Application of chemical geothermometers to a low temperature thermal system

The Tiermas geothermal system is one of the areas with the greatest geothermal potential in Aragón, however, its hydrogeological and geochemical features are still poorly known. In this study, the main hydrochemical features of these waters are presented and the reservoir temperature is approached by applying chemical geothermometers. These waters have a sulphate chloride sodium affinity, with nearly 40 ºC of spring temperature and an approximate flow rate of 200 l/s. The most likely aquifer seems to be located in the Paleocene and Eocene carbonates. However, due to the structural complexity of the area, the waters would also interact with the evaporitic facies present in the Eocene–Oligocene boundary. Two different hydrochemical groups have been distinguished based on their salinity, Na/Cl ratios, SO4 concentrations and TDS values. Despite the compositional variations detected in the springs, the geothermometric calculations allow to infer a reservoir temperature of 85 ± 17 °C. Good consistency has been obtained with the cationic geothermometers, which is an unusual situation for a geothermal system in carbonate–evaporitic materialsEl sistema geotermal de Tiermas representa una de las zonas con mayor potencial geotérmico de Aragón y, sin embargo, se sabe todavía poco acerca de sus características hidrológicas y geoquímicas. En este trabajo se presentan los principales rasgos hidroquímicos de estas aguas y se determina su temperatura en profundidad mediante la aplicación de geotermómetros químicos. Estas aguas tienen una afinidad clorurada sulfatada sódica, una temperatura de surgencia de casi 40 °C y un caudal de unos 200 l/s. El acuífero más probable se localizaría en los carbonatos del Paleoceno y Eoceno, pero debido a la complejidad estructural de la zona, las aguas entrarían en contacto con la facies evaporítica del tránsito Eoceno–Oligoceno, adquiriendo así dicha afinidad. Se han distinguido dos grupos hidroquímicos con una diferente salinidad, relación Na/Cl y concentraciones de SO4 y TSD. A pesar de las variaciones composicionales detectadas en las surgencias, los cálculos geotermométricos realizados permiten establecer un rango de temperaturas en el reservorio de 85 ± 17 °C, habiéndose obtenido buenos resultados con los geotermómetros catiónicos, situación poco habitual en sistemas termales instalados en materiales carbonatados – evaporítico

First monitoring results in the El Recuenco Cave (Ejulve, Teruel)

El Recuenco Cave (Ejulve, Teruel, NE Spain) is developed with a complex topography in Upper Cretaceous dolomitic limestones. A monitoring survey is in progress in the cave (covering now the 1st semester of 2013) in order to know the isotopic path from rainfall to dripwater and in-situ farmed calcite. Rainfall results show that δ18O values reveal a clear seasonality (-12,73‰V-SMOW in winter, -8,94‰V-SMOW in spring). Dripwater values are mainly influenced by homogenization processes in the epikarst and also reveals seasonality in δ18O values (-10,9‰ V-SMOW in winter, -9,8‰ V-SMOW in spring). Finally, isotopic values of in-situ farmed calcite confirm this seasonality pattern (in δ18O values, -8,17‰ PDB in winter, -8,11‰ PDB in spring; also in δ13C values, -9,84‰ PDB in winter, -9,68‰ PDB in spring). Nonetheless, new monitoring tasks are needed to confirm this preliminary pattern. These conclusions will help to better interpret of speleothem records in this cave for paleoclimatic reconstructionsLa cueva de El Recuenco (Ejulve, Teruel) presenta una topografía compleja desarrollada en calizas dolomíticas del Cretácico superior. En ella se ha efectuado un seguimiento instrumental del desarrollo espeleotémico actual (primer semestre de 2013) de cara a evaluar el recorrido isotópico desde el agua de lluvia, pasando por el goteo interno hasta el carbonato precipitado. Los resultados del agua de lluvia evidencian que el δ18O muestra una clara estacionalidad (-12,73‰ V-SMOW en invierno, -8,94‰ V-SMOW en primavera). Los valores isotópicos del goteo se encuentran controlados por la homogeneización producida en el epikarst,mostrando de nuevo cierta estacionalidad en δ18O (-10,9‰V-SMOW en invierno, -9,8‰V-SMOW en primavera). Finalmente, la señal isotópica del carbonato resultante confirma este patrón de estacionalidad (en δ18O, -8,17‰ PDB en invierno, -8,11‰ PDB en primavera; en δ13C, -9,84‰ PDB en invierno, -9,68‰ PDB en primavera). No obstante, es necesario ampliar el seguimiento temporal para confirmar este patrón estacional preliminar. Estas consideraciones ayudarán a una mejor interpretación de los registros espeleotémicos en esta cueva de cara a realizar reconstrucciones paleoclimática

Evolución estacional y decenal de isótopos estables registrada en tobas recientes depositadas en substratos artificiales en el Parque del Monasterio de Piedra (NE España)

Identification of six-month intervals in carbonate deposits formed on tablets installed in several fluvial subenvironments of the Monasterio de Piedra Natural Park, from 1999 to 2009, allowed six-monthly stable-isotope analysis of such records. Slight differences in δ13C and δ18O exist between stromatolites (fast-flowing water areas) and moss-bearing deposits (cascades). Sediment δ13C values did not show clear regular variations through time. A chiefly cyclic pattern of sediment δ18O values reflected the seasonal variations in temperature. The calculated water temperature values were consistent with measured air and water temperature values. The increasing tendency of air temperature is closely reflected by the estimated temperature tendencies. The isotopic results stress the validity of the seasonal variation pattern detected through thickness measures, and underscore the environmental significance of tufas, which accounts for the use of this type of analysis in climate interpretation from ancient tufa recordsLa identificación de intervalos semestrales en depósitos carbonatados formados sobre losetas instaladas en diversos subambientes fluviales del Parque Natural del Monasterio de Piedra, desde 1999 hasta 2009, ha permitido el análisis semestral de isótopos estables de dichos registros. Existen pequeñas diferencias en δ13C y δ18O entre las facies estromatolíticas (áreas de flujo rápido) y las ricas en musgos (cascadas). Los valores de δ13C no muestran variaciones temporales regulares. Los valores de δ18O presentan una pauta cíclica que refleja las variaciones estacionales de temperatura. Los valores calculados de la temperatura estacional del agua son acordes con las temperaturas medidas de aire y agua. La tendencia creciente de la temperatura del aire se refleja en las tendencias de temperatura estimadas. Estos resultados refuerzan la validez del patrón estacional detectado mediante la medida de espesores de los depósitos, y confirman la utilidad de este tipo de análisis en la interpretación climática de tobas antigua

Efficacy of several organic products for the treatment of sandstone at the Real Monastery of Sijena (Huesca)

The aim of this paper is to test the effectiveness of certain methods of consolidation in sandstones of different grades of damage. Three organic silicon compounds in different concentrations were applied by spraying. Treated and untreated samples were examined by SEM in order to observe the products of polymerization. Laboratory tests were performed and a comparison of consolidated and original stone has shown that some physical properties have been improved, particularly the reduction of capillarity suction and water absorption. A crystallization test points out the efficacy of the treatment

Quaternary tufas of the River Añamaza (NW Iberian Ranges, Spain): a chronological approach

High-gradient, stepped fluvial tufa systems with dammed areas existed in the River Añamaza valley (NW Iberian Ranges, Spain) during Quaternary times. Single deposits range from a few meters to about 70 m thick, in which prograding-aggrading wedges separated by erosional surfaces exist. Several episodes of tufa formation have been distinguished by means of U-series, Amino-acid racemization and radiocarbon techniques. These correlate to MIS 8, 7, 5 and 1. The presence of MIS 9 is uncertain, as chronological data may also correspond to older stages. Most tufas in this area formed in MIS 5. Distinct tufa episodes can also be distinguished in the Holocene. These are the first chronological data presented for one of the northernmost Quaternary tufa systems in the Iberian Range

Preliminary chronology of the Quaternary tufas from the Piedra River (Iberian Range)

A preliminary absolute chronology for the Quaternary calcareous tufa deposits from the Piedra River valley (Iberian Range, NE Spain) has been carried out based on U series dating, Amino Acid Racemization, Optically Stimulated Luminescence and Radiocarbon dating techniques. Although the age uncertainties of the obtained dates are substantial, four stages of tufa accumulation correlated to MIS 9, 7-6, 5 and 1 can be distinguished. The most favourable period for tufa accumulation is located around the isotopic stage

Preliminary analysis of the Quaternary tufas of the River Ebrón (Castielfabib, Valencia, Iberian Range)

En el valle del río Ebrón (sector central de la Cordillera Ibérica), cerca de Castielfabib (provincia de Valencia), se diferencian dos unidades tobáceas encajadas. La antigua, de 77 m de espesor, tiene una edad de 180-100 ka obtenida mediante Racemización de Aminoácidos, y se correlaciona con los MIS 6 y 5. Los 25 m superiores de la unidad moderna presentan una edad de radiocarbono comprendida entre 6 y 2 ka (MIS 1). La sedimentación tiene lugar en un sistema de barrera y represamiento cuya nucleación parece controlada por un aumento en el gradiente del perfil del ríoTwo fluvial tufa units forming a nested fill terrace system were differentiated near Castielfabib (Valencia province) in the River Ebrón valley (central sector of the Iberian Ranges). The older unit (measured ≈ 77 m thick) was correlated to MIS 6 and 5 (180-100 ka) based on Aminoacid Racemization ages. The younger one (minimum measured ≈ 25 m thick) was correlated to MIS 1 (6-2 ka) according to the obtained Radiocarbon dates. Tufa sedimentation was mainly produced in a high gradient, stepped fluvial stretch displaying both barrage-cascade and dammed water area