Hypertufa[4] is a mixture of Portland cement and various aggregates in imitation of naturally-occurring tufa.
Most limestones exhibit some evidence of pedogenic brecciation and root penetration, and porous fabrics similar to those of modern limestone tufas occur locally.
Field observations also showed that tufa deposition occurred mainly at waterfall sites.
The results show that the principal cause of waterfall tufa formation is the enhanced inorganic carbon dioxide outgassing resulted from the sudden hydrological changes occurring at waterfall sites, rather than organisms, evaporation or the solid water interface.
Transfer of the plastid tufA to the nucleus was predicted to occur in the common ancestor of land plants (Baldauf and Palmer 1990).
Of the 27 synonymous and 6 non-synonymous single nucleotide variants that occurred at frequencies >5%, 18 synonymous mutations were found to be due to contaminating tufA gene sequences from other microorganisms present in the natural microbiota and 15 being due to C. trachomatis mutations.
Epsomite and hexahydrate occur in the form of efflorescence on the church walls made of pure calcium carbonate – tufa stone.
"I couldn't believe it," Tufa said.
Locations include Iceland; New Zealand Yellowstone National Parkk, Wyo., U.S.; and Steamboat Springs, Colo., U.S. Calcareous sinter, sometimes called tufa, calcareous tufa, or calc-tufa, is a deposit of calcium carbonate, exemplified by travertine.
The museum was faced in tufa, an unlikeably dead pale stone.
