Third-Party Funded Project

MEMIN Sub-Project: Projectile-target interaction, melting and vaporization in hypervelocity experiments and natural impactites
01.11.2013 – 31.10.2016

The subproject investigates the chemical-physical interaction between projectile and target during impact events, focusing on carbonates and impact melts.

This sub-project focused on the chemical and physical interactions between the ‘projectile’ (the impacting asteroid) and the ‘target’ (the planetary surface struck) during impact events. Using a combination of high-speed impact experiments, innovative laser experiments and petrological analyses of natural impact rocks, we were able to gain a better understanding of the chemical and physical processes involved in the formation of so-called impact melts and condensates. 

Whilst the chemical and physical interaction between silicate rocks and metallic impactors was the main focus of the first funding phase of MEMIN, the focus of the second funding phase of this sub-project was on the reaction of carbonates to extreme pressure and temperature conditions during the decompression phase of impact events. 

A key finding of this sub-project during the second funding phase is that carbonates decompose extremely rapidly and efficiently when in contact with silicate impact melts, leading to the release of CO₂ and the enrichment of the silicate melt with CaO (and MgO in the case of dolomite-bearing target rocks). The observed interfacial processes resemble skarn-forming reactions, and the experimental products show strong parallels with natural impact melts from carbonate-bearing craters (e.g. Nördlinger Ries, Haughton, Meteor Crater, etc.). 

Our results suggest that the delayed decomposition of carbonates during and after pressure relief is a key process in the formation of such impact melts. At the same time, our results suggest that carbonate impact melts can form during the decompression phase as silicate–carbonate melt emulsions due to physical contrasts, but probably not through the separation of a homogeneous melt. The CO₂ outgassing of carbonate-rich target rocks is thus interpreted as a complex, scenario-dependent process.

 

Collaborating partners

Fraunhofer Institute for High-Speed Dynamics, Ernst Mach Institute, EMI
Institute for Planetology, University of Münster (WWU)
Institute of Earth and Environmental Sciences, University of Freiburg

 

Publications

  • Hamann C., Bläsing S., Hecht L., Schäffer S., Deutsch A., Osterholz J., Lexow B. (2018). The reaction of carbonates in contact with laser-generated, superheated silicate melts: Constraining impact metamorphism of carbonate-bearing target rocks. Meteoritics & Planetary Science 53, 1644–1686. doi:10.1111/maps.13133
  • Hamann C., Fazio A., Ebert M., Hecht L., Wirth R., Folco L., Deutsch A., Reimold W.U. (2018). Silicate liquid immiscibility in impact melts. Meteoritics & Planetary Science 53, 1594–1632. doi:10.1111/maps.12907
  • Ebert M., Hecht L., Hamann C., Luther R. (2017). Laser-induced melting experiments: Simulation of short-term high-temperature impact processes. Meteoritics & Planetary Science 52, 1475–1494. doi:10.1111/maps.12809
  • Van Roosbroek N., Hamann C., McKibbin S., Greshake A., Wirth R., Pittarello L., Hecht L., Claeys P., Debaille V. (2017). Immiscible silicate liquids and phosphoran olivine in Netschaëvo IIE silicate: Analogue for planetesimal core–mantle boundaries. Geochimica et Cosmochimica Acta 192, 295–317. doi:10.1016/j.gca.2016.10.042
  • Hamann C., Luther R., Ebert M., Hecht L., Deutsch A., Wünnemann K., Schäffer S., Osterholz J., Lexow B. (2016). Correlating laser-generated melts with impact-generated melts: An integrated thermodynamic–petrologic approach. Geophysical Research Letters 43, 10602–10610. doi:10.1002/2016GL071050
  • Schultze D.S., Jourdan F., Hecht L., Reimold W.U., Schmitt R.-T. (2016). Tenoumer impact crater, Mauritania: Impact melt genesis from a lithologically diverse target. Meteoritics & Planetary Science 51, 323–350. doi:10.1111/maps.12593
  • Hamann C., Stöffler D., Reimold W.U. (2016). Interaction of aluminium projectiles with quartz sand in impact experiments: Formation of khatyrkite (CuAl₂) and reduction of SiO₂ to Si. Geochimica et Cosmochimica Acta 192, 295–317. doi:10.1016/j.gca.2016.07.018
  • Ebert M., Hecht L., Deutsch A., Kenkmann T., Wirth R., Berndt J. (2014). Geochemical processes between steel projectiles and silica-rich targets in hypervelocity impact experiments. Geochimica et Cosmochimica Acta 133, 257–279. doi:10.1016/j.gca.2014.02.034
  • Hamann C., Hecht L., Ebert M., Wirth R. (2013). Chemical projectile–target interaction and liquid immiscibility in impact glass from the Wabar craters, Saudi Arabia. Geochimica et Cosmochimica Acta 121, 291–310. doi:10.1016/j.gca.2013.07.030
  • Ebert M., Hecht L., Deutsch A., Kenkmann T. (2013). Chemical modification of projectile residues in a MEMIN cratering experiment. Meteoritics & Planetary Science 48, 134–149. doi:10.1111/j.1945-5100.2012.1429.x