Travertines

Trapzene Trauzl block test Travase Travertine Travogen Trazodone [19794-93-5]... 

Definitions. In addition to showing varying degrees of chemical purity, limestone assumes a number of widely divergent physical forms, including marble, travertine, chalk, calcareous mad, coral, shell, ooHtes, stalagmites, and stalactites. AH these materials are essentially carbonate rocks of the same approximate chemical composition as conventional limestone (2—4). 

Travertine is a calcium carbonate formed by chemical precipitation from natural hot-water mineral springs. In appearance and use it is closely akin to... 

Richter S, Goldberg SA, Mason PB, Traina AJ, Schwieters JB (2001) Linearity tests for secondary electron multipliers used in isotope ratio mass spectrometry. Inti J Mass Spectrom 206 105-127 Rihs S, Condomines M, Sigmarsson O (2000) U, Ra, and Ba incorporation dining precipitation of hydrothermal carbonates imphcations for Ra-Ba dating of impure travertines. Geochim Cosmochim Acta 64 661-671... 

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... 

A priori considerations. An extensive review of the form and mineralogy of the secondary cave deposits is provided by Hill and Forti (1997), but also see Ford and Williams (1989). By far the most useful speleothems for geological purposes are the most common forms stalactites, stalagmites and flowstones composed of calcite, and occasionally aragonite. Other deposits that have been used to derive useful information include travertines, gypsum crusts, calcite veins and scalenohedral calcite (dog-tooth spar). 

Atkinson TC, Rowe PJ (1992) Applications of dating to denudation chronology and landscape evolution. In Uranium-series disequilibriiun Applications to Earth, Marine and Enviromnental Sciences, Ivanovich M, Harmon RS (eds) Oxford University Press, Oxford, p 669-703 Auler AS, Smart PL (2001) Late Quaternary paleoclimate in semiarid Northeastern Brazil from U-series dating of travertines and water table speleothems. Quat Res 55 159-167 Ayliffe LK, Marianelh PC, Moriarty KC, Wells RT, McCulloch MT, Mortimer GE, Hellstrom JC (1998) 500 ka precipitation record from southeastern Australia Evidence for interglacial relative aridity. Geology 26 147-150... 

Gordon D, Smart PL (1984) Comments on "Speleothems Travertines and Paleoclimates" by G.J. Hennig, R. Griin and K. Bnmnacker. (Jnat Res 22 144-147... 

Hancock PL, Chalmers RML, Altunel E, Cakir Z (1999) Travitonics using travertines in active fault studies. J Stract Geol 21 903-916... 

Absolute Dating of Travertines from Archaeological Sites... 

Figure 2. Stone artifact (hand-ax) embedded in travertine in the Zuttiyeh cave,...

C-dating of travertines is possible in some instances the initial 14C/12C ratio of speleothem or travertine will generally be less than that of the atmosphere at the time of deposition, due to admixture of dead carbon from the limestone from which the Ca and part of carbonate have been obtained. But, where active... 

Pa, and 226Ra. The latter isotope, with a 1600 y half life, is a monitor of relatively recent disturbances of the deposits. Nevertheless, Cherdyntsev et al., believed that the data were consistent with an age of about 115 ky, which agreed with the estimates based on the faunal remains in the travertine. 

In Greece, the cave of Petralona has yielded a skull of a variety of Homo erectus. A number of workers including the present writer have attempted to determine the age of this site [25-27]. Although the samples of travertine cannot be very accurately located with respect to the former location of the skull, the various analysts concur that these travertine layers must be greater than 350 ky in age. Liritzis has attempted to estimate the age on the basis of 234U/238U ratios 500 50 ky the assumptions in such a date are however very shaky. 

Figure 5. Schematic cross section of the cave of Lachaise-de-Vouthon, Charente, France, showing the relation between dated travertine layers and the artifact- and...

Figure 6. Variation of the Th/ Th ratio for samples of travertine that contained contaminant Th at the time of deposition with varying initial Th/ Th...

The observed mean and standard deviation of nine analyses of travertine from the watt of the cave of Combarettes is shown on the right (X a). The age of the wall inscriptions in this cave as deduced from archaeological data and 14C ages elsewhere, is shown by the vertical dashed lines. The U-series data are consistent with this age estimate, for (230Th/Z32Th)o values in the range commonly observed in cave deposits (1.25 to 1.75). 

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