Travertines associated with the Alhama-Jaraba thermal waters (NE, Spain): genesis and geochemistry Maria P. Asta(1)*, Luis F. Auqué(2), Francisco J. Sanz(2), Maria J. Gimeno(2), Patricia Acero(2), Mónica Blasco(2), Antonio García-Alix(3), Javier Gómez(2), Antonio Delgado-Huertas(4), Juan Mandado(2) (1)Environmental Microbiology Laboratory (EML), École Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland (2)Petrology and Geochemistry Area, Earth Sciences Department, C/Pedro Cerbuna 12, 50009 Zaragoza, Spain (3)School of Geographical and Earth Sciences, University of Glasgow, United Kingdom (4) Instituto Andaluz de Ciencias de la Tierra (IACT) (CSIC-UGR), Avda. de las Palmeras, 4; 18100 Armilla, Granada, Spain. *Corresponding author:
[email protected] 1 1 Abstract 2 Freshwater carbonates are interesting archives in palaeoenvironmental reconstructions. 3 However, more studies of those systems are needed to fully understand past environments. 4 In this work the actively-forming travertines of the Alhama-Jaraba thermal system were 5 studied for the first time in order to evaluate the relationship between the geochemical and 6 mineralogical composition and the environmental conditions during their formation. With 7 that aim, a combination of petrographical, mineralogical, geochemical and stable isotope 8 analyses were carried out. These carbonates provide a natural laboratory for the study of the 9 effect of different variables (natural and anthropogenic) on carbonate precipitation. 10 The results showed that there is a close relationship between the mineralogy of the solid 11 precipitates and the formation temperature, and only the samples formed from overheated 12 waters (40-60 ºC) show significant concentrations of aragonite.