%0 Journal Article
%T Origin and hydrogeochemistry of a shallow flow-through lake on a Pleistocene piedmont, northern Spanish Meseta
%A Clemente Recio
%A Ildefonso Armenteros
%A Margarita Jambrina
%A 芍ngel Corrochano
%J -
%D 2013
%R 10.4081/jlimnol.2013.e29
%X The Cristo lagoon, situated on Neogene deposits in the northern Spanish Meseta, occupies a shallow depression on a Pleistoceneˋpiedmont. The development of the lacustrine depression on the piedmont was favoured by the fault network, reinforced by substrateloss by weathering, probably during the late Quaternary. Even during the hot summer season, salinity is low, with concentrations ofˋtotal dissolved solids (TDS) being around 150 mg L每1. Only when the lagoon is almost dry do TDS concentrations exceed 500 mg L每1,ˋsometimes rising as high as 1700 mg L每1. Whenthe lake level is high, lake chemistry is dominated by Na+, Ca2+, HCO3每 and Cl每. Duringˋdrier stages, there is a relative increase in Ca2+, Mg2+, Cl每, and SO42每, trending toward a calcium chloride-sulphate brine. Values of pHˋare above 9 during late spring and summer, resulting primarily from evaporative degassing favoured by the shallow depth of water, andˋsecondarily from photosynthesis by the abundant submerged macrophytes. The infilling deposits, less than 0.5 m thick, are dark brown,ˋmassive, sandy muds consisting of quartz and clays (illite, kaolinite, smectite), all of which are allogenic in origin. The main source ofˋdissolved sulphate was the oxidation of sulphides during weathering of lower Palaeozoic rocks in the catchment area. Theˋ13C-depletedˋnature of dissolved inorganic carbon indicates an origin mostly by respiration and oxidation of organic matter. Geomorphology andˋhydrogeochemistry indicate a flow-through lake dominated essentially by groundwater flows.
%K [Cristo laggon
%K geolimnology
%K hydrogeochemistry
%K stable isotopes]
%U https://www.jlimnol.it/index.php/jlimnol/article/view/jlimnol.2013.e29