Bosumtwi is one of only 18 currently confirmed African impact craters (Koeberl, 1994a; Master and Reimold, 2000), and one of only four known impact craters associated with tektite strewn fields Koeberl et al., 1997). Its location is shown in Fig. 1. The 1.07 Ma Bosumtwi crater (centered at 06°30'N and 01°25'W) is situated in the Ashanti Region of Ghana, West Africa, and centered about 32 km from Kumasi, the regional capital. It is a well-preserved complex impact structure that displays a pronounced rim and is almost completely filled by the 8 km diameter Lake Bosumtwi. The crater is excavated in 2 Ga old metamorphosed and crystalline rocks of the Birimian System (Junner, 1937). It has a rim-to-rim diameter of about 10.5 km. The crater is surrounded by a slight near-circular depression and an outer ring of minor topographic highs with a diameter about 20 km.
