Geomorphological and environmental characteristics of the travertine deposits of Rapolano Terme area (Siena, Italy)

Abstract

The travertine deposits in the Rapolano Terme area has been studied to define geomorphological, environmental and climatic conditions of deposition and for a better knowledge of the interaction between the depositional processes and the human activity, developed since ancient times with thermal and estractive aims. Different morphological types of travertine accumulations, such as tabular and fan-shaped bodies, fissure ridges, terraced mounds, cones, and waterfall deposits have been identified. They are strictly connected to the palaeomorphology of the substratum and generally are superimposed to one another or interfingered and often are separated by erosional surfaces. The facies analysis has permitted the identification of the depositional environments, i.e.: palustrine, fluvio-lacustri-ne, thin water layers running on variably steeping slopes, pool gradines, etc. The palinological analysis of the fluvio-lacustrine sediments intercalated in the upper part of the studied sequence does not allow a palaeoenvironmental reconstruction as a preferential conservation of some resistent types of palinomorfs has taken place. It proves, nevertheless, that Abies and Picea were present in Tuscan Apennines during the Holocene. Radiometric datings indicate that the sequence, about 40 m thick, has been deposited during the upper part of the Upper Pleistocene to the Holocene. At this moment the human activity began to influence and deeply modify the travertine deposition.