Travertine deposition and faulting the faultrela

Authors: Andrea Brogi Enrico Capezzuoli

Publish Date: 2008/01/03

Volume: 98, Issue: 4, Pages: 931-947

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Abstract

In this paper we describe an example of travertine fissureridge development along the trace of a normal fault with metre displacement located in the eastern margin of the Neogene–Quaternary Siena Basin in the Terme S Giovanni area Rapolano Terme Italy This morphotectonic feature 250 m long 30 m wide and 10 m high formed from supersaturated hot waters 399°C flowing from thermal springs aligned along the trace of the normal fault dissecting travertines not older than Late Pleistocene 24 ± 3 ka A straight continuous fissure with a maximum width of 20 cm occurs at the top of the ridge along its crest Hot fluids flow from cones mainly located at the extremities of the ridge where travertine is depositing The travertine fissureridge shows an asymmetrical profile since it buries the fault scarp The difference in height of slopes corresponds to the vertical displacement of the normal fault Fissuring of the recent travertine deposits along the strike of the crestal fissure as well as recent hydrothermal circulation lead us to believe that the Terme S Giovanni normal fault may be currently active On the whole the Terme S Giovanni fissure ridge can be defined as a travertine fault trace fissureridge adding a helpful example for studying the relationship between faulting and travertine depositionWe are very grateful to E Altunel F Storti D Liotta and A Gandin for the discussion on the topics of this paper The reviewers JJ Martinez Diaz and E Turco are thanked for their constructive comments and remarks very useful to improve the manuscript B Terrosi and A Mancini helped us to prepare the final editing of some figures This paper was funded by the Siena University research grants PAR2005 coord A Lazzarotto

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