ventifact

A ventifact is a rock whose surface has been sculpted by wind-blown sand, a process known as aeolian abrasion. The term is used in geology and geomorphology to describe rocks that have been abraded to produce polished facets, grooves, flutes, and pits.

Ventifacts form in arid or semi-arid environments where strong, persistent winds transport sand grains. Over time, these grains strike exposed rock surfaces, preferentially abrading certain faces. The resulting surfaces may be polished and smooth, with sharp or beveled edges and distinctive striations or flutes. Facets often align with the prevailing wind direction, and multiple faces indicate exposure to different wind regimes over time.

Ventifacts can form on a variety of rock types, including sandstone and granite, and are commonly found on desert pavements, boulder fields, coastal zones, high plateaus, and periglacial landscapes. The rate of ventifact formation depends on factors such as rock hardness, grain size, wind speed, moisture, and duration of exposure.

Because the orientation and development of ventifacts preserve information about past wind regimes, they are useful for inferring paleowind directions and reconstructing aeolian landscape evolution. They help scientists interpret past aridity, erosion rates, and environmental change in desert, tundra, and alpine settings.