Abstract: Application of LANDSAT Imagery and Related Remote Sensing Techniques to Mineral Resources Exploration in Australasia
J. F. Huntington, A. A. Green
For several reasons Australasia is exceptionally amenable to practical geologic remote sensing. Since 1972, its geologic community has been the largest user of LANDSAT imagery in Australia, but not without some difficulties. The initial poor quality of the imagery and several characteristics of Australia's environment, such as extremes of brightness and a very extensive weathering history, have limited the imagery's usefulness in certain areas.
The effective use of LANDSAT imagery and its integration with other exploration techniques have required research into both the imagery itself and the geologic and terrain characteristics which strongly influence its utility.
Image quality has been greatly improved by image-enhancement techniques optimized for photointerpretation. Geologic and terrain characteristics indicate that contrast-enhanced color images have a valid role in reconnaissance geologic mapping of both lithology and structure. This adaptability applies to most of Australia's extensive Proterozoic, Mesozoic, and Tertiary platforms and basins in the drier parts of the continent. In the more highly deformed orogenic and metamorphic provinces, such as the Archean of Western Australia or the lower Proterozoic of northwest Queensland, LANDSAT is less effective. The high spatial detail of the geology is not fully resolved and the blanketing effects of weathered profiles and laterites mask subsurface features. For these situations, specialized t chniques are being developed to increase the effective resolution of the imagery and to extract the very subtle spectral information that permits a further improvement in rock-type discrimination and structural mapping.
By use of an interactive TV display at 1:80,000 scale, useful information can be interpreted even in deformed terrains for mineral exploration and 1:100,000-scale survey mapping. The 1:80,000 scale is the same as the higher resolution panchromatic RC9 photo coverage available for the whole continent.
In the highly vegetated east coast foldbelt, the value of LANDSAT is primarily structural. Here, too, certain tailored processing may yield improvements over previously available imagery.
AAPG Search and Discovery Article #90962©1978 AAPG 2nd Circum-Pacific Energy and Minerals Resource Conference, Honolulu, Hawaii