Authors / CoAuthors
Sedgmen, A. | Larson, R.
Abstract
The Northern Australian Project online GIS, which has been chiefly designed to highlight the results of geochronological research within the project area, was first published in 2003 and updated in July 2004. GIS data reference layers include 1: 250,000, 1: 1 million, and 1: 2,500,000 geological data, regional geophysical images and a topographic map image. The geochronology and fluid inclusion points have been linked live to Geoscience Australia's OZROCKS, OZCHRON and PETROG Oracle databases. Forms display data to the user from these databases using customised query statements. Queries directed to geological layers display information derived from static ArcInfo shapefiles. The North Australia Project geochronology research has chiefly targeted the Arunta Block, Davenport Geosyncline, and the Granites-Tanami Block provinces within the project area.
Product Type
dataset
eCat Id
41257
Contact for the resource
Custodian
Owner
Custodian
Cnr Jerrabomberra Ave and Hindmarsh Dr GPO Box 378
Canberra
ACT
2601
Australia
Keywords
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- GIS DatasetRegional
- ( Theme )
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- geochronology
- ( Theme )
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- geology
- ( Theme )
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- geophysics
- ( Theme )
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- culture
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- AU-NTAU-WA
- Australian and New Zealand Standard Research Classification (ANZSRC)
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- Earth Sciences
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- Published_Internal
Publication Date
2004-01-01T00:00:00
Creation Date
Security Constraints
Legal Constraints
Status
Purpose
Maintenance Information
continual
Topic Category
geoscientificInformation
Series Information
Lineage
The regional outcrop geology layer is an aggregation of 1:250 000 geological maps of the project area, with Quaternary and Cainozoic units removed (note that the sheets are NOT edge matched). All 1:250 000 geological map sheets were produced by Geoscience Australia, except for Tennant Creek which was produced by the Northern Territory Geological Survey. The maps were produced using information acquired from interpretation (mostly airphoto), field observation, and subsequent investigation (eg sample analysis for age and rock-type determination). Some detail may have been generalised, repositioned, or omitted from the primary data for cartographic purposes. Maps were compiled from unrectified photo overlays onto topographic bases supplied by Commonwealth mapping authorities. Drainage and, where necessary, other topographic features (eg fence lines) were used for spatial control of the geological data. The national geology layer is a subset of the Geology of Australia dataset from the National Geoscience Dataset. The Geology of Australia dataset was compiled from digital data, mainly at 1:2 500 000 scale, supplied by AGSO, GSWA, NTGS, PIRSA, GSQ, GSTAS, GSNSW and GSVIC and from data obtained from many other groups. The standardisation process was carried out by the dataset authors. In order to synthesise data from a variety of sources into a coherent product, the degree and nature of modification of the source data varied from case to case. The digital geological data for the metamorphic unit layer has been compiled mainly from 1: 250 000 series mapping from GA's previously completed NTData Project in the Northern Territory with reference to 1: 100 000 scale maps where available. Additional information was gathered from researching the explanatory notes to these sheets, selected journal papers and in personal communication with NTGS geologists. Linework for the geological polygons has been edgematched along sheet joins and generalised to depict features at the plotted scale of the map (1: 850 000). The Total Magnetic Intensity (Reduced to Pole) image is a composite of a large number (approximately 35) of aeromagnetic surveys, acquired from 1965 to 2001, using a wide range of survey parameters. The International Geomagnetic reference Field for an appropriate epoch has been removed from each survey and a grid created. Individual grids were then merged using Intrepid software, with a cell size of 100 m. The composite grid of the total magnetic intensity was then reduced to the pole. The gravity component of the Bouguer Gravity with Total Magnetic Intensity (Reduced to Pole) Illumination image is a gravity grid generated from gravity stations spaced at 11 km or better. The gravity stations were gridded using a variable density gridding routine within Intrepid software, to a cell size of 800 m. The Total Magnetic Intensity component is described above. Data comprising the geochronological layers (SHRIMP Pooled Ages, Conventional U-Pb Ages, Sm-Nd Isochron Ages, Sm-Nd Model Ages, Rb-Sr Isochron Ages) are sourced from OZROX, GA's corporate field geology database, and OZCHRON, GA's corporate geochronological database. Point locations for the geochronological layers are plotted using static ESRI shapefiles generated from the OZROX and OZCHRON databases. The attribute data are obtained by live queries to the OZROX and OZCHRON databases. Data origin, positional and analytical accuracies, and data acquisition and processing methodologies vary widely across OZROX and OZCHRON data. Comprehensive metadata describing data lineage are captured in the OZROX and OZCHRON databases. The fluid inclusion point data are linked live to GA's PETROG database. The topographic map is a subsection of the 1:5 000 000 General Reference Map of Australia, second edition, AUSLIG 1986. The digital image being used was scanned from a hardcopy map and warped from a simple conic projection into the geodetic coordinate system.
Parent Information
Extents
[-24.0, -18.0, 127.5, 138.0]
Reference System
Spatial Resolution
Service Information
Associations
Source Information
Source data not available.