Fig. 4:  SNC METEORITE CROSS SECTION  This image shows multiple tiny vein like cracks in this Shergottite that are filled with melt glass. The huge asteroid impact that ejected this rock from its parent body as a meteorite also created a shock wave that melted the walls of these cracks and produced melt glass as it passed through them. Any of these cracks that connected with the surface would have been filled with atmosphere from the parent body, and melt glass could have trapped and preserved some of this atmosphere inside glass bubbles.