• Numerical simulation of temperature effects at fissures due to shock loading

      Heider, N.; Kenkmann, T. (The Meteoritical Society, 2003-01-01)
      The localized appearance of specific shock features in target rocks and meteorites such as melt veins and high pressure polymorphs suggests that regions with a local increase in pressure and temperature exist as a shock wave propagates through an inhomogeneous rock. In this paper, we investigate the effect of planar fissures on the local temperature distribution using numerical simulations. Time-dependent parameters such as temperature, pressure, and displacement are evaluated. The simulation model is based on a shock equation of state for the involved materials, dunite and quartzite, and simulates geometries that were also used in shock-loading experiments. An artificial gap between the materials simulates an open fissure at the interface. A strong temperature increase occurs at a gap size of 0.1 mm, which potentially can cause melting in a thin layer at the interfaces. The temperature decreases with decreasing gap size. Temperature and pressure excursions at the interface are induced by the closure of the gap, which causes a second shock wave to superpose the primary wave. Open fissures and fractures, which occur ubiquitously in shallow-buried target rocks and projectiles, thus, act as local pressure and temperature amplyfiers and may be responsible for thin melt vein formation in shocked rocks.