Flowstone

Flowstones are sheetlike deposits of calcite or other carbonate minerals, formed where water flows down the walls or along the floors of a cave.

These secondary deposits created outside the cave environment, which mimic the shapes and forms of speleothems, are classified as "calthemites" and are associated with concrete degradation.

[3] Flowing films of water that move along floors or down positive-sloping walls build up layers of calcium carbonate (calcite), aragonite, gypsum,[4][5] or other cave minerals.

Travertine is a calcium carbonate deposit often formed in creeks or rivers; its nature is laminated, and it includes such structures as stalagmites and stalactites.

[2] Flowstone derived from concrete, lime or mortar, can form on manmade structures, much more rapidly than in the natural cave environment due to the different chemistry involved.

"[8] Other trace elements such as iron from rusting reinforcing or copper oxide from pipework may be transported by the leachate and deposited at the same time as the CaCO3.