A REVIEW OF TUFA AND TRAVERTINE DEPOSITS OF THE WORLD

A general review of the nature and classification of tufas is presente d and the available literature is summarised. An attempt is made to st andardise the terminology currently in use and to distinguish clearly between ambient temperature deposits (tufas), thermal deposits (traver tines) and speleothems. Consideration is also presented of the physico -chemical and biological processes, often acting together, which are r esponsible for the precipitation of freshwater calcium carbonate withi n tufa systems. These processes appear to be climatically controlled. Therefore, tufas may be of value in palaeo-environmental reconstructio n, especially if intercalated with peaty material. While the majority of tufa deposits are of post-glacial age some of the most spectacular carbonate precipitates are thermal travertines. The second part of the paper deals with a world-wide survey of the principal deposits of tuf a and travertine. Space prevents a fuller account of the European depo sits and the reader is referred to Pentecost (1995) for a wide range o f specific examples from Europe and Asia Minor.