Abstract

Record documenting sources of gravity and magnetic data covering the Capel and Faust basins (Lord Howe Rise) and the processes applied to level the data.
Google map showing geographic bounding box with values North bound -24.0 East bound 165.0 West bound 157.0 South bound -31.0
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Product Type/Sub Type

nonGeographicDataset

Constraints

Creative Commons Attribution 4.0 International Licence

IP Owner

Commonwealth of Australia (Geoscience Australia)

Author(s)

Date (publication)

2010-01-01T00:00:00

Product Type

nonGeographicDataset

Topic Category

geoscientificInformation

GA Catalogue Number

70711 Product http://www.ga.gov.au/metadata-gateway/metadata/record/70711/

Keywords

GA Publication
Record
continental margins
data
gravity
magnetics
marine survey
marine
Earth Sciences

Resource Language

English

Resource Character Set

utf8

Resource Security Classification

unclassified

Geographic Extent

North bound
-24.0
East bound
165.0
West bound
157.0
South bound
-31.0

Lineage

The source data used to generate a levelled dataset for the Capel and Faust basins includes: 1) a dataset of gravity and magnetic data for the Australian region sourced internally from Geoscience Australia holdings of ship-track data and levelled by Desmond Fitzgerald and Associates Pty Ltd (now Intrepid Geophysics) in the late 1990s under contract to the Australian Geological Survey Organisation (now Geoscience Australia); 2) gravity and magnetic data from Geoscience Australia seismic survey GA-302 (2006/2007); and 3) gravity and magnetic data from Geoscience Australia marine survey GA-2436 (2007). The data for the GA-302 and GA-2436 surveys were provided to Geoscience Australia in mid-2008 by Fugro Robertson LCT Gravity and Magnetics Division (Job Numbers 4640 and 4731), the contractor used by Geoscience Australia to process gravity and magnetic data from these surveys. The processing steps applied to this dataset include: 1) re-computation of free-air gravity anomalies to ensure consistent computation of gravity anomalies between the different datasets; 2) splitting ship-tracks into relatively straight line segments to avoid multiple cross-overs between any pair of lines; 3) line filtering of the previously-levelled Australia-wide dataset to reduce noise and improve cross-over computations; 4) merge the individual datasets into a single master dataset for levelling; 5) editing to remove lines or line segments with spurious data - lines that were too short or too close to other line segments were also removed in order to improve levelling results; 6) line levelling - gravity data were levelled using a polynomial levelling technique referenced to a satellite radar altimetry-derived dataset, magnetic data were loop levelled (minmising misclosures around closed loops formed by ship tracks); 7) computation of simple Bouguer gravity anomalies (ie. without terrain corrections) using a spherical-cap Bouguer correction and a density contrast between water and sediment of 970 kilograms per cubic metre and water depths interpolated at each data point from the 2009 Bathymetry and Topography Grid of Australia. The data processing and levelling were conducted using the INTREPID software from Intrepid Geophysics (versions 4.2.756 and 4.2.1782). The resulting gravity and magnetic data for the Capel and Faust basins are contained in INTREPID vector databases and are also available in an ascii column-based file exported from INTREPID.

Digital Transfer Options

onLine

Distributor

Role
distributor
Organisation Name
Commonwealth of Australia (Geoscience Australia)
City
Canberra
Administrative Area
ACT
Postal Code
2601
Country
Australia
Email Address

Source Description

Source data not available.

Metadata File Identifier

a05f7892-f884-7506-e044-00144fdd4fa6

Metadata Standard Name

ANZLIC Metadata Profile: An Australian/New Zealand Profile of AS/NZS ISO 19115:2005, Geographic information - Metadata

Metadata Standard Version

1.1

METADATA SECURITY CLASSIFICATION

unclassified

Metadata Contact

Role
pointOfContact
Organisation Name
Commonwealth of Australia (Geoscience Australia)
City
Canberra
Administrative Area
ACT
Postal Code
2601
Country
Australia
Email Address
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