Integrating airborne SAR, Landsat TM and airborne geophysics data for improving geological mapping in the Amazon region: the Cigano Granite, Carajás Province, Brazil

Abstract

This study examines the value of integrating airborne C‐band Synthetic Aperture Radar (SAR), Landsat Thematic Mapper (TM) and airborne gamma spectroradiometric data with field, petrographic and geochemical data for geological mapping of the Cigano batholith, an important representative of the Paleoproterozoic granitic magmatism in the Carajás Mineral Province (CMP), Amazon region. Distinct schemes for the integration of radar/optical and radar/optical/gamma data were evaluated and the geological information derived from the integrated products was verified in the field. The investigation allowed the re‐evaluation of previous geological information and the definition of distinct domains within the Cigano pluton and country rocks. The importance of brittle structures related to the tectonic evolution of the area and the location of intensely altered zones in the pluton was emphasized, favouring new insights into current geological and exploratory models of the area. The application of a similar approach as operational routine in exploration programmes in the Amazon region is justified considering the limited geological information, the availability of aerogeophysical data and airborne/spaceborne remote sensing data (radar, optical) and the high costs of field mapping in this kind of terrain.

Acknowledgements

We thank the referees for their critiques and suggestions, which helped to improve the quality of this paper. Special thanks to Drs Marcelo Blum and Augusto Pires (University of Brasilia) for processing the PGBC gamma data, to CAPES for funding the MSc thesis of R. K. Teruiya and to CNPq for a grant (no. 300985/90‐8) received by W. R. Paradella during this investigation. We thank M. G. B. Gonçalez for her relevant pioneering contribution to the study of the Cigano pluton. This paper is a contribution to the IGCP 510 project.