Image processing of aeromagnetic data and integration with Landsat images for improved structural interpretation

Abstract

Digital image processing of aeromagnetic data from three mineral prospects significantly improved the existing structural interpretations that were made from contour maps of the aeromagnetic data. Useful imageprocessing techniques include (1) presentation as smallscale, gray-level images, (2) local contrast enhancement, (3) artificial illumination, and (4) directional filtering. Digital processing also enables direct comparison between Landsat data and aeromagnetic data. Interpretations were improved by the study of the integrated data sets.Images of aeromagnetic data from one prospect in a Precambrian granite-greenstone terrane show major folds and faults that were not previously recognized from contour maps of the aeromagnetic data. A Land-

Integrated geophysical mapping of the Ifewara transcurrent fault system, Nigeria

“…The use of inte gra tion of geo phys i cal meth ods such as elec tri cal resis tiv ity, elec tro mag netic and mag netic tech niques as a geo log ical and litho struc tur al map ping tool have been con firmed by several authors (e.g., Kowa lik and Glenn, 1987;Barker et al, 1992). A resis tiv ity sur vey is com monly used to map frac ture zones in hard rock ter rains (e.g., Car ru thers and Smith, 1992;Ako et al, 1978) because high resis tiv ity con trasts usu ally occur between solid rocks and sat u rated frac ture zones (Adepe lu mi et al, 2006).…”

“…The main thrust of this study is to con firm the exis tence and loca tion of the Ifew ara shear zone (ISZ) using inte grated geo phys i cal meth ods involv ing dipole-dipole resis tiv ity (imag ing tech nique), and mag netic methods. Also, to deter mine the struc tural attri butes like dip, strike and width and depth extent of the shear zone.The use of inte gra tion of geo phys i cal meth ods such as elec tri cal resis tiv ity, elec tro mag netic and mag netic tech niques as a geo log ical and litho struc tur al map ping tool have been con firmed by several authors (e.g., Kowa lik and Glenn, 1987;Barker et al, 1992). A resis tiv ity sur vey is com monly used to map frac ture zones in hard rock ter rains (e.g., Car ru thers and Smith, 1992;Ako et al, 1978) because high resis tiv ity con trasts usu ally occur between solid rocks and sat u rated frac ture zones (Adepe lu mi et al, 2006).…”

Aeromagnetic and Landsat TM structural interpretation for identifying regional groundwater exploration targets, south-central Zimbabwe Craton

“…The combined interpretation of enhanced aeromagnetic and geo-referenced TM images (e.g., Fig. 5) allowed subtle anomaly patterns to be identified and traced with much greater certainty than in one dataset alone (e.g., Kowalik and Glen, 1987;Zeil et al, 1991). These data reveal the presence of several previously undetected regional lineaments cutting across the study area (~100 km; e.g., Figs.…”

“…Fortunately, the processing and presentation techniques are generally similar (e.g., Reeves and Zeil, 1990;Milligan and Gunn, 1997). There are therefore numerous digital processing techniques which could be employed to enhance the AM and TM datasets for maximum extraction and display of the required lithologic and structural information (e.g., Kowalik and Glen, 1987;Reeves and Zeil, 1990;Reeves et al, 1997). A summary of some of the processing techniques applied is given below and more details can be found in various texts (e.g., Drury, 1993;Blakely, 1995).…”

“…3; e.g., Kowalik and Glen, 1987;Broome, 1990). This is particularly useful for enhancing linear, low amplitude short wavelength anomalies.…”