Shelfstone
Encyclopedia
Speleothem
A speleothem , commonly known as a cave formation, is a secondary mineral deposit formed in a cave. Speleothems are typically formed in limestone or dolostone solutional caves.-Origin and composition:...
that grows inwards from the edge of a cave pool. It takes the form of ledges that tend to be flat on top and sloping undernerth. They are almost always formed from calcite
Calcite
Calcite is a carbonate mineral and the most stable polymorph of calcium carbonate . The other polymorphs are the minerals aragonite and vaterite. Aragonite will change to calcite at 380-470°C, and vaterite is even less stable.-Properties:...
, when materials precipitated from dripping water onto a cave pool attach to the side. The deposition continues to grow laterally, underneath. The shelfstone above the current water level in a pool is an indicator of past levels of the pool. Shelfstone can be very thick when the water level has stayed constant over a long period of time. If the water level is constantly changing, the shelfstone will be thin and delicate.