Delineation of structural elements in Melut Basin (Sudan) using satelite images of Landsat 4 and Landsat 7

Melut Basin is located onshore Sudan approximately 550 km south of Khartoum. It lies along the Mesozoic/Cenozoic trend of rift–related basins running from Nigeria to the west through Chad, the Central African Republic, Sudan and possibly into Kenya. Of elongated form, the basin is about 175 miles long and 60 miles wide, exhibiting rift extensional tectonic feature with stike-slip compressional effects resulting in a complex fault-bounded anticlines. Major fault trends throughout the basin are SSE-NNW, similar to the trend of the basin. In the present time Melut is considered as one of the most potential basins with respect to petroleum in Sudan. Many oil fields have been discovered in this area and prospecting activities are, so far, going on.
The analysis of multi-source remote sensing data can provide rich, reliable and useful information. The following remote sensing data were used in this study:
- TM 171-54 (13-01-1987), ETM 171-54 (06-05-2002)
- TM 172-53 (17-01-1986), ETM 172-53 (03-02-2001)
- TM 172-54 (17-01-1986), ETM 172-54 (12-09-2000)
- TM 173-53 (18-11-1984), ETM 173-53 (04-11-1999)
- TM 173-54 (08-01-1986), ETM 173-54 (24-12-2000)
Various remotely sensed data has different spatial resolution. The integration of these data through fusion techniques may increase the information content of the resulting images and improves the accuracy of image interpretation. The corresponding five TM bands were merged to facilitate the production of a mosaic for bands 7,4 and 1. Five ETM panchromatic bands were used to produce a panchromatic mosaic. The merged multispectral and panchromatic bands were subset to portray Melut Basin. The multispectral and panchromatic subsets were then co-registered to a common cartographic base and integrated through resolution merge technique.
The resulted image from the above mentioned processing procedures seems to be spatially enhanced, since it’s pixel size is about 15 m. So the new image has the spectral resolution of TM bands (Landsat 4) and the spatial resolution of the panchromatic band (Landsat 7). In addition to that, the fusion has sharpened the image. This advantage is very helpful in delineating lineaments, which may represent the surface expressions of structural elements such as faults, joints, etc. These structures have special importance in Melut Basin in concern to oil exploration, since in most of the discovered oil fields the trapping styles identified are either titled fault-blocks or fault-bounded anticlines.
Delineation of structural elements can be performed with high degree of accuracy utilizing the fusion techniques, which serves to increase the image sharpness by merging high resolution panchromatic bands with medium resolution multispectral bands. The produced lineaments map is considered a new addition to the geology of Melut Basin and it can be used as a guide in the exploration activities.