Using remote sensing and potential field data to interpret basin fill compositional variations and structures

Abstract

SUMMARYCombined mapping of variations in sedimentary basin fill composition and a structural interpretation is a step towards defining significant crustal scale structures and developing tectonic models in basin dominated terranes. The Bresnahan Group, part of the siliclastic Bresnahan Basin in the Capricorn Orogen was deposited in one such region. New geophysical and remote sensing datasets have been processed to interpret the basin composition and structure. Fieldwork to ground truth the interpretations, including mapping, petrophysical measurements and petrographic examination has also been completed. A northwest-trending fault in the eastern part of the Bresnahan Group has been identified as being in close proximity to compositional changes in basin fill observed on hyperspectral mineral maps. The structure has a similar orientation to a fault that cuts the older Hamersley Basin. A previously interpreted northeast-trending basin-controlling fault mapped in the west has observed differences in radiogenic components north to south in the Bresnahan Group that could reflect changes in basin fill composition. Although, the actual fault could not be mapped in any of the datasets. A west-trending fault in the north that bounds the group, is co-incident to a fault that is thought to control the deposition of the underlying Ashburton Basin, which might indicate a degree of depositional control on sedimentation by pre-existing structures. Faults mapped within the Bresnahan Group, mainly by Landsat 8 and hyperspectral datasets, appear to be mostly post basin fill deposition because of compositional offsets observed. Overall, mapping out compositional variations and structures has indicated regions of the basin fill that might have been fault controlled, that is a step towards defining crustal scale structures and tectonic models in the region.