Resumen: En el presente artículo se muestra el análisis estratigráfico realizado en el embalse subterráneo de Torrevieja, a partir de una serie de sondeos
realizados en el mismo, para desvelar las incertidumbres surgidas en el modelo conceptual del acuífero. Éstas hacían referencia a
la posible conexión con el mar de este acuífero, pues los datos hidroquímicos,
que se tenían, no explicaban claramente ésta. Inicialmente
se realizaron dos sondeos, que dieron lugar a tres posibles hipótesis, en función de donde se situó en el pasado la línea de costa, que
barajaban la posibilidad de que dicho acuífero no estaba conectado con el mar, que existía conexión con el mar o que esta conexión era
parcial, por lo que no concretaban la incertidumbre inicial que se planteaba sobre el modelo conceptual relativa a las altas concentraciones
de cloruros que se presentaban en zonas relativamente alejadas de la costa, por lo que la contaminación por este ión podía ser debida
a otras causas antrópicas o naturales distintas de la intrusión de agua de mar. Al objeto de poder definir un único modelo conceptual
se perforaron otros cinco sondeos de investigación hidrogeológica, cuya interpretación paleogeográfica, que se presenta en este artículo,
concreta un único modelo conceptual de funcionamiento del acuífero compatible con la existencia de intrusión marina.
[ABSTRACT]
The current article shows the stratigraphic analysis carried out in Torrevieja underground reservoir from its multiple wells, in order to
reveal the uncertainties arisen from the conceptual model as a consequence of hydroquemical data, whose study was not able to determine
the connection between the aquifer and the sea. Taking into account the coastal line which was defined in the past, two first wells
were made in the aquifer, giving rise to three possible hypothesis: its complete connection with the sea, the total absence of connection
with it or a partial connection between both of them. Under these circumstances, the initial uncertainty posed, further to the cause of high
chloride concentrations detected in some zones located far away from the sea, could not be specified, and this was the reason why it was
necessary to consider other causes for this kind of pollution instead of the connection with the sea, either the anthropic or another natural
one. Lastly, the paleogeographic interpretation of five other investigation wells were made in the aquifer with the purpose of defining
an only conceptual model, compatible with the existence of seawater intrusion.
Resumen: The aim of this study is the hydrogeological exploration and characterization using Geophisical surveying in the vicinity of Dakhla Basin (Algeria). To that end, it has been used the method of resistivities through Vertical Electric Sounding (VES) on a campaign carried out in April 2009. The work
included 19 VES, which have been calibrated with existing wells and with field geological observations. The results have allowed the characterization of Tertiary deposits as well as Ordovician sandstones. With these data, it has been possible to identify the position and thickness of a shallow salty aquifer, and the roof of a deep freshwater aquifer developed on the Ordovician sandstones. The integration of the geometry of the aquifers with the resistivity values obtained in the Ordovician sandstones has allowed the location of a favorable area for the situation of a new well.
Resumen: During the Middle Jurassic, the domain of the Iberian and Catalan Coastal ranges of eastern Spain was occupied by a system of
fault-controlled carbonate platforms that flanked the Iberian Massif to the East. This platform system marked the transition between
the shelves of the Alpine Tethys and the Central Atlantic Ocean. The palaeogeographic reconstruction
of the Iberian Middle
Jurassic platform system is based on more than 199 surface sections and 37 wells. From southwest to northeast, eight main
palaeogeographic elements with associated characteristic facies are recognized. These represent a system of horsts and grabens. In
the southwest, the Internal Castilian Platform is characterized by the frequently dolomitized oolitic and restricted facies of the
Yemeda Formation. To the northeast, the NW-trending open-marine carbonate environments of the External Castilian and
Aragonese platforms were separated by the fault-controlled El Maestrazgo High that is characterized mainly by the dolomitized
Rafales Formation. The External Castilian and Aragonese platforms consist from bottom to top of the microfilament mudstones to
wackestones of the El Pedregal Formation, the bioclastic and oolitic grainstones to packstones of the Moscardon Formation, and
the DomenËœo Formation, that reflects a return to an open-marine low-energy wackestone to mudstone facies, locally containing
patches of oolitic grainstones. The highly subsiding Tortosa Platform, represented by the Sant Blai, Cardo and La Tossa formations,
is bounded by the dolomitic facies deposited on the El Maestrazgo and the Tarragona highs, and by the Catalan Massif where no
Middle Jurassic deposits have been recorded. The open-marine facies and condensed sections of the Beceite Strait separated the
Aragonese and Tortosa platforms. A regional stratigraphical gap spanning the upper Callovian Lamberti Zone to the lower
Oxfordian Cordatum Zone is evident. A system of northwest- and northeast-trending normal faults controlled thickness and facies
distribution. Data from the Iberian carbonate-platform system indicate that expanded sections were not necessarily associated with
open-marine environments. Condensed and expanded sections are developed in open and restricted-marine facies, even on such
palaeogeographic highs as the El Maestrazgo High. Restricted and shallow-marine environments occasionally developed in parts of
the External Castilian Platform.
