The Physics of Shock Waves and Experimental Shock Metamorphism: Dieter

Introduction: The cooperation between Dieter Stöffler and Ernst-Mach-Institut (EMI) [1-14] goes back to 1972 when first experiments were performed to shock single crystal feldspars by steel plates that were accelerated with an explosive plane wave generator [1,7]. The shock experiments initiated a series of studies that required versatile and reliable test methods for the generation of Hugoniot shock pressures in the range of 5-80 GPa, where shock metamorphism is the dominant physical process. Experimental Methods: In solids, Hugoniot shock pressures in the range of 1-20 GPa are generated from flyer plates accelerated to velocities of between 10 and 1000 m/s. Higher pressures are reached for the same velocity using multiple shock reverberations. With explosively driven flyer plates reaching impact velocities of between 1000-3000 m/s, Hugoniot pressures of between 20-80 GPa are reached. Two-stage light-gas guns, accelerating flyer plates to velocities of 2000-6000 m/s, generate Hugo-niot shock pressures of above 100 GPa in the impacted samples. Results: Stöffler's early work with EMI investigates shock metamorphism of single crystal feldspars [1, 3], of rocks such as dunite [2], and of single-crystal quartz [4]. Stöffler applied extensively EMI's explosively driven flyer plate method, that allows recovery of the specimen, for mineralogical shock wave barome-try of α-Quartz and Gneiss [5,6,7] and for investigating temperature effects on shock metamorphism of single-crystal quartz [8,9]. His contributions to understanding the formation of pseu-dotachylites along lithological surfaces is published in [10]. In [11], Stöffler was involved in synthesizing diamonds from graphite and gneiss. Recent work investigates survival rates of bacteria following high shock loads, to understand whether bacteria can survive loads from impact ejection from Mars [12-14]. Conclusions and Outlook: Dieter Stöffler has been cooperating with EMI over 35 years, investigating shock metamorphosis by employing the method of explosively driven flyer plates, a versatile and reliable tool for geological and mineralogical shock wave research. As consequence of this long lasting cooperation the aspect of morphological changes introduced from a hyperve-locity impact in sandstone will be further studied in a joint project intended to create and analyze meteorite impacts under lab conditions (MEMIN-Multidisciplinary Multidisciplinary Experimental and Modeling Impact crater research Network [15]).