Tufa sedimentation in changing hydrological conditions : the River Mesa (Spain)
Auque, Luis Francisco (Universidad de Zaragoza. Departamento de Ciencias de la Tierra)
Arenas Abad, María Concepción (Universidad de Zaragoza. Departamento de Ciencias de la Tierra)
Osácar Soriano, María Cinta (Universidad de Zaragoza. Departamento de Ciencias de la Tierra)
Pardo Tirapu, Gonzalo Martín (Universidad de Zaragoza. Departamento de Ciencias de la Tierra)
Sancho Marcén, Carlos (Universidad de Zaragoza. Departamento de Ciencias de la Tierra)
Vázquez-Urbez, Marta (Universidad de Zaragoza. Departamento de Ciencias de la Tierra)

Data:	2013
Resum:	The processes controlling tufa deposition along the River Mesa (NE Spain) were studied from April 2003 to September 2009, based on six-monthly monitoring of physical and chemical parameters of the river water and sedimentological characteristics, including deposition rates on tablets. With a mean annual discharge around 1. 5m3 /s, the sedimentation rate (mean 2mm/yr) recorded important spatial, seasonal and interannual variations. The river waters are of the calcium bicarbonate type. In this study, three distinct river stretches were distinguished based on the steady groundwater inputs, some of low-thermal nature. Groundwater discharges controlled the water chemical composition, and some sedimentation features too. At each stretch, an increase in pCO2 and conductivity was measured around the spring sites. Decreasing trends in conductivity or alkalinity with high enough saturation values with respect to calcite were only clearly observed in the intermediate stretch, which had higher tufa deposition rates than the other two. Tufa deposition rates were higher in cool (autumn+winter) than in warm (spring+summer) periods. In some low-rainfall warm periods, tufa deposition was inhibited or limited due to the low flow -mainly from groundwater inputs- and to the dryness of some river sites, which indeed favoured erosion during flooding. A decrease in yearly deposition rates from April 2006 onwards paralleled an important reduction in the river discharge. Groundwater inputs, drought periods and flood events should therefore be considered to understand fluvial tufa sedimentation in semi-arid conditions.
Drets:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, la comunicació pública de l'obra i la creació d'obres derivades, fins i tot amb finalitats comercials, sempre i quan aquestes es distribueixin sota la mateixa llicència que regula l'obra original i es reconegui l'autoria de l'obra original.
Llengua:	Anglès
Document:	Article ; recerca ; Versió publicada
Matèria:	Recent fluvial tufas ; Deposition rates ; Hydrochemistry ; Hydrological variability ; Continental Mediterranean climate
Publicat a:	Geologica acta, Vol. 11, Núm. 1 (març 2013) , p. 85-102, ISSN 1696-5728

Adreça alternativa: https://raco.cat/index.php/GeologicaActa/article/view/263720
Adreça alternativa: https://revistes.ub.edu/index.php/GEOACTA/article/view/105.000001774
DOI: 10.1344/105.000001774

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