Gawler Craton Airborne Survey Merge Magnetics - TMI pseudocolor image (AWAGS)  


Authors / CoAuthors

Geophysical Acquisition & Processing Section

Abstract

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 Gawler Craton Airborne Survey Merge Magnetics - TMI pseudocolor image (AWAGS) is a pseudocolour image of the TMI grid of the Gawler Craton Airborne Survey Magnetic Radiometric and DEM Merge, SA, 2017-2019 survey. The grid used to produce this image has a cell size of 0.0004 degrees (approximately 41m). The data used to produce the TMI grid was acquired in 2017-2019 by the SA Government, and consisted of 1660000 line-kilometres of data at 200m line spacing and 60m terrain clearance. To constrain long wavelengths in the grid, an independent data set, the Australia-wide Airborne Geophysical Survey (AWAGS) airborne magnetic data, was used to control the base levels of the survey grid. This survey grid is essentially levelled to AWAGS. This pseudocolour 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.

Product Type

dataset

eCat Id

144815

Contact for the resource

  Point of contact

Commonwealth of Australia (Geoscience Australia)  
Cnr Jerrabomberra Ave and Hindmarsh Dr GPO Box 378
Canberra
ACT
2601
Australia

Keywords

theme.ANZRC Fields of Research.rdf
  • EARTH SCIENCES
( Data centre )
  • NCI
( Discipline )
  • Earth sciences
( Discipline )
  • geophysics
( Feature type )
  • image
( Place )
  • Australia
( Place )
  • SA
( Project )
  • survey 5000
( Theme )
  • GADDS2.0
( Theme )
  • TMI
( Theme )
  • magnetics
( Theme )
  • magnetism
( Theme )
  • palaeomagnetism
( Theme )
  • airborne digital data
( Theme )
  • geophysical survey
( Theme )
  • mag
( Theme )
  • total magnetic intensity
( Theme )
  • pseudocolour
( Theme )
  • image
  • Published_External

Publication Date

2020-11-09T00:00:00

Creation Date

2020-11-09T00:00:00

Security Constraints

Australian Government Security ClassificationSystem    

Classification - unclassified

Legal Constraints

Creative Commons Attribution 4.0 International Licence    

Access - license

Use - license

Status

completed

Purpose

Maintenance Information

notPlanned

Topic Category

geoscientificInformation

Series Information

Lineage

This Gawler Craton Airborne Survey Merge Magnetics - TMI pseudocolor image (AWAGS) is a pseudocolour image of the TMI data for the Gawler Craton Airborne Survey Magnetic Radiometric and DEM Merge, SA, 2017-2019 produced by Geoscience Australia. The Gawler Craton Airborne Survey Magnetic Radiometric and DEM Merge, SA, 2017-2019 was produced with a grid cell size of 0.00042 degrees (approximately 40m). The data are in nanoTesla (or nT). The data used to produce this grid was acquired in 2017-2019 by the SA Government, and consisted of 1660000 line-kilometres of data at 200m line spacing and 60m terrain clearance. To constrain long wavelengths in the grid, an independent data set, the Australia-wide Airborne Geophysical Survey (AWAGS) airborne magnetic data, was used to control the base levels of the survey grid. This survey grid is essentially levelled to AWAGS (Milligan et al., 2009). The levelling and grid-merging procedure is described in detail in Minty et al. (2003). The image shows the magnetic response of subsurface features with contrasting magnetic susceptibilities and 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: Milligan, P.R., Minty, B.R.S., Richardson, M. and Franklin, R., 2009. The Australia-wide Airborne Geophysical Survey accurate continental magnetic coverage. Preview, No. 138, p. 1-128. Minty, B.R.S., Milligan, P.R., Luyendyk, A.P.J. and Mackey, T., 2003. Merging airborne magnetic surveys into continental-scale compilations. Geophysics, 68 (3), 988-995. Percival, P.J., 2014. Index of airborne geophysical surveys (Fourteenth Edition);

Parent Information

Geophysical Data Collection - Airborne Geophysics

UUID - ddeb0fc4-32e3-4913-80f2-f4249b17a925,

eCat ID - 111301

Extents

[-32.6745, -27.3437, 130.9839, 138.0123]

Reference System

GDA94 (EPSG:4283)

Spatial Resolution

Service Information

Associations

Downloads and Links

File available for download in various formats from the GADDS2 portal  

/g/data/iv65/Geoscience_Australia_Geophysics_Reference_Data_Collection/airborne_geophysics/SA/image/P5000/P5000-image-magnetic-tmi-AWAGS_MAG_2019.nc file at NCI  

/g/data/iv65/Geoscience_Australia_Geophysics_Reference_Data_Collection/airborne_geophysics/SA/image/P5000/P5000-image-magnetic-tmi-AWAGS_MAG_2019.nc file download  

Source Information

This Gawler Craton Airborne Survey Merge Magnetics - TMI pseudocolor image (AWAGS) is a pseudocolour image of the TMI data for the Gawler Craton Airborne Survey Magnetic Radiometric and DEM Merge, SA, 2017-2019 produced by Geoscience Australia.