Imaging sedimentary basins from high-resolution aeromagnetics and texture analysis

Abstract

Image texture is an important property of gridded aeromagnetic data that together with the availability of closer survey line-spacings and more sensitive instrumentation, has become more relevant for qualitative interpretations. Problems arise though when it is used as a basis for geological interpretation, since visual textures are difficult to define. This can introduce bias when interpretations are not validated against repeatable and testable quantitative measures. We propose the use of well-established unsupervised texture segmentation techniques that use multi-scale, orientation-selective Gabor filters to automatically domain contrasting textures in aeromagnetic maps. These methods are applied to tilt-derivative reduced-to-pole magnetics over the Palaeoproterozoic Earaheedy Basin, that was deposited over the northeastern Yilgarn Craton in a marginal setting prior to the ca. 1800 Ma Capricorn Orogeny Western Australia. These results are then validated against a geophysically constrained interpretation of the area and a review of the magnetic characteristics of the region. Our results demonstrate how automatic texture domaining from gridded magnetic-field data can produce geologically feasible results that can be used to constrain the architecture of basins that contain magnetic sedimentary rocks.