A acção dos pipekrakes na morfogénese actual na Serra do Gerês

NEEDLE ICE EROSION IN THE SERRA DO GERES (NW PORTUGAL)- After a short review of the studies on needle ice in the world, its morphogenetic significance in the Serra do Geres is discussed. Several needle ice induced morphological features were identified in the field. Nevertheless, cryogenic features are in most cases ephemeral, being destroyed by the action of processes with higher morphogenetic capacity (i.e. runoff). Needle ice acts mostly as a disruptive agent, causing the desagregation of weathered granite or other non-choesive deposits. The resultant material is easily transported by other processes, like runoff or wind. The more prone areas to needle ice formation are also discussed.