[1] Stream aquifer hydrology and nitrate removal were studied, over a period of 2 years, in an unsaturated riparian zone, bounded by an intermittent Mediterranean stream, (Fuirosos, northeastern Spain). The riparian groundwater system is characterized by drastic hydrological changes and by mixing of stream water with hillslope groundwater. The hillslope groundwater flowed through a medium with low hydraulic conductivity (9.6 10 À3 < k s < 0.1 m d À1 ) and low specific discharges (1.7 10 À3 < q hll < 15 10). In contrast, stream water infiltrated through the near stream porous medium with relatively high hydraulic conductivity (4.8 < k s < 19 m d À1 ) and variable specific discharges (i.e., 0.03 < q st < 1.5 m d À1 ). An intense and short stream discharge period occurred in autumn, when stream water infiltrated a maximum of 10 m into the riparian zone. Nitrate concentration and nitrate removal spatial rates (h NO3 ) showed wide spatial heterogeneity. Higher nitrate concentrations (3.4 NO 3 -N mg L À1 ) and effective nitrate removal (h NO3 = 0.098 ± 0.04 m À1 ) were found in the deep groundwater of hillslope zone associated to low water fluxes. In contrast, in the stream edge zone (with higher water fluxes), nitrate release predominated over depletion (h NO3 = À0.13 ± 0.04 m À1

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The La Trocha fault zone acted as a major left‐lateral transfer zone and is bounded by the La Trocha (LTF), Zaza‐Tuinicú (ZTF), Cristales (CTF) and Taguasco (TGF) faults. These faults were consistent with the clockwise rotation of convergence and shortening in central Cuba. From the Paleocene to the Early Eocene (65–48 Ma), a SSW‐NNE shortening produced transtension in the LTF and transpression in the ZTF. Subsequently, during the Middle Eocene (48–37 Ma), shortening shifted to a SW‐NE direction, resulting in the normal component of the LTF and transpression in the ZTF and CTF. Since the Late Eocene (37 Ma), central Cuba has been welded to the North American Plate. The post‐welding deformation gave rise to transtension of the LTF and TGF. This deformation is consistent with a WSW‐ENE shortening and reflects activity in the transform boundary of the Cayman Trough. Both the normal and thrust displacements of these previous faults are corroborated by structural data whereas left‐lateral displacement is deduced from the concordance between oblique collision and structural features. Plate‐kinematics and the structural evolution of the La Trocha fault zone indicate that the related Central Basin is a strike‐slip polygenetic basin and that the formation of this system (i.e., fault zone – strike‐slip basin) was a consequence of the Paleogene oblique collision between the Caribbean Volcanic Arc and the Bahamas Borderland (North American plate).

An integrated geophysical survey has been conducted at the Tarragona's Cathedral (Catalonia, NE Spain) with the aim to confirm the potential occurrence of archaeological remains of the Roman Temple dedicated to the Emperor Augustus. Many hypotheses have been proposed about its possible location, the last ones regarding the inner part of the Cathedral, which is one of the most renowned temples of Spain (twelfth century) evolving from Romanesque to Gothic styles. A geophysical project including electrical resistivity tomography (ERT) and ground probing radar (GPR) was planned over 1 year considering the administrative and logistic difficulties of such a project inside a cathedral of religious veneration. Finally, both ERT and GPR have been conducted during a week of intensive overnight surveys that provided detailed information on subsurface existing structures. The ERT method has been applied using different techniques and arrays, ranging from standard Wenner-Schlumberger 2D sections to full 3D electrical imaging with the advanced Maximum Yield Grid array. Electrical resistivity data were recorded extensively, making available many thousands of apparent resistivity data to obtain a complete 3D image after a full inversion. In conclusion, some significant buried structures have been revealed providing conclusive information for archaeologists. GPR results provided additional information about shallowest structures. The geophysical results were clear enough to persuade religious authorities and archaeologists to conduct selected excavations in the most promising areas that confirmed the interpretation of geophysical data. In conclusion, the significant buried structures revealed by geophysical methods under the cathedral were confirmed by archaeological digging as the basement of the impressive Roman Temple that headed the Provincial Forum of Tarraco, seat of the Concilium of Hispania Citerior Province.

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Gypsum rocks are widely exploited in the world as industrial minerals. The purity of the gypsum rocks (percentage in gypsum mineral in the whole rock) is a critical factor to evaluate the potential exploitability of a gypsum deposit. It is considered than purities higher than 80% in gypsum are required to be economically profitable. Gypsum deposits have been studied with geoelectrical methods; a direct relationship between the electrical resistivity values of the gypsum rocks and its lithological composition has been established, with the presence of lutites being the main controlling factor in the geoelectrical response of the deposit. This phenomenon has been quantified in the present study, by means of a combination of theoretical calculations, laboratory measurements and field data acquisition. Direct modelling has been performed; the data have been inverted to obtain the mean electrical resistivity of the models. The laboratory measurements have been obtained from artificial gypsum-clay mixture pills, and the electrical resistivity has been measured using a simple electrical circuit with direct current power supply. Finally, electrical resistivity tomography data have been acquired in different evaporite Tertiary basins located in North East Spain; the selected gypsum deposits have different gypsum compositions. The geoelectrical response of gypsum rocks has been determined by comparing the resistivity values obtained from theoretical models, laboratory tests and field