Spherical shock experiments with Chelyabinsk meteorite: reflectance spectra changes with increasing shock

Spherical shock experiments produced gradual pressure changes from S4 level up to complete melting. At ~50 GPa peak pressure shock darkening of silicates is observed due to troilite melt penetrating silicate grains associated with reduction in intensity of silicate 1 and 2 µm absorptions. This process stops at higher pressures as partial melting of silicates along grain boundaries isolates troilite melt. Darkening occurs again upon material complete melting. In MIR region, spectral trends are similar, however the reststrahlen silicate bands are still resolved in shock-darkened or impact melt zone

Experimental Constraints on the Ordinary Chondrite Shock Darkening Caused by Asteroid Collisions

Shock darkening is caused by two distinct mechanisms with characteristic pressure regions, which are separated by an interval where the darkening ceases. This implies a reduced amount of shock-darkened material produced during the asteroid collisions