Formation of central uplift structures in large, complex impact craters: Mechanical importance of pseudotachylitic breccia zones and prominent dislocations in the development of the Vredefort Dome, South Africa

• Applicant: Professor Dr. Wolf Uwe Reimold
• Subject Area: Palaeontology
• Term: from 2006 to 2012
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 30307603

Despite the fact that large meteorite impact belongs to the least understood processes in planetary geology, detailed structural studies of terrestrial impact structures, let alone of large complex ones, are still in their infancy. Considerable uncertainty centres around the formation of central uplifts, more specifically, the (1) geometric and kinematic significance of prominent dislocations, (2) the temporal and mechanical relationships between continuous and discontinuous deformation and (3) the mechanical role of voluminous pseudotachylitic breccia bodies in this process. These issues are addressed in a combined field-structural, laboratory and 3D geometric restoration analysis using the Vredefort Dome, a deeply eroded relic of a central uplift and best preserved natural laboratory on Earth for such study. The study will also test whether shock-induced melt, i.e., pseudotachylitic breccia, was transported from highpressure to low-pressure sites during formation of the central uplift, und thus pertains directly to solving the pseudotachylite controversy . Structural analyses proposed herein are intimately linked with the petrographic and geochemical and analyses of pseudotachylitic breccia delineated in the companion proposal by Prof. U. Reimold.

• DFG Programme: Research Grants
• International Connection: Canada, South Africa
• Participating Persons: Professor Dr. Roger Gibson; Professor Dr. Ulrich Peter Riller