Geogaceta -- Nº 43, (2007)

Permanent URI for this collectionhttps://hdl.handle.net/10272/8296

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Variación espacio-temporal de Ca-Mg-Sr en el agua de goteo de la Cueva del Canelobre (Alicante): ejemplo de procesos de infiltración en ambientes kársticos semiáridos
(2007) Fernández Cortés, A.; Cuevas González, Jaime; Cañaveras, J.C.; Andreu Rodes, José Miguel; Sánchez Moral, S.; García del Cura, María Angeles; Hernández Bravo, J. A.
From may/2006 to april/2007 a monthly sampling of the recharge conditions and main hydrogeochemical parameters was conducted at a network of dripping points within Canelobre cave (Alicante). Speleothems are fed by a combination of seepage and fracture water, indicating that the system consists of a matrix with a network of discontinuities (fractures or conduits) with different characteristics. Control of Mg/Ca and Sr/ Ca indexes has provided data to identify several water infiltration processes into the vadose zone under arid conditions: ranges of flow-through times to drips, prior calcite precipitation and dissolution of Mg and Sr. Both indexes depend on the discharge intensity, though their variability adjust to a spatial framework determined by cave geomorphology (grade of karst development, stratigraphic contacts and fractures)
Variación en el fraccionamiento de Tierras Raras en la materia en suspensión de la Ría de Huelva (SO de España)
(2007) Carro Flores, Berta; Borrego Flores, José; López González, Nieves
Concentrations and partitioning of particulate rare earth elements are studied in an estuary affected by acid mine drainage. A sequential extraction procedure was applied to 14 suspended matter samples collected from four cruises. The results show that easy reducible fraction are mainly linked to LREEs>MREEs=HREEs. The total concentration of REEs in the suspended matter varies according to the volume of the fluvial contributions that arrive at Ría, thus these increases significantly at the times of greater contribution
Variabilidad milenaria registrada por la fauna bentónica en el Golfo de León (Mediterráneo noroccidental) entre los eventos Heinrich 3 y 4
(2007) González Mora, Beatriz; Sierro, Francisco Javier; Flores, José Abel; Berné, S.
Variations in the benthic foraminifer assemblage have been studied from a 300m-depth core in the Gulf of Lions (PRGL1-4) during the last 41-28 kyr (between Heinrich events 4 and 3). The number of benthic foraminifers per gram, the infaunal/epifaunal ratio, and most of the benthic species relative abundance show a very clear Dansgaard-Oeschger variability. The stadial species suggest a well oxygenated oligotrophic environment with low organic matter content in the sediment. By contrast, the interstadial assemblage implies a more eutrophic environment with high organic matter and low oxygen content. No relevant differences are observed in the benthic fauna between Heinrich events and the other stadials
Sismotectónica en relación con la Zona de Fractura Azores –Gibraltar: Análisis del terremoto de 12 de febrero de 2007, SO del Banco de Gorringe
(2007) Alonso Chaves, Francisco Manuel; García Navarro, Encarnación; Mantero Romero, Elena María; Fernández Rodríguez, Carlos; Camacho Cerro, Manuel Alejandro; Morales González, Juan Antonio
This work deals with the analysis of the seismicity and tectonic evolution of the eastern end of the Azores – Gibraltar Fracture Zone. The location of the main seismogenetic areas in this region is related to the complex geometry of the boundary between the Iberian and African lithospheric plates. To the west of the San Vicente Cape the seismicity can be related to a local compression at the Gorringe Bank. A detailed seismotectonic analysis allows the geological interpretation of the position of the hypocenter for the 12th February 2007 earthquake. It had Mw 6.0 and was placed on a fault having a NNE-SSW strike and a high dip to NW. The fault shows an oblique displacement (sinistral) and locates in the margin of the Horseshoe abyssal basin. Displacement along this fault is here tentatively related to complex deformation in the outer swell of an incipient downgoing plate. This can be the first indication of the beginning of subduction of the northern part of the African plate under the continental margin of Iberia. On the other hand, an analysis of the location of earthquakes having Mw >6.0 generated to the SW of the San Vicente Cape and the estimated isoseismal map has been made. It can be noted the importance of the uppermost crustal materials on the seismic intensity measurement. Sea waves resulting from these earthquakes and measured in the littoral of the Huelva province have an average velocity of propagation of approximately 600 km/h
Relación entre periodos frios y cambios de patrón de macroescala (oscilación del Atlántico Norte) en las inundaciones en el Río Guadiana
(2007) Ortega, J.A.; Garzón Heydt, Guillermina
Global changes in climate have been widely documented but the relationships between these changes and floods are not easy to establish. Hydroclimatology offers an important tool in order to improve our knowledge about the flood producing mechanisms, which can be used to explain historical and palaeohydrological events. Storm cells and mesoscale systems develop into small floods, mainly at tributary streams. But a synoptic scale relates better to Guadiana River floods, dominant in winter. At a higher level, macroscale atmospheric configuration can also explain flood generation at the Guadiana River and, particularly, the North Atlantic Oscillation (NAO) that is one of the most important recurrent patterns of atmospheric circulation. There is no reliable evidence, however relating NAO and historical floods in Europe, especially for central European countries. This situation changes in the Iberian Peninsula, specially in the Southwest that shows a good relationship between winter floods and a negative NAO phase. Recent Guadiana River floods (XX century) could be related to these phenomena, but there´s not and index who covers previous events. Guadiana palaeoflood records compiled using slackwater deposits are dated by 14C radiometric methods and associated, when it is possible to a historical flood event. Results shows event clusters during cooling phases and it is likely that they reflect moments of climatic variability
Paleosismicidad asociada al tránsito Devónico – Carbonífero en la Zona Surportuguesa (SW Ibérico)
(2007) Moreno Garrido, María Carmen; Sáez Ramos, Reinaldo; González Barrionuevo, Felipe
In this paper several evidences of seismic activity in the latest Devonian deposits of the South Portuguese Zone are reported. They are represented by deposits and sedimentary structures associated with processes such sediment liquefactions and fluidifications, tsunamis, fracturations, synsedimentary deformations, slidings or mass flows, that were generated during the rupture and shaking of the ground. As a result, two different levels of seismites related with two major paleoseismic events have been identified in SW Iberian close to the D-C boundary
Nota sobre la presencia de una sucesión cretácica en el Macizo de Las Ubiñas (Cordillera Cantábrica). Implicaciones tectónicas y geomorfológicas
(2007) Alonso, J. L.; Martínez Abad, I.; García Ramos, José Carlos
This paper describes the stratigraphy and structural setting of a new outcrop of Cretaceous sands and clays located in the center of the exposure of Palaeozoic rocks in the Cantabrian Zone. This isolated outcrop of Cretaceous rocks provides information on the uplift and structural imprint of the Variscan basement during the Alpine times. Thus, the uplift of the Ubiñas Massif, 400m above the regional level of summits, is the result of a reverse fault, which overrides the Cretaceous succession
Movilidad de las formas de fondo en la desembocadura del estuario del Río Piedras (Huelva) durante las mareas vivas
(2007) Delgado Rodríguez, Irene; Morales González, Juan Antonio; Gutiérrez Mas, José Manuel
The present work analyzes the bed mobility in the outer area of the estuary of Piedras River by observing the changes of morphology, dimensions and orientation of bedforms by means of the use of technical of Side-Scan Sonar. This coastal system is a small and narrow estuary, with a reduced fluvial input that develops a wide littoral spit in its mouth in whose apex a wide ebb-tidal delta is developed. On the back area of the deltas flood and ebb tidal currents develop a variety of sandy bedforms. The comparison of flood and ebb forms allows analyze the hydrodynamic regime and the sand mobility due to the action of the main currents
Movilidad de metales en residuos mineros y valoración del impacto ambiental del distrito minero de São Domingos (Faja Pirítica Ibérica), SW de la Península Ibérica
(2007) Delgado Rodríguez, Joaquín María; Pérez López, Rafael; Nieto Liñán, José Miguel; Álvarez Valero, Antonio Miguel; Sáez Ramos, Reinaldo; Matos, J. X.
São Domingos is one of the most emblematic Portuguese mining districts in the Iberian Pyrite Belt (IPB). The beginning of mining exploitation in the area has been dated back to pre-Roman times, remaining in activity until 1966 when it was definitely halted. The intense mining labours are reflected in the presence of a huge amount of sulphide-mining wastes and downstream production of acid mine drainage (AMD). The chemical speciation of potentially toxic elements (As, Cd, Cr, Cu, Fe, Mn, Pb, S, Sb and Zn) in the highly heterogeneous mine wastes from São Domingos was performed by modified BCR-sequential extraction. The oxidizable fraction is the most pollutant fraction for the environment in this type of residues. Part of this fraction is retained by precipitation of soluble secondary minerals in warm periods, moving to the bio-available fraction that is dissolved in rainy periods. Just considering the bio-available fraction, all mine wastes from São Domingos may leach up to 207031 tons of Fe, 14859 t of S, 6305 t of Pb, 3259 t of Zn, 1316 t of Mn, 1143 t of Cu, 219 t of Cr, 163 t of As, 40 t of Sb and 1.7 t of Cd. As a function of the seasonal variation, this fraction is self-fed every year by oxidation of the oxidizable fraction. Thus, the present study shows the pollutant potential of this IPB mining district and justifies the spoiled state of the fluvial courses in the region
Modelo de distribución espacial continua de d18O en la precipitación en la provincia de Burgos. Desarrollo de la metodología y aplicación en hidrología
(2007) Rodríguez Arévalo, Javier; Castaño Castaño, Silvino; Díaz Teijeiro, M. F.; Marcos, L. A.; Vázquez Marroquín, M.
The main aim of this paper is to develop a methodology to obtain a continuous spatial distribution of isotopic composition in precipitation over Spain. The methodololgy applies Geographic Information Systems (GIS) tools to a polynomial model that relates d18O to latitude and elevation. First steps in the development of this methodology have been made and tested in a limited part of Spain, the province of Burgos, where the resulting map of d18O in precipitation has been compared with isotope data from river water and ground-water
Modelo de evolución topográfica en el NO de la Península Ibérica durante la delaminación litosférica al final de la Orogenia Varisca
(2007) Muñoz Quijano, I. N.; Gutiérrez Alonso, Gabriel
Through a simple isostatic balance modelization we attempt an approach to one of the possible lithospheric and topographical scenarios that took place in the aftermath of the Variscan Orogeny. From this point of view, the results obtained, together with their comparison with the geologic, sedimentary and igneous record, during the Upper Carboniferous and the Early Permian, allow to explain most of the geological processes that took place in the studied region due to a process of lithospheric thickening under the Cantabrian Zone and the subsequent lithospheric delamination of the formerly generated root. This process caused a topographical inversion of the relief, from initially higher mountains in the western part of the Variscan Orogen (In present day coordinates) to subsequent dominant elevations in the east (Cantabrian Zone), contemporary with the lithospheric delamination
La Zona Sudportuguesa: propuesta para la división de un bloque continental en dominios
(2007) Mantero Romero, Elena María; García Navarro, Encarnación; Alonso Chaves, Francisco Manuel; Martín Parra, L. M.; Matas, J.; Azor, A.
Three major tectonic domains have been established in the South Portuguese Zone on the basis of cartographic, stratigraphic, lithologic, structural and metamorphic criteria. They are from north to south and from the upper to lowest tectonic position: Northern Domain, Central Domain or Iberian Pyrite Belt and Southern Domain
La serie paleógena de la unidad superior del Gomáride en Talembote (Rif Interno, Marruecos)
(2007) Hlila, Rachid; Maaté, Ali; Sanz de Galdeano, Carlos; Serra Kiel, Josep; Serrano Lozano, Francisco; El Kadiri, Khalil
The lower Paleogene stratigraphic successions of the Talembote upper Ghomaride Unit represent an interval of age going from the (middle?) Ilerdian to the early Bartonian, showing a transgressive sequence interrupted by intermittent sedimentary gaps, which are indicated by surfaces of discontinuity. These sediments correspond essentially to carbonatic facies with benthic foraminifers deposited in a shallow platform that was maintained probably until the late Lutetian. The abrupt rupture of this platform allowed, during the early Bartonian, sedimentation of pelagic to hemipelagic facies in a bathyal sedimentary environment. Later, the sudden interruption of the sedimentation in the early Bartonian, indicated by a paleosoil, may be better explained by tectonic reason than eustatism taking into account many actual geodynamic reconstructions
La fauna de vertebrados del Dolmen de Errekatxuetako Atxa (Holoceno) (Zeanuri, Bizkaia)
(2007) Murelaga, Xabier; Bailon, Salvador; Castaños, Pedro; López Quintana, J. C.; Guenaga Lizasu, A.; Sáez de Lafuente, Xabier; Zubeldia, H.
During the excavation of the Dolmen of Errekatxuetako Atxa in 2006 several vertebrate remains were found. Mammals are represented in the site by one lagomorph, six rodents, three insectivores, three artiodactyls, two carnivores and one primate, the reptilians by one saurian and one ophidian and the amphibians by one urodele and three anuran. The amphibians and reptilies are the most abundant microvertebrate.which is not usual in other Holocene archeological and Paleontological sites of the Cantabrian Basin. This could result from the presence of a wetland near the studied site. The vertebrate assemblage indicates a humid temperate climate quite similar to that occurring in the area at present day
Industria del Paleolítico Medio en Beefsteak Cave (Gibraltar): implicaciones paleoambientales
(2007) Giles, Francisco; Finlayson, Clive; Finlayson, Geraldine; Fa, Darren A.; Rodríguez Vidal, Joaquín; Cáceres Puro, Luis Miguel; Martínez Aguirre, Arancha; Santiago, A.; Gutiérrez López, José María
Beefsteak Cave is located towards the southern end of the Rock of Gibraltar, along the cliff line between the wave-eroded platforms of Europa and Windmill Hill Flats. Set within the grey dolomites of the early Jurassic Europa Member, the Cave is almost certainly of marine origin. It was probably formed during a sea-level highstand earlier than 250 ky. The exposed brecciated deposits form part of an earlier gallery within a larger cave system that has since been eroded away. The Cave still contains almost 5m of brecchiated deposits, within which six broad levels are identified. At least three of these levels contain in situ lithic industry. The lithic tools are identified as Middle Palaeolithic, with flint, jasper and sandstone being used as raw materials. A sample from Level D was dated using Useries (alpha-spectrometry) and gave an age of 98.8 ±15.5 ky BP. The results here presented are the earliest known recorded Middle Palaeolithic artefacts from Gibraltar. During periods of human occupation, this cave would have commanded a strong position above Europa Flats with Windmill Hill Flats in close proximity. Fossil evidence from the area suggests that a diverse community of ungulate herbivores would have inhabited both plains and would have been an accessible food resource for the human inhabitants of the Cave
Geometría y distribución espacial de la transmisividad en el Acuífero Mioceno del Sistema Mancha Oriental (Cuenca del Júcar)
(2007) Sanz Mangas, David; Castaño Fernández, Santiago; Gómez Alday, Juan José; Martínez Alfaro, P.E.
The hydrogeologic unit UH2 (Miocene Aquifer) supports a great amount groundwater abstractions and it is hydraulically connected to the Jucar river. Water withdrawal for irrigation purposes has driven to a regional groundwater level lowering which affects not only the river-aquifer system but probably the evolution and the status of the river ecosystems as well. Transmissivity is one of the main factors that control the interactions between groundwater and surface water bodies. In this work, the spatial distribution of transmissivity is analysed by means the use of geostatistical and GIS tools. This hydraulic parameter is studied in combination with the spatial variation of the saturated aquifer thickness. A non-linear relationship is found between transmissivity and saturated thickness as conconsequence of differences in the development of karstification in the UH2
Geología de los materiales de construcción de la Iglesia de SantaMaria degli Angeli de Alì Superiore (Sicilia nororiental, Italia)
(2007) Cultrone, Giuseppe; López Rodríguez, C.F.; Gambuzza, S.; Sebastián Reques, Eva
This study deals with the petrographic analysis of a great variety of construction materials used to build a 16th century church in NE Sicily. X-ray diffraction and optical microscopy techniques were useful to establish the composition and the texture of natural stones (phyllites, schists, marbles and volcanic scoriae) and artificial materials (mortars and bricks). The quarry areas of natural stones are located around the church where they can be correlated to geological formations. Information about mortars and brick production is provided
Evolución metamórfica de los esquistos de AP/BT de Ceán (Unidad de Malpica-Tui, NW del Macizo Ibérico)
(2007) López Carmona, A.; Abati, Jacobo; Reche, J.
Metapelitic schists from the upper structural levels of the Malpica-Tui Unit contain an initial blueschist facies mineral assemblage that appears mainly preserved as micro-inclusions in garnet, albite and chloritoid porphiroblasts defining a S1 foliation. The main foliation (S2) represents an evolution of the S1 to slightly higher temperature and lower pressure, but it is still developed in blueschist facies conditions. Post-S2 deformations include restricted development of spaced C’ shear bands, tight and straight D3 folds and a later gentle subhorizontal crenulation formed in greenschists facies conditions. Garnet-phengite thermometry and GRIPS and GASP barometry calculations, using micro-inclusion compositions, indicate peak conditions around P=19-22 Kbar and T=430-500 ºC. The same calculations using the S2 fabric minerals yield approximate values of P=16-19 Kbar and T=440-515 ºC
Estudio morfológico y microestructural de Crassostrea gigas en estuarios y puertos deportivos del oeste de la costa de Bizkaia
(2007) Ibisate, Ruth; Elorza, Javier
This work analyses the morphology and the microstructural characteristics of some specimens of Crassostrea gigas collected in diferents points of the Biscay coast. Oysters recollected in yachting harbours, where they are in contact with tributyl-tin (TBT), have morphologycal and microstructural shell anomalies. The presence of TBT in the sea water and the associated shell anomalies in oyster are more obvious and detectables in spring because of the maintenance of the ships. In other sampling areas, although the bivalves have not shown any malformations, other morphologycal variations associated to the abundance of nutrients have been determinated
Estudio preliminar de la paleointensidad de rocas volcánicas del Mioceno superior y Plioceno del sudeste de la Península Ibérica
(2007) Calvo Rathert, M.; Vegas, Néstor; Gogichaichvili, A.
A paleointensity study has been carried out on samples from 13 volcanic sites belonging to four different types of volcanism of late Miocene to Pliocene age from south-eastern Spain. Rock-magnetic experiments including measurement of thermomagnetic curves and hysteresis parameters as well as ore microscopy showed that the main carriers of remanence were low-Ti titanomagnetite and titanohematite. A PSD domain structure was observed in most samples. 43 of 90 samples from only 7 sites provided successful paleointensity determinations. 4 sites yield very low paleointensity values, but only in sites M4 and G15 anomalous paleomagnetic directions confirm an intermediate polarity. Lamproitic and calc-alkaline volcanics proved to be more suitable for paleointensity determinations in this area

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