Landslides in the Remolinos gypsum escarpment (NE Spain): controls imposed by stratigraphy, fluvial erosion, and interstratal salt dissolution

Abstract Dissolution of karst rocks (evaporites and carbonates) can cause significant mechanical weakening, but its preparatory role for landslide development has been scarcely explored. Fluvial valleys carved in gypsum bedrock typically display prominent escarpments with numerous landslides perched indicative rapid retreat rate. The stratigraphic cartographic analysis the 37-km-long Remolinos escarpment Ebro Valley (NE Spain) reveals that types are controlled by lithological succession: (1) rotational slides sections mudstones marls at base; (2) rock-slope collapses (massive rock-falls) where cliff includes halite packages foot; (3) relatively small rock-falls topples being main failures affecting cliffs entirely made gypsum. undercutting highly mobile River is process controls spatial temporal distribution slope instability. Geomorphic chronological evidence supports abandonment 1574 El Castellar village was least partially motivated a shift river channel toward consequent activity. Several lines support concept whereby interstratal salt dissolution (halite glauberite), here designated as subsurface solutional undermining, play development: close to scarp inward advance fronts subsidence overlying strata; collapsed fault blocks no offset across grabens; brine seepages extensive efflorescences precipitates Na-sulfates halite.