Brief description
Gravity data measures small changes in gravity due to changes in the density of rocks beneath the Earth's surface. The data collected 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 Mt Isa E Gravity Complete Bouguer Anomaly 1VD geodetic is a complete Bouguer anomaly grid for the Mt Isa Area E Gravity Survey (P200644). A Fast Fourier Transform (FFT) process was applied to the original grid to calculate the first vertical derivative grid. This gravity survey was acquired under the project No. 200644 for the geological survey of QLD. The grid has a cell size of 0.0075 degrees (approximately 802m). A total of 6123 gravity stations were acquired to produce this grid.Lineage
Maintenance and Update Frequency: notPlanned
Statement: This Mt Isa E Gravity Complete Bouguer Anomaly 1VD geodetic is a first vertical derivative of the complete Bouguer anomaly grid for the Mt Isa Area E Gravity Survey (P200644). This gravity survey was acquired under the project No. 200644 for the geological survey of QLD. The grid has a cell size of 0.0075 degrees (approximately 802m). A total of 6123 gravity stations at 4000m spacing were acquired to produce this grid. The complete Bouguer gravity anomalies were calculated by applying terrain correction (Bullard C - which accounts for the undulations of the surrounding topography) to the spherical cap Bouguer anomaly point data of Mt Isa Area E Gravity Survey (P200644). These terrain corrections were calculated using software from INTREPID Geophysics. The Intrepid algorithm utilises concentric rings subdivided into cells (Direen, 2001) to calculate the terrain correction. The data were then gridded using a gridding technique provided by the INTREPID Geophysics software package. A Fast Fourier Transform (FFT) process was applied to the complete infinite slab Bouguer gravity grid of the survey area to calculate the first vertical derivative grid. The processed data are checked by GA geophysicists using standard methods for assessing quality to ensure that the final data are fit-for-purpose. Details of the specifications of individual surveys held in the Australian National Gravity Database (ANGD) can be found in the Second Edition of the Index of Gravity Surveys (Wynne and Bacchin, 2009).
References:
Direen, N.G., 2001. Application of terrain corrections in Australia (2001).
Intrepid Geophysics, http://www.intrepid-geophysics.com;
Wynne, P., and Bacchin, M., 2009. Index of Gravity Surveys (Second Edition). Geoscience Australia, Record 2009/07.
Created: 09 03 2020
Issued: 09 03 2020
Modified: 05 07 2021
Data time period: 04 02 2007 to 11 05 2007
text: westlimit=140.953; southlimit=-24.029; eastlimit=144.1105; northlimit=-19.9715; projection=GDA94 (EPSG:4283)
Subjects
1VD |
Australia |
Bouguer |
EARTH SCIENCES |
Earth sciences |
GADDS2.0 |
NCI |
Published_External |
QLD |
complete |
first vertical derivative |
geophysical survey |
geophysics |
geoscientificInformation |
grav |
gravity |
grid |
ground digital data |
infinite slab |
raster |
survey 200644 |
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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/144017
- global : 47958528-9ac0-4fc2-b67e-52ddeb434ec4
