Brief 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 GSQ Rockhampton Monto Qld magnetic vd2 grid geodetic is a Second vertical derivative of the Total Magnetic Intensity grid for the Rockhampton 1 & 2, Monto & Munduberra, 1994-1995, Qld,AIRDATA. This grid has a cell size of 0.00096 degrees (approximately 102m). The data used to produce the TMI grid was acquired in 1994 by the QLD Government, and consisted of 156236 line-kilometres of data at 400m line spacing and 80m terrain clearance. A Fast Fourier Transform (FFT) process was applied to the original TMI grid to calculate the Second vertical derivative grid.Lineage
Maintenance and Update Frequency: notPlanned
Statement: This GSQ Rockhampton Monto Qld magnetic vd2 grid geodetic is a second vertical derivative grid of the Total Magnetic Intensity (TMI) anomaly for the Rockhampton 1 & 2, Monto & Munduberra, 1994-1995, Qld,AIRDATA. The survey was acquired under the project No. 790 for the geological survey of QLD. A total of 156236 line-kilometres of data at a line spacing of 400m and 80m terrain clearance were acquired to produce the TMI grid. A Second vertical derivative was calculated by applying a fast Fourier transform (FFT) process to the Total Magnetic Intensity grid of the Rockhampton 1 & 2, Monto & Munduberra, 1994-1995, Qld,AIRDATA to produce this grid. This grid was calculated using an algorithm from the INTREPID Geophysics software package. The processed data are checked by GA geophysicists using standard methods for assessing quality to ensure that the final data are fit-for-purpose. The grid has a cell size of 0.00096 degrees (approximately 102m). The Second vertical derivative grid is very helpful for the enhancement of near surface and structural features such as faults and 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:
Intrepid Geophysics, http://www.intrepid-geophysics.com;
Percival, P.J., 2014. Index of airborne geophysical surveys (Fourteenth Edition).
Created: 07 03 2020
Issued: 07 03 2020
Modified: 06 07 2021
Data time period: 08 12 1994 to 22 03 1995
text: westlimit=149.7226; southlimit=-25.0118; eastlimit=152.1398; northlimit=-22.7309; projection=AGD66 (EPSG:4202)
Subjects
2VD |
2nd vertical derivative |
Australia |
EARTH SCIENCES |
Earth sciences |
GADDS2.0 |
NCI |
Published_External |
QLD |
airborne digital data |
geophysical survey |
geophysics |
geoscientificInformation |
grid |
magnetics |
magnetism |
palaeomagnetism |
raster |
second vertical derivative |
survey 790 |
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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)
Identifiers
- URI : pid.geoscience.gov.au/dataset/ga/141882
- global : 5c8e80b4-adca-4add-a228-2147efbc9eb5
