For example, polygonal cracks with various scales have been reported in many impact craters at all latitudes (El-Maarry et al., 2010), in putative chloride-rich terrains in the southern mid-latitudes (Osterloo et al., 2008, 2010), in regions that display spectral signatures of clay minerals (e.g., Wray et al., 2008), and in the Meridiani plains as imaged by the MER Opportunity (Watters and Squyres, 2012). El-Maarry et al. (2010) developed an analytical model that suggested that the size of the polygonal cracks and their geographical location can be used to distinguish between polygonal cracks created by desiccation and those created by thermal contraction (i.e., periglacial cracks).