The Zhamanshin impact feature: A new class of complex crater?

Examination of the topographic and orbital remote sensing signatures of two 10-km-class complex impact structures, Zhamanshin (Kazakhstan) and Bosumtwi (Ghana), both of which formed in the past 1 m.y., suggests either extreme differences in regional crater erosion rates during the Quaternary or some sort of fundamental difference in the preerosional topography of the structures. The visible to near-infrared spectral signature of the 14-km Zhamanshin feature is subtle, and is dominated by breccia and impact-glass covered hills apparently associated with the inner ring of a multiringed complex crater that formed only 870,000 years ago. The total dynamic range of relief at...