The use of airborne gamma‐ray spectrometry—A case study from the Mount Isa inlier, northwest Queensland, Australia

Abstract

An airborne survey was undertaken on the Mount Isa inlier in 1990–1992. During this survey, both airborne magnetic and gamma‐ray spectrometric data were recorded over 639 170 line-km. Because of perceived value of the radiometric data, stringent calibration procedures, including the creation of a test range, were adopted. In addition to the data from the newly‐flown areas, 76 760 line‐km of existing data were acquired from other companies, and were reprocessed and merged with the Mount Isa survey. The total area covered by the Mount Isa airborne survey was 151 300 km2. Over the last five years, several studies have been undertaken that seek to exploit the Mount Isa region gamma‐ray database and maximise the use of radiometrics for mineral exploration. This paper highlights the results of these studies by focussing on radiometric signatures of major mines in the Mount Isa Inlier, radioelement contour maps, geomagnetic/radiometric interpretation maps, lithological mapping, regolith mapping, geochemical sampling, and spatial modeling using geographical information systems (GIS). Due to the recent introduction of GIS technology and better techniques for handling high quality digital data, there has been a revived interest in making more use of image data sets. The integration of raster and vector data sets for both spectral and spatial modeling has maximized the potential of this approach.

Mapping Soil Surface Mineralogy at Tick Hill, North-Western Queensland, Australia, Using Airborne Hyperspectral Imagery

“…• Airborne gamma radiometric data collected at 200 m line spacing and resampled/ interpolated to 50 m pixels (Jayawardhana and Sheard, 2000). …”

Application of High-Resolution Aeromagnetic and Gamma-ray Spectrometry Surveys for Litho-Structural Mapping in Southwest China

“…It is particularly effective in distinguishing different lithologies and accurately characterizing geological units. Therefore, it has been widely employed in geological mapping and often complements aeromagnetic survey [17][18][19][20][21][22]. In this study, we utilized high-precision aeromagnetic and gamma-ray spectrometry data, in conjunction with geological information, to conduct a comprehensive analysis of the structural distribution, stratigraphy, and distribution characteristics of igneous rocks in the study area.…”

Petrofísica e interpretación integrada de datos aeromagnéticos, radiométricos y gravimétricos : aplicaciones a los complejos ígneos del área de Monesterio

“…Por lo que respecta al tratamiento de los datos espectrométricos en términos de unidades geológicas individuales, se puede llevar a cabo según un método estadístico simple, basado en las eliminaciones de los extremos del histograma de concentraciones de cada radioelemento, según diversos métodos (v.g., Saunders, 1976, Abd el Nabi, S.H., 1995, Jayawardhana y Sheard, 2000.…”

“…Las zonas de alteración mencionadas pueden ser objeto de tratamientos de separación de anomalías radiométricas como los que se han usado en la obtención de las propuestas de cartografía geofísica de los complejos zonados estudiadas en el capítulo 6 (Abd el Nabi, 1995, Jayawardhana y Sheard, 2000. Trateimientos específicos (uso de ratios, análisis de componentes principales), e integración con datos magnéticos y de geoquímica terrestre (v.g, Smith, 1985, Ranjbar et al, 2001, mejoran la delineación de las zonas alteradas, aunque sean pequeñas y supongan sólo ligeras redistribuciones de las concentraciones de los radioelementos naturales (la alteración hidrotermal suele implicar aumentos de K de la roca original y removilizaciones sobre todo de U, por el material aportado por los fluidos y los cambios de T, P, pH y Eh.…”