Full description
Total magnetic intensity (TMI) data measures variations in the intensity of the Earth's magnetic field caused by the contrasting content of rock-forming minerals in the Earth crust. Magnetic anomalies can be either positive (field stronger than normal) or negative (field weaker) depending on the susceptibility of the rock. The data are processed via standard methods to ensure the response recorded is that due only to the rocks in the ground. The results produce datasets that can be interpreted to reveal the geological structure of the sub-surface. The processed data is checked for quality by GA geophysicists to ensure that the final data released by GA are fit-for-purpose. .This Tanami NS 1D - TMI RTP 1VD grid (AWAGS) is the first vertical derivative of the TMI RTP grid of the NTGS Tanami NS 1D Region Detailed Airborne Magnetic Radiometric and Digital Elevation Survey, NT, 2018 survey.
This grid has a cell size of 0.00018 degrees (approximately 20m) , and given in units of nT per metre (nT/m). The data used to produce the TMI grid was acquired in 2018 by the NT Government, and consisted of 2188 line-kilometres of data at 100m line spacing and 60m terrain clearance. The data has had a variable reduction to the pole applied to centre the magnetic anomaly over the magnetised body. The VRTP processing followed a differential reduction to pole calculation up to 5th order polynomial. Magnetic inclination and declination were derived from the IGRF-11 geomagnetic reference model using a data representative date and elevation representative of the survey. A first vertical derivative was calculated by applying a fast Fourier transform (FFT) process to the TMI RTP grid of the NTGS Tanami NS 1D Region Detailed Airborne Magnetic Radiometric and Digital Elevation Survey, NT, 2018 survey to produce this grid. This grid was calculated using an algorithm from the INTREPID Geophysics software package. This grid shows the magnetic response of subsurface features with contrasting magnetic susceptibilities. The grid can also be used to locate structural features such as dykes.
Lineage
Maintenance and Update Frequency: notPlanned
Statement: This Tanami NS 1D - TMI RTP 1VD grid (AWAGS) is the first vertical derivative grid of an airborne-derived Total Magnetic Intensity (TMI) Reduced to the Pole (RTP) grid for the NTGS Tanami NS 1D Region Detailed Airborne Magnetic Radiometric and Digital Elevation Survey, NT, 2018 survey. The survey was acquired under the project No. 1312 for the geological survey of NT. A total of 2188 line-kilometres of data at a line spacing of 100m were acquired to produce the TMI grid. The data has had a variable reduction to the pole applied to centre the magnetic anomaly over the magnetised body. The VRTP processing followed a differential reduction to pole calculation up to 5th order polynomial. Magnetic inclination and declination were derived from the IGRF-11 geomagnetic reference model using a data representative date and elevation representative of the survey. A first vertical derivative was calculated by applying a fast Fourier transform (FFT) process to the TMI RTP grid of the NTGS Tanami NS 1D Region Detailed Airborne Magnetic Radiometric and Digital Elevation Survey, NT, 2018 survey to produce this grid. This grid was calculated using an algorithm from the INTREPID Geophysics software package. The image shows the magnetic response of subsurface features with contrasting magnetic susceptibilities. The image can also be used to locate structural features such as dykes. Details of the specifications of individual airborne surveys can be found in the Fourteenth Edition of the Index of Airborne Geophysical Surveys (Percival, 2014). This Index is also available online at http://pid.geoscience.gov.au/dataset/79134.
References
Percival, P.J., 2014. Index of airborne geophysical surveys (Fourteenth Edition).
Intrepid Geophysics http://intrepid-geophysics.com
Created: 31 10 2020
Issued: 31 10 2020
Modified: 05 07 2021
Data time period: 13 07 2018 to 23 10 2018
text: westlimit=130.9134; southlimit=-20.703; eastlimit=131.073; northlimit=-20.5527; projection=GDA94 (EPSG:4283)
Subjects
1VD |
Australia |
EARTH SCIENCES |
Earth sciences |
GADDS2.0 |
NCI |
NT |
Published_External |
RTP |
TMI |
airborne digital data |
first vertical derivative |
geophysical survey |
geophysics |
geoscientificInformation |
greyscale |
grid |
image |
mag |
magnetics |
magnetism |
palaeomagnetism |
reduced to the pole |
survey 1312 |
total magnetic intensity |
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Other Information
The Geophysical Archive Data Delivery System (GADDS2) portal provides HTTP download of geophysics datasets in a number of formats. Point and line datasets are available in NetCDF and ASEG-GDF2. Grid datasets are available in NetCDF, GeoTIFF and ERS. (File available for download in various formats from the GADDS2 portal)
uri :
https://portal.ga.gov.au/persona/gadds
File download for Tanami NS 1D - TMI RTP 1VD grid (AWAGS) (Tanami NS 1D - TMI RTP 1VD grid (AWAGS) file download)
NetCDF Subsetting Service (NCSS) for Tanami NS 1D - TMI RTP 1VD grid (AWAGS) (Tanami NS 1D - TMI RTP 1VD grid (AWAGS) NCSS)
OPeNDAP web service for Tanami NS 1D - TMI RTP 1VD grid (AWAGS) (Tanami NS 1D - TMI RTP 1VD grid (AWAGS) OPeNDAP)
OGC Web Mapping Service (WMS) for Tanami NS 1D - TMI RTP 1VD grid (AWAGS) (Tanami NS 1D - TMI RTP 1VD grid (AWAGS) WMS)
OGC Web Coverage Service (WCS) for Tanami NS 1D - TMI RTP 1VD grid (AWAGS) (Tanami NS 1D - TMI RTP 1VD grid (AWAGS) WCS)
Tanami NS 1D - TMI RTP 1VD grid (AWAGS) NCSS
Tanami NS 1D - TMI RTP 1VD grid (AWAGS) OPeNDAP
Tanami NS 1D - TMI RTP 1VD grid (AWAGS) WMS
Tanami NS 1D - TMI RTP 1VD grid (AWAGS) WCS
Identifiers
- Local : pid.geoscience.gov.au/dataset/ga/144885
- global : 0249a0ef-c862-4bc5-8b76-e9640a9464fa
