The Benefits of Wide Line Spaced Airborne Gravity Gradiometry On Regional Surveys

Abstract

To stimulate the development of natural resources most governments maintain a basic national geophysical database to outline regional structural geology and basin geometries. Magnetics and gravity are normally the tools of choice. There is an obvious trade-off between cost and detail. Airborne gravity gradiometry can be configured to optimise this trade off. It is known that gravity gradiometry detects shorter wavelengths then what is possible with conventional airborne gravity but longer wavelengths are also captured on regional surveys as is demonstrated with an example survey. An airborne gravity gradiometry survey was conducted in Arnhem Land, Northern territory, that was previously covered by conventional airborne gravity. Analysis of the data shows that the conventional airborne gravity dataset has limited content at spatial wavelengths shorter than 4 kilometre whereas the gravity gradiometry data resolves wavelengths shorter than 1 km, while also maintaining the long wavelength information. The analysis indicates that airborne gravity gradiometry offers better resolution at the same line spacing. An additional benefit is the option to infill areas of interest to capture detail not possible with conventional airborne gravity. This enables more effective use of the regional gravity gradiometry data in an exploration programme.