tufa

plural tufas

1. countableuncountableCalcareous lime deposited by precipitation from a body of water, such as a hot spring.

   Resedimented tufas also contribute where erosion has washed detritus from other hillside tufa deposits.

   2003, Martyn Pedley, Ian Hill, “The recognition of barrage and paludal tufa systems by GPR: case studies of the geometry and correlation of Quaternary freshwater carbonates”, in C. S. Bristow, Harry M. Jol, editors, Ground Penetrating Radar in Sediments, page 208

   2 more examples

   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 error in age estimates made using uranium-series methods is not small enough to confirm results from ¹⁴C determinations.

   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 Geological Survey, page 1

   The tufas at Tianshengqiao have different shapes in different development stages and in different structural sections.

   2011, Chuxing Huang, “9: Characteristics and Formation Mechanism of the Tufa Landscape in Tianshengqiao in Zhongdian County”, in Tadej Slabe, editor, South China Karst II, page 95

2. countableuncountablegeographyA variety of volcanic rock, tuff.

   1825, "Oliver Oldschool" (Joseph Dennie), John Elihu Hall (editors), The Port Folio, page 426, 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.

   Synonyms: tuff