Shelfstone is a ledge or projection extending from the edge of a cave pool or attached to a speleothem dipped in a cave pool. Typically they may ring the entire edge of a pool basin. It is almost always formed from calcite, when material precipitated on top of a cave pool (such as rafts) attach to the side, and depostion continues to add growth laterally and underneath. As such, they are indicators of past pool levels. Shelfstone may be quite thick when a pool has stayed at the same level for a long time (as in the first and second photos), or thin and delicate (as in the third photo). Shelfstone may acrete as a ring around the base of a stalactite that has become inundated by a standing pool, creating what is sometimes called lily-pad shelfstone. Examples are shown in the two lower photos.

very large shelfstone

large thick shelfstone

lace-thin shelfstone

tiers of shelfstone

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	Created: June 19, 1995 Last Updated: Nov 20, 2016 Author: Dave Bunnell