Tufa

Duckstein, m. calcareous tufa, duff, a. dull, dead. 

Tuff, m. tuff, tufa dust, tuffartig, a. tufaceous. 

Tuff-erde, /. tufaceous earth, -kalk, m. tufaceous limestone, -stein, m. tufa, tuff, tuffsteinartig, a. tufaceous. 

Speleothems and other secondary carbonate deposits such as tufa, travertines, lake carbonates and vein calcites have the potential to provide valuable information about past climate, hydrogeochemistry, landscape development and hominid evolution during the early Quaternary and Tertiary periods. Electron-spin resonance (Griin 1989, Rink 1997) and disequilibrium methods (Ludwig et al. 1992) have proved to be useful in... 

Bischoff, J. L., J. A. Fitzpatrick and R. J. Rosenbauer, 1993, The solubility and stabilization of ikaite (CaC03 6H2O) from 0 °C to 25 °C, environmental and paleoclimatic implications for thinalite tufa. Journal of Geology 101, 21-33. 

Tufa fished 6y Yfova Science Tuhfishers, Inc. -f- Yfew York... 

When M. H Klaproth analyzed some native alum (alunite) from Cape Miseno, near Naples, he computed that one thousand pounds of it contained 470 pounds of alum provided by Nature herself with the requisite quantity of pot-ash" and 290 pounds of alum whose crystallization is promoted by adding pot-ash (21). The presence of this alkali raised in his mind the question "As this grotto consists merely of volcanic tufa, in which no vegetation takes place, whence does Nature procure the vegetable alkali requisite to the generation of the crystalhzable alum (21). 

Stoneware, composed of plastia clay from the Palatinate, ground quartz from Oberwald or Bern-cast e, calcareous tufa from Stork. The glaze contains lead, and the waie has ft yellow tint. 

Chemical Dripstone (cave deposits), tufa, opal, travertine... 

Pleistocene tufa (with Mimomys stehlini-polonicus) have yielded an estimate of 3 million years. 

In her furthest retreat is a woodland cavern not artificially elaborated Nature by her own skill bath hollowed it out she bath constructed it of living Pumice Stone and light Tufa". 

Pentecost A. (1985a) Association of cyanobacteria and tufa deposits identity, enumeration and nature of the sheath material revealed by histochemistry. Geomicrobiol. J. 4,285-298. 

Calcification and deposition of carbonates in rivers are uncommon but may be found in some stagnant parts, and in the upper reaches, when the deposits may occur as calcareous tufas, travertines, and sinters (Golubic, 1967,1973). In some rivers, oncoids and algal balls are formed. 

Chen, J.A., Zhang, D.D., Wang, S.J., Xiao, T.F. Huang, R.E. (2004) Factors controlling tufa deposition in natural waters at waterfall sites. Sedimentary Geology 166, 353-366. 

Zhang, D.D., Zhang, Y., Zhu, A. Cheng, X. (2001) Physical mechanisms of river waterfall tufa (travertines) formation. Journal of Sedimentary Research A71, 205-216. 

Figure 6.1 Thin section of a sample of tufa from a Holocene paludal deposit at Wateringbury, Kent (c. 6000 years old) viewed under crossed nicols. The mould of a moss stem with attached leaves is encrusted by micrite and microspar. The high porosity of this sample results from the original open framework of the structure (shelter porosity) and the decay of bryophytes. There has been little diagenesis. Scale bar 250 pm.

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