Robert Smithson

Land art, Earthworks (coined by Robert Smithson), or Earth art is an art movement which emerged in the United States in the late 1960s and early 1970s, in which landscape and the work of art are inextricably linked. It is also an art form that is created in nature, using natural materials such as soil, rock (bed rock, boulders, stones), organic media (logs, branches, leaves), and water with introduced materials such as concrete, metal, asphalt, mineral pigments. Sculptures are not placed in the landscape, rather, the landscape is the means of their creation. Often earth moving equipment is involved. The works frequently exist in the open, located well away from civilization, left to change and erode under natural conditions. Many of the first works, created in the deserts of Nevada, New Mexico, Utah or Arizona were ephemeral in nature and now only exist as video recordings or photographic documents.

From http://en.wikipedia.org/wiki/Land_art