Fig. 3

Model of the disruption process by crystallizing salts (modified after Zehnder and Arnold 1989). a Saline solution evaporates first from large pores, and then smaller pores, which makes salts growing in large pores form aggregates or granular crusts. b Cohesion or strength of the host material is reduced by disruption along cracks caused by the crystallization pressure of clustered aggregates growing on pore walls. c Crystallization concentrated in cracks continues isometrically when the crystals are covered by solution film, which produces columnar crystals when evaporation dominates. d Columnar crystal growth thins out as the cracks open, forming whisker-like crystals when their growing tips are in contact with solution, and the crystal lift debris or fragments produced by disruption of the host material