Updated:  11 May 2007

Eastern Lachlan Orogen 3D model

Screen capture of the Eastern Lachlan Orogen 3D Model showing solid geology structures, sections and fault planes (GA9167).  Click to view the 3D model.

About the Eastern Lachlan Orogen 3D model

Geographic extent

The Eastern Lachlan Orogen region is located north of the ACT in eastern central NSW near Orange.

Contents

This VRML model contains DEM surface, basement geology interpretation, gravity image, magnetic image, 3D geology surfaces, fault surfaces, geological cross sections, seismic interpretations and gravity strings of the Eastern Lachlan Orogen region.

Size

Approximately 6.5MB. Startup download only 764.5KB - remaining data downloads when layers are selected.


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Metadata

EASTERN LACHLAN OROGEN 3D VRML

The Australian Geodynamics Cooperative Research (AGCRC) Project was designed to shed light on the crustal architecture of different belts of Ordovician volcanics, volcaniclastics and intrusives that form part of the Macquarie Arc. This arc was disrupted during Silurian and Devonian extension and by later contraction. The work was also designed to contribute to the understanding of the geodynamic setting of some Lachlan Orogen mineral systems. North-south and east-west seismic reflection data were acquired across the Molong volcanic belt north and south of Orange; and east-west seismic lines were acquired across the Junee-Narromine volcanic belt south of Lake Cowal, and several kilometres north of the Gidginbung deposit.

This VRML model contains a subset of the project data .The data are available as a Fracsys database from Fractal Technologies.

Data includes:

  • DEM Surface
  • Basement geology interpretation
  • Gravity image
  • Magnetic image
  • 3D geology surfaces
  • Fault surfaces
  • Geological cross sections
  • Seismic interpretations
  • Gravity strings

This tool is ideal for those interested in quickly understanding the geometry and structural architecture of the Eastern Lachlan Orogen, as well as a quick look at the seismic interpretations and other datasets used for 3D map construction


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Data

DEM surface generated from 9 sec data
Surface generated with GOCAD from Geoscience Australia 9 second data.

Basement geology interpretation
Output of Lachlan fold belt project
http://www.ga.gov.au/minerals/research/archive/lachlan_fold_belt

Gravity image
Lachlan_Boug267_GA
Direen N. G., Lyons P., Korsch R. J. & Glen R. A. 2001 Integrated geophysical appraisal of crustal architecture in the eastern Lachlan Orogen. Exploration Geophysics, 32, 252-262

Magnetic image
LFB_tmi_GA_sub
Direen N. G., Lyons P., Korsch R. J. & Glen R. A. 2001 Integrated geophysical appraisal of crustal architecture in the eastern Lachlan Orogen. Exploration Geophysics, 32, 252-262

3D geology surfaces
Constructed with VULCAN by Fractal Graphics

Fault surfaces
Constructed with VULCAN by Fractal Graphics

Geological cross sections
Output of Lachlan fold belt project
http://www.ga.gov.au/minerals/research/archive/lachlan_fold_belt

Seismic interpretations
Glen, R.A., Korsch, R.J., Direen, N.G., Jones, L.E.A., Johnstone, D.W., Lawrie, K.C., Finlayson, D.M., Shaw, R.D., .2002, Crustal structure of the Ordovician Macquarie Arc, Eastern Lachlan Orogen, based on seismic-reflection profiling, Australian Journal of Earth Sciences, 49 (2), p323-348.

Finlayson, D.M., Korsch , R.J., Glen, R.A., Leven, J.H. and Johnstone, D.W, 2002. Seismic imaging and crustal architecture across the Lachlan Transverse Zone, a possible early cross-cutting feature of Eastern Australia. Australian Journal of Earth Sciences, vol. 49, pp. 311-321.

Gravity strings
Generated by P.R. Milligan, Geoscience Australia. With a combination of INTREPID software and in-house software.

These vector strings result from "Multiscale Edge Analysis" applied to the original grids of magnetic and gravity data.

Potential field data collected at or near the Earth's surface contain a spectrum of wavelengths. Short wavelengths usually result from near-surface property distributions (or "bodies"), while longer wavelengths usually result from deeper bodies. Such generalisations must be used with caution because, due to the non-uniqueness of potential field data, an infinite number of property distributions are possible which give rise to the same measured field at the surface.

This concept of depth as a function of wavelength led to the development of a multi-scale approach to the detection of property boundaries. From potential field theory, data collected at one level above the Earth's surface can be transformed to data that could be acquired at any other level. This process is termed "continuation", and while there are practical considerations concerning noise degradation in the downward continuation process, upward continuation, which is essentially a smoothing process, can be successfully achieved.

Thus, if data are upward continued to a number of levels, which represent successive removal of short-wavelength information as height increases, the maximum gradients (edges) selected from such data provide information concerning the depth and attitude of source discontinuities (e.g. Archibald et al., 1999; Hornby et al., 1999; Hobbs et al., 2000).

The utility of maxima points resulting from multi-scale edge detection is enhanced if they are converted into polylines or "strings", with the wavelet scale strength retained as an attribute for each point making up the string.


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References:

Archibald, N., Gow, P. & Boschetti, F., 1999. Multiscale edge analysis of potential field data. Exploration Geophysics, 30, 38-44.

Canny, J., 1986. A computational approach to edge detection. IEEE Transactions on Pattern Analysis and Machine Intelligence, 8, 679-698.

Hobbs, B.E., Ord, A., Archibald, N.J., Walshe, J.L., Zhang, Y., Brown, M. & Zhao, C., 2000. Geodynamic modelling as an exploration tool: Published in: After 2000: the future of mining. The impact of new technology and changing demands on the mining industry, Sydney, 10-12 April, 2000. Proceedings. AusIMM Publication Series.

Hornby, P., Boschetti, F. & Horowity, F.G., 1999. Analysis of potential field data in the wavelet domain. Geophysical Journal International, 137, 175-196.

Milligan, P.R., Lyons, P. & Direen, N., 2003. Spatial and directional analysis of potential field gradients - new methods to help solve and display three-dimensional crustal architecture. Extended Abstracts. ASEG 16th Geophysical Conference and Exhibition, February 2003, Adelaide.


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Coordinates

Projection

Universal Tranverse Mercator (UTM) Zone 55 South

Datum

Geocentric Datum of Australia 1994 (GDA94).

Bounding box

Map Grid of Australia 1994 (MGA94) coordinates

  • Lower left:   500000 E   6122843 N
  • Upper right: 786460 E   6571398 N

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Product Information

For a complete metadata reference, please see the ANZLIC metadata record 9629.

For product information, please see Geocat record 65091.


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For more information please contact: web3d@ga.gov.au.
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