Tectonic control on travertine and calcareous tufa deposition in a low-temperature geothermal system (Sarteano, Central Italy)

Abstract

This paper presents an integrated study directed toward an understanding of the tectonic control on the hydrothermal circulation and resulting deposition of Middle–Late Pleistocene travertine in a low-temperature geothermal field of southern Tuscany, located in the Sarteano area (Central Italy). The study area is characterized by thermal springs ( c . 25 °C) and related continental carbonate deposits, structurally controlled by SW–NE-trending oblique to strike-slip faults dissecting previous normal faults. Sedimentological–stratigraphical data and 230 Th/ 234 U radiometric age determination for the travertine indicate that continental carbonates were deposited in a tectonically controlled, perched-spring system from 268 ± 22 ka (at least) to the present. The hydrothermal system is (and was) characterized by meteoric waters with a minor contribution from fluids of deeper origin. Meteoric waters infiltrated to depth through tectonically damaged zones of Mesozoic and Cenozoic carbonate rocks and overheated as a result of localized, anomalous geothermal gradient. Then, fluids enriched in bicarbonate–sulphate moved up along highly fractured rock masses at the intersection between strike-slip faults and normal faults. This paper highlights the use of continental carbonates in the reconstruction of palaeohydrothermal systems, in terms of the location of the main conduits for hydrothermal fluid flow, age of faulting and physical properties of hydrothermal fluids.

Tectonic control of tufa occurrences in the Podhale Synclinorium (Central Western Carpathians, southern Poland)

“…Travertines and tufas are con sid ered to be in di ca tors of tectonic ac tiv ity and can be used as a tool for iden ti fi ca tion of a nearby fault trace (Han cock et al, 1999;Brogi et al, 2012), of es ti mat ing the age of tec tonic ac tiv ity (Sibson, 1987;Altunel and Han cock, 1993;Han cock et al, 1999;Brogi et al, 2010) or of the per me abil ity of faults and as so ci ated brit tle struc tures (Brogi, 2004(Brogi, , 2012) that played a role as con duits of flu ids (Cain et al, 1996;Sibson, 1996Sibson, , 2000.…”

Travertine occurrences along major strike-slip fault zones: structural, depositional and geochemical constraints from the Eastern Anatolian Fault System (EAFS), Turkey

“…Damage zones in these provinces, which resulted from normal faulting, accompanied often by numerous extensional fractures, are appropriate environs for circulation of thermal fluids and consequently have a significant potential for travertine deposition (Brogi & Capezzuoli, 2009;Brogi, Capezzuoli, Buracchi, & Branca, 2012).…”

“…Hydrothermal systems and spring cabonates are therefore controlled by brittle structures (Brogi et al, 2012). Consequently, in both extensional and strike-slip tectonic settings, prerequsite parameters for travertine precipitation are: (1) a fracture system in permeable bedrocks that alllow fluids to circulate and (2) overpressured hydrothermal waters rich in CO 2 and bicarbonate.…”

“…In previous studies, U-series age data obtained from travertine deposits, and particularly from vein travertines (or vertically banded travertines) have been used for some neotectonic interpretations such as the calculation of dilation in fisssure ridges, the lateral propagation along the length of travertine-filled fissures (Altunel & Hancock, 1993a, 1993bAltunel & Karabacak, 2005;Hancock et al, 1999;Mesci et al, 2008) to determine fault activity (Brogi et al, 2012;Temiz et al, 2013) and seismicity (Uysal et al, 2009(Uysal et al, , 2011. In geothermal fields, circulation and upwelling of hydrothermal fluids and consequently travertine precipitation become easy during faulting and fracturing periods (Brogi & Capezzuoli, 2009).…”

“…Most studies on the travertine-tectonic relationship are concentrated on extensional provinces (Altunel & Hancock, 1993a, 1993bAltunel & Karabacak, 2005;Brogi & Capezzuoli, 2009;Brogi, Capezzuoli, Alçiçek, & Gandin, 2014;De Filippis et al, 2012;Hancock et al, 1999;Renaut et al, 2013;Selim & Yanik, 2009;Uysal et al, 2007;Van Noten et al, 2013) where travertines are deposited at the tip zone of fault segments, in extensional stepover zones between fault segments (Çakır, 1999), at the intersection point of normal and strike-slip faults (Brogi, 2004;Brogi et al, 2012Brogi et al, , 2014 or along normal faults (Mesci, Gürsoy, & Tatar, 2008).…”