POSSIBLE PLANAR ELEMENTS IN ZIRCON AS INDICATOR OF PEAK IMPACT PRESSURES FROM THE SIERRA MADERA IMPACT CRATER, WEST TEXAS

Geologic Setting: The Sierra Madera structure in west Texas is an ~12km well-exposed eroded remnant of a complex impact crater. Permian and Cretaceous age siliciclastic and carbonate rocks were deformed during the impact event. Shock deformational features at the Sierra Madera crater include breccias, shatter cones, planar deformational features (PDFs) in quartz, grain fracturing and deformed quartz and carbonate minerals [2]. The structure was last studied in the late 1960’s and early 1970’s and is an excellent site for largeand small-scale deformation studies using modern research techniques.