Original paper

Generation of radial and concentric melt-filled dislocation zones in the central uplift of the Vredefort Impact Structure, South Africa

Lieger, Daniel; Rille, Ulrich


Target rocks underlying the central portions of large terrestrial impact structures, such as 2023 ±4 Ma Vredefort, are characterized by the pervasive presence of melt-filled dislocation zones. Uncertainty regarding the generation of these zones exists regarding the strain field during cratering, origin of melt (i. e., friction- vs. shock-induced), emplacementof melt and evolution of central uplift structures. Collectively, this is paramount for assessing the kinematics and mechanics of rock deformation during formation of central uplift structures in large impact structures, a major focus in impact geology. We address these issues with a quantitative, field- based structuralanalysis focussing on dislocation zones and pseudotachyliticbreccia bodies in the central portion of the Vredefort Impact Structure, the Vredefort Dome.