The Bosumtwi meteorite impact crater, Ghana : New Results on the impact direction of the meteorite from 2D Electrical Resistivity Tomography (ERT) Survey
Résumé
The 10.5 km diameter Bosumtwi meteorite impact crater in Ghana was formed about 1.07 million years ago. It is the source crater of the Ivory Coast tektites strewn field. The crater is occupied by a lake of diameter 8.5 km. Electrical resistivity tomography (ERT) survey using the multi-electrode gradient array was carried out along sixteen radial profiles around the lake to determine the sediment/bedrock contact, impact related structures and the impact direction of the meteorite. The data were corrected for topography and inverted using the L 1 –norm. The subsurface images highlighted areas that are characterized by faults, fractures, lake sediments and impact related breccias such as allochthonous and parautochthonous breccias and dikes. The sediment/bedrock contact, which marks the crater geometry, was successfully mapped and it shows symmetry in the NE–SW direction and dips between 16 0 in the NE to 36 0 in the SW. The faults were mostly delineated in the west and they dip averagely 60 0 to the east and 80 0 to the west. The dips of the faults were statistically treated and were found to have a preferred direction. The results of the crater geometry and the orientation of the faults indicate that the meteorite came from the NE. Research paper: The Bosumtwi meteorite impact crater, Ghana : New Results on the impact direction of the meteorite from 2D Electrical Resistivity Tomography (ERT) Survey. Available from the NE.