Basalt boulder beside the West Links, North Berwick, showing smoothing and oriented pits

 

 

 

 

 

 

 

 

 

 

 

 

Facetted basalt boulder from the same location

 

Beach ventifact

Definition: a fixed, projecting stone or boulder on a sandy beach with one of more faces showing the effects of wind abrasion

Ventifacts are stones which have been smoothed, grooved and facetted by the abrasion of wind-blown sand. Ventifacts have been described mainly from deserts, high mountains and rubble-covered deflation surfaces in the periglacial zone. Recently Knight and others have identified ventifacts on beaches in western Ireland and elsewhere. In Oregon rates of abrasion are high, around 0.2-1.0 mm pa.

The examples from near North Berwick show the classic features of ventifacts, including polished surfaces, pits and grooves. The boulders are of fine-grained basalt, with keels oriented roughly north-south. Wind erosion was achieved under northerly winds, perhaps during the stormy period of the Little Ice Age.