talus (tāˈləs) [key], deposit of rock fragments detached from cliffs or mountain slopes by weathering and piled up at their bases. A talus is a common geologic feature in regions of high cliffs. The angle of slope of a talus is rarely greater than 40°. The constant weathering to which a talus is subjected, which breaks the rock fragments into finer pieces, and the impact of new material being added from above give the base of the talus a tendency to creep and slide. The term talus is often used to refer to the fragments themselves.