Lapiás ou lapiaz [1] (word derived from lapiaz, from the Jura dialect) is a typical karst relief formation, produced by the superficial dissolution of calcareous or dolomitic rocks. It can also be caused by freezing and thawing cycles in cold weather regions.
Lapiás, together with dolines, cenotes, cones and karst valleys, form the outer portion of the karst relief, also known as exocarste, while caves, crevices and speleothems make up the underground part of karst, or endocarste.
Lapiás consist of fractures in the superficial rocks that expand through the dissolution of the rock, resulting in large channels that groove the rocks horizontally or vertically, as well as fields of large rocks, isolated from each other and with different types of flutes, fringes and surface holes. In some cases, only depressions occur along the surface of the rock, which is not fragmented.
Lapiás are formed initially by dissolving the rock at the interface with the soil and cracks are opened. After erosion of the topsoil, the rocks are exposed and the dissolution of the rock continues to expand the cracks. Eventually the rocks are completely separated and form fields of level rocks or groove and crevice patterns. Soil and vegetation can fill the spaces between rocks.