Unidad docente Geología
http://hdl.handle.net/10017/212
GEOLOGIA2024-03-28T15:25:31ZThe Turonian-Campanian rudist bivalve succession in the Central Iberian Basin
http://hdl.handle.net/10017/60723
The Turonian-Campanian rudist bivalve succession in the Central Iberian Basin
Gil Gil, Javier; Pons Muñoz, Josep María; Vicens Batet, Enric; García-Hidalgo Pallarés, José Francisco; Segura Redondo, Manuel Francisco
Four rudist assemblages: lower Turonian, upper Turonian, upper Coniacian, and Santonian??Campanian, are distinguished in the shallow water carbonate platform successions of the Iberian Basin, nowadays Iberian Range, a Mesozoic intra-continental basin in the western margin of the Mediterranean Tethys. Because of the depositional evolution of the Iberian Basin, the occurrence, abundance, taxonomic diversity, diagenetic processes, and shell preservation, for each assemblage, is linked, both, to the shallow character of these carbonate platform successions, and the successive high and low frequency sea level falls. Twenty identified rudist taxa are described and figured: Hippuritidae, six species of two genera; Radiolitidae, ten species of six genera, one new, Hoyosites tozoi gen. et sp. nov; Requieniidae, one genus. The knowledge of the shell characters of some taxa has been improved and the taxonomic, biostratigraphic, and palaeobiogeographic significance of most of them increased. The precise positioning of the first three rudist assemblages in high-frequency depositional stacking pattern (parasequence sets) and their correlation and calibration with ammonite biozones provide biostratigraphic datums of great importance. This fact notably improves the chronostratigraphic framework of the Cretaceous sedimentary successions of the Iberian Basin, especially towards the coastal margins, and allows the accurate quantification of the hiatuses associated with the parasequence sets boundaries, so enabling their precise hierarchization.
92 p.
2024-01-03T00:00:00ZHydrogeochemistry of granitic mountain zones and the influence of adjacent sedimentary basins at their tectonic borders: the case of the Spanish Central System batholith
http://hdl.handle.net/10017/59909
Hydrogeochemistry of granitic mountain zones and the influence of adjacent sedimentary basins at their tectonic borders: the case of the Spanish Central System batholith
Martín-Loeches Garrido, Miguel; Pavón García, Javier; Molina Navarro, Eugenio; Martínez-Santos, Pedro; Reyes-López, Jaime; Almeida, Carlos; Cienfuegos Hevia, Ignacio; Sastre Merlín, Antonio
Se describen las características hidrogeoquímicas de manantiales en granitos del Sistema Central Español (SCS), una cadena montañosa afectada por estructuras tectónicas corticales, junto con una investigación sobre su origen. En manantiales con caudal variable y asociados con pequeñas alteraciones y fracturas, el tipo hidroquímico predominante es Ca-(Na)-HCO3, con bajo contenido de sólidos disueltos totales (TDS) (54&-200 ppm) y pH neutro o ligeramente ácido. En manantiales de caudal continuo y asociados con fracturas relevantes, el tipo de agua es Na-HCO3, con mayor pH y TDS (240&-563 ppm). Hay cinco manantiales con agua del tipo Na-(Ca)-Cl y alto TDS (780&-9,205 ppm) cerca de los bordes tectónicos del sur del SCS. El agua subterránea del tipo Ca-(Na)-HCO3, evoluciona a agua del tipo Ca-(Na)-HCO3 antes de 5,000 años de edad aparente, aumentando ligeramente el contenido de HCO3, perdiendo Ca debido a la precipitación de calcita e intercambio iónico, y ganando S debido a la reducción de sulfatos. No se observan cambios después de 20,000 años de edad aparente. Las características del agua del tipo Na-HCO3 son compatibles con una posible influencia de CO2 de origen interno movilizado a través de fracturas. El agua de la mayoría de los manantiales es fría, por lo que se puede deducir una profundidad de flujo de hasta 500 m. Solo en la región afectada por la falla Messejana-Plasencia y sus asociadas, existen manantiales termales, del tipo Na-HCO3. Los manantiales con aguas cloruradas son el resultado de la influencia del agua subterránea de las cuencas terciarias que fluyen hacia el borde sur del SCS. La falla inversa que marca dicho borde, junto con las estructuras subverticales afectadas por ella, son responsables de la aparición de estos manantiales clorurados. El borde norte del SCS muestra un comportamiento opuesto.
26 p.
2020-06-27T00:00:00ZA geostatistical protocol to optimize spatial sampling of domestic drinking water supplies in remote environments
http://hdl.handle.net/10017/59901
A geostatistical protocol to optimize spatial sampling of domestic drinking water supplies in remote environments
Pardo Iguzquiza, Eulogio; Martínez-Santos, Pedro; Martín-Loeches Garrido, Miguel
This paper deals with the design of optimal spatial sampling of water quality variables in remote regions, where logistics are complicated and the optimization of monitoring networks may be critical to maximize the effectiveness of human and material resources. A methodology that combines the probability of exceeding some particular thresholds with a measurement of the information provided by each pair of experimental points has been introduced. This network optimization concept, where the basic unit of information is not a single spatial location but a pair of spatial locations, is used to emphasize the locations with the greatest information, which are those at the border of the phenomenon (for example contamination or a quality variable exceeding a given threshold), that is, where the variable at one of the locations in the pair is above the threshold value and the other is below the threshold. The methodology is illustrated with a case of optimizing the monitoring network by optimal selection of the subset that best describes the information provided by an exhaustive survey done at a given moment in time but which cannot be repeated systematically due to time or economic constrains.
14 p.
2018-08-02T00:00:00ZComparison of RS/GIS analysis with classic mapping approaches for siting low-yield boreholes for hand pumps in crystalline terrains. An application to rural communities of the Caimbambo province, Angola
http://hdl.handle.net/10017/59895
Comparison of RS/GIS analysis with classic mapping approaches for siting low-yield boreholes for hand pumps in crystalline terrains. An application to rural communities of the Caimbambo province, Angola
Martín-Loeches Garrido, Miguel; Ramírez Hernández, Jorge; Reyes-López, Jaime; Martínez-Santos, Pedro; Temiño Vela, Javier
In poverty-stricken regions of Sub-Saharan Africa, groundwater for supply is often obtained by means of hand pumps, which means that low-yield boreholes are acceptable. However, boreholes are often sited without sufficient hydrogeological information due to budget constraints, which leads to high failure rates. Cost-effective techniques for borehole siting need to be developed in order to maximize the success rate. In regions underlain by granite, weathered formations are usually targeted for drilling, as these are generally presented as a better cost-benefit ratio than the fractured basement. Within this context, this research focuses on a granite region of Angola. A comparison of two mapping techniques for borehole siting-groundwater prospect is presented. A classic hydrogeomorphological map was developed first based on aerial photographs, field mapping and a geophysical survey. This map represents a considerable time investment and was developed by qualified technicians. The second map (RS/GIS) is considerably simpler and more cost-effective. It was developed by the integration in a GIS platform of six maps of equal importance-slope, drainage density, vegetation vigor, presence of clay in the soil, lineaments and rock outcrops-prepared from Landsat 8 imagery and a Digital Elevation Model (DEM). Similar results were obtained in both cases. By means of a supervised classification of Landsat images, RS/GIS analysis allows for the identification of granitic outcrops, house clusters and sandy alluvial valleys. This in turn allows for the delineation of low-interest or contamination-prone areas, thus contributing additional qualitative information. The position of a well that is going to be powered by a handpump is chosen also upon social and local matters as the distance to the stakeholders, information that are not difficult to integrate in the GIS. Although the second map needs some field inputs (i.e. surveys to determine the thickness of the weathered pack), results show that RS/GIS analyses such as this one provide a valuable and cost-effective alternative for siting low-yield boreholes in remote region
12 p.
2018-02-01T00:00:00Z