Characterising flow regime and interrelation between surface-water and ground-water in the Fuente de Piedra salt lake basin by means of stable isotopes, hydrogeochemical and hydraulic data

Abstract

Summary This research reports the characterisation of ground-and surface-water interaction in the Fuente de Piedra Salt lake basin in southern Spain by a combined approach using hydraulic, hydrogeochemical and stable isotope data. During three sampling campaigns (February 2004, 2005 and October 2005) ground-and surface-water samples were collected for stable isotope studies ( 18 O, D) and for major and minor ion analysis. Hydraulic measurements at multilevel piezometers were carried out at four different locations around the lake edge. Conductivity logs were performed at four piezometers located along a profile at the northern lake border and at two deeper piezometers in the Miocene basin at a greater distance from the lake. To describe processes that control the brine evolution different hydrogeochemical simulations were performed. Hydrogeochemical data show a variety of brines related to thickness variations of lacustrine evaporites around the lake. Salinity profiles in combination with stable isotope and hydraulic data indicate the existence of convection cells and recycled brines. ground-water inflow into the lake was detected. Dedolomitisation processes were identified by hydrogeochemical simulations and different brine origins were reproduced by inverse modelling approaches. ª

Lateglacial and Holocene isotopic and environmental history of northern coastal Alaska – Results from a buried ice-wedge system at Barrow

“…highly saline samples measured with the equilibration method might be erroneous (Kohfahl et al, 2008), by up to 10& in dD and 1& in d 18 O, these results suggest a non-marine origin of the brine water. Even though the resulting d excess of brine water of À5&, (as a combination of d 18 O and dD) should therefore be interpreted with caution, it is situated well underneath the GMWL, thus pointing to secondary fractionation (e.g.…”

“…They are given as per mil difference to V-SMOW (&, Vienna Standard Mean Ocean Water), with internal 1s errors of better than 0.8& and 0.1& for dD and d 18 O, respectively (Meyer et al, 2000). Highly saline (brine) samples are difficult to measure with the equilibration method used in this study (Kohfahl et al, 2008) (1) precipitation deriving from the evaporation of ocean water in different regions and (2) participation of secondary evaporation processes (Dansgaard, 1964). The deuterium excess Dansgaard (1964) is an indicator for kinetic (non-equilibrium) fractionation processes and generally related to conditions (humidity, sea surface temperature, wind speed) in the initial moisture source region.…”

Groundwater ages, recharge conditions and hydrochemical evolution of a barrier island freshwater lens (Spiekeroog, Northern Germany)

“…Due to preferential binding of either heavy or light water molecules in hydration spheres of ions and due to changes in bulk water structure as a consequence of the addition of salts, a socalled isotope salt effect can be observed in saline aqueous solutions (Horita et al, 1993). This effect on the isotopic fractionation of oxygen and hydrogen was determined for the equilibration technique (Bourg et al, 2001) and revised for the AWI instrumentation on the basis of synthetic solutions of Na-Cl (Kohfahl et al, 2008). The curve progresses nearly linear.…”

“…where c is the concentration in mol/l (Kohfahl et al, 2008). This was taken into account for calculating the results of samples with electric conductivities exceeding 5 mS/cm (Table 1).…”

Isotopic composition (δ18O and δD) of precipitation and groundwater in a semi‐arid, mountainous area (Guadiana Menor basin, Southeast Spain)

“…On the other hand, the sample taken from the San Clemente reservoir (R-1, Figure 9) showed a strong influence of evaporation, typical of lakes and reservoirs with a large expanse of water (Mayr et al, 2007;Kohfahl et al, 2008b). This reservoir is situated on the carbonate aquifer and so loses water by leakage to the aquifer beneath it.…”