Some people believe it may be millions of years old. - [Ryan] Mono Lake in particular has these tufa towers that are these limestone rocks that are made when the salt water mixes with the fresh water.

and this is a tufa deposit. It's formed by the reprecipitation of dissolved limestone. Tom: Smooth. Not much friction. Dr Tom Challands: This is because limestone is a soft rock, made from the ...

Tufa mounds are formed when heated water rises ... Nahanni — it continues to cut enormous ribbons through the limestone rock. Further downstream, the river calms and widens.