Crystaline labyrinths
The unusual, maze like soil textures seen in most of the micro pics looks like the crusts that you might get from drying out mixtures of various salts. There seems to be quite a lot of hopper crystals, which are indicative of rapid growth. Could such textures be produced just by frosts? It looks more like rapid crystalization from saturated brines to me. This would make a good subject for simple study, I think.