Low-gradient landslides; Lateral spreading; Gravitational folding; Radiocarbon dating; Crimean Mountains; Alma River.

Large-scale ancient landslides of the area of more than 5 km2 and volume exceeding 200x106m3 are characteristic features of the valleys incised in the northern periphery of the Crimean Mountains (Ukraine). The largely affected area is located in the outermost cuesta range of the Crimean Mountains which consists of rigid Sarmatian limestones overlying weak Middle Miocene and Upper Palaeogene deposits. A giant landslide arose in the Alma water gap as a reflection of several coincident preparatory factors such as suitable bedrock stratification, smectite-rich bedrock exposed to swelling activity, presence of faults parallel to the valley trend, and river capture event which preceded the landslide event.