tufas

Noun

tufa (countable and uncountable, plural tufas)

1. Calcareous lime deposited by precipitation from a body of water, such as a hot spring.
   • B.J. Szabo presented the results of a survey of the tufa mounds that border Pyramid Lake indicating that uranium-series methods can be used to approximate the ages of such tufa deposits. In the Pyramid Lake Basin, tufas less than 50,000 years old contain large quantities of excess thorium, and the...1993, George V. Benson, Meeting Highlights, George V. Benson (editor), Proceedings of the Workshop "Ongoing Paleoclimatic Studies in the Northern Great Basin", Geological Survey Circular, US...
2. A variety of volcanic rock, tuff.
   • This again is followed by a bed of stony tufa of a reddish colour, containing fragments of a spongy lava, amphigone, pyroxene, mica, and common lava; and, like the former, traversed by argillaceous veins.1825, "Oliver Oldschool" (Joseph Dennie), John Elihu Hall (editors), The Port Folio, page 426

   Synonyms:

   tuff