South Nicholson Gravity Survey GA P201701 CSCBA267GUVD  


Authors / CoAuthors

Geophysical Acquisition & Processing Section

Abstract

Gravity data measure 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 South Nicholson Gravity Survey GA P201701 CSCBA267GUVD is the first vertical derivative of the complete spherical cap Bouguer anomaly grid for the South Nicholson Gravity Survey (P201701). This gravity survey was acquired under the project No. 201701 for the geological survey of NT. The grid has a cell size of 0.00742 degrees (approximately 800m). A Fast Fourier Transform (FFT) process was applied to the original grid to calculate the first vertical derivative grid. A total of 2725 gravity stations at 400m spacing were acquired to produce this grid.

Product Type

dataset

eCat Id

143865

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 )
  • grid
( Place )
  • Australia
( Place )
  • NT
( Project )
  • survey 201701
( Theme )
  • GADDS2.0
( Theme )
  • gravity
( Theme )
  • spherical cap
( Theme )
  • Bouguer
( Theme )
  • complete
( Theme )
  • 1VD
( Theme )
  • first vertical derivative
( Theme )
  • ground digital data
( Theme )
  • geophysical survey
( Theme )
  • grav
( Theme )
  • grid
( Theme )
  • raster
  • Published_External

Publication Date

2020-03-07T00:00:00

Creation Date

2020-03-07T00:00:00

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 South Nicholson Gravity Survey GA P201701 CSCBA267GUVD is the first vertical derivative of the complete spherical cap Bouguer anomaly grid for the South Nicholson Gravity Survey (P201701). This gravity survey was acquired under the project No. 201701 for the geological survey of NT. The grid has a cell size of 0.00742 degrees (approximately 800m). A total of 2725 gravity stations at 400m spacing were acquired to produce this grid. Three processes are required to correct the gravity observations for the effects of the surrounding topography: (1) a Bouguer correction (Bullard A), which approximates the topography as an infinite horizontal slab; (2) a correction to that horizontal slab for the curvature of the Earth (Bullard B); and (3) a terrain correction (Bullard C), which accounts for the undulations of the surrounding topography. The complete spherical cap Bouguer gravity anomalies were calculated by applying terrain correction (Bullard C) to the spherical cap Bouguer anomaly point data of South Nicholson Gravity Survey (P201701). 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 terrain corrected data were then gridded using a gridding technique provided by the INTREPID Geophysics software package. A first vertical derivative was calculated by applying a fast Fourier transform (FFT) process to the Bouguer gravity grid of the South Nicholson Gravity Survey (P201701) survey 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. 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: Intrepid Geophysics, http://www.intrepid-geophysics.com; Wynne, P. and Bacchin, M., 2009. Index of Gravity Surveys (Second Edition). Geoscience Australia, Record 2009/07.

Parent Information

Geophysical Data Collection - gravity

UUID - c6b58f54-102c-19e9-e044-00144fdd4fa6,

eCat ID - 74512

Extents

[-21.3764, -17.9708, 135.922, 138.1108]

Reference System

GDA94 (EPSG:4283)

Spatial Resolution

Service Information

Associations

Association Type - operatedOnBy

South Nicholson Gravity Survey GA P201701 CSCBA267GUVD NCSS    

Association Type - operatedOnBy

South Nicholson Gravity Survey GA P201701 CSCBA267GUVD OPeNDAP    

Association Type - operatedOnBy

South Nicholson Gravity Survey GA P201701 CSCBA267GUVD WMS    

Association Type - operatedOnBy

South Nicholson Gravity Survey GA P201701 CSCBA267GUVD WCS    

Downloads and Links

File available for download in various formats from the GADDS2 portal  

South Nicholson Gravity Survey GA P201701 CSCBA267GUVD file download  

South Nicholson Gravity Survey GA P201701 CSCBA267GUVD NCSS  

South Nicholson Gravity Survey GA P201701 CSCBA267GUVD OPeNDAP  

South Nicholson Gravity Survey GA P201701 CSCBA267GUVD WMS  

South Nicholson Gravity Survey GA P201701 CSCBA267GUVD WCS  

Source Information

This South Nicholson Gravity Survey GA P201701 CSCBA267GUVD includes ground gravity data for the South Nicholson Gravity Survey (P201701) acquired for the geological survey of NT