Towards an Australian radioelement baseline database

Abstract

Approximately 75% of Australia is covered by public-domain, airborne gamma-ray spectrometric surveys. However, all the older surveys are in units of c/s and their data values depend on the survey instrumentation and acquisition parameters. Also, many of the newer surveys were inadequately calibrated with the result that data values on adjacent surveys are not necessarily comparable. This limits the usefulness of these data. Geoscience Australia and State Geological Surveys are working towards establishing a national baseline database of Australian gamma-ray spectrometric data that is consistent with the global radioelement baseline established by the International Atomic Energy Agency. This will be achieved by: (a) ensuring consistency in the calibration and processing of new gamma-ray spectrometric data through the use of standard processing procedures and calibration facilities that are tied to the global datum, and; (b) adjusting older surveys to the global datum through back-calibration and automatic grid merging. Surveys that are registered to the same datum are easily merged into regional compilations which facilitate the recognition and interpretation of broad-scale regional features, and allow lessons learnt in one area to be more easily applied to other areas.