gour

   Flowstone deposit, normally of calcite, built up along the edge of a pool due to precipitation from a thin film of overflow water. Once initiated, by calcite-saturated water overflowing from floor hollows, development is selfenhancing, and the gours can grow into large dams many meters high and wide. Inside the gour pool, more calcite may be precipitated as crystals or pearls. Large flights of gours occur in many caves, with spectacular and well known examples around the Hall of Thirteen in the Gouffre Berger, France. Large travertine, gours can form in the open air, as at Band-i-Amir, Afghanistan [9].

   See also rimstone barrage; rimstone barrier; rimstone dam.