Narrow veins or shoots and pods in veins in fault zones of argentiferous galena bearing siderite quartz veins.
Thackaringa Type and Giant Broken Hill Type Deposits
Mount Robe Type Deposits
Narrow long tabular bodies of galena-sphalerite-chalcopyrite-(gold) bearing quartz fluorite veinswhere the veins transgress layering in host.
Mt Robe and Giant Broken Hill Type Deposits
Gold Vein Type Deposits
Pyritic or cupriferous quartz vein with gold.
Gold Vein Type and Giant Broken Hill Type Deposits
The High Temperature Giant Broken Hill Type and the Three Lower Temperature Type Deposits
Giant High Temperature and Lower Temperature Type Deposits
The following image shows the probable thermal gradient in the Broken Hill Region when the giant deposits were forming.
The Paleothermal Thermometer
The HOT ZONE is delineated by the Lower Temperature Deposits.
The HOT ZONE in the Broken Hill Region
The majority of the Broken Hill Type Deposits occur in the HOT ZONE.
The HOT ZONE and Polygonization of Broken Hill Type Deposits
The ellipticity of the HOT ZONE indicates that compressional forces, in an E-W direction, distorted the original spatial distribution of the deposits.
The HOT ZONE with compression arrows (blue)
The Complex Geology in the Broken Hill Region
A prime example of the small-scale complexity in the crust and the large-scale simplicity in the underlying mantle.
From 1969 to about 1972, the impact of the geological ideas stemming from plate tectonics was muted by the characteristic geological aversion to bold, rational solutions to geological problems: small-scale complexity commonly retards and obscures our understanding of larger-scale simplicity. (p. 237)
John F. DeweyPlate Tectonics and Geology, 1965 to Today
(Oreskes, 2001)
Thank You
The End
References
1. NewSouthWales_MineralExplorationDataPackage, 2004, New South Wales mineral exploration data package: Sydney, New South Wales Department of Mineral Resources, p. 1 CD-ROM
2. Barnes, R. G., 1980, Types of mineralization in the Broken Hill Block and their relationship to stratigraphy, in Stevens, B. P. J., ed., A Guide to the Stratigraphy and Mineralization of the Broken Hill Block, New South Wales - Record 20, Geological Survey of New South Wales, p. 33-70
3. V. Estivill-Castro and I. Lee. AUTOCLUST: Automatic Clustering via Boundary Extraction for Massive Point-data Sets. In Proceedings of the 5th International Conference onGeocomputation, 2000. to appear. Extended version is available at http://www.cs.newcastle.edu.au/Dept/techrep.html as a technical report.
4. * http://users.indigo.net.au/don/ore/executive.html
5. Oreskes, N., and Le Grand, H., 2001, Plate tectonics : an insider's history of the modern theory of the Earth, Boulder, Colo., Westview Press, xxiv, 424 p.